JPS58197796A - Method of producing ceramic board - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a ceramic substrate that reduces dimensional shrinkage over time and deformation due to handling in the process of manufacturing a ceramic substrate.

Figure 1 shows the manufacturing process of a multilayer ceramic substrate using conventional technology. show. Conventionally, after manufacturing the green sheet, it takes at least one week, usually 2 to 5 weeks, before drilling the guide holes.
Green Sea) Y was stored. This is due to the following reason. In other words, as shown in FIG. 5, after the green sheet is manufactured, dimensional shrinkage occurs as storage days elapse.

This tendency is particularly remarkable immediately after production. Accordingly,
If guide holes are punched immediately after the green sheet is manufactured, the pitch of the guide holes will shrink due to subsequent dimensional shrinkage, which will hinder alignment in subsequent steps. In order to solve this problem Y, conventionally, after manufacturing the green sheet,
The guide hole was drilled after storage for at least one week, usually for two to three weeks or more, and when the dimensional shrinkage became relatively slow. However, although the dimensional shrinkage is gradual, it does not stop, so for example, if there is a long period of time between drilling the through hole and filling the Ouchi conductor paste, the hole pitch of the green sheet and the screen/saw hole pinch for filling the conductor will be affected. This caused problems such as misalignment and poor filling of the conductor paste.

In addition, when the thickness of the green sheet becomes thin, especially when the thickness becomes less than 0.31131, the green sheet may be deformed due to slight mechanical force during handling, and the process of filling conductor paste, printing, and lamination bonding may cause deformation of the green sheet. This causes misalignment and is a major hindrance when manufacturing high-density multilayer ceramic substrates.

An object of the present invention is to provide a method for preventing deformation of a green sheet during the manufacturing process of a multilayer ceramic substrate.

The present inventors have invented a method of performing pressure heat treatment χ as a method for preventing dimensional shrinkage of green sheets over time, but this pressure heat treatment is usually performed by applying a support film such as a polyester film to the front and back of the green sheet. However, after the pressure and heat treatment, only the front support film is peeled off, and the back film is left in close contact with the green sheet as a support for the subsequent steps of guide hole drilling, through hole drilling, If through-hole conductor paste filling and surface conductor paste printing are performed, further dimensional shrinkage over time and mechanical deformation due to hendling G can be prevented in these steps.

An embodiment of the present invention? Shown in Figure 2.

Is the green sheet manufactured in ■ by pulverizing and mixing ceramic raw material powder such as alumina, sintering aid, and organic binder, and then adding a solvent to the mixture to form a slip? , between Doctor Blade? This is done by passing it through, forming it into a sheet with a predetermined thickness, and drying and removing only the solvent. Green sheets manufactured in this way have residual solvent residual stress, uneven density, etc., so dimensional shrinkage occurs over time due to residual solvent volatilization and release of residual stress after manufacturing. . In the present invention, in order to prevent this dimensional shrinkage over time, the dimensional stabilization process (2) is performed. That is, as shown in FIG. 4, a support film 2 having excellent dimensional stability such as a polyester film is placed on the front and back sides of the green sheet 10. Place them in close contact and heat under pressure. At this time, in order to perform the pressure and heat treatment all at once, a support film 2 is closely attached to the front and back surfaces of the green sheet 10, and a large number of sets are stacked with the metal plates 5χ interposed between them. Stabilization treatment is carried out by sandwiching between plates 4 and 4' and applying pressure and heat all at once. The pressure at this time is 1 to 100 kg/cII, preferably 5 to 20 #
/cd is good. If the pressure is too low, the effect of the stabilization treatment will be weakened, and if the pressure is too high, the green sheet will become too dense, and the organic binder will not be fully decomposed and removed in the subsequent sintering process, resulting in dense sintering. It becomes impossible to obtain a solid body. In addition, the temperature is room temperature to 250°C1, preferably 70°C to
150°C is good. The temperature is preferably at least the softening point of the organic binder used, and for example, when polyvinyl butyral is used as the organic binder, it is preferably at least 80°C. On the contrary °
If the temperature is too high, the organic binder will decompose and the green sheet will lose its flexibility, which is undesirable. When polyvinyl butyral is used, if the temperature exceeds 150°C, decomposition and hardening will occur and the green sheet will become brittle.

Through the above-described stabilization treatment using pressure and heating, the residual solvent and residual stress in the green sheet are removed, and the green sheet becomes densified and stable with little dimensional change. In addition, the support film becomes in close contact with the green sheet by the pressure and heat treatment, and exhibits an effect χ in preventing dimensional changes in the green sheet.

