阅读说明：本技术 用于制造半导体器件芯片的方法和保护性组合物 (Method and protective composition for manufacturing semiconductor device chip ) 是由 榊原辉 驹引伸哉 前田浩司 唐崎秀彦 于 2020-03-09 设计创作，主要内容包括：通过本公开要克服的问题是当半导体器件芯片1通过包括用例如激光束对基底2上的保护性涂层3进行照射的方法来制造时,使保护性涂层3容易地形成,使保护性涂层3保护基底2和半导体器件芯片1,以及使保护性涂层3被容易地去除。根据本公开,保护性组合物包含含有多元羧酸残基(a)和多元醇残基(b)的水溶性聚酯树脂(A)。多元羧酸残基(a)包括：具有金属磺酸盐基团的多元羧酸残基(a1)；和萘二羧酸残基(a2)。多元羧酸残基(a1)相对于多元羧酸残基(a)的比例落在25mol％至70mol％的范围内。萘二羧酸残基(a2)相对于多元羧酸残基(a)的比例落在30mol％至75mol％的范围内。(The problem to be overcome by the present disclosure is to make the protective coating 3 easily formed, to make the protective coating 3 protect the substrate 2 and the semiconductor device chip 1, and to make the protective coating 3 easily removed when the semiconductor device chip 1 is manufactured by a method including irradiating the protective coating 3 on the substrate 2 with, for example, a laser beam. According to the present disclosure, a protective composition comprises a water-soluble polyester resin (a) comprising polycarboxylic acid residues (a) and polyol residues (b). The polycarboxylic acid residue (a) includes: a polycarboxylic acid residue having a metal sulfonate group (a 1); and naphthalenedicarboxylic acid residues (a 2). The proportion of the polycarboxylic acid residue (a1) relative to the polycarboxylic acid residue (a) falls within the range of 25 to 70 mol%. The proportion of the naphthalenedicarboxylic acid residue (a2) relative to the polycarboxylic acid residue (a) falls within the range of 30 to 75 mol%.)

1. A method for manufacturing semiconductor device chips by dividing a substrate into a plurality of semiconductor device chips, the method comprising:

forming a protective coating overlying the substrate by applying a protective composition to the substrate;

irradiating the protective coating with at least one of a laser beam or a plasma;

dividing the substrate into a plurality of semiconductor device chips by cutting the substrate; and

removing the protective coating from the substrate or the semiconductor device chip by contacting the protective coating with an aqueous cleaning solution,

the protective composition comprises a water-soluble polyester resin (A) containing a polycarboxylic acid residue (a) and a polyhydric alcohol residue (b),

the polycarboxylic acid residue (a) includes: a polycarboxylic acid residue having a metal sulfonate group (a 1); and naphthalenedicarboxylic acid residues (a2),

the proportion of the polycarboxylic acid residue (a1) relative to the polycarboxylic acid residue (a) falls within the range of 25 to 70 mol%,

the proportion of the naphthalenedicarboxylic acid residue (a2) relative to the polycarboxylic acid residue (a) falls within the range of 30 to 75 mol%.

2. The method of claim 1, wherein

The polycarboxylic acid residue (a) further includes at least one aliphatic dicarboxylic acid residue selected from the group consisting of succinic acid residues, adipic acid residues, sebacic acid residues, dodecanedioic acid residues, and 1, 4-cyclohexanedicarboxylic acid residues.

3. The method of claim 1 or 2, wherein

The polyol residue (b) includes at least one diol residue selected from the group consisting of an ethylene glycol residue, a diethylene glycol residue, a polyethylene glycol residue, a1, 4-butanediol residue, a1, 6-hexanediol residue, and a neopentyl glycol residue.

4. The method of any one of claims 1 to 3, wherein

The acid value of the water-soluble polyester resin (A) is 10mgKOH/g or less.

5. The method of any one of claims 1 to 4, wherein

The glass transition temperature of the water-soluble polyester resin (A) is 10 ℃ to 100 ℃.

6. The method of any one of claims 1 to 5, comprising at least partially removing the protective coating from the substrate using laser ablation by irradiating the protective coating with the laser beam.

7. The method of any one of claims 1 to 6, comprising removing a portion of the protective coating from the substrate and then irradiating the protective coating and the portion of the substrate exposed by removing a portion of the protective coating with the plasma to at least partially remove the portion of the substrate.

8. The method of any one of claims 1 to 7, comprising applying the protective composition to the substrate by spray coating or spin coating.

9. The method of any one of claims 1 to 8, wherein

The protective composition has a viscosity at room temperature of from 0.5 to 1000 mPas.

10. A protective composition for manufacturing semiconductor device chips by dividing a substrate into a plurality of semiconductor device chips,

the method for manufacturing the semiconductor device chip includes:

forming a protective coating overlying the substrate by applying the protective composition to the substrate;

irradiating the protective coating with at least one of a laser beam or a plasma;

dividing the substrate into the plurality of semiconductor device chips by cutting the substrate; and

removing the protective coating from the substrate or the semiconductor device chip by contacting the protective coating with an aqueous cleaning solution,

the protective composition comprises a water-soluble polyester resin (A) containing a polycarboxylic acid residue (a) and a polyhydric alcohol residue (b),

the polycarboxylic acid residue (a) includes: a polycarboxylic acid residue having a metal sulfonate group (a 1); and naphthalenedicarboxylic acid residues (a2),

the proportion of the polycarboxylic acid residue (a1) relative to the polycarboxylic acid residue (a) falls within the range of 25 to 70 mol%,

the proportion of the naphthalenedicarboxylic acid residue (a2) relative to the polycarboxylic acid residue (a) falls within the range of 30 to 75 mol%.

11. The protective composition according to claim 10, wherein

The polycarboxylic acid residue (a) further includes at least one aliphatic dicarboxylic acid residue selected from the group consisting of succinic acid residues, adipic acid residues, sebacic acid residues, dodecanedioic acid residues, and 1, 4-cyclohexanedicarboxylic acid residues.

12. The protective composition according to claim 10 or 11, wherein

The polyol residue (b) includes at least one diol residue selected from the group consisting of an ethylene glycol residue, a diethylene glycol residue, a polyethylene glycol residue, a1, 4-butanediol residue, a1, 6-hexanediol residue, and a neopentyl glycol residue.

13. The protective composition according to any one of claims 10 to 12, wherein

The acid value of the water-soluble polyester resin (A) is 10mgKOH/g or less.

14. The protective composition according to any one of claims 10 to 13, wherein

The glass transition temperature of the water-soluble polyester resin (A) is 10 ℃ to 100 ℃.

Technical Field

The present disclosure relates generally to a method for manufacturing a semiconductor device chip and a protective composition, and more particularly to a method for manufacturing a semiconductor device chip and a protective composition for a method for manufacturing a semiconductor device chip including dividing a substrate into a plurality of semiconductor device chips by dicing.

Background

Plasma dicing is one of the techniques used to manufacture a plurality of semiconductor device chips by dicing a substrate (e.g., a silicon wafer) after integrated circuits have been formed on the substrate. When plasma dicing is performed, protective coatings are sometimes used to protect the substrate.

