JP2010109135A - Method for producing multilayer ceramic substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a multilayer ceramic substrate capable of preventing the contraction factor of the multilayer ceramic substrate after baking from exceeding 0.17%. <P>SOLUTION: The method for producing the multilayer ceramic substrate by laminating a plurality of green sheets includes: a first step for producing a laminated body to produce a tentative laminated body by adding first pressure after the plurality of green sheets are laminated; a pressure release step to release the tentative laminated body from the first pressure after the first step for producing the laminated body is completed; and a second step for producing the laminated body to add second pressure, which is smaller than the first pressure, to the tentative laminated body. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

 The present invention relates to a method for manufacturing a ceramic multilayer substrate, and more particularly to a method for manufacturing a ceramic multilayer substrate capable of reducing the firing shrinkage rate.

  In recent years, a glass ceramic multilayer substrate has been used as an insulating substrate for mounting semiconductor elements and mounting components. This glass ceramic multilayer substrate is required to have high dimensional accuracy in order to mount an ultra-small mounting component made with high dimensional accuracy with high accuracy. A glass-ceramic multilayer substrate produces a green sheet by mixing an inorganic powder of glass powder and ceramic powder with an organic binder, a plasticizer, and a solvent to prepare a slurry, and forming the slurry by a doctor blade method or the like.

  Next, after punching the green sheet as necessary, printing is performed using a conductive paste mainly composed of a low-resistance metal such as silver or gold, and a plurality of green sheets are laminated. After placing the constrained green sheets on the front and back surfaces, thermocompression bonding was performed, followed by sintering at a temperature of 800 to 1000 ° C., and the constrained green sheets disposed on the front and back surfaces were removed by a wet blast method or the like. Then, a glass-ceramic multilayer substrate is manufactured by printing outermost layer conductor wiring on the front and back surfaces of the baked substrate.

  However, the glass ceramic multilayer substrate undergoes sintering shrinkage due to shrinkage accompanied by dimensional change during the firing process. This sintering shrinkage is generally called the shrinkage rate. This shrinkage rate varies depending on various factors such as the difference in pattern area for printing the conductor wiring on the green sheet and the thickness in the height direction when laminating. Since non-uniformity occurs, the shrinkage rate generally shrinks by about 0.2%. Generally, the shrinkage rate indicates the ratio of the dimension value Y after firing to the dimension X of the design value, and is represented by (Y / X-1) × 100 (%). When the shrinkage rate is greater than zero, the dimension Y is larger than the dimension X, indicating that it is stretched. Conversely, when the shrinkage rate is less than zero, it indicates that the dimension is shrinking. The contraction of about 0.2% indicates that the dimension Y is smaller than the dimension X.

In order to further reduce the shrinkage rate, a technique shown in FIG. 3 is known. As shown in FIG. 3A, a plurality of green sheets 1 in which via conductors 3 are embedded and green sheets 1 in which conductor patterns 2 are printed on the via conductors 3 are prepared and aligned. A stacked laminate is produced. Thereafter, as shown in FIG. 3B, a constraining sheet 12 containing alumina, a small amount of glass powder and an organic binder, and a constraining sheet 13 containing an organic binder having a molecular weight smaller than the organic binder of the constraining sheet 12 are displayed on the surface of the laminate. Place on the back and apply pressure. In this way, a laminate having constraining sheets on both sides is produced. Then, after firing, the ceramic multilayer substrate shown in FIG. 3C can be produced by removing the restraining sheets 12 and 13 (see, for example, Patent Document 1).
JP 2004-256358 A

  However, the conventional configuration has a problem that the shrinkage ratio of the fired ceramic multilayer substrate cannot be suppressed to 0.17% or less.

 SUMMARY OF THE INVENTION An object of the present invention is to solve the conventional problem and to provide a method for producing a ceramic multilayer substrate capable of suppressing the shrinkage ratio of the fired ceramic multilayer substrate to 0.17% or less.

In order to solve the above-described conventional problems, a method for producing a glass ceramic multilayer substrate according to the present invention is the method for producing a ceramic multilayer substrate in which a plurality of green sheets are laminated to form the ceramic multilayer substrate. A first laminated body production step for producing a temporary laminated body to which a first pressure is applied by stacking, and a pressure for releasing the temporary laminated body from the first pressure after the first laminated body production step After the release step, and after the pressure release step, the temporary laminate is composed of a second laminate manufacturing step in which a second pressure smaller than the first pressure is applied.

  According to the method for producing a glass ceramic multilayer substrate of the present invention, a ceramic multilayer substrate capable of suppressing the shrinkage ratio after firing to 0.17% or less can be produced.

An embodiment of a method for producing a ceramic multilayer substrate according to the present invention will be described in detail with reference to the drawings.
(Embodiment 1)
The example which produces the ceramic multilayer substrate of this invention is shown. 1A to 1I show a process for manufacturing a ceramic multilayer substrate of the present invention. For the sake of simplicity, an example of a three-layer ceramic multilayer substrate is given, but actually an eight-layer ceramic multilayer substrate was fabricated.

Step (a)
The green sheet 1 for producing the ceramic multilayer substrate of each layer is shown. The green sheet 1 is made of glass powder, ceramic powder, an organic binder, an organic solvent, and the like. In this example, SiO2-B2O3-MO system (where M is an alkali metal or an alkali metal earth metal) was used for the glass powder, and Al2O3 was used for the ceramic powder. If a slurry is prepared by mixing the glass powder, ceramic powder, organic binder, organic solvent and the like at an optimum ratio, it can be formed into a sheet by a known doctor blade method or the like. In this example, a green sheet 1 having a thickness of 0.11 mm was produced. These green sheets 1 are formed with through holes for dimension measurement using a laser processing machine, filled with via conductors 3 in all the through holes using a metal screen plate making, and using screen plate making as needed. The wiring conductor 2 is printed using an internal electrode paste obtained by pasting silver, palladium and an organic binder at an optimum mixing ratio.

Step (b)
The green sheets 1 prepared in the step (a) are sequentially laminated on the temporary lamination body-dedicated lamination jig 4. At this time, the PET film 5 is disposed on the uppermost surface and the lowermost surface side of the laminated green sheets 1. This is for the purpose of facilitating separation of the laminated grease sheet 1 and the dedicated laminating jig 4 in the subsequent steps. In this example, the green sheets 1 were thermocompression bonded to these laminates with a processing machine capable of maintaining a pressure of 10 kg / cm ² for a certain time while maintaining a temperature of 65 ° C.

Step (c)
A laminate composed of the green sheet 1 and the PET film 5 was taken out from the dedicated laminating jig 4 to obtain a temporary laminate 6.

Step (d)
The temporary laminate 6 was placed on a laminating jig 7 dedicated to a hydrostatic press, and held at a temperature of 75 ° C. and a pressure of 100 kg / cm ² (referred to as the first pressure of the present invention) for 20 minutes with a hydrostatic press.

Step (e)
The laminated body holding this first pressure for 20 minutes was taken out from the laminating jig 7 and used as the first laminated body 11.

Step (f)
The PET film 5 is removed from the first laminate 11, and the restraint sheet 8 is disposed on the front and back surfaces of the first laminate 11. As the restraint sheet 8, a slurry made of ceramic powder, an organic binder, and an organic solvent was prepared, and a sheet having a thickness of 0.15 mm was used by using a doctor blade method. Furthermore, the PET film 5 was arrange | positioned on the outer side of these restraint sheets. The PET film 5 may be reused from the previously removed PET film. This first laminate 11 was held for 2 minutes at a temperature of 85 ° C. and a pressure of 130 kg / cm ² (referred to as the second pressure of the present invention) in a processing machine capable of applying pressure.

Step (g)
The 1st laminated body 11 was taken out from this processing machine, PET film 5 of the front and back of the 1st laminated body 11 was peeled, and the 2nd laminated body 9 was produced.

Step (h)
In order to thermally decompose the organic binder contained in the second laminate 9, after heating at 600 ° C. for 2 hours in the air with a debinding apparatus, baking is performed at 900 ° C. for 2 hours, and the remaining materials on the front and back surfaces The constraining sheet 8 being removed was removed by wet blasting by projecting high-pressure air in which Al2O3 fine powder and pure water were mixed, to obtain a ceramic multilayer substrate 10.

  The present inventor changed the conditions of the first pressure in the step (d) and the second pressure in the step (f) shown in FIG. We found a phenomenon in which the shrinkage rate of the substrate changes greatly. In order to obtain this relationship, the ceramic multilayer substrate is previously filled with the via conductor 3 in the hole for dimension measurement, the dimension value Y after firing is measured by measuring the dimension of this dimension measurement part, and the shrinkage rate Was calculated. The shrinkage rate is calculated by (Y / X-1) × 100 (%), and is represented by the ratio of the dimension value Y after firing the ceramic multilayer substrate to the dimension value X of the design value. That is, a shrinkage rate of 0% indicates that the fired ceramic multilayer substrate does not shrink at all. If the shrinkage rate is positive, it means that the ceramic substrate after firing becomes larger than before firing, and if it is minus, it means that the ceramic substrate after firing becomes smaller than before firing.

Pressure conditions, when the second pressure was ^{100kg / cm 2, 130kg / cm} 2, 160kg / cm 2, was assumed to change the first pressure to 100~400kg / cm ^2. The temperature when applying the first pressure was 75 ° C., and the temperature when applying the second pressure was 85 ° C. Under these conditions, the shrinkage ratio of the fired ceramic substrate was measured.

FIG. 2 shows the relationship between the first pressure and the second pressure obtained in the experiment and the shrinkage ratio of the ceramic substrate after firing. The horizontal axis represents the first pressure in step (d), and the vertical axis represents the contraction rate. When the first pressure is 100 kg / cm ² and the second pressure is 100 kg / cm ² , the shrinkage rate is −0.14%. That is, it indicates that the fired ceramic substrate is contracted. Next, when the first pressure is 400 kg / cm ² , in the case of / cm ² , the shrinkage rate is 0.02%, and the fired ceramic substrate is expanded. Therefore, there is a first pressure at which the fired ceramic substrate can be made completely non-shrinkable (shrinkage rate 0%). From the results obtained in this experiment, when the second pressure is 100 kg / cm ² , the first pressure is about 370 kg / cm ² . Similarly, when the second pressure is set to 130 and 160 kg / cm ² , the first pressures that can make the fired ceramic substrate completely non-shrinkable (shrinkage rate 0%) are 315 and 270 kg / cm, respectively. ² or so.

  From the above results, before placing the constraining sheet 8 on the front and back surfaces of the first laminate 11, the first pressure is applied to the first laminate 11 in the step (d), and this first pressure is applied to the step. The ceramic substrate after firing can be made completely non-shrinkable (shrinkage rate 0%) by adjusting to a value at which the shrinkage rate becomes 0% according to the second pressure applied in (d). The value of the first pressure at which the shrinkage rate becomes 0% according to the second pressure may be measured in advance.

  Thus, it is possible to produce a ceramic multilayer substrate with a shrinkage rate smaller than the conventional shrinkage rate, and by appropriately adjusting the value of the first pressure, the shrinkage rate of the ceramic substrate after firing is − It can be adjusted within a range of about 0.15 to 0.1.

80 sheets of 18-layer ceramic multilayer substrates for mounting fine pitch IC chips were manufactured using the present invention. At this time, the first pressure was 370 kg / cm ² and the second pressure was 100 kg / cm ² . At this time, the temperature and pressure were applied under the same conditions as those shown in FIG. The shrinkage ratio after firing of the produced 18-layer ceramic multilayer substrate was in the range of -0.01% to + 0.02%. There was no dimensional deviation of the IC chip to be mounted in the subsequent process, and very good component mounting could be performed.

  The method for producing a glass-ceramic multilayer substrate according to the present invention has the effect of producing a glass-ceramic multilayer substrate that does not substantially shrink by reducing the shrinkage rate of the glass-ceramic multilayer substrate by orders of magnitude, and that requires positional accuracy. Useful for ceramic multilayer substrates.

The figure of the manufacturing method of the glass ceramic multilayer substrate which implemented this invention The figure which shows the relationship of the shrinkage rate obtained from the relationship between the 1st pressure and the 2nd pressure in Embodiment 1 of this invention Diagram of conventional glass ceramic multilayer substrate manufacturing method

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Green sheet 2 Wiring conductor 3 Via conductor 4 Dedicated lamination jig for preparation of temporary laminated body 5 PET film 6 Temporary laminated body 7 Lamination jig only for hydrostatic pressure press
8 Constraint Sheet 9 Second Laminated Body with Constraint Sheet for Firing 10 Substrate after Constraint Sheet is Removed After Firing 11 First Laminated Body 12 Constraint Sheet 13 Constraint Sheet 14 Outermost Layer Conductor Wiring

Claims (8)

In a method for producing a ceramic multilayer substrate in which a plurality of green sheets are laminated to produce a ceramic multilayer substrate,
A first laminate production step of producing a temporary laminate by applying a first pressure by laminating the plurality of green sheets;
A pressure release step of releasing the temporary laminate from the first pressure after the first laminate production step;
After the said pressure release process, the manufacturing method of the ceramic multilayer substrate which consists of the 2nd laminated body preparation process which applies the 2nd pressure smaller than the said 1st pressure to the said temporary laminated body. The method for manufacturing a ceramic multilayer substrate according to claim 1, wherein the green sheet is a glass ceramic green sheet. 2. The method for manufacturing a ceramic multilayer substrate according to claim 1, wherein, in the first laminate manufacturing step, the time for applying the first pressure is about 20 minutes. 2. The method for manufacturing a ceramic multilayer substrate according to claim 1, wherein in the first laminate manufacturing step, a temperature when the first pressure is applied is about 75 degrees. The method for producing a ceramic multilayer substrate according to claim 1, wherein in the first laminate manufacturing step, the first pressure is applied using an isostatic press. 2. The method for manufacturing a ceramic multilayer substrate according to claim 1, wherein, in the second laminate manufacturing step, the temperature when the second pressure is applied is about 85 degrees. 2. The method for manufacturing a ceramic multilayer substrate according to claim 1, wherein, in the second laminate manufacturing step, the time for applying the second pressure is about 2 minutes. In the second laminate manufacturing step, the second pressure is applied after laminating a constraining sheet for suppressing thermal shrinkage during firing of the temporary laminate on both surfaces of the temporary laminate. The manufacturing method of the ceramic multilayer substrate of description.

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