Next, before drilling guide holes in the next step, the support film χ on the front surface is peeled off, and the support film on the back surface of the green sheet is left in close contact with the green sheet. By pressure and heat treatment, the support film 2 becomes the green sheet 1.
Subsequent dimensional changes and deformation? strong enough to prevent
It is in close contact with the green sheet 1.

As the support film, for example, a polyester film with excellent dimensional stability is preferable, and its thickness depends on the thickness of the green sheet, but it is preferably 0.3 to 0.20 m, and when the green sheet thickness is 0.2111 mm. ,005~0.10
In is preferable. In this way, with the support film tightly attached to the back side, punch holes through holes. conduct. In FIG. 5, with the support film 2 in close contact with the back surface of the green sheet 1, guide holes 5 are bored (■
(Guide hole drilling) A through hole 6 is drilled based on this guide hole 57a (■Through hole drilling) The guide hole and through hole are drilled by a well-known method such as punching or drilling, and the green sheet and the support film are The holes are drilled at the same time.

Next, by using a well-known method such as screen printing or vacuum suction, conductive paste Y is filled into the through holes. Print and form wiring lines etc? Complete (■ Conductor paste printing).

Next, after gently peeling off the support film on the back side (■ Support peeling), a predetermined number of printed green sheets are laminated in a predetermined combination based on the guide hole, and integrated by pressure heating (■ Lamination connection i) At this time, both the pressure and the moisture content are preferably set higher than the values at the time of stabilization treatment. Subsequently, sintering (■) and plating (O>W) are performed to complete the production of the multilayer ceramic substrate.

Is Fig. 6 the stabilization process according to the embodiment? As is clear from the dimensional change T0 of the applied green sheet, it has excellent dimensional stability due to pressure heating and close contact with the support. Such excellent dimensional stability has the following effects, making it possible to manufacture high-precision σ] high-density multilayer ceramic substrates.

(1) Since there is no dimensional shrinkage of the guide hole pitch after drilling the guide holes, the guide hole diameter of the green sheet? It can be made close to the diameter of the positioning guide bin, and alignment errors due to play in the guide hole can be reduced. For this reason, it becomes possible to perform through-hole drilling, conductor paste filling in the holes, conductor paste printing, and lamination bonding with high precision.

(2) Since there is no dimensional change over time, there is no need for storage time from manufacturing the green sheet to drilling guide holes, reducing delivery time. It can be measured.

(3) Since there is no dimensional change over time, even if the time required for the guide hole drilling and lamination bonding becomes longer, there will be no possibility of filling defects due to hole pitch deviation between the through holes and the screen during the Ouchi conductor paste filling process. Due to the pitch deviation between the conductor-filling through-hole position and the printing screen position during the conductor paste printing process, the through-hole conductor and 51
Seats may occur between the first connection wiring line, or the sheets may be misaligned between the laminated sheets due to uneven shrinkage of the dimensions of the green sheets during the lamination bonding process. Problems such as open defects are eliminated, and high-precision multilayer ceramic substrates can be manufactured.

(4) Since the green sheet is attached to a support, handling of a thin green sheet such as 0.1 to 0.3 μ becomes easier, and defects due to mechanical deformation during handling do not occur.

(5) The support film protects the guide hole.

This eliminates deformation of the guide hole (sheet debris) due to insertion and removal of the green sheet into the guide bin.

As described above, according to the present invention, with the support film in close contact with the green sheet, hole filling and paste printing can be performed. As a result, deformation of the green sheet during the manufacturing process can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing the manufacturing process of a multilayer ceramic substrate according to the prior art, FIG. 2 is a diagram showing the manufacturing process of an embodiment of the present invention, and FIG. 3 is a diagram showing the dimensional change over time of a green sheet in the conventional technology. , FIG. 4 is a cross-sectional view for explaining the present invention, FIG. FIG. 3 is a diagram showing dimensional changes over time of a green sheet subjected to stabilization treatment according to the present invention. DESCRIPTION OF SYMBOLS 1...Green sheet, 2...Support film 3...Metal plate, 4/4'...Jig plate for pressure and heat treatment, 5...Guide hole, 6...Through hole. Sai 1 figure f2 area O 3 times ゛ 7 ゛ Lean seat Deaf town, 1st Iyu J-eup of Zoune 2, 48th daily income! I 〃RO IE770 Koki F
5 diagram O 6 note −U, υ0 −0. fo 0 tO;'0 30 40 stable, constant 4
t: AB several days after treatment →

Claims (1)

[Claims] Filling, sheet surface conductor paste printing? A method for manufacturing a ceramic substrate characterized by: