JP2013021195A - Method of manufacturing ceramic substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of manufacturing a ceramic substrate in which position data by image processing of an alignment mark formed on the surface of the substrate can be recognized without being hindered by glass coming up to the surface in the manufacturing process thereof.SOLUTION: A method of manufacturing a ceramic substrate 1 includes a surface reforming process for reforming the surface of the alignment mark 8 and the surface of a ceramic part, such as reducing glass coming up to these surfaces for instance, by injecting slurry made of a polishing material such as water (liquid) and alumina particles together with high pressure air to the alignment mark 8 and the ceramic part s around the mark 8, in the ceramic substrate 1 made of ceramic containing glass while having a surface 2 and a back and the alignment mark 8 formed on at least one of the surface 2 and the back.

Description

  The present invention relates to a ceramic substrate in which, in the process of manufacturing a ceramic substrate, the glass floating on the surface of the substrate does not hinder the recognition of positional information using image processing for the vicinity of the alignment mark formed on the surface. It relates to the manufacturing method.

  For example, in a ceramic substrate made of a low-temperature fired ceramic such as glass-ceramic, the plating property to the conductor pattern is increased by the glass raised from the conductor pattern formed on the surface of the ceramic substrate during the manufacturing process, specifically, firing. May decrease. In order to prevent this, a method for manufacturing a low-temperature fired ceramic substrate has been proposed in which wet blasting is performed on the surface of the conductor pattern by spraying a mixture of an abrasive such as alumina and water at a high pressure (for example, , See Patent Document 1).

  However, the alignment mark formed in advance on the surface of the ceramic substrate with the conductive paste as described above is formed by the glass that is raised on the surface of the ceramic substrate during firing even when the conductive pattern as described above is subjected to wet blasting. In some cases, position information cannot be recognized after binarization processing based on imaging by a CCD camera. As a result, there has been a problem that, for example, electronic components may not be mounted on the surface of the ceramic substrate accurately at a predetermined position on the surface.

Japanese Patent No. 4089902 (pages 1 to 7, FIGS. 1 and 2)

  The present invention solves the problems described in the background art, and is a ceramic substrate on which glass can be raised on the surface of the substrate in the manufacturing process, and the position information obtained by image processing of the alignment mark formed in advance on the surface of the substrate. It is an object of the present invention to provide a method for manufacturing a ceramic substrate that can be recognized without any problem.

Means for Solving the Problems and Effects of the Invention

In order to solve the above-mentioned problems, the present invention is conceived by injecting a slurry made of a polishing material and a liquid such as water, together with high-pressure air, onto the surface including the alignment mark of the fired ceramic substrate. It was made.
That is, a method of manufacturing a ceramic substrate according to the present invention (Claim 1) is a ceramic substrate comprising a ceramic containing glass, having a front surface and a back surface, and an alignment mark formed on at least one of the front surface and the back surface. Further, surface modification is performed by spraying a slurry made of a liquid and an abrasive together with high-pressure air onto the alignment mark and the ceramic portion around the mark to improve the surface of the alignment mark and the surface of the ceramic portion. Including a process.
In addition, the ceramic substrate which is the subject of the present invention includes a multi-piece ceramic substrate assembly having a plurality of ceramic substrates in both vertical and horizontal directions.

  According to this, since a slurry composed of an abrasive and a liquid such as water is jetted together with high-pressure air to the surface near the alignment mark of the fired ceramic substrate, the surface of the alignment mark and the ceramic portion An abrasive and a liquid such as water collide with the surface with a relatively uniform pressure. As a result, it is possible to remove or reduce or deform the glass that has been raised during firing relatively uniformly from the surface of the ceramic portion and the surface of the alignment mark made of a conductor such as Ag, or to obtain and obtain an image with a CCD camera. Surface modification (surface roughness or the like) that does not hinder the recognition of position information after binarization processing of the image can be easily performed. Therefore, since positioning based on the image (position) information obtained by the binarization processing can be performed accurately, for example, a SAW filter, a crystal resonator, an IC chip, or the like is placed at a predetermined position on the surface of the ceramic substrate. It is possible to mount electronic components with high accuracy, or to divide a multi-chip substrate into individual ceramic substrates with high accuracy.

The ceramic containing the glass component includes, for example, a low-temperature fired ceramic (LTCC) such as glass-ceramic and a high-temperature fired ceramic (HTCC) that may cause the glass to float on the surface of the fired ceramic substrate.
In addition, the alignment mark is formed on the surface of a ceramic substrate (aggregate) obtained by firing a multi-sheet green sheet, for example, on the outside of a product area where surface wiring such as pads is formed (for example, four corners of an ear). The conductive paste is printed in a pattern such as a circle or a square in plan view, or the ceramic powder and glass have a lightness and color different from the ceramic constituting the ceramic substrate (aggregate). It is formed by printing a paste.
However, a part of the surface wiring formed on the surface of a single ceramic substrate (for example, a part of pads) or one surface wiring formed on the surface of each substrate portion of the ceramic substrate assembly for multi-piece production. The portion may be used also as an alignment mark.
Furthermore, the alignment mark includes the same metal as the conductor pattern formed on the surface of the ceramic substrate, or is formed of a ceramic including glass of a different type and a color different from the ceramic substrate. .
Further, the ceramic portion around the alignment mark is the surface of the ceramic substrate adjacent to the mark so that it is captured in the same image together with the mark during the binarization process.

Furthermore, the liquid contains lubricating oil such as coolant in addition to water containing pure water.
In addition, ceramic powder such as alumina, mullite, or zirconia having a relatively small average particle size of, for example, 10 μm or less is used for the abrasive.
Also, the high-pressure air containing the slurry is injected from a plurality of nozzle holes having a circular cross section in a conical shape and these are arranged in a straight line, or from a slit-shaped nozzle hole, the cross section is a film shape. And the form which injects linearly is illustrated. In the case of spraying from the latter slit-shaped nozzle hole, it is possible to make the spraying pressure on the surface of the ceramic substrate relatively uniform.
Furthermore, before the surface modification step, a step of forming a plurality of green sheets, via conductors are formed in via holes penetrating the green sheets, and wiring patterns and alignment marks are formed on at least the surface of the green sheets. Are formed by printing, a step of laminating and pressure-bonding a plurality of green sheets, and a step of firing the obtained green sheet laminate.
In addition, after the surface modification step, a step of plating the conductive pattern formed on the front and back surfaces of the ceramic laminate obtained by firing, a SAW filter, a crystal on a plurality of pads formed on the surface In the case of mounting a vibrator or an electronic component such as an IC, and in the case of taking a large number of pieces, a step of dividing into individual ceramic substrates is performed. The plating may be electrolytic plating or electroless plating.

According to the present invention, in the manufacturing of a ceramic substrate, the surface modification step removes or reduces the glass raised on the surface of the mark and the surface of the ceramic portion, or deforms the glass. A method (claim 2) is also included.
According to this, whether to remove the glass raised on the surface of the alignment mark and the surface of the surrounding ceramic part, or reduce the glass thin enough to binarize the captured image, The surface roughness on the surface layer side of the glass can be changed. Therefore, the optimum surface modification can be performed according to the degree of the glass raised on the surface of each of the mark and the ceramic portion.
The surface modification step can be performed mainly on a single ceramic substrate as well as on an assembly of multiple ceramic substrates.

The top view which shows the ceramic substrate (aggregate) for multi-piece taking of the Example and comparative example to which this invention is applied. The top view which shows the ceramic substrate of a different form to which this invention is applied.

Hereinafter, modes for carrying out the present invention will be described.
(Green sheet creation process)
A mixture of about 50 parts by weight of alumina powder and about 50 parts by weight of glass powder is mixed and kneaded with appropriate amounts of solvent and binder resin, and the resulting ceramic slurry is made into a sheet by a doctor blade method. A plurality of relatively large green sheets (not shown) for taking a large number of pieces were prepared by thinly stretching the film and drying it at the end.
The glass powder is made of borosilicate glass, and the solvent is, for example, toluene, ethanol, or xylene.

(Process for forming conductors and alignment marks)
Next, a conductive paste containing Ag powder is applied to a plurality of via holes obtained by punching using a punch and a receiving die at predetermined positions in the plurality of green sheets using negative pressure. By filling, a via conductor (conductor) was formed inside each via hole. Furthermore, after masking at least one of the front surface and the back surface of the green sheet, the same conductive paste as described above is printed in accordance with a predetermined pattern, so that the surface wiring (conductor) including pads and external connection terminals, Internal wiring (conductor) and alignment marks were formed.
The surface wiring and the internal wiring are formed in a product region to be a plurality of ceramic substrates adjacent to each other in the vertical and horizontal directions, and the alignment mark is in an ear portion (discard allowance) located outside the product region. It was formed around each corner of the four corners.

(Green sheet laminate formation process)
Next, the green sheets were laminated and pressed together in the thickness direction to form a green sheet laminate. At this time, in the ceramic substrate portion in the product region, the surface wiring and the internal wiring can be electrically connected to each other through the via conductor.

(Green sheet laminate firing process)
Subsequently, the obtained green sheet laminate is inserted into a firing furnace (not shown), heated to 300 to 400 ° C., and subjected to a binder removal process for decomposing or burning the binder resin, and then 800 to 1000. The baking process which heats and hold | maintains at ° C was performed. As a result, as illustrated in FIG. 1, a plurality of pads (surface wiring) 7 and internal wiring (not shown) are simultaneously fired for each ceramic substrate portion 4 in the product region 3 divided by the boundary 8 on the surface 2. As a result, a ceramic laminate (ceramic substrate aggregate) 1 in which four alignment marks 8 were simultaneously fired at the four corners of the ear 6 was obtained.
Further, along with the firing, the surface and back surface of the ceramic portion s in the ceramic laminate 1, and further, the surface of the surface wiring 7 and the alignment mark 8 and the surface of the ceramic portion s around the mark are partially applied. In some cases, glass (glass frit) may come out. Among these, the glass raised on the surface of the surface wiring 7 and the alignment mark 8 increases the adhesion of the mark to the ceramic laminate (ceramic substrate) 1 mainly composed of the alumina and glass. Glass contained in the adhesive paste.

(Surface modification process of ceramic laminate)
Further, in the ceramic laminate 1, a surface (position of the mark 8) is formed in which the alignment mark 8 is formed near each corner of the ear 6 and the surface wiring 7 is formed for each ceramic substrate portion 4 in the product region 3. A slurry made of water (liquid) and alumina particles (abrasive) was sprayed along with high-pressure (compressed) air onto the surface 2 including the surface and the surface of the ceramic portion s located in the vicinity thereof. Since the high-pressure air is used in combination with the above alumina particles, relatively fine and uniform particles having an average particle diameter of 10 μm or less could be used. At this time, the mixture of the slurry and the high-pressure air is formed by arranging a plurality of nozzle holes having a circular cross section in a straight line at right angles to the feed direction, or from a single nozzle hole having a slit cross section. Sprayed against surface 2.

In the case of a nozzle hole having a circular cross section, a plurality of nozzles having the nozzle hole were scanned in a straight line along the direction perpendicular to the feed direction. On the other hand, in the case of a nozzle hole having a slit cross section, a single elongated nozzle having the nozzle hole was scanned along the width direction.
As a result, almost all of the glass that had been raised on the surface 2 of the ceramic laminate 1 composed of the ears 6 on which the marks 8 were formed and the product region 3 surrounded by the ears 6 could be removed. Alternatively, it could be reduced to a relatively uniform thickness, the surface layer side of the glass was deformed to a gentle uneven surface, or so-called surface modification could be performed to deform the glass part.
Therefore, as described later, after the vicinity of the mark 8 is imaged and binarized, the positional information based on, for example, the brightness difference between the surface of the mark 8 and the surface of the surrounding ceramic portion s. It became possible to recognize this reliably.
The surface modification step as described above can also be performed on the back side of the ceramic laminate (ceramic substrate) 1.

(Plating process)
Next, after the surface modification, the ceramic laminate 1 is subjected to electroless Ni plating to cover the surface of the surface wiring and the alignment mark with a Ni plating film having a thickness of 1 to 8 μm. did. Subsequently, electroless Au plating was performed to further cover the Ni plating film with an Au plating film having a thickness of about 0.05 to 1 μm. In this case, when almost all the glass was removed from the surface of the mark 8 in the surface modification step, the Ni plating film and the Au plating film could be coated with a predetermined thickness.

(Electronic component mounting process)
Next, an electronic component such as a SAW filter or an IC chip was mounted on the surface wiring 7 coated with the Ni and Au plating films via solder (not shown).
At this time, the alignment mark 8 located near each corner of the ear portion 6 and densely coated with the Au plating film or the like and the surrounding ceramic portion s were imaged with a CCD camera and obtained. By binarizing the image, it was possible to accurately recognize the position of the surface wiring 7 such as a pad positioned on the surface of each ceramic substrate portion 4 in the product region 3. As a result, it was possible to accurately arrange the solder and mount electronic components such as a SAW filter.

(Separation process)
Each ceramic substrate portion 4 in the product region 3 on which the electronic component is mounted is preliminarily formed on at least one of the front surface and the back surface along the boundary 5 by cutting along these boundaries 5. The plurality of ceramic substrates 4 were divided by shearing along the divided grooves.
Through the above steps, a plurality of ceramic substrates 4 having electronic components mounted on the surface could be obtained simultaneously.

In the following, specific examples of the present invention will be described in comparison with comparative examples.
As shown in the plan view of FIG. 1, a large number of green sheets are formed through the green sheet forming process, the conductor and alignment mark forming process, the green sheet laminated body forming process, and the green sheet laminated body firing process. Twenty ceramic laminates (ceramic substrate aggregates) 1 were prepared.
The ceramic laminate 1 is made of alumina and glass of approximately 1: 1 by weight, has a front surface 2 and a back surface (not shown) made of a square having a thickness of 1 mm and a side of 95 mm. A product region 3 having a plurality of ceramic substrate portions 4 surrounded by a boundary 5 indicated by a broken line in the vertical and horizontal directions and a square frame-shaped ear portion 6 surrounding the periphery of the product region 3 are provided. In addition, the symbol s in FIG.
When the ceramic substrate portion 4 is divided along the boundary 5 later, the ceramic substrate portion 4 becomes a ceramic substrate of the product, and a plurality of pads (surface wiring) made of Ag and glass are provided at the center of the surface. 7 is formed.
As shown in FIG. 1, a total of four alignment marks 8 made of Ag and glass and exhibiting a circular shape having a diameter of 600 μm are formed in the vicinity of each corner of the ear portion 6.

The 20 ceramic laminates 1 that are the aggregates of the ceramic substrates (4) as described above are divided into two groups of 10 pieces, and the implementation of the present invention shown on the left side of Table 1 is performed for one group. A surface modification step according to the example was applied. Furthermore, the surface modification process by the comparative example shown on the right side of Table 1 was applied to the other group. At this time, in the example, the blast medium and air were ejected using an elongated nozzle having a slit hole having a width of 1 mm. On the other hand, in the comparative example, a plurality of nozzles having an elliptical hole with an inner diameter of 1 to 3.5 mm were used in parallel to inject abrasive and water.
In the ceramic laminate 1 subjected to the surface modification and plating step, the four alignment marks 8 for each ceramic laminate 1 in each group and the ceramic portion s located around these are imaged with a CCD camera, The obtained image was subjected to a binarization process based on a difference in brightness between each mark 8 and the ceramic portion s adjacent thereto. It was examined whether or not all four alignment marks 8 could be read after the binarization process, and the results are also shown in Table 1.

尚、表１中に示す研磨材の濃度は、実施例および比較例共に、アルミナと水との合計体積に対するアルミナの体積率を示す。

In addition, the density | concentration of the abrasive | polishing material shown in Table 1 shows the volume ratio of the alumina with respect to the total volume of an alumina and water with an Example and a comparative example.

According to Table 1, the ceramic laminate 1 subjected to the surface modification process of the example could recognize the positions of all the four alignment marks 8 in ten. On the other hand, the ceramic laminate 1 subjected to the surface modification process of the comparative example could not recognize the positions of all four alignment marks 8 in ten.
As a result as described above, in the surface modification step of the embodiment, a slurry made of water and relatively fine alumina particles (abrasive) is sprayed onto the surface 2 in the vicinity of the alignment mark 8 together with high-pressure air. Therefore, as a result of the glass that has been raised on the surface of the mark 8 and the ceramic portion s near the mark 8 being subjected to a relatively uniform collision pressure, the surface is modified such that the glass is removed or deformed. It is presumed that the positions of all the marks 8 could be recognized after the conversion processing. Further, it is presumed that the above-described slurry and high-pressure air were ejected from the slit-like nozzle holes, which contributed to the above results.
On the other hand, in the surface modification process of the comparative example, relatively large-diameter alumina particles were sprayed onto the surface 2 near the alignment mark 8 together with high-pressure water, so that a plurality of elliptical nozzle holes were used. Combined with this, the glass that floated on the surface of the mark 8 and the ceramic part s in the vicinity thereof received a large variation of collision pressure, and the surface modification that removes or deforms the glass was randomized. Thereafter, in all the ceramic laminates 1, it is presumed that the positions of at least one mark 8 could not be recognized.

FIG. 2 is a plan view showing a single ceramic substrate 10 to which the present invention is applied.
The ceramic substrate 10 is made of ceramic such as alumina containing about 50 parts by weight of glass, and has a surface 12 and a back surface (not shown) that are square in plan view, as shown in FIG. A plurality of pads 13 are arranged in a grid pattern. Of these, the four corner pads 14 also serve as alignment marks.
The ceramic substrate 10 has internal wiring (not shown) between a plurality of ceramic layers, and via conductors (not shown) connecting the pads 13 and the internal wiring are formed in each ceramic layer. Yes.
Also for the ceramic substrate 10 as described above, by performing the surface modification process according to the present invention, the pad 14 that also serves as four alignment marks and the surrounding ceramic portion s are imaged by, for example, a CCD camera. After the obtained image is binarized, the position of the pad 14 that also serves as the mark can be reliably recognized based on the difference in brightness.

The present invention is not limited to the form described above.
For example, the ceramic substrate that is the subject of the present invention is not limited to one made of a low-temperature fired ceramic, and may be made of, for example, a high-temperature fired ceramic as long as it contains glass and can be raised on the surface during firing. good.
Further, the alignment mark may be in a form in which a part of the pads on the surface of each ceramic substrate portion in the multi-piece ceramic substrate assembly is also used.
Furthermore, the alignment marks may be formed in a form in which at least two or three are formed on the surface of a single ceramic substrate or the surface of a ceramic substrate assembly for taking multiple pieces, or five or more are placed in place. It is good also as the form made into the formed form.

  According to the present invention, there is provided a method for manufacturing a ceramic substrate which can reliably recognize the position of a registration mark formed on the surface after binarization processing without any trouble by using the glass which is raised on the surface of the substrate in the manufacturing process. It becomes possible to do.

DESCRIPTION OF SYMBOLS 1,10 ... Ceramic laminated body (ceramic substrate aggregate) / Ceramic substrate 2,12 ... Surface 8, 14 ... Alignment mark s ............ Ceramic part

Claims (2)

In a ceramic substrate made of ceramic containing glass and having a front surface and a back surface, and an alignment mark is formed on at least one of the front surface and the back surface, a liquid and a ceramic portion around the alignment mark and the mark Including a surface modification step of modifying a surface of the alignment mark and a surface of the ceramic part by injecting a slurry made of an abrasive together with high-pressure air.
A method for manufacturing a ceramic substrate. The surface modification step is to remove or reduce the glass raised on the surface of the mark and the surface of the ceramic part, or to deform the glass.
The method for producing a ceramic substrate according to claim 1.

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