For example, patent document 1 discloses a resin agent for forming a protective coating. The resin agent contains a water-soluble resin and fine particles of a metal oxide which are dispersed in the water-soluble resin and whose cross section is an elongated shape having a major axis and a minor axis perpendicular to the major axis. Patent document 1 teaches forming a protective coating by applying a resin agent for forming a protective coating onto a wafer and irradiating the protective coating with a laser beam to subject the wafer to laser ablation. Patent document 1 also teaches that a protective coating can be used as an etching mask during plasma dicing. Patent document 1 teaches the use of, for example, polyvinyl alcohol as a water-soluble resin.

The technique disclosed in patent document 1 allows a wafer and semiconductor device chips to be protected during laser ablation and plasma dicing, and also allows a protective coating to be removed from the semiconductor device chips by washing the semiconductor device chips with water after the semiconductor device chips have been formed from the wafer. However, the protective coating is exposed to the laser beam during laser ablation and/or to the plasma during plasma cutting, and thus may alter the protective coating and cause a decrease in its water solubility. In that case, it will take some time to sufficiently remove the protective coating from the semiconductor device chip by washing the semiconductor device chip with water, thus often resulting in a decrease in the manufacturing efficiency of the semiconductor device chip.

Reference list

Patent document

Patent document 1: JP 2017-42786A

Disclosure of Invention

The problem to be overcome by the present disclosure is to provide a method for manufacturing a semiconductor device chip that allows a protective coating to be easily formed, allows the protective coating to protect a substrate and a semiconductor device chip when irradiated with a laser beam and/or plasma, and allows the protective coating to be easily removed, when the semiconductor device chip is manufactured by a method including irradiating the protective coating that has been formed on the substrate with at least one of a laser beam or plasma, and also provides a protective composition used in the method for manufacturing a semiconductor device chip.

A method for manufacturing a semiconductor device chip according to an aspect of the present disclosure is a method for manufacturing a semiconductor device chip by dividing a substrate into a plurality of semiconductor device chips. The method comprises the following steps: forming a protective coating covering the substrate by applying the protective composition to the substrate; irradiating the protective coating with at least one of a laser beam or a plasma; dividing the substrate into a plurality of semiconductor device chips by cutting the substrate; and removing the protective coating covering the semiconductor device chip from the substrate or the semiconductor device chip by contacting the protective coating with an aqueous cleaning solution. The protective composition comprises a water-soluble polyester resin (A) containing a polycarboxylic acid residue (a) and a polyhydric alcohol residue (b). The polycarboxylic acid residue (a) includes: a polycarboxylic acid residue having a metal sulfonate group (a 1); and naphthalenedicarboxylic acid residues (a 2). The proportion of the polycarboxylic acid residue (a1) relative to the polycarboxylic acid residue (a) falls within the range of 25 to 70 mol%. The proportion of the naphthalenedicarboxylic acid residue (a2) relative to the polycarboxylic acid residue (a) falls within the range of 30 to 75 mol%.

A protective composition according to another aspect of the present disclosure is used in the manufacture of semiconductor device chips. The method for manufacturing a semiconductor device chip is a method for manufacturing a semiconductor device chip by dividing a substrate into a plurality of semiconductor device chips. The method comprises the following steps: forming a protective coating covering the substrate by applying the protective composition to the substrate; irradiating the protective coating with at least one of a laser beam or a plasma; dividing the substrate into a plurality of semiconductor device chips by cutting the substrate; and removing the protective coating from the substrate or semiconductor device chip by contacting the protective coating with an aqueous cleaning solution. The protective composition comprises a water-soluble polyester resin (A) containing a polycarboxylic acid residue (a) and a polyhydric alcohol residue (b). The polycarboxylic acid residue (a) includes: a polycarboxylic acid residue having a metal sulfonate group (a 1); and naphthalenedicarboxylic acid residues (a 2). The proportion of the polycarboxylic acid residue (a1) relative to the polycarboxylic acid residue (a) falls within the range of 25 to 70 mol%. The proportion of the naphthalenedicarboxylic acid residue (a2) relative to the polycarboxylic acid residue (a) falls within the range of 30 to 75 mol%.

Drawings

Fig. 1 is a plan view of a substrate according to an exemplary embodiment of the present disclosure;

fig. 2 is a schematic cross-sectional view illustrating one process step for fabricating a semiconductor device chip according to an exemplary embodiment of the present disclosure;

fig. 3 is a schematic cross-sectional view illustrating another process step for fabricating a semiconductor device chip according to an exemplary embodiment of the present disclosure;

fig. 4 is a schematic cross-sectional view illustrating yet another process step for fabricating a semiconductor device chip according to an exemplary embodiment of the present disclosure;

fig. 5 is a schematic cross-sectional view illustrating yet another process step for fabricating a semiconductor device chip according to an exemplary embodiment of the present disclosure.

Detailed Description

An outline of a method for manufacturing the semiconductor device chip 1 according to the present disclosure will be described.

According to the method for manufacturing the semiconductor device chip 1, the substrate 2 is divided into a plurality of semiconductor device chips 1. According to this method, a protective coating 3 is formed covering a substrate 2 by applying a protective composition onto the substrate 2. The protective coating 3 is irradiated with at least one of a laser beam or a plasma. The substrate 2 is divided into a plurality of semiconductor device chips 1 by cutting the substrate 2. The protective coating 3 is removed from the substrate 2 or the semiconductor device chip 1 by contacting the protective coating 3 with an aqueous cleaning solution. The protective composition comprises a water-soluble polyester resin (A) containing a polycarboxylic acid residue (a) and a polyhydric alcohol residue (b). The polycarboxylic acid residue (a) includes: a polycarboxylic acid residue having a metal sulfonate group (a 1); and naphthalenedicarboxylic acid residues (a 2). The proportion of the polycarboxylic acid residue (a1) relative to the polycarboxylic acid residue (a) falls within the range of 25 to 70 mol%. The proportion of the naphthalenedicarboxylic acid residue (a2) relative to the polycarboxylic acid residue (a) falls within the range of 30 to 75 mol%.

According to the method, the protective coating 3 is easily formed using the protective composition, the protective coating 3 also protects the substrate 2 or the semiconductor device chip 1 from at least one of a laser beam or plasma, and the possibility of causing a decrease in water solubility of the protective coating 3 is reduced even when the protective coating 3 is exposed to at least one of a laser beam or plasma. This makes the protective coating 3 easily removable from the semiconductor device chip 1 using an aqueous cleaning solution. Therefore, the manufacturing efficiency of the semiconductor device chip 1 can be easily improved.

According to this method, the protective coating 3 may be irradiated with at least one of a laser beam or plasma for any purpose without limitation. For example, the protective coating 3 can be irradiated with at least one of a laser beam or a plasma to at least partially remove the protective coating 3 from the substrate 2. More specifically, for example, the protective coating 3 may be at least partially removed from the substrate 2 by laser ablation by irradiating the protective coating 3 with a laser beam. This allows the protective coating 3 to protect the substrate 2 during laser ablation. Furthermore, this also reduces the possibility of causing a decrease in the water solubility of the protective coating 3, even when the substrate 2 is partially exposed through the protective coating 3 by laser ablation, thus making the protective coating 3 easily removable with an aqueous cleaning solution. In that case, the substrate 2 may be divided by any method. For example, the substrate 2 may be divided by irradiating the substrate 2 with at least one of a laser beam or plasma that is not selected according to the above-described method. Alternatively still, the substrate 2 may be divided, for example, by a blade. When a blade is used, for example, the substrate 2 does not have to be divided at the region where the protective coating 3 has been removed, but may be divided at a region between two regions where the protective coating 3 has been removed. Further, when a blade is used, the protective coating 3 may be removed from the substrate 2 by contacting the protective coating 3 with an aqueous cleaning solution, and then the substrate 2 may be divided using the blade.

Alternatively, the substrate 2 may be divided into the plurality of semiconductor device chips 1 by removing a portion of the protective coating 3 from the substrate 2 and then irradiating the protective coating 3 and the portion of the substrate 2 exposed by removing a portion of the protective coating 3 with plasma. That is, the protective coating 3 may be used as a mask for plasma dicing. This allows the protective coating 3 to protect the substrate 2 from the plasma. Furthermore, this even allows the protective coating 3, which has been irradiated with plasma, to be easily removed with an aqueous cleaning solution. In that case, a portion of the protective coating 3 may be removed from the substrate 2 by any method without limitation. For example, to at least partially remove the protective coating 3 from the substrate 2, the protective coating 3 may be irradiated with at least one of a laser beam or a plasma as described above. Alternatively, a portion of the protective coating 3 may also be removed from the substrate 2 by mechanical means, such as with a scriber, or by chemical means, such as with a chemical liquid.

Still alternatively, the substrate 2 may be divided by removing a portion of the protective coating 3 from the substrate 2 by irradiating the protective coating 3 with at least one of a laser beam or a plasma, and then irradiating the portion of the substrate 2 exposed by removing a portion of the protective coating 3 with the laser beam and/or the plasma.

In an exemplary embodiment of the present disclosure, a portion of the protective coating 3 is removed from the substrate 2 by irradiating the portion with a laser beam. Subsequently, the protective coating 3 and the portion of the substrate 2 exposed by removing a portion of the protective coating 3 are irradiated with plasma, thereby dividing the substrate 2 into a plurality of semiconductor device chips 1. This embodiment will now be described in further detail with reference to fig. 2 to 5. Note that the embodiment to be described below is only one of various embodiments of the present disclosure, and should not be construed as limiting.

According to this embodiment, after the protective coating 3 has been formed to cover the substrate 2, a part of the protective coating 3 is removed from the substrate 2 by laser ablation by irradiating the protective coating 3 with a laser beam, thereby forming the groove 31 through the protective coating 3 to partially expose the substrate 2. Thereafter, the substrate 2 is cut along the grooves 31 by plasma dicing to divide the substrate 2 into a plurality of semiconductor device chips 1. In this process step, not only the portion of the substrate 2 exposed through the groove 31 but also the protective coating 3 covering the remaining portion of the substrate 2 other than the portion exposed through the groove 31 is irradiated with plasma. Thereafter, the protective coating 3 covering the semiconductor device chip 1 is removed from the semiconductor device chip 1 by bringing the protective coating 3 into contact with an aqueous cleaning liquid.

According to this embodiment, the semiconductor device chip 1 can be manufactured by performing laser ablation and plasma dicing after the protective coating 3 has been formed on the substrate 2. At this time, the protective coating 3 can be easily formed by using the protective composition. This allows the protective coating 3 to protect the substrate 2 and the semiconductor device chip 1 during laser ablation and plasma dicing.

Next, a manufacturing process of the semiconductor device chip 1 according to this embodiment will be described in further detail.

First, a substrate 2 is provided. The substrate 2 is divided into a plurality of semiconductor device chips 1 by dicing. The substrate 2 may be a wafer, for example. The wafer is made of a semiconductor. Examples of materials for the wafer include silicon (Si), gallium arsenide (GaAs), gallium nitride (GaN), and silicon carbide (SiC). Note that these are exemplary materials for the wafer and should not be construed as limiting. The wafer may have any size without limitation, but for example, may have a diameter of 50mm to 450mm and a thickness of 1 μm to 800 μm. Note that the substrate 2 does not need to be a semiconductor wafer as long as the substrate 2 can be divided into a plurality of semiconductor device chips 1 by dicing. Alternatively, the substrate 2 may also be a multilayer stack, for example, in which a semiconductor wafer and a resin substrate, a metal substrate, or a ceramic substrate are stacked one on top of the other. Further, the semiconductor device chip 1 is not necessarily a chip each including a semiconductor device (e.g., a transistor or an integrated circuit). Alternatively, each semiconductor device chip 1 may also be a multilayer stack in which semiconductor devices and layers of materials other than semiconductors, such as metal layers, resin layers, or ceramic layers, are stacked one on top of the other. Still alternatively, the respective semiconductor device chips 1 may also be a multilayer stack in which semiconductor devices and functional elements such as optical elements or MEMS elements are stacked one on top of the other.

The substrate 2 includes a first surface 21 and a second surface 22 facing in a direction opposite to the first surface 21 (see fig. 1 and 2). As shown in fig. 1, the substrate 2 has a plurality of chip regions 51 and dicing regions 52 on the first surface 21 thereof, the dicing regions 52 each being disposed between a pair of chip regions 51 adjacent to each other. In each chip region 51, an integrated circuit has been formed.

The substrate 2 is covered with a protective coating 3. To form the protective coating 3, the substrate 2 may be held by a holder 6, for example, as shown in fig. 2. The substrate 2 may be held by the holder 6 before the integrated circuit is formed thereon or after the integrated circuit has been formed thereon, as appropriate. The holder 6 includes a main body 61 and a pressure-sensitive adhesive layer 62 covering one surface of the main body 61. The main body 61 is made of a thermoplastic resin such as polyolefin or polyester. The pressure-sensitive adhesive layer 62 may be made of a pressure-sensitive adhesive such as a UV-curable acrylic pressure-sensitive adhesive. The thickness of the pressure-sensitive adhesive layer 62 may be, for example, 5 μm to 20 μm. The substrate 2 is held by the holder 6 by placing the second surface 22 of the substrate 2 on top of the pressure sensitive adhesive layer 62 of the holder 6.

The protective coating 3 may be formed by applying a protective composition onto the first surface 21 of the substrate 2 that has been held by the holder 6, and then drying the protective coating 3 as needed.

The protective composition can be applied by any method without limitation. For example, the protective composition may be applied by spray coating or spin coating or by a combination of spray coating and spin coating. In order to dry the applied coating of the protective composition, the coating may be heated, for example to a temperature below the heat resistant temperature of the holder 6, for example to a temperature of 60 ℃ or less. Optionally, the coating may be dried under reduced pressure. The thickness of the coating may be set to any suitable value and is not limited to any particular value.

Next, as shown in fig. 3, a groove 31 is formed through the protective coating 3 by removing a part of the protective coating 3 by laser ablation. The formation of the groove 31 by laser ablation will be referred to as "laser grooving" hereinafter. When laser grooving is performed, a portion of the protective coating 3 covering the cut region 52 of the substrate 2 is irradiated with a laser beam, and is thereby removed from the substrate 2. This causes the grooves 31 reaching the cutting area 52 to be formed through the protective coating 3. That is, the cut region 52 forming part of the first surface 21 of the substrate 2 is exposed inside the groove 31. Even if debris is left due to laser grooving, the chip area 51 on the first surface 21 of the substrate 2 is still protected since the chip area 51 is covered with the protective coating 3.

The light source for laser grooving may be, for example, a nanosecond laser diode emitting a laser beam having a UV wavelength (e.g., 355 nm). The laser beam may be irradiated under conditions including, for example, a pulse frequency of 50kHz, an output of 0.1W, and a laser beam spot moving speed of 100 mm/sec. However, this condition is only an example and should not be construed as limiting.

Next, as shown in fig. 4, the substrate 2 is divided into a plurality of semiconductor device chips 1 by plasma dicing. The protective coating 3 is used as a mask in the plasma dicing process step. For plasma dicing, a plasma processor is used. For example, when an inductively coupled plasma processor including a coil is used as the plasma source, the substrate 2 is arranged on a stage provided in a chamber of the plasma processor so as to be held by the holder 6. A process gas is supplied into the chamber, and RF power is supplied to a coil provided in the chamber and a lower electrode installed in the stage, thereby generating plasma in the chamber and exposing the protective coating 3 and the cutting region 52 inside the groove 31 to the plasma. This causes the substrate 2 to be cut along the cutting region 52 by plasma etching. During this plasma dicing, the chip region 51 is protected from the plasma by the protective coating 3. In this way, a plurality of semiconductor device chips 1 are obtained. At the point when the substrate 2 is cut off, the chip region 51 of the semiconductor device chip 1 is covered with the protective coating 3.

The conditions under which the plasma is generated may be set, for example, according to the material used for the substrate 2. For example, if the substrate 2 comprises silicon, the substrate 2 may be patterned by a Bosch process. The Bosch process includes etching silicon in a depth direction by sequentially repeating a deposition step, an etching step of depositing a coating layer, and a Si etching step a plurality of times.

The deposition step may be carried out, for example, for 2 seconds to 15 seconds under the following conditions: in the process of mixing C₄F₈The pressure within the chamber is adjusted to be in a range of 15Pa to 25Pa while supplying a gas as a process gas into the chamber at a flow rate of 150sccm to 250sccm, and a power of 1500W to 2500W is applied to the coil and a power of 0W to 50W is applied to the lower electrode.

Etching step of the deposited coatingThe step may be performed, for example, for 2 seconds to 10 seconds under the following conditions: in the presence of SF₆The pressure within the chamber is adjusted to be in a range of 5Pa to 15Pa while supplying a gas as a process gas into the chamber at a flow rate of 200sccm to 400sccm, and a power of 1500W to 2500W is applied to the coil and a power of 300W to 1000W is applied to the lower electrode.

The Si etching step may be performed, for example, for 10 seconds to 20 seconds under the following conditions: in the presence of SF₆The pressure within the chamber is adjusted to be in a range of 5Pa to 15Pa while supplying a gas as a process gas into the chamber at a flow rate of 200sccm to 400sccm, and a power of 1500W to 2500W is applied to the coil and a power of 50W to 500W is applied to the lower electrode.

Repeating the deposition step, the etching step of depositing the coating, and the Si etching step in this order under such conditions causes the substrate 2 containing silicon to be etched at a rate of 10 μm/min to 20 μm/min in the depth direction, and also causes portions in the dicing regions 52 of the substrate 2 to be etched through the holder 6, thus cutting the substrate 2 held by the holder 6 into a plurality of semiconductor device chips 1.

Next, as shown in fig. 5, the protective coating 3 covering each semiconductor device chip 1 is brought into contact with an aqueous cleaning solution, thereby being removed from the semiconductor device chip 1. The aqueous cleaning solution may be water or a mixed solvent containing water and an organic solvent, as appropriate. The organic solvent comprises at least one solvent selected from the group consisting of methanol, ethanol, acetone, methyl ethyl ketone, acetonitrile and dimethylacetamide. Note that these organic solvents are merely examples and should not be construed as limiting. Optionally, the aqueous cleaning solution may contain additives as needed. Examples of the additives include acids, surfactants, and metal corrosion inhibitors. When the protective coating 3 is brought into contact with the aqueous cleaning liquid, the protective coating 3 may be immersed in the aqueous cleaning liquid or the aqueous cleaning liquid may be sprayed onto the protective coating 3. Alternatively, the protective coating 3 may also be contacted with the aqueous cleaning solution by any other method. After the protective coating 3 has been removed, the individual semiconductor device chips 1 are removed from the holder 6.

The protective composition will be described in further detail.

As described above, the protective composition comprises a water-soluble polyester resin (a) comprising a polycarboxylic acid residue (a) and a polyhydric alcohol residue (b).

The water-soluble polyester resin (a) is, for example, a polymerization product of monomer components including a polycarboxylic acid component and a diol component. This allows the water-soluble polyester resin (A) to contain a polycarboxylic acid residue (a) derived from the polycarboxylic acid component and a polyhydric alcohol residue (b) derived from the diol component.

It is within the technical common knowledge to determine that the water-soluble polyester resin (A) should have water solubility. It is particularly appropriate that the water-soluble polyester resin (a) is soluble in water even without using any dispersant such as a hydrophilic organic solvent or surfactant. For example, the water-soluble polyester resin (a) is properly completely dissolved in water by mixing the water-soluble polyester resin (a) with water at 90 ℃ in a mass ratio of 1 to 3, and stirring the mixture at a sufficiently high speed for 2 hours while maintaining the temperature of the solution thus obtained at 90 ℃.

The polycarboxylic acid component includes at least one compound selected from the group consisting of polycarboxylic acids having a valence of 2 or more and ester-forming derivatives of the polycarboxylic acids. Examples of the ester-forming derivatives of polycarboxylic acids include derivatives of polycarboxylic acids, such as anhydrides, esters, acid chlorides, and halides of polycarboxylic acids. The ester-forming derivative of the polycarboxylic acid is a compound that forms an ester by reacting with a polyol component described later. The polycarboxylic acid has two or more carboxyl groups per molecule.

The polyol component includes at least one compound selected from the group consisting of a polyol having a valence of 2 or more and an ester-forming derivative of the polyol. Examples of the ester-forming derivative of the polyhydric alcohol include derivatives of the polyhydric alcohol, for example, diacetate compounds corresponding to the polyhydric alcohol. Ester-forming derivatives of polyols are compounds which form esters by reaction with polycarboxylic acid components. The polyol has two or more hydroxyl groups per molecule.

Further, the monomer component may comprise a compound comprising: carboxyl groups or ester-forming derivative groups thereof, such as hydroxy acids, ester-forming derivatives of hydroxy acids and lactones; and hydroxyl and ester-forming derivative groups thereof.

The polycarboxylic acid residue (a) is suitably free of reactive functional groups, but has a carboxyl group and an ester-forming derivative group thereof. Likewise, the polyol residue (b) suitably has no reactive functional group, but has a hydroxyl group and an ester-forming derivative group thereof. As used herein, reactive functional groups refer to, for example, ethylenically unsaturated bonds and reactive groups such as amino, imino, hydrazino, nitro, epoxy, cyano, and azo groups.

