阅读说明：本技术 陶瓷生片、陶瓷基板、陶瓷生片的制造方法及陶瓷基板的制造方法 (Ceramic green sheet, ceramic substrate, method for producing ceramic green sheet, and method for producing ceramic substrate ) 是由 汤浅晃正 小桥圣治 西村浩二 于 2020-02-28 设计创作，主要内容包括：本发明提供具备多个基板形成区域的陶瓷生片。在该陶瓷生片的一部分,描绘有条形码或二维码。该条形码或二维码是将下述信息(a)至(d)中的一者或两者以上进行编码而得到的,(a)与制造陶瓷生片时的原材料相关的信息；(b)与陶瓷生片的成型条件相关的信息；(c)与堆积多张陶瓷生片时使用的脱模剂相关的信息；(d)序列号。(The invention provides a ceramic green sheet having a plurality of substrate forming regions. A barcode or a two-dimensional code is drawn on a part of the ceramic green sheet. The bar code or the two-dimensional code is obtained by encoding one or more of the following information (a) to (d), (a) information related to a raw material at the time of manufacturing the ceramic green sheet; (b) information relating to molding conditions of the ceramic green sheet; (c) information on a release agent used when a plurality of ceramic green sheets are stacked; (d) a serial number.)

1. A ceramic green sheet having a plurality of substrate forming regions,

a bar code or a two-dimensional code is drawn on a part of the ceramic green sheet,

the bar code or the two-dimensional code is obtained by encoding one or more of the following information (a) to (d),

(a) information on raw materials at the time of manufacturing the ceramic green sheet;

(b) information relating to molding conditions of the ceramic green sheet;

(c) information on a release agent used when a plurality of ceramic green sheets are stacked;

(d) a serial number.

2. The ceramic green sheet according to claim 1, wherein a recess corresponding to a line of the barcode or a cell of the two-dimensional code is present in a portion of the ceramic green sheet where the barcode or the two-dimensional code is drawn.

3. The ceramic green sheet according to claim 2, wherein the depth of the recessed portion is 10 μm or more and 100 μm or less.

4. The ceramic green sheet according to any one of claims 1 to 3, wherein a barcode or a two-dimensional code is drawn in two or more of the plurality of substrate forming regions.

5. The ceramic green sheet according to claim 4, wherein said two or more bar codes or two-dimensional codes are each encoded with different information.

6. The ceramic green sheet according to any one of claims 1 to 3, wherein a barcode or a two-dimensional code is drawn on each of the plurality of substrate forming regions.

7. The ceramic green sheet according to claim 6, wherein all of said bar codes or two-dimensional codes are respectively encoded with different information.

8. The ceramic green sheet according to any one of claims 1 to 7, which contains at least one selected from the group consisting of silicon nitride and aluminum nitride.

9. The ceramic green sheet according to any one of claims 1 to 8, which contains a binder resin.

10. A ceramic substrate provided with a plurality of substrate-forming regions, which is a fired body of the ceramic green sheet according to any one of claims 1 to 9.

11. A ceramic substrate obtained by dividing the ceramic substrate having a plurality of substrate forming regions according to claim 10.

12. A method for producing a ceramic green sheet, comprising the steps of:

a preparation step of preparing a ceramic green sheet having a plurality of substrate forming regions; and the combination of (a) and (b),

a drawing step of irradiating a part of the ceramic green sheet with laser light to draw a barcode or a two-dimensional code,

the bar code or the two-dimensional code is obtained by encoding one or more of the following information (a) to (d),

(a) information on raw materials at the time of manufacturing the ceramic green sheet;

(b) information relating to molding conditions of the ceramic green sheet;

(c) information on a release agent used when a plurality of ceramic green sheets are stacked;

(d) a serial number.

13. The method of manufacturing a ceramic green sheet according to claim 12, wherein the laser is an infrared laser.

14. A method for manufacturing a ceramic substrate having a plurality of substrate forming regions, comprising the following firing step: firing the ceramic green sheet obtained by the method for producing a ceramic green sheet according to claim 12 or 13.

15. A method for manufacturing a ceramic substrate, comprising the following dividing steps: dividing the ceramic substrate having the plurality of substrate forming regions obtained by the manufacturing method according to claim 14 to obtain a plurality of ceramic substrates.

16. The method of manufacturing a ceramic substrate according to claim 15, wherein the dividing step is performed by a laser.

Technical Field

The present invention relates to a ceramic green sheet, a ceramic substrate, a method for manufacturing the ceramic green sheet, and a method for manufacturing the ceramic substrate.

Background

In preparing a ceramic substrate for manufacturing an electronic device, it is known to attempt to record information useful in manufacturing by marking the substrate with a laser.

As an example, patent document 1 describes that a ceramic molded body containing, as a color-changing agent, a simple substance, an oxide or a composite oxide of at least one metal selected from the group consisting of Mn, Fe, V, Se and Cu is fired, and then a specific portion of the obtained sintered body is heated in another atmosphere to form a mark portion having a color tone different from that of the other portion.

As another example, patent document 2 describes a ceramic plate including a mark pattern in the specification, drawings, and the like. In patent document 2, the mark pattern may be a two-dimensional code, and the ceramic plate may be Al₂O₃、Si₃N₄And AlN.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open No. 2001-97786

Patent document 2: european patent application publication No. 3361504

Disclosure of Invention

Problems to be solved by the invention

The ceramic substrate is generally manufactured by firing a ceramic green sheet (also simply referred to as a green sheet, hereinafter the same). In particular, in order to improve the efficiency of manufacturing ceramic substrates, a plurality of ceramic substrates may be obtained by the following steps: (1) first, a large green sheet is manufactured; (2) firing the green sheet to obtain a fired body; (3) the fired body was divided into individual pieces.

In recent years, with further improvement in performance of electronic devices, there has been an increasing demand for further improvement in quality of ceramic substrates, reduction in quality unevenness, improvement in yield, and the like.

In particular, when a ceramic substrate is manufactured through the step of firing a large-area green sheet to obtain a single sheet as in the above-described (1) to (3), it is considered important to perform appropriate quality control and optimization of manufacturing conditions from the initial stage of manufacturing (i.e., the stage of manufacturing the green sheet) in order to reduce quality unevenness and improve yield.

Accordingly, the present inventors have intensively studied for the purpose of providing a new means capable of performing appropriate quality control and optimization of manufacturing conditions in the manufacture of a plurality of ceramic substrates from ceramic green sheets.

Means for solving the problems

The inventors of the present application have conducted intensive studies and, as a result, have completed the invention provided below and have solved the above-mentioned problems.

According to the present invention, the following means is provided.

A ceramic green sheet having a plurality of substrate forming regions,

a bar code or a two-dimensional code is drawn on a part of the ceramic green sheet,

the bar code or the two-dimensional code is obtained by encoding one or more of the following information (a) to (d),

(a) information on raw materials at the time of manufacturing the ceramic green sheet;

(b) information relating to molding conditions of the ceramic green sheet;

(c) information on a release agent used when a plurality of ceramic green sheets are stacked;

(d) a serial number.

Further, according to the present invention, there is provided a ceramic substrate including a plurality of substrate forming regions, which is a fired body of the ceramic green sheet.

Further, according to the present invention, there is provided a ceramic substrate obtained by dividing the above-described ceramic substrate having a plurality of substrate forming regions.

Further, according to the present invention, the following means is provided.

A method for producing a ceramic green sheet, comprising the steps of:

a preparation step of preparing a ceramic green sheet having a plurality of substrate forming regions; and the combination of (a) and (b),

a drawing step of irradiating a part of the ceramic green sheet with laser light to draw a barcode or a two-dimensional code,

the bar code or the two-dimensional code is obtained by encoding one or more of the following information (a) to (d),

(a) information on raw materials at the time of manufacturing the ceramic green sheet;

(b) information relating to molding conditions of the ceramic green sheet;

(c) information on a release agent used when a plurality of ceramic green sheets are stacked;

(d) a serial number.

Further, according to the present invention, there is provided a method for manufacturing a ceramic substrate having a plurality of substrate forming regions, comprising the steps of: the ceramic green sheet obtained by the above-mentioned method for producing a ceramic green sheet is fired,

further, according to the present invention, there is provided a method for manufacturing a ceramic substrate, comprising the following dividing steps: the ceramic substrate having the plurality of substrate forming regions obtained by the above-described manufacturing method is divided to obtain a plurality of ceramic substrates.

ADVANTAGEOUS EFFECTS OF INVENTION

The present invention provides a new means capable of performing appropriate quality control and optimization of manufacturing conditions when a plurality of ceramic substrates are manufactured from ceramic green sheets.

Drawings

Fig. 1(a) is a diagram schematically showing a ceramic green sheet according to the present embodiment. Fig. 1(B) is an enlarged view of a portion indicated by α in fig. 1 (a).

Fig. 2 is a view schematically showing a ceramic green sheet according to the present embodiment, which is different from fig. 1 (a).

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

In all the drawings, the same components are denoted by the same reference numerals, and the description thereof is omitted as appropriate.

In order to avoid complication, (i) sometimes only one of them is labeled and not all are labeled; (ii) in particular, in the drawings of fig. 2 and subsequent drawings, the same components as those in fig. 1 may not be given the same reference numerals.

All figures are for illustration only. The shape, size ratio, and the like of each member in the drawings do not necessarily correspond to actual articles.

The expression "(meth) acryloyl" in the present specification means a concept including both acryloyl and methacryloyl. The same applies to the similar expressions such as "(meth) acrylate".

The term "electronic device" in this specification is used in a meaning including elements, devices, end products, and the like to which electronic engineering technology is applied, such as a semiconductor chip, a semiconductor element, a printed wiring board, an electric circuit display device, an information communication terminal, a light-emitting diode, a physical battery, and a chemical battery.

The term "QR code" appearing in this specification is a registered trademark.

< ceramic Green sheet (Green sheet) >

Fig. 1 a is a diagram schematically showing a ceramic green sheet 1 (also referred to simply as a green sheet 1) according to the present embodiment. Fig. 1(B) is an enlarged view of a portion indicated by α in fig. 1 (a).

The green sheet 1 includes a plurality of substrate forming regions 2 (rectangular regions indicated by broken lines). Specifically, in the green sheet 1 of fig. 1 a, there are 32 (8 columns in the longitudinal direction and 4 columns in the lateral direction) substrate forming regions 2 in total.

The green sheet 1 may have, for example, the outer peripheral region 3 as a region different from the substrate forming region 2.

The material constituting the green sheet 1 is not particularly limited as long as it is a material that forms a ceramic substrate by firing. Specific materials and the like are as described later.

A two-dimensional code 5 is drawn on a part of the green sheet 1. In the green sheet 1 of fig. 1 a, a two-dimensional code 5 is drawn in each substrate forming region 2 (see also fig. 1B). Instead of the two-dimensional code 5, a barcode may be drawn.

Each two-dimensional code 5 (or bar code) is obtained by encoding one or more of the following information (a) to (d),

(a) information on raw materials at the time of manufacturing the ceramic green sheet 1;

(b) information on molding conditions of the ceramic green sheet 1;

(c) information on a release agent used when the ceramic green sheet 1 is stacked;

(d) sequence number (serial number).

As described above, in order to further improve the quality of a ceramic substrate as a final product, reduce quality unevenness, improve yield, and the like, it is considered important to perform appropriate quality control and optimization of manufacturing conditions from the initial stage of manufacturing (i.e., the stage of manufacturing green sheets).

By drawing the two-dimensional code 5 or the barcode including one or two or more of the above-described information (a) to (d) in advance at a stage "before" the ceramic substrate is obtained by firing as in the green sheet 1, "the above-described" appropriate quality management and optimization of manufacturing conditions from the initial stage of manufacturing (that is, the stage of manufacturing the green sheet ") can be easily performed.

As another way, by previously drawing the two-dimensional code 5 or the barcode encoded with appropriate information on the green sheet 1 at the stage before firing, it is possible to easily track "from the first to the last" of the manufacture of the ceramic substrate (improve traceability). Therefore, it is easy to perform more appropriate quality control and optimization of manufacturing conditions as the whole manufacturing process of the ceramic substrate.

The information (a) about the raw material refers to information about the raw material and its compounding in the production of the green sheet 1. Specific examples of the information include the name of the compound of the raw material used in producing the green sheet 1, the trade name of the raw material, the grade of the raw material, the particle diameter of the powder contained in the raw material, the acquisition route of each raw material, the blending amount (blending ratio) of each raw material, the amount of impurities contained, the lot number of the slurry (composition for green sheet molding) before molding into a sheet shape, and the like. Of course, the information is not limited to these.

For example, if a two-dimensional code 5 or a barcode encoding the lot number of the slurry before being molded into a sheet shape is drawn on the green sheet 1 in advance, the lot number of the slurry can be easily associated with the final product (ceramic substrate). That is, the raw material data of the final product can be associated with the quality of the final product one-to-one, and quality control and quality improvement can be easily performed from the viewpoint of raw materials.

The information on the molding conditions (b) includes, for example, information on various molding conditions in the "preparation step-molding" described later, a molding lot number (a number given to 1 molding step or numbers given to a plurality of molding steps in a batch), and the like. Of course, the information is not limited to these.

For example, if the two-dimensional code 5 or the barcode in which the information of the molding lot is encoded is drawn on the green sheet 1 in advance, the molding lot can be easily associated with the final product (ceramic substrate). Further, if various molding conditions in each molding lot are recorded in advance together with the molding lot number, the molding conditions can be easily correlated with the quality of the final product. This facilitates quality control and quality improvement of the finally obtained ceramic substrate.

The information on the release agent (c) includes, for example, the composition, the amount of the release agent (powder having a property of not easily reacting with the green sheet, etc.) used in "stacking of green sheets" described later to facilitate separation of the substrate obtained after firing, and the lot number of the release agent. Of course, the information is not limited to these.

For example, if a two-dimensional code 5 or a barcode encoding a lot number of a release agent to be used/used is drawn on the green sheet 1 in advance, the lot number of the release agent can be easily associated with a final product (ceramic substrate). That is, the data of the used release agent can be correlated with the quality of the final product one-to-one, and quality control and quality improvement of the finally obtained ceramic substrate can be easily performed.

The serial number (d) is a number different from one green sheet 1 to another or a number different from one substrate forming region 2 to another.

Next, specific embodiments and the like of the green sheet 1 will be described.

(means of the Bar code or two-dimensional code 5 itself)

In terms of the abundance of information, the two-dimensional code is preferably drawn on the green sheet instead of the barcode. Of course, depending on the amount of information, a barcode may be sufficient.

The two-dimensional code 5 is preferably a QR code from the viewpoint of versatility, readability, and the like. Of course, the two-dimensional code 5 is not limited to the QR code, and may be in other formats such as DataMatrix and PDF 417.

The size of the barcode or the two-dimensional code 5 is not particularly limited as long as it can be read by a generally available reading device. Typically, the size is controlled to be about 1mm × 1mm to 5mm × 5 mm. By having an appropriate size, space can be saved and sufficient readability can be obtained.

As one embodiment, there are recesses corresponding to the lines of the barcode or the cells of the two-dimensional code 5 in the portion of the green sheet 1 where the barcode or the two-dimensional code 5 is drawn (embodiment 1). The depth of the recess is preferably 10 μm to 100 μm, more preferably 12 μm to 80 μm.

By forming the barcode or the two-dimensional code 5 by the physical unevenness, the readability of the barcode or the two-dimensional code can be further improved. Further, even when the green sheet 1 is fired to produce a ceramic substrate, the effect of easily obtaining sufficient readability of a barcode or a two-dimensional code is obtained (particularly, when the depth of the recess is 10 μm or more, the effect is more remarkable).

As another mode, a portion constituting the barcode or the two-dimensional code 5 is in a different color from other portions of the green sheet 1 (mode 2). For example, the cell portions constituting the barcode or the two-dimensional code 5 are blackened.

In the present embodiment, for example, by containing a binder resin in the green sheet 1, the binder resin can be carbonized when irradiated with laser light, and the cell portion can be blackened.

The barcode or the two-dimensional code 5 preferably has the features of both the above-described modes 1 and 2. By having both of these characteristics, the readability can be further improved before and after firing.

Typically, the barcode or two-dimensional code 5 may be traced by a laser. The specific case of the laser is as described later.

(setting position, number, etc. of the bar code or two-dimensional code 5)

As one embodiment, the barcode or the two-dimensional code 5 is preferably drawn on two or more of the substrate forming regions 2 in which a plurality of barcodes are present, instead of one barcode. In this case, it is preferable that the two or more barcodes or two-dimensional codes have information encoded therein that is different from each other.

By providing two or more barcodes or two-dimensional codes 5 in one green sheet 1 instead of only one barcode or two-dimensional code 5, one final ceramic substrate obtained by firing and dividing (singulating) the green sheet 1 can be associated with the green sheet 1. That is, traceability of the entire ceramic substrate manufacturing process can be further improved.

Further, by encoding two or more bar codes or two-dimensional codes with different information (for example, different serial numbers), for example, "the position in the furnace" at the time of firing the green sheet 1 can be correlated with the quality of the final ceramic substrate. The quality of the ceramic substrate may vary depending on the fine firing conditions. Therefore, by making such a relationship, more appropriate quality control and optimization of manufacturing conditions are facilitated.

In particular, by drawing a barcode or a two-dimensional code 5 on all of the substrate forming regions 2 in which a plurality of barcodes or two-dimensional codes 5 are present and recording different pieces of information on all of the barcodes or two-dimensional codes 5, the advantage of further improving traceability as described above can be significantly obtained.

On the other hand, as another aspect, the barcode or the two-dimensional code may be drawn on the outer peripheral area 3 or the like which is an area different from the substrate forming area 2 as shown in fig. 2.

In this case, since the bar code or the two-dimensional code 5 is not drawn in the substrate forming region, the green sheet 1 cannot be associated with a final ceramic substrate obtained by firing and further singulation. However, it is needless to say that the green sheet 1 can be associated with a ceramic substrate (including a plurality of substrate formation regions) obtained by firing the green sheet.

The approach of fig. 2 is advantageous in particular in the following respects: the bar code or the two-dimensional code 5 as "an unnecessary part of the product" is not provided in the part of the substrate forming region 2 which will eventually become the product. For example, when emphasis is placed on forming a circuit or a connecting element "without a gap" on the final ceramic substrate, it is preferable to draw a barcode or a two-dimensional code as shown in fig. 2 (instead of fig. 1).

(various sizes, etc.)

The size of the green sheet 1 is not particularly limited. From the viewpoint of achieving both mass productivity and handling property, the thickness is typically about 100cm × 150cm to 250cm × 350 cm.

The size of each substrate forming region 2 is, for example, about 75cm × 115cm to 190cm × 270cm, although it varies depending on the size of the ceramic substrate to be finally obtained.

From the viewpoint of mass productivity and the like, one green sheet 1 preferably includes 2 to 200 substrate formation regions 2.

(Material/production method of Green sheet)

The green sheet 1 can be manufactured, for example, by a series of steps including: a preparation step of preparing a green sheet having a plurality of substrate forming regions; and a drawing step of irradiating a part of the green sheet with laser light to draw a barcode or a two-dimensional code. Here, the barcode or the two-dimensional code to be drawn is encoded with one or two or more of the above-described information (a) to (d).

The "preparation step" may specifically include the steps of "preparation of raw materials, mixing", "molding", and the like.

These steps and the "drawing step" will be described below.

Preparation step-preparation and mixing of raw materials

Typically, the green sheet is produced by molding a mixture (for example, a slurry) containing a powder of an inorganic compound such as a nitride, an oxide, or a carbide, a binder resin, a sintering aid, a plasticizer, a dispersant, a solvent, and the like.

Examples of the inorganic compound include silicon nitride (Si)₃N₄) Aluminum nitride (AlN), silicon carbide, aluminum oxide, and the like. Among these, silicon nitride and aluminum nitride are preferable.

The average particle diameter of the inorganic compound powder is preferably 5 μm or less from the viewpoint of uniformity of components in the green sheet and the like.

Examples of the sintering aid include rare earth metals, alkaline earth metals, metal oxides, fluorides, chlorides, nitrates, sulfates, and the like. These may be used alone or in combination of two or more. By using the sintering aid, sintering of the inorganic compound powder can be promoted.

From the viewpoint of appropriately promoting sintering, the amount of the sintering aid used is preferably 1 part by mass or more and 15 parts by mass or less with respect to 100 parts by mass of the powder of the inorganic compound.

Specific examples of a preferable sintering aid include yttrium oxide (Y)₂O₃) Magnesium oxide (MgO), aluminum oxide (Al)₂O₃) And the like.

The binder resin may be any resin as long as it is a resin that improves moldability, which is insufficient by itself, such as powder of an inorganic compound. In the present embodiment, a resin that is blackened (carbonized) by laser irradiation to improve the contrast of the barcode or the two-dimensional code is particularly preferable. In this respect, the binder resin is typically an organic resin binder. The organic resin binder may be in the form of powder or liquid at room temperature.

For example, the binder resin is preferably at least one of methyl cellulose, ethyl cellulose, polyvinyl alcohol, polyvinyl butyral, a (meth) acrylic resin, and the like.

The amount of the binder resin is preferably 0.5 to 30 parts by mass with respect to 100 parts by mass of the powder of the inorganic compound.

By using a binder resin in an appropriately large amount, the sheet-like article can be easily molded, and a sufficient strength of the molded article can be easily obtained. In addition, sufficient blackening (carbonization) by laser irradiation can be obtained, which contributes to improvement of the contrast of the barcode or the two-dimensional code. On the other hand, by appropriately reducing the amount of the binder resin, the time for degreasing treatment described later tends to be shortened.

Examples of the plasticizer include phthalic acid plasticizers such as purified glycerin, glycerol trioleate, diethylene glycol and di-n-butyl phthalate, and dibasic acid plasticizers such as di-2-ethylhexyl sebacate.

When the plasticizer is used, the amount thereof is preferably 0.1 to 10 parts by mass with respect to 100 parts by mass of the powder of the inorganic compound. By using a suitably large amount of the plasticizer, crack generation and the like during molding into a green sheet tend to be easily suppressed. On the other hand, by using a moderately small amount of the plasticizer, the shape of the green sheet is easily maintained.

The dispersant is not particularly limited, and examples thereof include poly (meth) acrylate and (meth) acrylic acid-maleic acid salt copolymer.

Examples of the solvent include organic solvents such as ethanol and toluene. On the other hand, water (for example, ion-exchanged water or pure water) may be used in consideration of the influence on the global environment and the countermeasure for explosion-proof equipment.

The amount of the solvent used is preferably 1 to 60 parts by mass per 100 parts by mass of the inorganic compound powder. By using an appropriate amount of the solvent, appropriate fluidity at the time of forming the green sheet and shape retainability of the green sheet can be simultaneously achieved.

For example, (1) first, powders of inorganic compounds among the above components and a sintering aid are mixed, and (2) next, other components such as a binder resin, a plasticizer, and an organic solvent are mixed, whereby a slurry for green sheet molding can be obtained.

The mixing here can be performed using, for example, a ball mill or the like.

Incidentally, the raw material constituting the green sheet 1 preferably does not contain a color-changing agent that changes color by irradiation with laser light as a substance other than the above-described raw materials. Even if such a color-changing agent is contained, the proportion thereof in the total solid content constituting the green sheet 1 is preferably 0.03 mass% or less. For example, the green sheet 1 preferably does not contain a color-changing agent of a simple substance, an oxide or a composite oxide of at least one metal selected from the group consisting of Mn, Fe, V, Se and Cu, which is exemplified in patent document 1, or contains an amount of the above-mentioned degree even if contained. The reason for this is that such a color-changing agent (particularly, a color-changing agent containing a metal element) may have an unexpected influence on the properties of the final ceramic substrate and the like.

Preparation procedure-Molding

The slurry obtained in the above manner was molded to form a green sheet. As the molding method, for example, a doctor blade method can be used. That is, a green sheet can be formed by providing a layer of slurry flowing out from a gap adjustable by a doctor blade (blade) on the surface of a film or sheet traveling in one direction.

Further, the molding may be performed by an extrusion molding method. Specifically, the green sheet may be formed by: the slurry having viscosity and fluidity adjusted to be suitable for extrusion molding is extrusion molded using an appropriate apparatus.

The thickness of the green sheet may be appropriately set in consideration of the thickness of the ceramic substrate to be finally obtained, shrinkage due to firing, and the like. The thickness is typically 0.25mm or more and 1.4mm or less, preferably 0.25mm or more and 0.9mm or less, and more preferably 0.25mm or more and 0.8mm or less.

In molding, the green sheet may be appropriately subjected to a drying treatment. Particularly, when the slurry contains an organic solvent, it is preferable to perform a drying process to reduce the amount of the organic solvent remaining in the green sheet.

The green sheet formed by the doctor blade method is generally in the form of a long strip. Therefore, the sheet is generally punched or divided into a predetermined shape and size. The punching and dividing can be performed by a press type cutter or the like, for example.

Drawing step (laser irradiation)

The green sheet molded in the above manner is irradiated with laser light, whereby a barcode or a two-dimensional code can be drawn. The laser energy can make the laser-irradiated portion concave or discolored as described above.

Thus, for example, as shown in fig. 1 a, a green sheet 1 having a two-dimensional code 5 (or a barcode) drawn thereon and a plurality of substrate forming regions 2 can be manufactured.

The wavelength of the laser light is not particularly limited as long as the two-dimensional code 5 or barcode can be drawn on the green sheet 1. In the present embodiment, for example, an infrared laser, specifically, an infrared laser having a wavelength of 1064nm or 1070nm, can be used. As another example, a visible laser beam (specifically, a laser beam having a wavelength of 532nm) or an ultraviolet laser beam (specifically, an ultraviolet laser beam having a wavelength of 355 nm) may be used.

From the practical viewpoint, a commercially available laser marker (laser marker) or the like can be used as the laser.

The scanning speed of the laser is not particularly limited. From the viewpoint of achieving both drawing of the two-dimensional code 5 or barcode with sufficient readability and productivity (rate), the range is 500mm/s to 4000 mm/s.

The output of the laser light is, for example, about 1W to 30W depending on the material constituting the green sheet 1.

The frequency when the laser is a pulsed laser may be 30kHz to 100kHz, preferably 40kHz to 60 kHz.

< ceramic substrate and method for producing the same >

The ceramic substrate having a plurality of substrate forming regions can be manufactured by firing the green sheet of the present embodiment (for example, a green sheet having a plurality of substrate forming regions such as the green sheet 1 and on which a barcode or a two-dimensional code is drawn) to obtain a fired body. Such a substrate may be referred to as a "multi-array substrate" or the like.

In addition, by the dividing step of dividing the ceramic substrate having the plurality of substrate forming regions to obtain a plurality of ceramic substrates, a singulated ceramic substrate can be obtained.

For example, a ceramic substrate having a plurality of substrate formation regions can be manufactured by firing green sheets through a series of steps of "deposition of green sheets", "degreasing", and "sintering" as described below. In addition, the ceramic substrate provided with the plurality of substrate forming regions can be divided by the dividing step described below to manufacture a plurality of ceramic substrates.

Deposition of Green sheets

In order to efficiently mass-produce ceramic substrates, it is preferable to stack (overlap) a plurality of green sheets to form a stack. Among them, in order to facilitate separation after firing, a release layer formed of a release agent is preferably provided between the green sheets.

The thickness of the release layer is not particularly limited, and is typically about 1 μm to 20 μm.

As the powder for providing the release layer, typically, a powder of Boron Nitride (BN), or a slurry thereof may be used. The average particle diameter of the powder is preferably 1 μm to 20 μm.

The release layer may be formed, for example, in the following manner: the slurry of boron nitride powder is applied by spraying, brushing, roll coating, screen printing, or the like.

From the viewpoint of achieving both the efficient mass production of the ceramic substrate and the sufficient degreasing described below, the number of stacked green sheets is preferably 8 to 100, more preferably 30 to 70.

Degreasing (removal of organic substances such as binder resin)

The green sheet contains organic substances such as a binder resin and a plasticizer. When the green sheet is directly fired, carbon remains in the final ceramic substrate increase, and the performance of the ceramic substrate is degraded. Therefore, it is preferable to heat the deposit at an appropriate temperature to "degrease" (remove organic substances) before firing described later.

Degreasing is performed at a temperature of 400 ℃ to 800 ℃ over a period of 0.5 hours to 20 hours, for example. By setting an appropriate temperature and time, the oxidation and deterioration of the inorganic compound can be suppressed while reducing the carbon residue.

Sintering of

The green sheet stacked and degreased as described above is heated to typically about 1700 to 1900 ℃ and sintered to produce a ceramic substrate.

The heating is preferably performed in a non-oxidizing gas atmosphere such as nitrogen, argon, ammonia, or hydrogen.

The heating here may be performed by charging the green sheet (or the stacked body) into an appropriate container. For example, when a nitride ceramic substrate is manufactured, it is preferable to heat a green sheet (or a stack) in a container made of boron nitride, graphite, silicon nitride, or the like.

The heating here may be carried out under pressure. The pressure at the time of pressurization is, for example, about 0.50MPa to 0.97 MPa.

In the present embodiment, even after the above steps, the barcode or two-dimensional code drawn at the stage of the green sheet can be sufficiently recognized. Therefore, as described above, the effect of improving traceability can be obtained as the whole manufacturing process of the ceramic substrate.

In particular, as described above, the two-dimensional code 5 or the barcode is formed of physical unevenness, and thus sufficient readability tends to be easily obtained even after firing.

Incidentally, the entire ceramic substrate and the substrate forming region are generally shrunk by degreasing, sintering, or the like. When the above-mentioned materials are used, the "green sheet size ÷ ceramic substrate size" is, for example, about 1.1 to 1.4. It is preferable to manufacture the green sheet slightly larger by reverse estimation from the size of the substrate formation region (ceramic substrate size) to be finally obtained.

Dividing step (singulation)

By dividing the ceramic substrate having the plurality of substrate forming regions and on which the barcode or the two-dimensional code is drawn, which is obtained as described above, a plurality of singulated ceramic substrates can be manufactured.

The dividing method is not particularly limited. For example, when a ceramic substrate is provided with dividing grooves, a force is applied to the dividing groove portions, and a monolithic ceramic substrate can be obtained.

Alternatively, the ceramic substrate may be singulated by applying a bending stress thereto.

Alternatively, the division may be performed by a cutting machine such as a dicing saw (rotary blade).

In addition, the dividing step may be performed by a laser. Specifically, it is conceivable to apply a laser scribing technique known as a semiconductor substrate processing technique or the like. The laser beam is preferably a carbon dioxide laser beam, a YAG laser beam, or the like, and more preferably a carbon dioxide laser beam having a pulse frequency of 1kHz or more and an output power of about 50W to 500W.

When the dividing step is performed by a laser, the ceramic substrate may be singulated by using only the laser, or may be singulated by using the laser and other methods in combination. The latter is more preferable because the inventors of the present application found that the generation of micro cracks can be further reduced. Of course, the ceramic substrate may be singulated by using only a laser, as long as a singulated ceramic substrate having sufficient quality can be obtained.

As a specific example of the latter method, first, scribe lines are provided around a substrate formation region to be singulated in a ceramic substrate using a laser. Here, the scribe line is formed of a plurality of concave portions formed in a linear shape on the ceramic substrate (each concave portion is formed by laser irradiation), for example. As another example, the scribe line has a groove shape extending in a specific direction. For the scribe line, reference may be made to the descriptions of Japanese patent laid-open Nos. 2007 and 324301, 2013 and 175667, and 2014 and 42066.

After the scribe line is provided on the ceramic substrate, a force is applied to the ceramic substrate provided with the scribe line by a manual work or a machine. Thereby, the ceramic substrate is divided at the scribe line portion.

In the case of using a laser, it is preferable to use an assist gas in combination. That is, by irradiating the substrate with the laser beam while ejecting the assist gas from the periphery of the laser light source, the following effects may be obtained: the efficiency is improved; or suppress the generation of unexpected decomposition products and precipitates.

From the viewpoint of improving efficiency, the auxiliary gas is preferably an oxidizing gas such as oxygen or air.

The amount of the assist gas to be ejected is preferably 0.1m from the viewpoint of achieving both sufficient effects of the assist gas and prevention of scattering of dust³1.0 m/min or more³Less than one minute.

For laser processing (laser scribing) using an assist gas, see, for example, japanese patent application laid-open No. 2004-181515 and the like.

In the dividing process, the entire substrate forming region may not be completely singulated. For example, 2 × 2 (4 in total) substrate formation regions may be divided into one unit to obtain a "four-array substrate".

Other procedures

For example, the formation of a metal circuit, the connection of an electronic element, and the like may be performed between the above-described "sintering" and "dividing step", after the "dividing step", between the step of providing a scribe line with a laser in the "dividing step" and the subsequent division, and the like. As for their practice, known methods can be suitably applied.

For the above-mentioned steps, raw materials, and the like, see, for example, japanese patent laid-open nos. 2018 and 70436 and 6399252.

While the embodiments of the present invention have been described above, these are examples of the present invention, and various configurations other than the above-described configurations may be adopted. The present invention is not limited to the above-described embodiments, and modifications, improvements, and the like within a range in which the object of the present invention can be achieved are included in the present invention.

Examples

The embodiments of the present invention will be described in detail based on examples and comparative examples. The present invention is not limited to the examples.

< production of Green sheet and production of ceramic substrate >

1. Preparation of slurry for Green sheet production

First, the following "inorganic mixture 1", "inorganic mixture 2", and "inorganic mixture 3" were prepared "

Inorganic mixture 1

Silicon nitride: 91.3% by mass

Y₂O₃: 6.0% by mass

MgO: 1.6% by mass

SiO₂: 1.1% by mass

Inorganic mixture 2

Silicon nitride: 95.2% by mass

Y₂O₃: 3.3% by mass

MgO: 1.5% by mass

Inorganic mixture 3

Aluminum nitride: 94.2% by mass

Y₂O₃: 4.0% by mass

Al₂O₃: 1.8% by mass

The details of the components are as follows.

Silicon nitride: product number SN-9FWS manufactured by electric company

Aluminum nitride: product number SR-7 manufactured by electric Co

Y₂O₃: product number UU manufactured by shin-Etsu chemical Co., Ltd

MgO: product number MJ-30 manufactured by Cigu chemical Co., Ltd

SiO₂: product number SFP-330MC manufactured by electric company

Al₂O₃: product number TM-5D manufactured by DAMING Chemicals Inc

Next, the following binder, plasticizer, dispersant and solvent were added to 100 parts by mass of the inorganic mixture 1, 2 or 3And putting the mixture into a ball mill, and mixing for 48 hours to obtain silicon nitride slurry. The ball of the ball mill is made of silicon nitrideThe ball of (1).

Adhesive: polyvinyl alcohol 18.1 parts by mass

Dispersing agent: sorbitan fatty acid ester 0.4 part by mass

Plasticizer: triethylene glycol 9.1 parts by mass

Solvent: 20.2 parts by mass of toluene

20.2 parts by mass of Methyl Ethyl Ketone (MEK)

Methanol 6.7 parts by mass

6.7 parts by mass of acetone

2. Molding of green sheet

The molding is carried out by a doctor blade method.

Specifically, the silicon nitride slurry obtained above was cast at a casting speed of 0.5 m/min, dried appropriately, and then punched out in a die, thereby obtaining a 177mm × 245mm × 0.44mmt green sheet.

(the fired dimensions were 136.2 mm. times.188.5 mm)

Here, the number of substrate formation regions (sections) included in 1 green sheet is 32 as shown in fig. 1, 4 rows × 8 rows, and the size of one substrate formation region is 40.3mm × 28.6 mm. The outer periphery of the substrate forming region includes an outer peripheral region (non-substrate forming region).

3. Two-dimensional code description

A QR code of 16 units × 16 units is drawn one by one for all of a plurality of substrate forming regions of the green sheet obtained by the above molding with a laser marker in a size of 100 to 250 μm per 1 unit (described in table 1).

The information recorded in the QR code includes at least (d) a serial number. The sequence numbers are consecutive sequence numbers starting from 1. That is, QR codes in which the serial numbers of 1, 2, and 3 · · are encoded are drawn in order for the 32 substrate formation regions. In examples 12 to 15, the information on the above (a) to (c) is included in the information recorded in the QR code, in addition to the serial number (see table 1 for details).

In examples 1 to 17 and 20, a laser marker was used which was manufactured by Keyence corporation and which was mounted with an infrared laser beam having a wavelength of 1064nm and a maximum output of 25W in "MD-X series". Various conditions such as the scanning speed are shown in table 1.

On the other hand, in examples 18 and 19, a laser marker equipped with an ultraviolet laser having a wavelength of 355nm and a maximum output of 2.5W in the "MD-U series" laser marker manufactured by Keyence was used. In example 19, a laser marker mounted with a visible laser beam having a wavelength of 532nm and a maximum output of 4W in the "MD-X series" laser marker manufactured by Keyence corporation was used.

In the drawn portion of the drawn QR code, a concave portion corresponding to a cell of the QR code is formed. In addition, blackening is caused which is considered to be caused by chemical change (carbonization or the like) of the binder resin in the green sheet.

4. Deposition, degreasing, firing, etc. of green sheets

A ceramic substrate (sintered body) having a plurality of substrate forming regions was obtained by the following procedure.

(1) First, boron nitride powder is deposited on the surface of the green sheet on the side opposite to the drawing surface on which the two-dimensional code is printed.

(2) Next, 60 sheets (1) of green sheets having boron nitride powder deposited thereon were stacked on a ceramic firing platform (setter) (NB 1000, manufactured by electrochemical corporation) made of porous boron nitride.

(3) The laminate obtained in (2) was subjected to a load for degreasing of 80kg, and then kept at 530 ℃ for 15 hours while introducing air. Thereby degreasing the substrate.

(4) After degreasing, the load for degreasing was removed, and instead, a 1.5kg tungsten weight was placed. The resultant was put into a firing vessel made of porous boron nitride, and fired at 1800 ℃ under 0.88MPa for 5 hours.

5. Singulating (dividing)

With reference to the conditions described in the examples (paragraph 0018, etc.) of Japanese patent application laid-open No. 2004-181515, use is made of CO₂And (4) forming a scribe line (dividing groove) on the ceramic substrate obtained in the step (4).

Then, the ceramic substrate is bent by hand, and thereby divided along the scribe lines. Thus, a monolithic ceramic substrate was obtained.

< evaluation: depth of working >

The maximum depth of the recess corresponding to the cell of the QR code is measured for (i) the QR code drawn on the green sheet, and (ii) the QR code on the ceramic substrate after firing and singulation of the green sheet. The measurement was carried out using a 3D shape measuring apparatus VR-3000 manufactured by Keyence.

< evaluation: readability >

Using a code reader (code reader) SR-2000 of Keyence corporation, under the condition of reading a distance of 100mm and 310 ten thousand pixels (2048 × 1536 pixels), a QR code (i) drawn on a green sheet and (ii) a QR code (QR code) on a ceramic substrate after firing and singulation of the green sheet are read. Then, evaluation was performed using the following two indexes.

(1) Read success rate

One QR code is read 10 times, and the evaluation is read several times.

(2) Match level (Matching level) evaluation

The "matching level" (margin index of reading) as a standard established by Keyence corporation was determined. When the numerical value is large, the error is few, and accurate reading can be realized.

The evaluation results and the like are summarized in the following table.

[ Table 1]

As described above, by appropriately drawing the two-dimensional code on the green sheet, the two-dimensional code can be read well even if the green sheet is fired and singulated (divided) to produce a ceramic substrate.

That is, it is shown that the "from the first to the last" of the production of the ceramic substrate can be easily followed by appropriately drawing the two-dimensional code (or the barcode) on the green sheet, and thereby more appropriate quality control and optimization of production conditions can be easily performed as the whole production process of the ceramic substrate.

Incidentally, as is clear from comparison of example 20 with other examples, a unit drawn with a laser beam having an output power as large as a certain level and processed to a depth of about 10 μm or more is preferable for further improvement of the readability.

The present application claims priority based on japanese application No. 2019-037595 filed on 3/1 of 2019, the entire disclosure of which is incorporated herein.

Description of the reference numerals

1 Green sheet (ceramic green sheet)

2 substrate forming region

3 peripheral region

5 two-dimensional code