JP2001072473A - Production of ceramic substrate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a ceramic substrate, by which mechanical strength of an insulator part after sintering is increased. SOLUTION: Insulator paste is printed onto a glass ceramic green sheet 1a which becomes a surface layer to form an insulator part 2 and green sheets are laminated thereon and Al2O3 green sheets 5 and 6 are arranged on upper and lower both faces of the green sheet laminate 1 and the laminate is burned while applying pressure to upper and lower faces of the green sheet laminate 1. As a result, space in the interior of the insulator part produced by influence of colored pigment is dispersed in minute size. Thereby, sintered film of the insulator part is compacted to increase mechanical strength. Therefore, it is made possible to apply treatment on which mechanical load such as shot blasting acts as cleaning for glass ceramic multilayer substrate after sintering and a step in post processing and freedom of selection in production step is increased and restriction for designing process of glass ceramic multilayer substrate is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for manufacturing a ceramic substrate, and more particularly to a method for manufacturing a ceramic substrate used as a ceramic package for electronics and a circuit board.

[0002]

2. Description of the Related Art In a semiconductor device, an IC chip or an LS
2. Description of the Related Art A semiconductor element such as an I-chip is mounted on a semiconductor element mounting portion provided on a substrate and put to practical use. Ceramics such as alumina are suitable as a material for this substrate because they have excellent heat resistance, durability, thermal conductivity, and the like, and ceramic semiconductor substrates are currently being used actively.

[0003] However, the alumina substrate has a relatively large relative dielectric constant, causing transmission signal delay, and has a larger coefficient of thermal expansion than silicon, so that reliability against temperature changes when components are mounted is ensured. There was a problem that it was difficult to do. Furthermore, since the firing temperature of alumina is as high as about 1600 ° C., it is necessary to use W or Mo having a high melting point and a large electric resistivity as the wiring of the inner layer. There was a problem of becoming larger.

For this reason, low-temperature fired ceramic substrates that can be fired simultaneously with low-resistance wiring materials such as Ag and Cu have been developed. Among them, the relative dielectric constant is relatively small, so that the transmission loss is small. In addition, since the thermal expansion coefficient is close to that of silicon, a glass ceramic substrate containing glass that can be mounted by a flip-chip method has been attracting attention. Glass materials used for this glass ceramic substrate include borosilicate glass, MgO-Al ₂ O ₃ -Si
O ₂ -based glass, CaO—Al ₂ O ₃ —SiO ₂ -based glass and the like can be mentioned. Usually, a glass ceramic substrate is manufactured using a raw material obtained by adding an aggregate to these glass powders.

In order to reduce the size of the glass ceramic substrate, improve the mounting density on the mounting board, and further improve the electrical characteristics, generally, a plurality of glass ceramic green sheets are laminated and fired. As a result, a glass ceramic multilayer substrate is manufactured.

[0006]

In general, a white ceramic substrate is used. In particular, the above-mentioned glass ceramic substrate is usually white, and one or both of its front and rear surfaces are made of Ag or Au. A relatively white conductor of the system is formed as a wiring pattern or a recognition mark for alignment in a production line. On the other hand, in recent years, as the speed of LSIs and the like has increased and the density has increased, the bonding method between the LSI and the like mounted on a ceramic substrate and the wiring formed on the ceramic substrate has been changed from a conventional wire bonding method to a multi-chip method. TAB (Tape Automated Bondin) suitable for high-density mounting
g) The method or flip-chip method is being adopted. For this reason, a demand for a ceramic substrate requires not only the physical properties of the substrate itself, but also a precise control technology for the dimensions and shape of the substrate so that the substrate can be mounted at a high density. Therefore, the importance of the inspection process of the ceramic substrate is increasing, and the difficulty is increasing.

[0007] The wiring pattern formed on the front and back surfaces of the ceramic substrate is visually inspected for its shape and the presence or absence of disconnection, and it is inspected that positioning by a CCD camera and automatic optical inspection can be used for the inspection. Desirable in improving accuracy. However, when the ceramic substrate and the wiring pattern are both white or a light color close to white as described above, the contrast between the two is weak, and the recognition mark for alignment cannot be identified, or the appearance inspection is difficult. I do. In particular, there is a problem that it is difficult to automatically check using an automatic inspection machine because pattern recognition by a CCD camera is not sufficient.

Therefore, by forming an insulator portion on one or both of the front surface and the back surface of the ceramic substrate using an insulating paste to which a transition metal such as Co is added, for example, a ceramic substrate of white or nearly white color is formed. Against
Even when a white conductor having a low contrast is used, the inspection of the wiring pattern is easy and the optical automatic inspection becomes possible. However, when a ceramic substrate is fired using an insulator paste to which a transition metal is added, the film quality of the insulator after sintering becomes porous due to the addition of the transition metal, and the mechanical strength is reduced. there were. For this reason, it is difficult to apply a process in which a mechanical load such as a shot blast is applied as a process for cleaning or post-processing the ceramic substrate, and the degree of freedom in the selection of the manufacturing process is low. There was a problem that the design was limited.

The present invention has been made to solve such a problem, and has as its object to provide a method of manufacturing a ceramic substrate in which the mechanical strength of an insulator portion after sintering is increased.

[0010]

According to the method of manufacturing a ceramic substrate according to the first aspect of the present invention, an insulating paste containing a ceramic raw material powder as a main component and a coloring pigment is added to one side of a ceramic molded body. Apply on both sides,
Sintering is performed while applying pressure to the upper and lower surfaces of the ceramic molded body to which the insulating paste is applied.

As the coloring pigment used in the present invention, a substance which can be colored in as small an amount as possible in order to prevent deterioration of electric characteristics is selected. The material is not limited as long as it has good compatibility with the ceramic substrate and the conductor material for wiring and has a strong contrast with a white or nearly white conductor.
For example, transition metals such as Co, Mn, Fe, and Ru, and oxides thereof are suitable. The color pigment is preferably used in an amount of 0.1 to 10 parts by weight based on the ceramic raw material powder. 0.1
If the amount is less than 10 parts by weight, the insulation resistance is deteriorated.

The ceramic compact of the present invention is not particularly limited. For example, glass ceramics fired at a low temperature are particularly preferable, but alumina and various ceramic materials containing alumina as a main component can also be used. As the glass ceramics fired at a low temperature, for example, glass ceramics that can be fired at 800 to 1000 ° C. are suitably used. In _{particular, CaO-Al 2 O 3 -SiO} 2
—B ₂ O ₃ system, CaO—Al ₂ O ₃ —SiO ₂ system, MgO—
Al ₂ O ₃ —SiO ₂ —B ₂ O ₃ system and CaO—MgO—
One having a composition in which 40 to 70 parts by weight of a glass component selected from the group consisting of Al ₂ O ₃ —SiO ₂ —B ₂ O ₃ and the remainder being alumina is preferred for the present invention.

[0013] The ceramic molded body is not particularly limited in structure, form and manufacturing method. It may be a single layer or a multilayer. Examples of a method for producing a multilayer ceramic molded body include a thick film multilayer printing method and a green sheet multilayer laminating method.

As a method of applying the insulating paste containing the coloring pigment to one or both surfaces of the ceramic molded body, a printing method such as screen printing is suitable. The insulator paste may be applied to only one side of the ceramic molded body, or the insulator paste may be applied to both sides of the ceramic molded body.

By firing while applying pressure to the upper and lower surfaces of the ceramic molded body to which the insulating paste is applied,
Voids inside the insulator portion generated by the influence of the coloring pigment are dispersed in a minute size. As a result, the quality of the sintered film of the insulator portion becomes dense, and the mechanical strength is increased. Therefore,
As a process for cleaning and post-processing of the ceramic substrate, it is possible to apply a process in which a mechanical load such as shot blasting is applied, thereby increasing a degree of freedom in selecting a manufacturing process, and limiting a process design of the ceramic substrate. Reduced.

On the insulator part after sintering, Au, Ag, A
A conductor material such as g-Pd is formed as a wiring pattern by printing such as screen printing or plating. In the inspection of the wiring pattern, after positioning with the recognition mark by the CCD camera, the contrast between the dark color of the substrate surface and the white or near-white color of the wiring pattern is distinguished by an image processing method, and the presence or absence of defects as products is determined. to decide. This operation can be performed automatically, and all the wiring patterns on the substrate can be inspected in a short time.

According to the method for manufacturing a ceramic substrate according to the second aspect of the present invention, the ceramic raw material powder is CaO-A
l ₂ O ₃ —SiO ₂ —B ₂ O ₃ system, CaO—Al ₂ O ₃ —Si
O ₂ system, MgO—Al ₂ O ₃ —SiO ₂ —B ₂ O ₃ system and C
_{aO-MgO-Al 2 O 3} -SiO 2 -B 2 O 3 glass component 40 to 70 parts by weight of one selected from the system and the remainder has a composition is alumina. Therefore, when glass ceramics fired at a low temperature is used as the ceramic molded body, it is possible to prevent the ceramic molded body from being warped during firing. Therefore, a ceramic substrate with good dimensional accuracy can be manufactured, and the number of manufacturing steps can be reduced to improve productivity.

According to the method of manufacturing a ceramic substrate according to the third aspect of the present invention, before the firing step, the inorganic molded body having a higher sintering temperature than the ceramic raw material powder is formed on both upper and lower surfaces of the ceramic molded body coated with the insulating paste. Since a molded body mainly containing components is arranged, a sintered body with good dimensional accuracy, which hardly shrinks in the plane direction of the ceramic molded body, can be obtained.

The inorganic component which does not sinter at the sintering temperature of the ceramic raw material powder disposed on the upper and lower surfaces of the ceramic compact (hereinafter referred to as "the inorganic component which does not sinter at the sintering temperature of the ceramic raw material powder") ), A green sheet of a non-sinterable inorganic component can be prepared by, for example, a normal doctor blade method. The green sheet is composed of a powder of a non-sinterable inorganic component, an organic solvent, a plasticizer, a binder, and the like.

As the non-sinterable inorganic component, for example, Al ₂
O ₃ , AlN, MgO, ZrO ₂ , TiO ₂ , BeO, B
N, include 3Al ₂ O ₃ 2SiO ₂ and the like. Examples of the organic solvent include toluene, xylene, and alcohols, and examples of the plasticizer include dibutyl phthalate and dioxyl phthalate. Examples of the binder include an acrylic resin and a butyral resin. The mixing ratio of these is based on the powder 1 of the non-sinterable inorganic component.
The organic solvent is preferably 20 to 80 parts by weight, the plasticizer is 1 to 5 parts by weight, and the binder is 5 to 20 parts by weight based on 00 parts by weight.

After firing, the hardly sinterable inorganic powder on the surface of the ceramic molded body can be easily removed by, for example, a general shot blast treatment using a fine glass powder.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 to 4 and 5 show an embodiment in which the present invention is applied to a method for manufacturing a glass ceramic multilayer substrate using CaO—Al ₂ O ₃ —SiO ₂ based glass.
This will be described with reference to FIG.

First, a method for producing a green sheet laminate of glass ceramics will be described. Here, the raw material powder of the glass ceramic is CaO—Al ₂ O ₃ —SiO ₂
Glass powder 60 wt% of -B ₂ O ₃ system and the Al ₂ O ₃ powder 40
wt.%, and has a mean particle size of about 3.5 μm.

(1) A plasticizer of dioxyl phthalate, a binder of an acrylic resin, and a solvent such as toluene, xylene and alcohol are added to a glass ceramic powder, and the mixture is sufficiently kneaded to obtain a slurry having a viscosity of 2000 to 40000 cps. Was prepared, and 0.3 was obtained by the doctor blade method.
Three glass ceramic green sheets having a thickness of mm are formed.

(2) A powder containing the same ceramic raw material powder as the glass ceramic green sheet produced in the above (1) as a main component and 0.3 parts by weight of CoO as a coloring pigment added thereto is mixed with ethyl cellulose and α. -Paste with three rolls using terpineol to produce an insulator paste. Then, as shown in FIG. 2, the above-mentioned insulator paste is applied by a screen printing method on the glass ceramic green sheet 1a to be the surface layer so as to have a thickness of about 25 μm, thereby forming the insulator portion 2.

(3) The glass ceramic green sheet is processed into a desired shape by using a punching die, a punching machine, or the like.
Are formed by punching, and each via hole is filled with an Ag-based conductor material. Ag or Ag- for internal wiring is provided on the front or back surface of the glass ceramic green sheet.
Conductive paste such as Pd, Ag-Pt, Ag-Pd-Pt, and Cu is screen-printed.

(4) A glass ceramic green sheet laminate obtained by laminating the respective glass ceramic green sheets so that the glass ceramic green sheets 1a shown in FIG.
/ Cm ² and integrated by thermocompression bonding.

By the above steps (1) to (4), the glass ceramic green sheet laminate 1 shown in FIG. 3 is obtained. In FIG. 3, a green sheet laminate 1 is a laminate of glass ceramic green sheets 1a, 1b, and 1c, and has an insulator portion 2, a wiring layer 3, and a through-hole portion 4.

Next, a method for sintering the green sheet laminate 1 will be described. (5) An organic solvent, an acrylic binder, a plasticizer, and a dispersant are added to Al ₂ O ₃ powder in advance and mixed with a ball mill to form a slurry. The slurry is used to form an Al ₂ O ₃ green sheet by a doctor blade method. Is formed. Then, as shown in FIG. 1, Al ₂ O ₃ green sheets 5 and 6 are arranged on both upper and lower surfaces of the green sheet laminate 1.
Here, the Al ₂ O ₃ green sheets 5 and 6 correspond to “a molded body mainly containing an inorganic component having a higher sintering temperature than the ceramic raw material powder” described in the claims.

(6) As shown in FIG. 1, Al ₂ O ₃ green sheets 5 and 6 are provided on the upper and lower surfaces of the green sheet laminate 1.
Is placed on the upper and lower surfaces of the green sheet laminate 1 by 5k.
While applying a pressure of g / cm ^2, the green sheet laminate 1 and the Al ₂ O ₃ green sheets 5 and 6 are fired in an air at 900 ° C. for 20 minutes using an electric continuous belt furnace. . When the conductive paste is Cu, the paste is reduced or fired in a neutral atmosphere.

(7) After sintering, the Al ₂ O ₃ powder on the surface of the glass ceramic laminate is removed by blasting glass beads or liquid honing, etc., and is placed on the insulator portion of the sintered glass ceramic multilayer substrate. Print Au conductor
It is formed by firing or plating. The glass-ceramic multilayer substrate 10 manufactured as described above has the insulator 2
0, a wiring layer 30, a through hole 40, and a wiring pattern 50 formed on the insulator 20. In the inspection of the wiring pattern 50, the contrast between the dark color of the surface of the insulator portion 20 and the white color or a color close to white of the wiring pattern 50 is distinguished by an image processing method using a CCD camera, and positioning is performed. The presence or absence of a defect is determined. This operation can be automatically performed, and all the wiring patterns on the substrate can be inspected in a short time.

Next, the glass-ceramic multilayer substrate 10 manufactured in the above (1) to (7) was shot blasted at a spray pressure of 5 kg / cm ² using glass beads of 30 to 60 μmφ, and the insulating The film quality of the body part 20 was normal, and the body part 20 did not peel off from the glass ceramic multilayer substrate 10.

As shown in FIG. 5A, voids 21 inside the insulator portion 20 generated by the influence of the coloring pigment are dispersed in a minute size in the insulator portion 20 before the shot blast. ing. Thereby, the quality of the sintered film of the insulator portion 20 is increased, and the mechanical strength is increased.

Next, a method of manufacturing a glass ceramic multilayer substrate according to a comparative example will be described with reference to FIG. In the comparative example, the green sheet laminate 1 produced in the steps (1) to (4) of this embodiment shown in FIG. 3 was fired without load. As shown in FIG. 5B, in the glass-ceramic multilayer substrate 100 according to the comparative example, the insulator portion 200 causes sintering inhibition due to the influence of the coloring pigment, and the void 201 inside the insulator portion 200 is huge. Yes, the film quality is porous. For this reason, the glass ceramic multilayer substrate 100 according to the comparative example was shot blasted at a blowing pressure of 5 kg / cm ² using glass beads of 30 to 60 μmφ, and as a result, the insulator portion 200 was almost peeled off from the glass ceramic multilayer substrate 100. I have.
Therefore, in the comparative example, the mechanical strength of the insulator portion 200 is reduced, and the glass ceramic multilayer substrate 10
It is difficult to apply a process in which a mechanical load such as shot blast acts as a process at the time of cleaning or post-processing of 0, and the degree of freedom of selection of a manufacturing process is low. There is a problem of being restricted.