It is particularly suitable that neither the polycarboxylic acid residue (a) nor the polyol residue (b) comprise any reactive functional groups. In those cases, the number of reactive functional groups of the water-soluble polyester resin (a) will be reduced or the water-soluble polyester resin (a) will not be reactive. Then, even if the water-soluble polyester resin (a) is heated to be dried after having been applied onto the substrate 2, or is heated by being irradiated with a laser beam in the laser ablation process step, or is heated by being exposed to plasma in the plasma cutting process step, the possibility of causing a decrease in the water solubility of the water-soluble polyester resin (a) can be reduced. Note that the metal sulfonate group is not included in the reactive functional group.

As mentioned above, the polycarboxylic acid residue (a) includes: a polycarboxylic acid residue having a metal sulfonate group (a 1); and naphthalenedicarboxylic acid residues (a 2). The polycarboxylic acid residue (a1) having a metal sulfonate group imparts good water solubility to the water-soluble polyester resin (a), thus making the protective coating 3 easily removable with an aqueous cleaning solution. In addition, the naphthalenedicarboxylic acid residue (a2) makes it easy for the protective coating 3 to absorb the laser beam, thus facilitating the formation of the grooves 31 through the protective coating 3 by laser ablation. Further, the naphthalenedicarboxylic acid residue (a2) imparts sufficient plasma resistance to the protective coating 3, thereby making it easier to manufacture the semiconductor device chip 1 by plasma dicing. In addition, the 0 water-soluble polyester resin (a) has no reactive functional group and thus tends not to discolor the metal part of the substrate 2.

The polycarboxylic acid residue having a metal sulfonate group (a1) includes at least one selected from the group consisting of: a residue of an alkali metal salt of 5-sulfoisophthalic acid; a residue of an alkali metal salt of 2-sulfoisophthalic acid; a residue of an alkali metal salt of 4-sulfoisophthalic acid; a residue of an alkali metal salt of sulfoterephthalic acid; and residues of alkali metal salts of 4-sulfonaphthalene-2, 6-dicarboxylate. In order to impart good water solubility to the water-soluble polyester resin (a), the alkali metal is suitably sodium, potassium or lithium. In particular, when the polycarboxylic acid residue having a metal sulfonate group contains a residue of sodium 5-sulfoisophthalate (e.g., a residue of sodium dimethyl 5-sulfoisophthalate or a residue of sodium 5-sulfoisophthalate), the sodium sulfonate group will be effectively retained in the water-soluble polyester resin (a), thus imparting good water solubility to the water-soluble polyester resin (a).

The proportion of the polycarboxylic acid residue (a1) having a metal sulfonate group relative to the polycarboxylic acid residue (a) falls within the range of 25 to 70 mol%. This allows the protective coating 3 to be easily removed with an aqueous cleaning solution. The proportion falls more suitably in the range of 30 to 65 mol%, even more suitably in the range of 35 to 60 mol%.

The proportion of the naphthalenedicarboxylic acid residue (a2) relative to the polycarboxylic acid residue (a) falls within the range of 30 to 75 mol%. This causes the protective coating 3 to exhibit a particularly high absorbance for laser beams having a wavelength of about 355 nm. This more easily improves the efficiency of laser grooving even if the protective composition does not contain any laser beam absorber, thus effectively improving the manufacturing efficiency of the semiconductor device chip 1. Furthermore, not adding a laser beam absorber to the protective composition tends to increase the stability of the protective composition and reduce the likelihood of causing the laser beam absorber to bleed out of the protective coating 3 and other problems. The proportion falls more suitably within the range of 35 mol% to 70 mol%, even more suitably within the range of 40 mol% to 65 mol%.

The polycarboxylic acid residue (a) may contain only a polycarboxylic acid residue (a1) having a metal sulfonate group and a naphthalenedicarboxylic acid residue (a 2). Alternatively, the polycarboxylic acid residue (a) may further contain another polycarboxylic acid residue (a3) other than these.

The polycarboxylic acid residues (a3) include dicarboxylic acid residues, such as aromatic dicarboxylic acid residues and aliphatic dicarboxylic acid residues. In particular, the polycarboxylic acid residue suitably comprises at least one selected from: residues of aromatic dicarboxylic acids, such as terephthalic acid residues and isophthalic acid residues; and residues of aliphatic dicarboxylic acids, such as succinic acid residues, adipic acid residues, sebacic acid residues, dodecanedioic acid residues, and 1, 4-cyclohexanedicarboxylic acid residues. This provides the water-soluble polyester resin (A) with good durability. Particularly when the polycarboxylic acid residue (a3) comprises at least one aliphatic dicarboxylic acid residue selected from the group consisting of a succinic acid residue, an adipic acid residue, a sebacic acid residue, a dodecanedioic acid residue and a1, 4-cyclohexanedicarboxylic acid residue, the glass transition temperature of the water-soluble polyester resin (a) can be easily lowered. The naphthalenedicarboxylic acid residue (a2) tends to raise the glass transition temperature of the water-soluble polyester resin (A). However, if the water-soluble polyester resin (a) further contains a residue of an aliphatic dicarboxylic acid, the possibility of causing the water-soluble polyester resin (a) to have an excessively high glass transition temperature is reduced.

The polyol residue suitably comprises a diol residue. The diol residue suitably comprises at least one diol residue selected from: ethylene glycol residues, diethylene glycol residues, polyethylene glycol residues, residues of butanediol (e.g., 1, 4-butanediol residues), residues of hexanediol (e.g., 1, 6-hexanediol residues), and neopentyl glycol residues. This provides the water-soluble polyester resin (a) with good durability and can easily lower the glass transition temperature of the water-soluble polyester resin (a). The residues contained in the polyol residues are not limited to these but may also include, for example, residues of 1, 4-cyclohexanedimethanol, bisphenol a residues, bisphenol fluorene residues, and bisphenoxyethanol fluorene residues.

If the water-soluble polyester resin (a) is synthesized from a polycarboxylic acid component and a polyol component, the ratio of the polycarboxylic acid component to the polyol component is appropriately adjusted so that the molar ratio of the total number of carboxyl groups and ester-forming derivative groups thereof contained in the polycarboxylic acid component to the total number of hydroxyl groups and ester-forming derivative groups thereof contained in the polyol component falls within the range of 1:1.1 to 1: 2.5.

The water-soluble polyester resin (a) can be produced by polymerizing a polycarboxylic acid component together with a polyol component by a known method for producing a polyester.

If the polycarboxylic acid component is a polycarboxylic acid and the polyol component is a polyol, for example, a direct esterification reaction that produces a reaction between the polycarboxylic acid and the polyol in a single stage may be employed.

If the polycarboxylic acid component is an ester-forming derivative of a polycarboxylic acid and the polyol component is a polyol, the water-soluble polyester resin (A) can be produced by a first-stage reaction which is an ester exchange reaction between the ester-forming derivative of the polycarboxylic acid and the polyol and a second-stage reaction in which the reaction product of the first-stage reaction undergoes polycondensation.

The method for producing the water-soluble polyester resin (a) by the first-stage reaction and the second-stage reaction will be described more specifically. In the transesterification reaction as the first-stage reaction, each material for producing the water-soluble polyester resin (A) may be contained in the reaction system from the beginning. The transesterification reaction can be carried out, for example, by the following steps: while maintaining the dicarboxylic acid diester and the polyol in the reaction vessel, the dicarboxylic acid diester and the polyol are gradually heated and increased in temperature to a temperature of 150 ℃ to 260 ℃ under normal pressure in an inert gas atmosphere (e.g., nitrogen).

The polycondensation reaction as the second-stage reaction may be carried out, for example, under reduced pressure of 6.7hPa (═ 5mmHg) or less and at a temperature of 160 ℃ to 280 ℃.

At any point during the first stage reaction and the second stage reaction, titanium, antimony, lead, zinc, magnesium, calcium, manganese, an alkali metal compound, or any other suitable substance may be added as a catalyst to the reaction system.

The number average molecular weight of the water-soluble polyester resin (a) suitably falls within the range of 1000 to 50000. If the number average molecular weight is 1000 or more, the protective coating 3 tends to have sufficient strength. If the number average molecular weight is equal to or less than 50000, the water solubility of the water-soluble polyester resin (A) is increased sufficiently to cause an effective increase in the water solubility of the protective coating layer. The number average molecular weight of the water-soluble polyester resin (a) falls more suitably in the range of 2000 to 40000.

Note that the number average molecular weight of the water-soluble polyester resin (a) can be found based on the result measured by a gel permeation chromatograph (by polystyrene conversion).

The degree of water solubility of the water-soluble polyester resin (a) can be adjusted by achieving an appropriate balance between the number average molecular weight of the water-soluble polyester resin (a) and the ratio of the polycarboxylic acid residue having a metal sulfonate group (a1) to the water-soluble polyester resin (a). In other words, the number average molecular weight of the water-soluble polyester resin (a) and the proportion of the polycarboxylic acid residue having a metal sulfonate group (a1) are appropriately set so that the water-soluble polyester resin (a) has sufficiently high water solubility. Further, the acid value of the water-soluble polyester resin (A) is suitably 10mgKOH/g or less. If the acid value thereof is 10mgKOH/g or less, the water-soluble polyester resin (A) tends not to discolor the metal part of the substrate 2.

The glass transition temperature of the water-soluble polyester resin (A) is suitably from 10 ℃ to 100 ℃. If the glass transition temperature is equal to or higher than 10 ℃, the protective coating 3 will not become excessively adhesive, thus generally making it easier to handle the protective coating 3. If the glass transition temperature is equal to or lower than 100 ℃, it is easier to form a coating layer of the water-soluble polyester resin (a), and therefore a sufficient degree of close contact between the protective coating 3 and the substrate 2 is generally achieved. The glass transition temperature falls more suitably in the range of 20 ℃ to 80 ℃, even more suitably in the range of 40 ℃ to 65 ℃. Note that the glass transition temperature can be derived based on the results of differential scanning calorimetry.

The proportion of the water-soluble polyester resin (a) in the protective composition falls suitably in the range of 1 to 100 mass%, more suitably in the range of 10 to 90 mass%, even more suitably in the range of 15 to 80 mass%, relative to the solid content (non-volatile component) of the protective composition.

The protective composition may further comprise an additional aqueous resin other than the water-soluble polyester resin (a). The presence of the additional aqueous resin may increase the degree of applicability of the protective composition, for example, by adjusting the viscosity of the protective composition. The aqueous resin contains, for example, at least one material selected from polyvinyl alcohol, polyurethane, acrylic resin, cellulose derivative, modified polypropylene, and modified polyethylene.

The protective composition may contain suitable additives. The additive contains, for example, at least one agent selected from leveling agents, antioxidants, ultraviolet absorbers, and defoaming agents.

The protective composition may comprise at least one of water or a hydrophilic organic solvent. This increases the degree of applicability of the protective composition, for example, by adjusting the viscosity of the protective composition. The hydrophilic organic solvent comprises at least one selected from the group consisting of: alcohols such as methanol, ethanol, 2-propanol and 1, 2-propanediol; glycol ethers such as propylene glycol monomethyl ether, ethyl cellosolve, and n-butyl cellosolve; and ketones such as acetone, methyl ethyl ketone, and cyclohexanone.

In particular, the protective composition according to this embodiment can be easily applied by spraying or spin coating.

The viscosity of the protective composition at room temperature suitably falls within the range of 0.5 to 1000 mPa-s. This makes the application of the protective composition to the substrate 2 particularly easy and helps to form the applied protective composition into the shape of a coating. In particular, the protective composition is particularly easy to apply when applied by spray coating or spin coating. Note that the viscosity can be measured with a vibratile viscometer. When applied by spraying, the viscosity of the protective composition is more suitably from 0.5 to 100 mPa-s. When applied by spin coating, the viscosity of the protective composition is more suitably from 20 to 1000 mPa-s.

Examples

Specific examples of this embodiment will now be described. Note that the following are merely examples of the present disclosure and should not be construed as limiting.

1. Preparation of the composition

A reaction vessel having a volume of 1000ml and comprising a stirrer, a nitrogen inlet, a thermometer, a rectification column and a cooling condenser is provided. To the reaction vessel were introduced materials shown in table 1 below and titanium potassium oxalate as a catalyst to obtain a mixture. The temperature of the mixture was increased to 200 ℃ while stirring and mixing the mixture under normal pressure and under a nitrogen atmosphere, and then gradually increased to 250 ℃ over 4 hours, thereby completing the transesterification reaction. Next, the pressure of the mixture was gradually reduced to 0.67hPa (═ 0.5mmHg) at a temperature of 250 ℃ and kept in this state for 2 hours to perform polycondensation reaction. In this way a polyester resin is obtained.

Next, 50 parts by mass of this polyester resin and 150 parts by mass of water were mixed together, and then the mixture was held at a temperature of 90 ℃ for 2 hours while stirring, thereby obtaining a composition having a polyester resin concentration of 25 mass%.

When applied by spraying, the viscosity of the composition is adjusted to a range of 0.5 to 100 mPa-s. On the other hand, when applied by spin coating, the viscosity of the composition is adjusted to a range of 20 to 1000 mPa · s.

2. Evaluation of physical Properties

(1) Number average molecular weight

The number average molecular weight of the composition was obtained based on the measurement results using a gel permeation chromatograph (conversion to polystyrene).

(2) Glass transition temperature

The glass transition temperature of the polyester resin in the composition is obtained based on the measurement result of differential scanning calorimetry.

(3) Acid value

The acid value of the polyester resin in the composition was measured by titration using an ethanol solution of potassium hydroxide.

3. Evaluation of characteristics

(1) Applicability of the invention

The composition was applied by spray coating onto a single crystal silicon substrate having a diameter of 300nm, and then naturally dried to form a protective coating having a thickness of 10 μm or 30 μm thereon. In this case, the applicability of the coating was evaluated as follows by observing the surface of the coating using an optical microscope and measuring the coating thickness distribution using a near infrared interference coating thickness meter.

When the method for applying the composition was changed to spin coating, the applicability was also evaluated in the same manner.

Grade A: when no unevenness was recognized anywhere in the coating layer thus formed, and the in-plane uniformity of the coating thickness was less than 10%;

grade B: when the unevenness is sporadically recognized in the coating thus formed, but the in-plane uniformity of the coating thickness is less than 10%; and

grade C: when unevenness is recognized almost everywhere in the coating layer thus formed, and the in-plane uniformity of the coating thickness is equal to or more than 10%.

(2) Degree of close contact

The composition was applied by spray coating onto a single crystal silicon substrate having a diameter of 300nm and then naturally dried to form a protective coating having a thickness of 10 μm or 30 μm. The state of the protective coating was evaluated by observing the protective coating by an optical microscope as follows.

When the method for applying the composition was changed to spin coating, the degree of close contact was also evaluated in the same manner.

Grade A: when no cracks or peelings are identified anywhere in the protective coating;

grade B: when cracks and/or debonds are sporadically identified in the protective coating; and

grade C: when cracks and/or debonds are identified almost everywhere in the protective coating.

(3) Laser patternable

The composition was applied by spray coating onto a single crystal silicon substrate having a diameter of 300nm and then naturally dried to form a protective coating having a thickness of 10 μm or 30 μm.

The protective coating was subjected to laser ablation in which the protective coating was irradiated with a UV laser beam (wavelength of 355nm) using a Q-switched laser diode to form grooves having a width of about 20 μm. The laser patternability of the protective coating was evaluated based on the results as follows.

The evaluation of laser patternability was also performed in the same manner when the method for applying the composition was changed to spin coating.

Grade A: when the coating can be patterned into a desired shape and no peeling is recognized anywhere between the protective coating and the substrate;

grade B: when the coating can be patterned into a desired shape and the delamination is sporadically recognized between the protective coating and the substrate; and

grade C: when the coating cannot be patterned into the desired shape and peeling is recognized between the protective coating and the substrate.

(4) Plasma resistance

The composition was applied by spray coating onto a single crystal silicon substrate having a diameter of 300nm and then naturally dried to form a protective coating having a thickness of 10 μm or 30 μm. The protective coating is subjected to laser patterning to form grooves thereon. Thereafter, the protective coating was subjected to plasma cutting for 20 minutes. Then, the state of the protective coating was evaluated by observing the state of the protective coating by an electron microscope as follows.

Plasma resistance was also evaluated in the same manner when the method for applying the composition was changed to spin coating.

Grade A: when neither peeling between the protective coating and the substrate nor burning of the protective coating is recognized;

grade B: when the peeling between the protective coating and the substrate and the burning of the protective coating are sporadically identified; and

grade C: when peeling between the protective coating and the substrate and burning of the protective coating are almost universally recognized.

Note that plasma treatment was performed under generally the same conditions as the plasma cutting process to evaluate plasma resistance and removability (described later). Specifically, the deposition step of the Bosch process, the etching step of the deposited coating, and the Si etching step are repeatedly performed until the total processing time reaches 20 minutes or more. In thatIn this case, the deposition step is carried out for 8 seconds under such conditions: wherein use is made of₄F₈Gas was supplied as a process gas into the chamber at a flow rate of 200sccm to adjust the pressure within the chamber to 20Pa, and 2000W of power was applied to the coil and 25W of power was applied to the lower electrode. The etching step to deposit the coating was carried out for 6 seconds under such conditions: wherein use is made of₆Gas was supplied as a process gas into the chamber at a flow rate of 300sccm to adjust the pressure within the chamber to 10Pa, and 2000W of power was applied to the coil and 650W of power was applied to the lower electrode. The Si etching step was performed for 15 seconds under the conditions: wherein SF is added₆Gas was supplied into the chamber as a process gas at a flow rate of 300sccm to adjust the pressure within the chamber to 10Pa, and 2000W of power was applied to the coil and 275W of power was applied to the lower electrode.

In the sample evaluated as grade a, the etching rate of the protective coating during plasma dicing was much lower (specifically, one tenth or less) than that of the silicon substrate.

(5) Removability #1

The composition was applied by spray coating to a single crystal silicon substrate having a diameter of 300nm in an atmosphere of 23 c and then naturally dried to form a protective coating having a thickness of 5 μm. The protective coating was cleaned with two fluids using water as the aqueous cleaning solution at a flow rate of 1.94L/min and a water temperature of 30 ℃ for 90 seconds. Thereafter, the appearance of the substrate was observed, and the removability of the protective coating was evaluated as follows.

When the method for applying the composition was changed to spin coating, the removability was also evaluated in the same manner.

Grade A: when no protective coating residue is identified on the substrate;

grade B: when protective coating residues are sporadically identified on the substrate; and

grade C: when protective coating residues are identified almost everywhere on the substrate.

(6) Removability #2

The composition was applied by spray coating to a single crystal silicon substrate having a diameter of 300nm in an atmosphere of 23 c and then naturally dried to form a protective coating having a thickness of 5 μm. The protective coating was subjected to laser ablation in which the protective coating was irradiated with a UV laser beam (wavelength of 355nm) using a Q-switched laser diode to form grooves having a width of about 20 μm. Subsequently, the protective coating is subjected to plasma cutting for 20 minutes or more. Thereafter, the protective coating was washed with two fluids using water as an aqueous wash at a flow rate of 1.94L/min and a water temperature of 30 ℃ for 90 seconds. Thereafter, the appearance of the substrate was observed, and the removability of the protective coating was evaluated as follows:

when the method for applying the composition was changed to spin coating, the removability was also evaluated in the same manner.

Grade A: when no protective coating residue is identified on the substrate;

grade B: when protective coating residues are sporadically identified on the substrate; and

grade C: when protective coating residues are identified almost everywhere on the substrate.

[ Table 1]

As can be readily seen from the foregoing description of the embodiments and examples, the method for manufacturing the semiconductor device chip 1 according to the first aspect of the present disclosure is a method for manufacturing the semiconductor device chip 1 by dividing the substrate 2 into a plurality of semiconductor device chips 1. The method comprises the following steps: forming a protective coating 3 covering the substrate 2 by applying the protective composition onto the substrate 2; irradiating the protective coating 3 with at least one of a laser beam or a plasma; dividing the substrate 2 into a plurality of semiconductor device chips 1 by cutting the substrate 2; and removing the protective coating 3 from the substrate 2 or the semiconductor device chip 1 by contacting the protective coating 3 with an aqueous cleaning solution. The protective composition comprises a water-soluble polyester resin (A) containing a polycarboxylic acid residue (a) and a polyhydric alcohol residue (b). The polycarboxylic acid residue (a) includes: a polycarboxylic acid residue having a metal sulfonate group (a 1); and naphthalenedicarboxylic acid residues (a 2). The proportion of the polycarboxylic acid residue (a1) relative to the polycarboxylic acid residue (a) falls within the range of 25 to 70 mol%. The proportion of the naphthalenedicarboxylic acid residue (a2) relative to the polycarboxylic acid residue (a) falls within the range of 30 to 75 mol%.

According to the first aspect, the protective coating 3 is easily formed using the protective composition, the substrate 2 and the semiconductor device chip 1 are protected from at least one of a laser beam or plasma by the protective coating 3, and the protective coating 3 is easily removed from the substrate 2 or the semiconductor device chip 1 using an aqueous cleaning liquid.

In the method for manufacturing a semiconductor device chip 1 according to the second aspect of the present disclosure, which may be implemented in combination with the first aspect, the polycarboxylic acid residue (a) further includes at least one aliphatic dicarboxylic acid residue selected from the group consisting of a succinic acid residue, an adipic acid residue, a sebacic acid residue, a dodecanedioic acid residue, and a1, 4-cyclohexanedicarboxylic acid residue.

The second aspect imparts good durability to the water-soluble polyester resin (a) and contributes to lowering the glass transition temperature of the water-soluble polyester resin (a).

In the method for manufacturing a semiconductor device chip 1 according to the third aspect of the present disclosure, which may be implemented in combination with the first aspect or the second aspect, the polyol residue (b) includes at least one diol residue selected from the group consisting of an ethylene glycol residue, a diethylene glycol residue, a polyethylene glycol residue, a1, 4-butanediol residue, a1, 6-hexanediol residue, and a neopentyl glycol residue.

The third aspect imparts good durability to the water-soluble polyester resin (a) and contributes to lowering the glass transition temperature of the water-soluble polyester resin (a).

In the method for manufacturing the semiconductor device chip 1 according to the fourth aspect of the present disclosure, which may be implemented in combination with any one of the first to third aspects, the acid value of the water-soluble polyester resin (a) is 10mgKOH/g or less.

The fourth aspect reduces the possibility that the water-soluble polyester resin (a) causes metallic discoloration.

In the method for manufacturing the semiconductor device chip 1 according to the fifth aspect of the present disclosure, which may be implemented in combination with any one of the first to fourth aspects, the glass transition temperature of the water-soluble polyester resin (a) is 10 ℃ to 100 ℃.

According to the fifth aspect, the water-soluble polyester resin (a) having a glass transition temperature of 10 ℃ or higher reduces the possibility that the protective coating 3 formed of the water-soluble polyester resin (a) becomes excessively adhesive, thus making it easier to handle the protective coating 3. Further, the water-soluble polyester resin (a) having a glass transition temperature of 100 ℃ or less makes the coating layer of the water-soluble polyester resin (a) more easily formed, and therefore, the degree of close contact between the protective coating layer 3 and the substrate 2 is more easily increased.

The method for manufacturing a semiconductor device chip 1 according to the sixth aspect of the present disclosure, which may be implemented in combination with any one of the first to fifth aspects, includes at least partially removing the protective coating 3 from the substrate 2 by laser ablation by irradiating the protective coating 3 with a laser beam.

Even when the groove exposing the substrate 2 is formed through the protective coating 3 by laser ablation, the sixth aspect reduces the possibility of causing a decrease in the water solubility of the protective coating 3, and still allows the protective coating 3 to be easily removed with an aqueous cleaning solution.

A method for manufacturing a semiconductor device chip 1 according to a seventh aspect of the present disclosure, which may be implemented in combination with any one of the first to sixth aspects, includes removing a portion of the protective coating 3 from the substrate 2, and then irradiating the protective coating 3 and the portion of the substrate 2 exposed by removing the portion of the protective coating 3 with plasma to at least partially remove the portion of the substrate 2.

The seventh aspect makes even the protective coating 3 irradiated with plasma easily removable with an aqueous cleaning solution.

The method for manufacturing a semiconductor device chip 1 according to the eighth aspect of the present disclosure, which may be implemented in combination with any one of the first to seventh aspects, includes applying a protective composition onto the substrate 2 by spraying or spin coating.

The eighth aspect makes the application of the protective composition to the substrate 2 particularly easy.

In the method for manufacturing the semiconductor device chip 1 according to the ninth aspect of the present disclosure, which may be practiced in combination with any one of the first to eighth aspects, the protective composition has a viscosity of 0.5mPa · s to 1000 mPa · s at room temperature.

The ninth aspect makes the application of the protective composition to the substrate 2 particularly easy.

The protective composition according to the tenth aspect of the present disclosure is used for manufacturing the semiconductor device chip 1 by dividing the substrate 2 into the plurality of semiconductor device chips 1. The method for manufacturing the semiconductor device chip 1 includes: forming a protective coating 3 covering the substrate 2 by applying the protective composition onto the substrate 2; irradiating the protective coating 3 with at least one of a laser beam or a plasma; dividing the substrate 2 into a plurality of semiconductor device chips 1 by cutting the substrate 2; and removing the protective coating 3 from the substrate 2 or the semiconductor device chip 1 by contacting the protective coating 3 with an aqueous cleaning solution. The protective composition comprises a water-soluble polyester resin (A) containing a polycarboxylic acid residue (a) and a polyhydric alcohol residue (b). The polycarboxylic acid residue (a) includes: a polycarboxylic acid residue having a metal sulfonate group (a 1); and naphthalenedicarboxylic acid residues (a 2). The proportion of the polycarboxylic acid residue (a1) relative to the polycarboxylic acid residue (a) falls within the range of 25 to 70 mol%. The proportion of the naphthalenedicarboxylic acid residue (a2) relative to the polycarboxylic acid residue (a) falls within the range of 30 to 75 mol%.

The tenth aspect causes the semiconductor device chip 1 to be manufactured by irradiating the protective coating 3, which has been formed on the substrate 2, with at least one of a laser beam or plasma. In this case, the protective coating 3 is easily formed using the protective composition, the substrate 2 and the semiconductor device chip 1 are protected from at least one of a laser beam or plasma by the protective coating 3, and the protective coating 3 is easily removed from the semiconductor device chip 1 using an aqueous cleaning liquid. Further, this also reduces the possibility of causing a decrease in the water solubility of the protective coating 3, thus improving the manufacturing efficiency of the semiconductor device chip 1.

In the protective composition according to the eleventh aspect of the present disclosure, the polycarboxylic acid residue (a) further includes at least one aliphatic dicarboxylic acid residue selected from the group consisting of a succinic acid residue, an adipic acid residue, a sebacic acid residue, a dodecanedicarboxylic acid residue, and a1, 4-cyclohexanedicarboxylic acid residue.

The eleventh aspect imparts good durability to the water-soluble polyester resin (a) and contributes to lowering the glass transition temperature of the water-soluble polyester resin (a).

In a protective composition according to a twelfth aspect of the present disclosure, which may be practiced in combination with the tenth or eleventh aspect, the polyhydric alcohol residue (b) includes at least one diol residue selected from the group consisting of an ethylene glycol residue, a diethylene glycol residue, a polyethylene glycol residue, a1, 4-butanediol residue, a1, 6-hexanediol residue, and a neopentyl glycol residue.

The twelfth aspect imparts good durability to the water-soluble polyester resin (a) and contributes to lowering the glass transition temperature of the water-soluble polyester resin (a).

In the protective composition according to a thirteenth aspect of the present disclosure, which may be practiced in combination with any one of the tenth to twelfth aspects, the water-soluble polyester resin (a) has an acid value of 10mgKOH/g or less.

The thirteenth aspect reduces the possibility that the water-soluble polyester resin (a) causes metallic discoloration.

In the protective composition according to the fourteenth aspect of the present disclosure, which may be practiced in combination with any one of the tenth to thirteenth aspects, the glass transition temperature of the water-soluble polyester resin (a) is 10 ℃ to 100 ℃.

According to the fourteenth aspect, the water-soluble polyester resin (a) having a glass transition temperature of 10 ℃ or more reduces the possibility that the protective coating 3 becomes to have excessive adhesiveness, thus making it easier to handle the protective coating 3. Further, the water-soluble polyester resin (a) having a glass transition temperature of 100 ℃ or less makes the coating layer of the water-soluble polyester resin (a) more easily formed, and thus more easily improves the degree of close contact between the protective coating layer 3 and the substrate 2.

List of reference numerals

1 semiconductor device chip

2 base

3 protective coating