JP2005136044A - Manufacturing method of glass ceramic substrate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a glass ceramic substrate for laminating a restraining sheet, made of an inorganic composition which is not sintered at the baking temperature of the ceramic substrate on at least one of surfaces of a green sheet laminate for baking, for obtaining the glass ceramic substrate suppressing dimensional variations within the substrate, even when baking in a continuous furnace and having high dimensional accuracy. <P>SOLUTION: The restraining sheet 7 on front and rear faces of the laminate 4 has a thin part, and is structured so that the width w2 of the thin part 7a, with respect to the width w1 vertical to the progress direction of the movable belt of the sheet 7, gradually increases with respect to the progress direction of the belt. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for manufacturing a glass ceramic substrate, and more particularly to a manufacturing method for forming a multilayer wiring substrate, a package for housing a semiconductor element, and the like with high dimensional accuracy.

  In recent years, in a wiring board applied to a package for housing a semiconductor element in which semiconductor elements such as IC and LSI, which have been highly integrated, are mounted, and a hybrid integrated circuit device in which various electronic components are mounted, the density and There is a demand for resistance and reduction in size and weight, and a low dielectric constant is obtained compared to alumina-based ceramic materials, and a low-resistance metal such as Cu can be used as a wiring circuit layer. The so-called glass-ceramic wiring board has attracted more attention.

  In addition, as the density of wiring boards increases, the demand for higher dimensional accuracy is also increasing. Since glass ceramics can be fired at a temperature lower than that of an alumina-based ceramic material or the like, for example, a firing method as described in Patent Document 1 has been proposed.

In the firing method disclosed in Patent Document 1, when firing a laminate formed by laminating a plurality of green sheets containing inorganic components such as glass powder and ceramic filler together with an electrode pattern, the firing temperature of this laminate is A sheet made of an inorganic composition that is not sintered is laminated on both sides of the laminate and subjected to a firing treatment. With such a sheet, the laminate can be sintered with almost no shrinkage in the plane direction. Higher dimensional accuracy can be obtained.
Japanese Patent Publication No. 8-25554415

  However, when the above-described method is applied to a continuous furnace, the firing shrinkage rate of the laminated body placed on the movable belt is changed from the entrance side to the exit side of the movable belt into the furnace, that is, the traveling direction of the movable belt. On the other hand, there is a problem that the shrinkage gradually decreases from the rear end side to the front end side, and as a result, the variation in the shrinkage rate in the substrate increases.

  Therefore, the present invention relates to a method for producing a multilayer ceramic substrate in which a constraining sheet made of an inorganic composition that does not sinter at the firing temperature of the ceramic substrate is laminated on at least one surface of the green sheet laminate and fired. An object of the present invention is to provide a method for manufacturing a ceramic wiring board for suppressing a dimensional variation in a substrate even when firing and obtaining a ceramic substrate having high dimensional accuracy.

  In the method for producing a glass ceramic substrate of the present invention, the glass ceramic is fired on a laminate in which an electrode pattern and an interlayer connection via are formed on a green sheet containing at least an inorganic component, and a desired number of green sheets are similarly laminated. After laminating sheets made of an inorganic composition that does not sinter at the temperature on the front and back surfaces of the laminate, the laminate is placed on a movable belt and fired by passing through a region heated to a desired temperature, Thereafter, in the method for producing a glass ceramic substrate, the sheet is removed, and the sheet provided on the front and back surfaces has a thin portion, and the direction of the thin portion is perpendicular to the moving direction of the movable belt. The width of is gradually increased with respect to the traveling direction of the movable belt.

  And in the manufacturing method of the said glass ceramic substrate, that the thin part is the same shape in the front and back of a laminated body, the ratio of a thin part is 10 to 60% by the area ratio of planar view, inorganic in a sheet | seat When the composition contains glass powder, the content is 1 to 15% by volume of the inorganic component in the green sheet, the maximum thickness of the sheet is t1, and the thickness of the laminate is t2. Therefore, it is desirable to satisfy the relationship of t1 / t2 ≧ 0.1.

The inorganic composition constituting the sheet mainly contains at least one of Al ₂ O ₃ , SiO ₂ , MgO, ZrO ₂ , TiO ₂ , MgAl ₂ O ₃ , ZnAl ₂ O ₄ , and Mg ₂ SiO _4. In particular, the electrode pattern is preferably made of a sintered metal or a metal foil containing at least one of Au, Ag, Cu, Pd, and Pt.

  In the present invention, the sheet made of the inorganic composition laminated on the front and back surfaces of the laminate made of the green sheet has a thin part, and the width with respect to the width in the direction perpendicular to the traveling direction of the movable belt. By forming the width of the thin portion so as to be gradually increased with respect to the moving direction of the movable belt, the substrate is moved backward with respect to the moving direction of the movable belt when firing in a continuous furnace having the movable belt. Even if it shrinks gradually from the end side to the front end side, it is possible to suppress a dimensional variation in the substrate and obtain a ceramic wiring board having high dimensional accuracy.

  Hereinafter, the glass ceramic substrate of the present invention will be described with reference to the drawings. FIG. 1 is an example of a schematic sectional view of a sheet made of an inorganic composition that does not sinter at the firing temperature of the glass ceramic substrate of the present invention and the glass ceramic.

  According to FIG. 1, the glass ceramic substrate as described above includes (a) a step of obtaining a green sheet made of a glass ceramic composition such as an inorganic component, and (b) punching the green sheet to form a via hole. A step of filling a via hole with a conductive paste, a step (c) a step of forming a wiring circuit layer on the surface of the green sheet by a screen printing method, and the steps of (a) to (c). And (d) producing a laminated body made of a glass ceramic composition, and (e) laminating a first sheet made of an inorganic composition that is not sintered at the firing temperature of the glass ceramic on both surfaces of the laminated body. And (f) partially removing the first sheet to produce the second sheet having a cut portion, and stacking the second sheet so as to cover the first sheet of the laminate. A step of obtaining a composite laminate, a step (g) of firing the composite laminate produced through the steps (a) to (f) at a temperature equal to or lower than the melting point of the metal conductor constituting the wiring circuit layer; h) It is manufactured through a step of removing the sheet from the composite laminate. Hereinafter, each process will be described in detail.

(A) In the step of obtaining a green sheet comprising a glass ceramic composition, a predetermined amount of glass powder and ceramic filler powder are weighed as raw material powders, and further an organic binder, plasticizer, organic solvent, etc. are added to prepare a slurry, A green sheet 1 forming a ceramic wiring board having a thickness of 50 to 500 μm is formed by forming into a sheet shape by a known forming method such as a doctor blade method, a rolling method, or a pressing method. As a glass component to be used, it contains at least SiO ₂ and contains at least one of Al ₂ O ₃ , B ₂ O ₃ , ZnO, PbO, alkaline earth metal oxide, and alkali metal oxide. For example, borosilicate such as SiO ₂ —B ₂ O ₃ system, SiO ₂ —B ₂ O ₃ —Al ₂ O ₃ system—MO system (wherein M represents Ca, Sr, Mg, Ba or Zn). Acid glass, alkali silicate glass, Ba glass, Pb glass, Bi glass, and the like can be given. These glasses are also amorphous glass by firing, and by firing, lithium silicate, quartz, cristobalite, cordierite, mullite, ananosite, serdian, spinel, garnite, willemite, What precipitates at least one kind of crystals of dolomite, petalite, diopside and substituted derivatives thereof is used.

As the ceramic filler, SiO ₂ such as quartz and cristobalite, Al ₂ O ₃ , ZrO ₂ , cordierite, mullite, forsterite, enstatite, spinel, magnesia and the like are preferably used.

  (B) In the process of drilling a green sheet, forming a via hole, and filling the via hole with a conductive paste, the diameter of the green sheet 1 obtained in (a) is increased by laser, micro drill, punching, or the like. A through hole of 30 to 300 μm is formed, and a via conductor paste is filled therein to form the via hole conductor 2. The conductive paste for vias is obtained by uniformly mixing an organic binder such as acrylic resin and an organic solvent such as terpineol or dibutyl phthalate into a metal powder mainly composed of at least one of Au, Cu, Ag, Pd, and Pt. Formed. The organic binder is mixed in an amount of 0.5 to 15.0% by mass with respect to 100% by mass of the metal component, and the organic solvent is mixed in a proportion of 5 to 100% by mass with respect to 100% by mass of the solid component and the organic binder. It is desirable. Note that a slight amount of ceramic filler or glass component may be added to the via conductor paste.

  (C) In the step of forming a wiring circuit layer on the surface of the green sheet by a screen printing method or the like, a wiring pattern 3 is formed on the surface of the green sheet 1 on which the via-hole conductor 2 is formed by a screen printing method. Alternatively, the electrode pattern 3 is formed by transferring a metal foil. The conductor paste for the electrode pattern 3 is produced by the same method as that for the via conductor paste, and is produced by changing components and blending ratios as necessary. On the other hand, as a method for forming the electrode pattern 3 by a transfer method using a metal foil, first, a metal foil is bonded onto a transfer film made of a polymer material or the like, and then a mirror image resist is applied to the surface of the metal foil on the circuit pattern. After coating, the etching process and the resist removal are performed to form a mirror image wiring circuit, and the transfer film on which the mirror image wiring circuit is formed is aligned with the surface of the green sheet 1 on which the via-hole conductor 2 is formed and laminated. After the pressure bonding, the green film 1 including the electrode pattern 3 connected to the via-hole conductor 2 is formed by peeling off the transfer film. It should be noted that the electrode pattern 3 formed by the printing method and the transfer method may be either one or both.

  (D) In the step of laminating the green sheets 1 on which the electrode patterns 3 are formed to produce a laminate, the laminate 4 is formed by laminating and pressing a plurality of green sheets 1 obtained in the same manner. For the lamination of the green sheets 1, a method of applying heat and pressure to the stacked green sheets 1 and thermocompression bonding, a method of applying an adhesive composed of an organic binder, a plasticizer, a solvent, etc. between the sheets, and thermocompression bonding, etc. Can be adopted.

  (E) In the step of laminating sheets made of an inorganic composition on both sides of the laminate 4, it is also possible to form two sheets on the front and back surfaces of the laminate as sheets having thin portions. That is, first, as shown below, the first sheet 5 made of an inorganic composition that does not sinter at the firing temperature of the glass ceramic is pressure-laminated on both surfaces of the laminate 4 to produce a composite laminate 6.

The first sheet 5 is mainly composed of at least one of Al ₂ O ₃ , SiO ₂ , MgO, ZrO ₂ , TiO ₂ , MgAl ₂ O ₄ , ZnAl ₂ O ₄ , and Mg ₂ SiO ₄ as an inorganic composition. The raw material powder having a particle size of 0.5 to 5 μm is 80 to 99.5% by mass, particularly 90 to 97% by mass, 450 to 950 ° C., particularly 1 to 15% by mass of glass powder having a softening point at 650 to 900 ° C. It is preferably 3 to 10% by mass and the powder filling rate as a green sheet is preferably 53 to 60%. Here, it is desirable that the sheet 5 contains a glass component, in other words, an amorphous component in an amount of 1 to 15% by mass, particularly 3 to 10% by mass.

  Moreover, as a glass component contained in the 1st sheet | seat 5, it is desirable that a softening point is below the calcination temperature of the laminated body 4, and is higher than the decomposition volatilization temperature of the organic component of the 1st sheet | seat 5. FIG. Specifically, the softening point of the glass of the first sheet 5 is preferably 450 to 950 ° C, particularly preferably 650 to 900 ° C. When the softening point of the glass is lower than 450 ° C., the glass softened during the removal of the organic component from the laminate 4 may block the organic component removal path, and the organic component may not be completely removed. On the other hand, when the glass softening point exceeds 950 ° C., it does not act as a binder to the green sheet 1 under the normal firing conditions of the laminate 4. The glass may be different from the glass component contained in the green sheet 1 described above, but it is desirable to use the same glass in order to prevent the diffusion of the glass of the laminate 4.

  The process of obtaining the 1st sheet | seat 5 is produced by the doctor blade method etc., after preparing a slurry similarly to the process of producing the green sheet 1. FIG. The second sheet 7 laminated on the upper and lower surface sides of the first sheet 5 is also produced in the same manner as the first sheet 5.

  (F) Next, a desired region of the first sheet 5 produced in (e) is cut to produce a second sheet 7 having a thin portion as shown in FIG. 2 (a).

  The second sheet 7 has, for example, a thin portion 7a having the same shape on both the upper and lower sides of the laminate, and the width of the thin portion 7a with respect to the width w1 of the second sheet 7 in the direction perpendicular to the traveling direction of the movable belt. It is important that the ratio of w2 is gradually increased with respect to the moving direction of the movable belt, and the shape of the thin portion 7a is a triangle or a trapezoid whose bottom is the moving direction of the movable belt. Things are desirable. Further, the inner side of the thin portion 7a may be curved as shown in FIG. 2B, or may be formed in a stepwise manner as long as the effects of the present invention are exhibited. The removal rate, which is the ratio of the thin-walled portion 7a, is suitably 10 to 60%, particularly 20 to 50%, with respect to the entire area of the second sheet 7, taking into consideration the rate of change of the shrinkage rate generated in the continuous furnace. It is desirable to select the optimum value.

  Here, the total thickness of the first and second sheets 5 and 7 laminated on the laminated body 4 is only on one side, and is 10% or more of the thickness of the laminated body 4, and optimally 25% or more. desirable. Specifically, if the volatilization of organic components is facilitated and the removability of the first and second sheets 5 and 7 from the glass ceramic substrate 9 is considered, the total thickness of the first and second sheets 5 and 7 is considered. Is preferably 800 μm or less, and most preferably 600 μm or less. Next, the composite laminate 8 is placed on a movable belt and subjected to a firing process by passing through a region heated to a desired temperature, and then the first and second sheets 5 and 7 are removed.

  When firing in a continuous furnace, the timing of shrinkage is shifted due to the temperature distribution in the traveling direction of the movable belt, and the firing shrinkage rate of the laminate placed on the movable belt is the furnace of this movable belt. From the entrance side to the exit side, that is, from the rear end side to the front end side with respect to the moving direction of the movable belt, the shrinkage gradually decreases, and as a result, the shrinkage rate in the substrate is reduced. However, according to the present invention, the restraint force can be adjusted by using the second sheet 7, and the in-plane firing shrinkage variation is ± 0. It becomes possible to keep it below 05%.

  (G) In the step of firing the prepared composite laminate 8 at a temperature not higher than the melting point of the metal conductor, the composite laminate 8 is heat-treated at 100 to 800 ° C., particularly 400 to 750 ° C. The organic components are decomposed and removed, and then co-fired at 800 to 1000 ° C. At this time, when the wiring pattern 3 and the via-hole conductor 2 are mainly composed of Cu, the wiring pattern 3 and the via-hole conductor 2 must be fired in a nitrogen atmosphere, and when Au, Ag, Pd, and Pt are mainly composed, the firing atmosphere is Can be done in the atmosphere. Further, if the cooling rate after firing is too fast, cracks due to the difference in thermal expansion between the glass ceramic substrate 9 and the wiring pattern 3, the first and second sheets 5 and 7 occur, so the cooling rate is 400 ° C./hr or less. It is desirable that Further, a load may be applied by placing a weight on the upper surface of the composite laminate 8 in order to prevent warping during firing. The load is suitably 25 Pa to 1 MPa, particularly 50 to 500 Pa.

  (H) In the step of removing the first and second sheets 5 and 7 from the composite laminate 8, the glass ceramic substrate 9 is used by a method such as ultrasonic cleaning, polishing, water jet, chemical blasting, sand blasting, wet blasting or the like. The first and second sheets 5 and 7 are removed.

  Since the glass ceramic substrate 9 obtained in this manner has shrinkage during firing suppressed only in the thickness direction by the first and second sheets 5 and 7, the in-plane shrinkage of the laminate 4 is 0.5% or less. In addition, since the laminate 4 is uniformly and reliably bonded to the entire surface by the first sheet 5, it is possible to prevent warping or deformation due to partial peeling of the first sheet 5. be able to.

  Moreover, it becomes possible to adjust a restraint force locally by using the 2nd sheet | seat 7 from which the desired area | region was removed. Thus, when firing in a continuous furnace, the firing shrinkage rate of the laminated body placed on the movable belt is from the entrance side to the exit side of the movable belt into the furnace, that is, the traveling direction of the movable belt. On the other hand, the phenomenon of shrinking gradually from the rear end side to the front end side can be prevented, and the in-plane firing shrinkage variation can be suppressed to ± 0.05% or less. Thereby, the glass-ceramic board | substrate 9 which has high dimensional accuracy can be provided.

The glass ceramic wiring board of the present invention was evaluated based on the examples. First, 60% by mass of a crystallized glass powder having a composition of SiO ₂ : 50% by mass, MgO: 18.5% by mass, CaO: 26% by mass, and Al ₂ O ₃ : 5.5% by mass, and a ceramic filler component As a result, 40% by mass of Al ₂ O ₃ was weighed to prepare a glass ceramic composition. Using a slurry prepared by adding an acrylic resin as an organic binder, DBP (dibutyl phthalate) as a plasticizer, and toluene and isopropyl alcohol as a solvent, a 200 μm thick grease is formed by a doctor blade method. A sheet was prepared.

  Next, 12% by mass of glass powder was weighed with respect to 100% by mass of Cu powder, and acrylic resin as an organic binder and DBP as a solvent were added and kneaded to prepare a via hole conductor paste sample. The amount of the organic binder in the via hole paste sample was 12% by mass with respect to the Cu powder, and the solvent was added at a ratio of 36% by mass with respect to the solid component and the organic binder. This Cu paste was filled in via holes formed at predetermined locations on the green sheet.

  Further, 0.2% by mass of alumina powder and 1% by mass of glass powder are weighed with respect to 100% by mass of Cu powder, and acrylic resin as an organic binder and DBP as a solvent are added and kneaded, and a Cu paste sample for pattern Was made. The amount of the organic binder was 15% by mass with respect to the main component, and the solvent was added at a rate of 13% by mass with respect to the solid component and the organic binder. A predetermined electrode pattern was formed by screen printing on a green sheet in which the obtained Cu paste was filled with the previous via-hole conductor paste. The printed thickness of the electrode pattern at this time was 10 to 30 μm. Thereafter, five green sheets each having a desired electrode pattern were laminated and pressure laminated under the conditions of 45 ° C. and 4 MPa to produce a laminate.

Next, as a restraining sheet for laminating on the front and back surfaces of this laminate, a composition shown in Table 1 is used with Al ₂ O ₃ having an average particle diameter of 3 μm and the same glass as the glass component in the green sheet. The sheet | seat used as a 1st sheet | seat with a thickness of 250 micrometers which consists of a thing was produced. The organic binder, plasticizer, solvent, and the like at the time of sheet preparation were the same as those for the green sheet. Half of the obtained sheets were removed as shown in Table 2 and used as the second sheet.

  Next, the first sheet is pressed and laminated at 45 ° C. and 5 MPa on both sides of the laminate, and then a part of the second sheet is removed on both sides to form a thin-walled portion as shown in FIG. Was laminated under pressure at 45 ° C. and 5 MPa to obtain a composite laminate.

Subsequently, the composite laminate was fired using a continuous furnace. First, the composite laminate is placed on a base plate made of Al ₂ O ₃ , fired at 750 ° C. in a nitrogen atmosphere in order to decompose and remove organic components such as an organic binder, and then 900 in a nitrogen atmosphere. Firing was carried out at 1 ° C. for 1 hour. Thereafter, the fired first and second sheets were removed by blasting to produce a glass ceramic wiring board.

Ten samples were prepared under the conditions shown in Table 2, and dimensional tolerances were evaluated using a three-dimensional measuring machine. That is, as shown in FIG. 3, dimensional variation after firing (6σ (σ: σ: 3) in three measurement points x1 to x3 in the direction perpendicular to the moving direction (in the direction of the arrow) of the movable belt of the continuous firing furnace. Standard deviation)). As a comparative example, a sample fired using a second sheet having no cut portion was produced and evaluated in the same manner as in the present invention.

  As is apparent from Table 2, in accordance with the present invention, Sample No. 1 was obtained by sequentially laminating and firing the first sheet and the second sheet from which the part was removed. In 2-9 and 11-13, a wiring board with high dimensional accuracy with a dimensional tolerance of ± 0.05% or less could be manufactured. In particular, the sample No. 2 in which the removal rate of the second sheet was 10 to 60%. In 3-9 and 11-13, the dimensional tolerance was ± 0.05% or less. On the other hand, sample No. using a sheet in which no region to be removed was provided. 1 exceeded ± 0.05%.

It is the schematic for demonstrating the multilayer wiring board of this invention. It is the schematic for demonstrating a 2nd sheet | seat. It is the schematic for demonstrating the measurement location of a sample.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Green sheet 2 Via-hole conductor 3 Wiring pattern 4 Laminated body 5 1st sheet | seat 6, 8 Composite laminated body 7 2nd sheet | seat 7a Thin part 9 Glass ceramic substrate

Claims (7)

A sheet made of an inorganic composition that does not sinter at the firing temperature of the glass ceramic on a laminate in which an electrode pattern and an interlayer connection via are formed on a green sheet containing at least an inorganic component, and a desired number of green sheets are similarly laminated. Is laminated on the front and back surfaces of the laminate, and then the laminate is placed on a movable belt, fired by passing through a region heated to a desired temperature, and then the sheet is removed. In the method for manufacturing a ceramic substrate, the sheet provided on the front and back surfaces has a thin portion, and a width of the thin portion in a direction perpendicular to the moving direction of the movable belt is set in the moving direction of the movable belt. A method for producing a glass ceramic substrate, characterized in that the glass ceramic substrate is gradually enlarged. The method for producing a glass ceramic substrate according to claim 1, wherein the thin-walled portions have the same shape on the front and back surfaces of the laminate. The method for producing a glass ceramic substrate according to claim 1 or 2, wherein the ratio of the thin-walled portion is 10 to 60% in an area ratio in plan view. The glass ceramic substrate according to any one of claims 1 to 3, wherein glass powder is contained as an inorganic composition in the sheet, and the content thereof is 1 to 15% by volume of the inorganic component in the green sheet. Manufacturing method. 5. The structure according to claim 1, wherein the relationship of t1 / t2 ≧ 0.1 is satisfied on one side when the maximum thickness of the sheet is t1 and the thickness of the laminate is t2. Method for producing a glass ceramic substrate. The inorganic composition mainly contains at least one of Al ₂ O ₃ , SiO ₂ , MgO, ZrO ₂ , TiO ₂ , MgAl ₂ O ₃ , ZnAl ₂ O ₄ , and Mg ₂ SiO _4. Item 6. The method for producing a glass ceramic substrate according to any one of Items 1 to 5. 7. The glass ceramic substrate according to claim 1, wherein the electrode pattern is made of a metal sintered body or metal foil containing at least one of Au, Ag, Cu, Pd, and Pt. Method.

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