On the other hand, in the present embodiment, by firing the green sheet laminate 1 while applying pressure to the upper and lower surfaces thereof, the insulator portion 20 formed by the influence of the coloring pigment is formed.
Is dispersed in a minute size. Thereby, the quality of the sintered film of the insulator part 20 is densified, and the mechanical strength is increased. Therefore, it is possible to apply a process in which a mechanical load such as shot blast is applied as a process of cleaning or post-processing the glass ceramic multilayer substrate after sintering, and the degree of freedom in selecting a manufacturing process is increased, and Restrictions on the process design of the ceramic multilayer substrate 10 are reduced.

Further, in this embodiment, the insulator pace
Glass ceramic green powder
CaO-Al same as the one that made the_TwoO_Three-SiO_Two−
B_TwoO _Three60 parts by weight of the glass component of the system and the balance being alumina
Using glass-ceramic powders with different compositions
Causes the glass ceramic laminate to warp during firing
Can be prevented. Therefore, the dimensional accuracy
A good glass ceramic multilayer substrate 10 can be manufactured.
Reduce the number of manufacturing processes and improve productivity.
You.

Further, in this embodiment, the green
Al on both upper and lower surfaces of the sheet laminate 1 _TwoO_ThreeGreen sheet
After placing 5 and 6, above the green sheet laminate 1
Since firing is performed while applying pressure to the lower surface, glass ceramic
Dimensional precision that hardly shrinks in the planar direction of
A good sintered body can be obtained. After firing, glass ceramic
Al on the surface of the laminate_TwoO_ThreePowder, fine glass powder
Easily removed by general shot blasting, etc.
You can leave.

In the embodiment of the present invention described above, the insulator portion 20 is formed on one surface of the glass ceramic multilayer substrate 10. However, in the present invention, the insulator portion may be formed on both surfaces of the glass ceramic multilayer substrate. Good.

In the present embodiment, the present invention is applied to the method for manufacturing the glass ceramic multilayer substrate 10 comprising a plurality of glass ceramic layers. However, the present invention can be applied to a single glass ceramic substrate, It goes without saying that various ceramic materials other than the above glass ceramics can be used.

[Brief description of the drawings]

FIG. 1 is a schematic cross-sectional view for explaining a method for manufacturing a glass ceramic multilayer substrate according to one embodiment of the present invention.

FIG. 2 is a schematic cross-sectional view illustrating a method for manufacturing a glass-ceramic multilayer substrate according to an embodiment of the present invention and showing a green sheet.

FIG. 3 is a schematic cross-sectional view illustrating a method for manufacturing a glass-ceramic multilayer substrate according to an embodiment of the present invention and illustrating a green sheet laminate.

FIG. 4 is a schematic sectional view showing a glass ceramic multilayer substrate according to one embodiment of the present invention.

FIG. 5A is an enlarged view of a main part of FIG. 4;
(B) is an enlarged sectional view of a main part of a glass ceramic multilayer substrate according to a comparative example.

[Explanation of symbols]

1 green sheet laminate 1a, 1b, 1c green sheet 2 insulator 3 wiring layer 4 through holes 5, 6 Al ₂ O ₃ green sheets 10 a glass ceramic multilayer substrate 20 insulator portion 21 gap 50 wiring pattern

Claims (3)

[Claims] 1. A method of manufacturing a ceramic substrate having an insulator portion on one or both of a front surface and a back surface, comprising: forming an insulator paste containing a ceramic raw material powder as a main component and a coloring pigment; A method of manufacturing a ceramic substrate, comprising: a step of applying to one or both surfaces of a body; and a step of firing while applying pressure to upper and lower surfaces of a ceramic molded body to which the insulating paste is applied. 2. The ceramic raw material powder is CaO-A.
l ₂ O ₃ —SiO ₂ —B ₂ O ₃ system, CaO—Al ₂ O ₃ —Si
O ₂ system, MgO—Al ₂ O ₃ —SiO ₂ —B ₂ O ₃ system and C
_{aO-MgO-Al 2 O 3} -SiO 2 -B ceramic substrate according to claim 1, characterized in that it has a composition type of glass component 40 to 70 parts by weight and the balance being alumina selected from ₂ O ₃ system Manufacturing method. 3. Prior to the firing step, a molded body mainly containing an inorganic component having a sintering temperature higher than that of the ceramic raw material powder is disposed on both upper and lower surfaces of the ceramic molded body coated with the insulating paste. The method for manufacturing a ceramic substrate according to claim 1, wherein: