JP4548244B2 - Method for manufacturing ceramic laminate - Google Patents

Description

  The present invention relates to a method for manufacturing a ceramic laminate, and more particularly, to a method for manufacturing a ceramic laminate that can prevent stacking misalignment, has few defective products, and is less contaminated with dust.

  As shown in the following Patent Document 1, a glass ceramic substrate has been proposed for a high-frequency circuit board. In order to manufacture this glass ceramic substrate, first, a glass ceramic green sheet is prepared, and a wiring pattern is formed on the surface of the green sheet. Thereafter, these green sheets are laminated, pressed and integrated, then cut into chips and fired.

  In the manufacturing process of this glass ceramic substrate, stacking deviation often occurs under some conditions. When stacking misalignment occurs, the wiring pattern formed on the surface of the green sheet is misaligned in the stacking direction, causing inconveniences such as inability to connect through-hole electrodes, resulting in defective products.

  Conventionally, the cause of the misalignment of green sheets has not always been clear.

In addition, as shown in the following Patent Document 2, a method of removing static electricity with a static eliminator when peeling a release film from a prepreg sheet is known. However, this method cannot prevent stacking misalignment when the green sheets are stacked.
JP-A-5-47960 Japanese Patent Laid-Open No. 2000-13018

  The present invention has been made in view of such a situation, and an object of the present invention is to provide a method for manufacturing a ceramic laminated body that can prevent stacking misalignment, has few defective products, and contains little dust. It is.

  As a result of earnestly examining the cause of green sheet stacking misalignment in the process of manufacturing a ceramic laminate such as a glass ceramic substrate, the present inventor has found that a green sheet having a relatively large area has already been stacked. When covering and laminating on a sheet, it was found that static electricity was generated, the sheet was repelled and adsorbed, and laminating displacement occurred, and the present invention was completed.

That is, the method for producing a ceramic laminate according to the present invention includes:
A process of stacking the green sheets formed on the surface of the carrier film while removing static electricity on the stacked green sheets;
Applying pressure from above the carrier film, and temporarily bonding the green sheets together;
Removing the carrier film from the green sheet.

  According to the method for producing a ceramic laminate of the present invention, when a green sheet having a relatively large area is covered and laminated on a green sheet already laminated together with a carrier film, static electricity is removed. For this reason, sheet repulsion and adsorption are prevented, and stacking deviation can be suppressed. Therefore, defective products in the manufacturing process of the ceramic laminate are reduced. In addition, since static electricity is removed from the green sheet, it is possible to prevent dust and the like from adhering to the sheet.

In addition, in this invention, it is especially effective when laminating | stacking the comparatively large area green sheet of 10000 mm < ² > or more.

  Preferably, the green sheet formed on the surface of the carrier film is positioned on the stacked green sheets, and is temporarily floated. The green sheet is positioned as follows, for example.

In other words, positioning pins are formed at multiple locations around the green sheet stacked on the stage,
Inserting the positioning pin through the positioning hole formed in the carrier film;
On the stacked green sheets, the green sheets formed on the surface of the carrier film are positioned and floated once.

  By positioning the green sheets in this manner, the green sheets to be stacked are positioned in a self-aligned manner (self-alignment) with respect to the already stacked green sheets.

  Preferably, a static eliminating gas (also referred to as a static eliminating gas) is allowed to flow between the stacked green sheets and the green sheets formed on the surface of the carrier film. This eliminates static electricity between the green sheets, prevents sheet slippage, wrinkles and twists, and is positioned and stacked accurately. In addition to removing static electricity and preventing dust from adhering to the static electricity by flowing the static elimination gas, there is an effect of discharging the dust existing between the green sheets along the gas flow. From the viewpoint of enhancing the effect, the static elimination gas is preferably flowed from one direction.

  Preferably, pressure is applied from above the carrier film while static electricity is removed, and the green sheets are temporarily pressed together. Preferably, when a pressure is applied from above the carrier film to temporarily press-bond the green sheets, a static eliminating gas is caused to flow around the stacked green sheets. By configuring in this way, static electricity at the time of temporary pressure bonding is also removed, and in this respect as well, stacking misalignment can be prevented and adhesion of dust and the like can be prevented.

  Preferably, the carrier film is peeled from the green sheet while removing static electricity. Preferably, when the carrier film is peeled from the green sheet, a green sheet unnecessary portion located on the outer periphery of the green sheet is also removed. Preferably, when the carrier film is peeled from the green sheet, a static eliminating gas is allowed to flow between the carrier film and the green sheet.

  By comprising in this way, when peeling a carrier film from a green sheet, static electricity is removed and a lamination shift can be prevented also in this point. In addition, when the carrier film is peeled from the green sheet, unnecessary portions (cutting waste) located on the outer periphery of the green sheet are also removed, but the cutting waste is also prevented from adhering to the green sheet due to static electricity. Can do.

  Preferably, the static eliminating gas is a gas containing positive ions and / or negative ions. Examples of the gas include inert gases such as nitrogen gas, air, and the like.

Hereinafter, the present invention will be described based on embodiments shown in the drawings.
FIG. 1 is a schematic cross-sectional view of a glass ceramic substrate obtained by a method for producing a ceramic laminate according to an embodiment of the present invention,
FIG. 2 is a schematic cross-sectional view showing one manufacturing process of the method for manufacturing a ceramic laminate according to one embodiment of the present invention.

  A glass ceramic substrate 2 shown in FIG. 1 is a glass ceramic substrate (LTCC substrate) obtained by low-temperature firing of a mixture of glass powder and ceramic powder. Glass ceramic has a low dielectric constant and is suitable as a high-frequency insulating substrate. Further, since the glass ceramic can be fired at a low temperature of about 800 to 1000 ° C., a low resistance metal such as copper, silver, or gold is placed inside the substrate 2 via the glass ceramic layer 4. There is merit that can be used as.

  The glass ceramic substrate 2 is manufactured as follows, for example. First, a glass ceramic green sheet is prepared. The glass ceramic green sheet is formed into a sheet shape by a doctor blade method or the like using, for example, a glass ceramic paste. As the glass ceramic paste, a mixture of glass powder, ceramic powder, an organic binder, a plasticizer, an organic solvent and the like can be used.

The glass powder is not particularly limited, for _example, SiO 2 _-B 2 _{O 3 based, SiO 2 -B 2 O 3 -Al} 2 O 3 _{based, SiO 2 -B 2 O 3 -Al} 2 O 3 -MO -based , SiO ₂ —Al ₂ O ₃ —M ₁ O—M ₂ O, SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ —M ₁ O—M ₂ O, SiO ₂ —B ₂ O ₃ —M _{3 2} O, SiO ₂ —B ₂ Examples thereof include O ₃ —Al ₂ O ₃ —M3 ₂ O-based, Pb-based glass, and Bi-based glass. However, the symbol M represents Ca, Sr, Mg, Ba or Zn, the symbol M1 and the symbol M2 represent Ca, Sr, Mg, Ba or Zn, and the symbol M3 represents Li, Na or K.

The ceramic powder is not particularly limited. For example, Al ₂ O ₃ , SiO ₂ , composite oxide of ZrO ₂ and alkaline earth metal oxide, composite oxide of TiO ₂ and alkaline earth metal oxide, Examples thereof include composite oxides containing at least one selected from Al ₂ O ₃ and SiO ₂ (for example, spinel, mullite, cordierite) and the like.

  The mixing ratio of the glass powder and the ceramic powder is not particularly limited, and can be 40:60 to 99: 1, for example, by weight.

  The organic binder is not particularly limited. For example, acrylic (acrylic acid, methacrylic acid or an ester homopolymer or copolymer thereof, specifically an acrylic ester copolymer, a methacrylic ester copolymer, Acrylic ester-methacrylic ester copolymer, etc.), polyvinyl butyral, polyvinyl alcohol, acrylic-styrene, polypropylene carbonate, cellulose, and other homopolymers or copolymers.

  The glass ceramic paste used in the present invention is made into a slurry by adding a predetermined amount of a plasticizer and a solvent (organic solvent, water, etc.) to the glass powder, ceramic powder, and organic binder as necessary. This paste is formed into a sheet by a doctor blade, rolling, a calender roll, a die press or the like, and becomes a glass ceramic green sheet.

  A conductive pattern layer (which becomes the internal wiring layer 6 shown in FIG. 1) is formed on the surface of the glass ceramic green sheet as necessary. To form the internal wiring layer 6, a conductive paste obtained by pasting a conductive material powder, for example, is printed on the surface of the glass ceramic green sheet by a screen printing method or a gravure printing method, or a metal foil having a predetermined pattern shape is transferred. And the like. Examples of the conductor material include one or more of Au, Ag, Cu, Pd, Pt, and the like. In the case of two or more, any form such as mixing, alloy, coating, etc. may be used.

  Note that the conductor pattern includes a portion where a through conductor such as a via conductor or a through hole conductor for connecting conductor patterns between upper and lower layers is exposed on the surface. These through conductors are formed by means such as embedding by printing a conductive paste obtained by pasting a conductive material powder into a through hole formed in a glass ceramic green sheet by punching or the like.

  The glass ceramic green sheets laminated through the conductor pattern layer are cut into chips and then fired. The firing conditions depend on the material of the green sheet laminate, but are, for example, 700 to 1000 ° C. and 0.5 to 10 hours in air. Firing is performed in a firing furnace such as an electric continuous belt furnace. When the conductor paste is Cu, it is fired in a reducing or neutral atmosphere.

  When laminating a glass ceramic green sheet (hereinafter also simply referred to as a green sheet) on which a conductor pattern layer is formed, the method shown in FIG. 2 is adopted in this embodiment. That is, as shown in FIG. 2, the green sheet 4a is laminated on the stage 10 via dust-free paper (not shown). The method of laminating the green sheet 4a is the same as the method of laminating the green sheet 4b formed on the surface of the carrier film 20 on the green sheet 4a that has been laminated in advance. Therefore, in the following description, description will be given focusing on the method of laminating the green sheets 4b.

In a step different from the step shown in FIG. 2, the green sheet 4b is formed on the surface of the carrier film 20 by the above-described doctor blade method or the like. At that time, a green sheet unnecessary portion 4c which is a larger portion than necessary is also formed around the green sheet 4b. Since this portion 4c is a portion that is finally unnecessary, after the green sheet is formed with the same width as the carrier film 20, a cutting line 8 that does not cut to the carrier film 20 is put in the green sheet, and the necessary green The sheet 4b and the unnecessary portion 4c are separated. However, both remain attached to the surface of the carrier film 20. On the surface of the green sheet 4b, an internal conductor pattern (not shown) to be the internal wiring layer 6 shown in FIG. 1 is formed as necessary.

  In the present embodiment, the carrier film 20 is not particularly limited, but a polyethylene terephthalate (PET) film having a thickness of 30 to 100 μm is used. The length and width of the green sheet 4b formed on the surface of the carrier film 20 are not particularly limited, but are preferably about 100 to 200 mm × 100 to 200 mm, and in this embodiment, 120 mm × 134 mm. In addition, the vertical and horizontal size of the green sheet including the green sheet unnecessary portion 4c is 135 mm × 152 mm in the present embodiment.

  After the green sheet 4b is formed on the surface of the carrier film 20 and a conductor pattern is formed as necessary, the front and back surfaces of the carrier film 20 are reversed, and the vacuum suction conveyance device 40 shown in FIG. Transport. After that, the alignment pins 12 formed at the four corner positions around the green sheet 4a already laminated on the stage 10 are inserted into the alignment holes 22 formed at the corresponding positions on the carrier film 20. The conveying device 40 is moved down to the position where insertion starts. Thereafter, the suction holding by the transport device 40 is released, and only the transport device 40 is moved upward.

  As a result, as shown in FIG. 2, in the state where a gap is formed between the green sheet 4b formed on the carrier film 20 and the green sheet 4a already laminated, the alignment between the two is self-aligned. Done. In that state, the carrier film 20 is temporarily in a floating state. As shown by the dotted arrow X between the green sheets 4a stacked by the static eliminator 30 and the green sheets 4b formed on the surface of the carrier film 20 from the previous state, (Static charge gas) flows.

  The static eliminator 30 is arranged near the stacked green sheets 4a, and the flow of the static eliminator gas from the static eliminator 30 is directed from one direction to the other along the surface of the green sheet 4a as indicated by an arrow X. It flows in parallel along the plane. The flow rate of the static elimination gas is not particularly limited, but is preferably about 0.5 to 3 m / s. If the flow rate is too small, the effect of removing static electricity is small, and if the flow rate is too large, the carrier film 20 swings in the wind together with the green sheet 4b, making positioning difficult.

The green sheet 4b formed on the surface of the carrier film 20 is temporarily suspended and aligned with the already stacked green sheet 4a, and then comes into contact with the static electricity removed by the charge eliminating gas. Thereafter, the conveying device 40 is pressed against the upper surface of the carrier film 20 (the surface opposite to the surface on which the green sheet 4b is formed), and the green sheet 4b is temporarily pressed against the green sheet 4a. Although the press pressure at the time of temporary pressure bonding is not particularly limited, it is preferably 2 to 7 MPa, and is about 4 MPa in the present embodiment.
The static elimination gas is kept flowing by the static elimination device 30 even during the temporary pressure bonding. In addition, the press pressure at the time of temporary press-fit is not applied to the unnecessary part 4c.

  Thereafter, the green sheet 4b temporarily bonded to the surface of the laminated green sheet 4a is left, and the carrier film 20 is peeled off from the green sheet 4b. At that time, the unnecessary portion 4 c is separated from the green sheet 4 b together with the carrier film 20.

  Since the static eliminator 30 continuously flows the static elimination gas in the above-described process, the static elimination gas flows between the carrier film 20 and the green sheet 4b even when the carrier film 20 is peeled off from the green sheet 4b. . The static elimination gas is not particularly limited, but is composed of, for example, a gas containing positive ions and / or negative ions. Nitrogen gas or air is used as the gas.

  The static eliminator 30 can adjust the amount of positive ions and / or negative ions, and can also adjust the gas blowing speed. The amount of positive ions and / or negative ions is adjusted according to the type and amount of electrostatic charges to be removed. If the static charge to be removed is positive, it is preferable that the gas blown out from the static eliminator 30 contains a lot of negative ions so as to neutralize it.

  In this way, the green sheets 4b are laminated on the surface of the already laminated green sheets 4a. By repeating this process, the lamination of the required number of green sheets is completed. Thereafter, the laminated green sheet laminate is taken out from the stage 10 and subjected to the main press. The pressing force during the pressing is hydrostatic pressure, preferably 30 to 100 MPa, and in this embodiment, about 74 MPa.

  After that, as described above, it is cut into a chip shape and fired, so that the glass ceramic substrate 2 shown in FIG. 1 is obtained.

  In the method according to the present embodiment, when the green sheet 4b having a relatively large area is covered with the carrier film 20 and laminated on the already laminated green sheet 4a, the static eliminator 30 applies static electricity. Can be removed. For this reason, the sheet 4a is prevented from shifting, wrinkling, twisting, and the like, and part of the sheet 4a, 4b is prevented from being repelled or partially adsorbed, so that stacking deviation can be suppressed. Therefore, defective products in the manufacturing process of the glass ceramic substrate 2 are reduced. Moreover, since the static electricity of the green sheets 4a and 4b is removed, it is possible to prevent dust and the like from adhering to the sheets 4a and 4b.

  In addition to removing static electricity by removing the static elimination gas from one direction and preventing dust from adhering to the static electricity, there is an effect that dust existing between the green sheets 4a and 4b can be discharged along the gas flow. .

  Furthermore, in this embodiment, while removing static electricity, pressure is applied from above the carrier film 20 to temporarily press-bond the green sheets 4a and 4b to each other, so that static electricity at the time of temporary pressing is also removed. Therefore, in this respect as well, stacking misalignment can be prevented and adhesion of dust and the like can be prevented.

  Furthermore, in this embodiment, since the carrier film 20 is peeled off from the green sheet 4b while removing static electricity, the static electricity is also removed at that time, and the stacking deviation can be prevented in this respect. Further, when the carrier film 20 is peeled off from the green sheet 4b, the green sheet unnecessary portion (including cutting waste) 4c located on the outer periphery of the green sheet 4b is also removed, but the cutting waste is caused by static electricity to cause the green sheet 4a or 4b. It is also possible to suppress reattachment to the surface. Conventionally, cutting waste cannot be removed only by nitrogen gas blowing.

  The present invention is not limited to the above-described embodiment, and can be variously modified within the scope of the present invention.

  For example, the method of the present invention can be used not only for a method of manufacturing a glass ceramic substrate (LTCC substrate) but also for a method of manufacturing other devices, for example, other ceramic laminates such as inductors, varistors and capacitors.

FIG. 1 is a schematic cross-sectional view of a glass ceramic substrate obtained by a method for producing a ceramic laminate according to an embodiment of the present invention. FIG. 2 is a schematic cross-sectional view showing one manufacturing process of the method for manufacturing a ceramic laminate according to one embodiment of the present invention.

Explanation of symbols

2 ... Glass ceramic substrate 4 ... Glass ceramic layer 4a, 4b ... Green sheet 4c ... Green sheet unnecessary part 6 ... Internal wiring layer 8 ... Cutting line 10 ... Stage 12 ... Positioning pin 20 ... Carrier film 22 ... Positioning hole 30 ... Static eliminator

Claims (7)

A process of stacking the green sheets formed on the surface of the carrier film while removing static electricity on the stacked green sheets;
Applying pressure from above the carrier film, and temporarily bonding the green sheets together;
Removing the carrier film from the green sheet,
Between the stacked green sheets and the green sheets formed on the surface of the carrier film, a static elimination gas is flowed in parallel along the plane from one direction to the other along the surface of the green sheets,
While removing static electricity, pressure is applied from above the carrier film, and the green sheets are temporarily pressed together,
Wherein the pressure is applied from above the carrier film, the green sheet between at the time of temporary compression bonding, and the flow of static electricity removing gas around the green sheet stacked in one direction,
While removing static electricity, peel off the carrier film from the green sheet,
A method for producing a ceramic laminate , wherein, when the carrier film is peeled from the green sheet, a green sheet unnecessary portion located on the outer periphery of the green sheet is also removed .   2. The method for manufacturing a ceramic laminate according to claim 1, wherein the green sheet formed on the surface of the carrier film is positioned on the stacked green sheets and is temporarily suspended. Positioning pins are formed at multiple locations around the green sheets stacked on the stage.
Inserting the positioning pin through the positioning hole formed in the carrier film;
2. The method of manufacturing a ceramic laminate according to claim 1, wherein the green sheet formed on the surface of the carrier film is positioned on the stacked green sheets and is temporarily suspended. After the green sheet is formed with the same width as the carrier film, a cutting line that does not cut up to the carrier film is put into the green sheet,
The method for producing a ceramic laminate according to any one of claims 1 to 3, wherein the green sheet unnecessary portion is an outer peripheral portion of the green sheet cut by the cutting line. The method for producing a ceramic laminate according to any one of claims 1 to 4, wherein a press pressure at the time of temporary pressure bonding between the green sheets is 2 to 7 MPa. The ceramic laminate according to any one of claims 1 to 5 , wherein when removing the carrier film from the green sheet, a static elimination gas is allowed to flow between the carrier film and the green sheet. Method.   The method for producing a ceramic laminate according to any one of claims 1 to 6, wherein the static elimination gas is a gas containing positive ions and / or negative ions.

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