阅读说明：本技术 金属电极剥离胶膜的制作方法及金属剥离电极的制作方法 (Manufacturing method of metal electrode stripping adhesive film and manufacturing method of metal stripping electrode ) 是由 刘海军 田坤 申志辉 刘奎余 吴畯 周帅 叶嗣荣 于 2021-07-30 设计创作，主要内容包括：本发明涉及一种金属电极剥离胶膜的制作方法及金属剥离电极的制作方法,金属电极剥离胶膜的制作方法包括采用碱性溶液浸泡清洗半成品芯片；依次采用丙酮、乙醇和去离子水清洗半成品芯片表面；将半成品芯片烘干；在半成品芯片上涂反转胶并进行前烘；对反转胶进行曝光、反转烘烤和泛曝光；对反转胶进行显影,形成电极剥离胶膜。本发明中,利用碱性溶液处理钝化层表面,能够使钝化层表面自由能降低,从而使钝化层表面呈现一定的亲水性,便于制作出胶膜倒台倾角和扩大倒台底部展宽,能够有效解决制作电极胶膜时倒台倾斜角不稳定和胶膜厚度变薄的问题,使剥离电极尺寸稳定可控,电极边沿无金属丝粘连,可广泛应用于半导体芯片的研制和批生产工艺中。(The invention relates to a manufacturing method of a metal electrode stripping adhesive film and a manufacturing method of a metal stripping electrode, wherein the manufacturing method of the metal electrode stripping adhesive film comprises the steps of soaking and cleaning a semi-finished chip by using an alkaline solution; sequentially cleaning the surface of the semi-finished chip by using acetone, ethanol and deionized water; drying the semi-finished chips; coating reverse glue on the semi-finished chip and pre-baking; carrying out exposure, reverse baking and flood exposure on the reverse glue; and developing the reversal adhesive to form an electrode stripping adhesive film. According to the invention, the surface of the passivation layer is treated by using an alkaline solution, so that the free energy of the surface of the passivation layer can be reduced, and the surface of the passivation layer presents certain hydrophilicity, thereby facilitating the manufacture of a reverse table inclination angle of an adhesive film and expanding the bottom broadening of the reverse table, effectively solving the problems of unstable reverse table inclination angle and thinned adhesive film thickness during the manufacture of an electrode adhesive film, enabling the size of a stripped electrode to be stable and controllable, and enabling the edge of the electrode not to be adhered by metal wires, and being widely applied to the development and batch production processes of semiconductor chips.)

1. The manufacturing method of the metal electrode stripping adhesive film is characterized by comprising the following steps:

soaking and cleaning the semi-finished chip by using an alkaline solution;

sequentially cleaning the surface of the semi-finished chip by using acetone, ethanol and deionized water;

drying the semi-finished chips;

after the semi-finished chip is cooled to normal temperature, coating reverse glue on the semi-finished chip and pre-drying;

exposing the reverse glue;

carrying out reverse baking and flood exposure on the reverse glue;

and developing the reversal adhesive to form an electrode stripping adhesive film.

2. The method for manufacturing a metal electrode stripping film according to claim 1, wherein the semi-finished chip is immersed and cleaned in an alkaline solution that is non-corrosive to a chip epitaxial material for 3min to 5 min.

3. The method for manufacturing a metal electrode stripping film as claimed in claim 1, wherein the semi-finished chip is baked at 120-130 ℃ for 10-20 min.

4. The method of claim 1, wherein the step of coating a reverse photoresist on the semi-finished chip and pre-baking is performed at a coating speed of 3000RPM to 5000RPM and a reverse thickness of 1.0 μm to 3.0 μm, and the semi-finished chip is baked at 90 ℃ to 100 ℃ for 150 ± 5S.

5. The method for manufacturing a metal electrode stripper rubber film according to claim 1, wherein when the reverse adhesive is exposed, a contact exposure machine is used for exposure, the exposure mode is soft contact, the exposure time is 1.2S-1.8S, and the light intensity is 11.5 +/-0.5 mJ/cm²。

6. The method for manufacturing a metal electrode stripper rubber film according to claim 1, wherein when the reverse adhesive is subjected to reverse baking and flood exposure, the reverse baking temperature is 110 ± 1 ℃, and the flood exposure time is 80S to 100S.

7. The method of claim 1, wherein the developing time is 30S-60S when developing the reverse photoresist, and the width of the reverse side of the formed electrode stripper photoresist film is 1.0 μm-3.0 μm.

8. The manufacturing method of the metal stripping electrode is characterized by comprising the following steps:

growing SiO on the surface of the epitaxial layer of the semi-finished chip₂Or a SiNx dielectric film or a composite film of the SiNx dielectric film and the SiNx dielectric film is used as a passivation layer;

manufacturing an electrode window on the passivation layer;

manufacturing an electrode stripping adhesive film on the passivation layer by adopting the manufacturing method of the metal electrode stripping adhesive film as claimed in any one of claims 1 to 7;

evaporating a metal electrode on the semi-finished chip;

stripping and cleaning the metal electrode.

9. The method for producing a metal lift-off electrode according to claim 8, wherein the substrate temperature at the time of evaporation of the metal electrode is RT to 100 ℃, the entire chip surface is covered with a metal layer of 0.2 μm to 0.8 μm by evaporation, and the metal layer in the electrode window forms the metal electrode.

10. The method for manufacturing a metal stripping electrode according to claim 8, wherein when stripping and cleaning the metal electrode, the semi-finished chip is first soaked in acetone to dissolve the electrode stripping adhesive film, then the suspended metal layer on the electrode stripping adhesive film is stripped off, the metal electrode in the electrode window area is retained, and then the chip surface is cleaned by using a chip cleaning agent.

Technical Field

The invention belongs to the technical field of semiconductor chip manufacturing, and relates to a manufacturing method of a metal electrode stripping adhesive film and a manufacturing method of a metal stripping electrode.

Background

In the semiconductor chip manufacturing process, the metal electrode manufacturing method mainly comprises a wet etching method and an electrode adhesive film stripping method, and the uniformity and the size controllability of wet etching lines are poor; therefore, the chip electrode is mainly manufactured by an electrode adhesive film stripping method in the semiconductor chip process. Although negative photoresist and multilayer positive photoresist can also be used as stripping electrode photoresist films, the size resolution is low, and the multilayer photoresist stripping process is also complex and has poor process controllability, so that single-layer reverse photoresist is generally used for preparing the electrode stripping photoresist films. The electrode stripping film is generally made of SiO₂Or the surface of SiNx dielectric film, SiO₂Or the SiNx dielectric film absorbs moisture when placed in the air, when the electrode stripper film is made of reverse photoresist, the angle of the inverted mesa of the developed pattern of the photoresist film is unstable, and the longer the placing time in the air, the larger the inward inclination angle of the side wall of the inverted table surface and the small broadening of the bottom of the inverted table are made under the same process condition, which causes the technical problems of large size deviation of the stripped metal electrode, adhesion of metal wires at the edge of the electrode and the like, when the exposure time of the reverse photoresist is reduced to a certain degree, although a smaller tilt angle of the reverse stage and a larger widening of the bottom of the reverse stage can be manufactured under certain limit conditions, the defects (such as stains, particles and the like on a photoetching layout) on the photoetching layout can be amplified during development, meanwhile, the developing speed of the non-pattern area adhesive film can be rapidly increased along with the reduction of the exposure time, so that the adhesive film becomes thinner, and the process and the result have larger uncertainty and instability.

Disclosure of Invention

In view of the above, the present invention provides a method for manufacturing a metal electrode stripping adhesive film and a method for manufacturing a metal stripping electrode, which are convenient for stripping a metal electrode.

In order to achieve the purpose, the invention provides the following technical scheme:

a manufacturing method of a metal electrode stripping adhesive film comprises the following steps:

soaking and cleaning the semi-finished chip by using an alkaline solution;

sequentially cleaning the surface of the semi-finished chip by using acetone, ethanol and deionized water;

drying the semi-finished chips;

after the semi-finished chip is cooled to normal temperature, coating reverse glue on the semi-finished chip and pre-drying;

exposing the reverse glue;

carrying out reverse baking and flood exposure on the reverse glue;

and developing the reversal adhesive to form an electrode stripping adhesive film.

Further, when the semi-finished chip is soaked and cleaned, the semi-finished chip is placed into an alkaline solution which is not corrosive to the epitaxial material of the chip to be soaked and cleaned for 3-5 min.

Further, when the semi-finished chips are dried, the semi-finished chips are placed in a temperature environment of 120-130 ℃ to be baked for 10-20 min.

Further, when the semi-finished chip is coated with reverse photoresist and is subjected to prebaking, the coating rotating speed is 3000 RPM-5000 RPM, the thickness of the reverse photoresist is 1.0 μm-3.0 μm, and then the semi-finished chip is baked for 150 +/-5 seconds in the temperature environment of 90-100 ℃.

Further, when the reversal adhesive is exposed, a contact type exposure machine is adopted for exposure, the exposure mode is soft contact, the exposure time is 1.2S-1.8S, and the light intensity is 11.5 +/-0.5 mJ/cm²。

Further, when the reverse glue is subjected to reverse baking and flood exposure, the reverse baking temperature is 110 +/-1 ℃, and the flood exposure time is 80-100S.

Furthermore, when the reversal adhesive is developed, the developing time is 30S-60S, and the range of the width of the reverse platform of the formed electrode stripping adhesive film is 1.0-3.0 μm.

A manufacturing method of a metal stripping electrode comprises the following steps:

growing SiO on the surface of the epitaxial layer of the semi-finished chip₂Or a SiNx dielectric film or a composite film of the SiNx dielectric film and the SiNx dielectric film is used as a passivation layer;

manufacturing an electrode window on the passivation layer;

manufacturing an electrode stripping adhesive film on the passivation layer;

evaporating a metal electrode on the semi-finished chip;

stripping and cleaning the metal electrode.

Furthermore, when the metal electrode is evaporated, the substrate temperature during evaporation is RT-100 ℃, the whole chip surface is covered with a metal layer with the thickness of 0.2-0.8 μm through evaporation, and the metal layer in the electrode window forms the metal electrode.

Further, when stripping and cleaning the metal electrode, firstly, the semi-finished chip is soaked by acetone to dissolve the electrode stripping adhesive film, then the suspended metal layer on the electrode stripping adhesive film is stripped, the metal electrode in the electrode window area is reserved, and then the surface of the chip is cleaned by using a chip cleaning agent.

In the invention, the surface of the dielectric film of the passivation layer is treated by the alkaline solution, so that the free energy of the surface of the dielectric film can be reduced, and the surface of the dielectric film presents certain hydrophilicity. The surface state of the processed dielectric film is stable, the inclination angle of the reverse stage of the glue film and the widening of the bottom of the reverse stage are convenient to manufacture, and the problem of SiO (silicon dioxide) phenomenon can be effectively solved₂Or the problems of unstable inverted platform inclination angle and thin film thickness of an adhesive film when the electrode adhesive film is manufactured on the surface of the SiNx dielectric film are solved, so that the size of the stripped electrode is stable and controllable, the edge of the electrode is not adhered by metal wires, and the method can be widely applied to the development and batch production processes of semiconductor chips.

Drawings

For the purposes of promoting a better understanding of the objects, aspects and advantages of the invention, reference will now be made to the following detailed description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a flow chart of a preferred embodiment of a method for manufacturing a metal electrode stripper rubber film according to the invention;

FIG. 2 is a schematic cross-sectional view of a peel-off electrode adhesive film fabricated on a semi-finished chip;

FIG. 3 is a flow chart of a method for manufacturing a metal stripping electrode according to a preferred embodiment of the present invention.

Detailed Description

The embodiments of the present invention are described below with reference to specific embodiments, and other advantages and effects of the present invention will be easily understood by those skilled in the art from the disclosure of the present specification. The invention is capable of other and different embodiments and of being practiced or of being carried out in various ways, and its several details are capable of modification in various respects, all without departing from the spirit and scope of the present invention. It should be noted that the drawings provided in the following embodiments are only for illustrating the basic idea of the present invention in a schematic way, and the features in the following embodiments and examples may be combined with each other without conflict.

The invention also discloses a manufacturing method of the metal electrode stripping adhesive film, as shown in fig. 1, a preferred embodiment of the manufacturing method of the metal electrode stripping adhesive film comprises the following steps:

and S101, soaking and cleaning the semi-finished chip by adopting an alkaline solution.

The method comprises the following specific steps: taking a semi-finished chip formed after an epitaxial layer 102 and a passivation layer 103 grow on a substrate wafer 101, wherein the passivation layer 103 is SiO₂A dielectric film or a SiNx dielectric film or a composite film of the dielectric film and the SiNx dielectric film; and (3) putting the semi-finished chip into an alkaline solution which has no corrosion to the epitaxial material of the chip, and soaking and cleaning for 3-5 min. The alkaline solution is preferably a weakly alkaline solution at 70 to 90 ℃, for example, N-methyl pyrrolidone (NMP) is used, and after the NMP is heated to 70 to 90 ℃, the semi-finished chip is soaked and cleaned in the NMP for 3 to 5 min. Treatment of SiO with NMP₂Or the surface of SiNx dielectric film, can be made of SiO₂Surface generation of hydroxyl group ≡ SiO^－Or generating hydroxyl group [ identical to ] SiO on the surface of the SiNx dielectric film^－And silicon amine ≡ Si₂N^－Radical, making a dielectric filmThe surface free energy is reduced, so that the surface of the dielectric film presents certain hydrophilicity. Of course, the alkaline solution may be a strong alkaline solution at normal temperature.

And S102, cleaning the surface of the semi-finished chip by sequentially adopting acetone, ethanol and deionized water.

In the step, the surface of the semi-finished chip is sequentially cleaned by acetone and ethanol to remove organic matters on the surface of the semi-finished chip, and then the surface of the semi-finished chip is cleaned by deionized water to remove residual ions and remove ethanol which is not volatilized completely.

And S103, drying the semi-finished product chip.

Preferably, baking the semi-finished chip for 10-20 min by adopting an oven or a hot plate with the temperature of 120-130 ℃, and drying the semi-finished chip; preferably, the semi-finished chip is put into an oven at 125 ℃ for baking for 15 min.

And step S104, after the semi-finished chip is cooled to normal temperature, coating reverse glue on the semi-finished chip and pre-baking the semi-finished chip. The method specifically comprises the following steps:

after the semi-finished product chip is cooled to normal temperature, coating reverse glue (namely reverse photoresist) on the semi-finished product chip, wherein the glue coating rotating speed is preferably 3000 RPM-5000 RPM, and the thickness of the reverse glue is 1.0-3.0 μm, preferably 1.2-1.5 μm; then, the semi-finished chip is placed on a hot plate at the temperature of 90-100 ℃ to be baked for 150 +/-5S; the hot plate temperature is preferably 95 ℃ and the baking time is preferably 150S.

Step S105, exposing the reverse glue, wherein the exposure time is 1.2S-1.8S, and the light intensity is 11.5 +/-0.5 mJ/cm²。

In this step, it is preferable to use a contact exposure machine for exposure, the exposure mode is soft contact, and the exposure time is preferably 1.5S.

And S106, carrying out reverse baking and flood exposure on the reverse glue.

In this step, the reverse baking temperature is preferably 110. + -. 1 ℃ and the flood exposure time is preferably 80S to 100S.

And S107, developing the reversal adhesive for 30-60S to form the electrode stripping adhesive film 104, wherein the width of the reversal table of the electrode stripping adhesive film 104 is 1.0-3.0 μm.

In this step, the development time may be more preferably 30S to 40S, and the range of the width of the land of the formed electrode separator film 104 may be more preferably 1.0 μm to 2.0 μm. As shown in fig. 2, a schematic view of the structure of the most common semiconductor chip after forming an electrode-stripping adhesive film 104 is shown. In the figure, a substrate wafer 101, an epitaxial layer 102, a passivation layer 103 and an electrode stripping film 104 are arranged from bottom to top in sequence; the purpose of this embodiment is to prepare a required electrode stripping adhesive film 104 on the basis of the substrate wafer 101, the epitaxial layer 102 and the passivation layer 103 of such a chip structure. Assuming that the flip-flop angle of the electrode stripper film 104 is θ, the inverse photoresist thickness is h, and the flip-flop width is d, the mathematical relationship between them can be approximated as:

θ＝arctan(h/d)

when washing SiO by NMP treatment₂Or SiN_xAfter the surface of the material, the lateral developing speed of the photoresist in the pattern area is increased during development, so that d is increased, and the stage inversion angle theta is inevitably reduced according to a relational expression of theta, the thickness of the photoresist is h, and the stage inversion width d. According to the change of the time and the condition of the surface treatment of NMP, the transverse developing speed can be changed, when the surface treatment of SiO₂Or SiN_xThe conditions such as surface time, temperature and the like and the exposure and development conditions of the photoresist are fixed, so that the width d of the reverse stage can be stably controlled, the smaller reverse stage angle theta can be stably controlled, the process of stripping the adhesive film is stable, and the problem of electrode edge metal wire adhesion in the metal electrode stripping process is finally solved.

Therefore, the surface state of the dielectric film subjected to NMP soaking treatment is very stable, the inclination angle of the reverse stage of the adhesive film and the widening of the bottom of the reverse stage are easily manufactured, the inclination angle of the reverse stage of the manufactured electrode stripping adhesive film 104 can be stably controlled to be 30-60 degrees, the lateral widening of the reverse stage can be stably controlled to be 1.0-3.0 microns, and the problem that the SiO film is in the SiO process can be effectively solved₂Or the problems of unstable inverted platform inclination angle and thin film thickness of an adhesive film when the electrode adhesive film is manufactured on the surface of the SiNx dielectric film are solved, the size of the stripped electrode is convenient to control, and the edge of the electrode is not adhered by metal wires after stripping, so that the method can be widely applied to the development and batch production processes of semiconductor chips.

The invention also discloses a manufacturing method of the metal stripping electrode, as shown in fig. 3, a preferred embodiment of the manufacturing method of the metal stripping electrode comprises the following steps:

step S1, a semi-finished chip formed after the epitaxial layer 102 is grown on the substrate wafer 101 is taken, and SiO is grown on the surface of the epitaxial layer 102 of the semi-finished chip₂Or a SiNx dielectric film or a composite film of both is used as the passivation layer 103.

Step S2, electrode window fabrication is performed on the passivation layer 103. The shape of the electrode window is shown in fig. 2 as a pattern window on the passivation layer 103 and the electrode stripper rubber film 104.

Step S3, an electrode-stripping film 104 is formed on the passivation layer 103. The method specifically comprises the following steps:

heating NMP to 70-90 ℃, and putting the semi-finished chip into NMP for soaking and cleaning for 3-5 min;

sequentially cleaning the surface of the semi-finished chip by using acetone, ethanol and deionized water;

baking the semi-finished chips for 10-20 min by adopting a baking oven or a hot plate with the temperature of 120-125 ℃, and drying the semi-finished chips;

after the semi-finished chip is cooled to normal temperature, reverse glue is coated on the semi-finished chip, the coating rotation speed is preferably 3000 RPM-5000 RPM, the thickness of the reverse glue is 1.0 μm-3.0 μm, and then the semi-finished chip is placed on a hot table at 90-100 ℃ to be baked for 150 +/-5S;

exposing the reversal adhesive in a soft contact exposure mode for 1.2-1.8S;

carrying out reverse baking and flood exposure on the reverse glue; the reverse baking temperature is 110 +/-1 ℃, and the flood exposure time is 80-100S;

developing the reverse adhesive to form an electrode stripping adhesive film 104; the developing time is 30-60S, and the width of the formed electrode stripping adhesive film 104 is 1.0-3.0 μm.

Step S4, evaporating the metal electrode on the semi-finished chip.

When the metal electrode is evaporated, the substrate temperature during evaporation is RT-100 ℃, the surface of the whole chip is covered with a metal layer with the thickness of 0.2-0.8 μm through evaporation, namely the surface of the electrode stripping adhesive film 104 and the electrode window are covered by the metal layer, and the metal layer in the electrode window (namely the metal layer covered on the epitaxial layer 102 and the passivation layer 103) is the metal electrode; the thickness of the metal layer is preferably 0.5 μm.

Step S5, stripping and cleaning the metal electrode.

The semi-finished chip is soaked by acetone to dissolve the electrode stripping adhesive film 104, the metal layer on the electrode stripping adhesive film 104 is suspended and stripped, the metal electrode in the electrode window area is reserved, and then the surface of the whole chip is cleaned by using a chip cleaning agent.

In this example, the semi-finished chips were soaked with N-methylpyrrolidone (NMP) to make SiO₂Hydroxyl radical (identical to SiO) is generated on the surface of the dielectric film^－Or generating hydroxyl group [ identical to ] SiO on the surface of the SiNx dielectric film^－And silicon amine ≡ Si₂N^－The radicals reduce the surface free energy of the dielectric film and make the surface of the dielectric film present certain hydrophilicity; and further, the surface state of the dielectric film is stable, when the electrode stripping adhesive film 104 is manufactured, the inclination angle of the reverse stage can be stably controlled to be 30-60 degrees, the lateral widening of the reverse stage can be stably controlled to be 1.0-3.0 microns, so that the size of the stripping electrode is stable and controllable, the edge of the electrode is not adhered by metal wires, and the electrode stripping adhesive film can be widely applied to the development and batch production processes of semiconductor chips.

Finally, the above embodiments are only intended to illustrate the technical solutions of the present invention and not to limit the present invention, and although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that modifications or equivalent substitutions may be made on the technical solutions of the present invention without departing from the spirit and scope of the technical solutions, and all of them should be covered by the claims of the present invention.