JPS6027191A - Method of laminating glass ceramic multilayer circuit 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] [Field of Application of the Invention] The present invention relates to a method for manufacturing a glass-ceramic multilayer wiring board, and in particular, to prevent air bubbles from being introduced into the ff1illJ1 of the green sheets in the step of laminating the green sheets. // Concerning a lean sheet lamination method suitable for //.

[Background of the invention]

Glass ceramics (BIat, Btus, A
A so-called glass-ceramic multilayer wiring board is produced by printing conductor pastes such as Ag, Au, Cu, etc. on a green sheet (JtOm, Mg0pbo, etc.), laminating them in multiple layers, and firing them all at once.These conductors have excellent conductivity. Furthermore, due to the low dielectric constant of glass ceramics, it is attracting attention as a mounting module method with low signal propagation delay time for future large-scale computers.

However, if air bubbles are introduced between the stacked green sheets in the process of laminating the green sheets to form a multilayer, the expansion of these air bubbles may cause some blisters on the sintered substrate in the subsequent firing process. This results in a large number of defective products during the production of the multilayer board.

Conventionally, this green sheet stacking method involves stacking the required number of printed green sheets (20 to 50 sheets) and stacking them into one layer.
It was placed between two metal plates heated to 20 to 130°C and pressed together using a hydraulic press using a hot press method. However, this method often leaves small gaps between the sheets during the stacking process before proceeding to the pressing process, and even after the hot pressing process, these gaps remain as small air bubbles. Exists within the green sheet of the multilayer tube.

This situation is similar to, for example, in everyday life, when many thin vinyl sheets are stacked on top of each other, air bubbles become trapped in some of the layers. Similarly, since green sheets are also flexible sheets, even if they are carefully stacked, mistakes may occur while stacking 20 to 30 sheets. In particular, in green sheets with a thickness of 0.2 mm or less, many defective products bulge due to the inclusion of air bubbles, which is a force majeure phenomenon that exceeds the limit of the operator's attentiveness.

[Purpose of the invention]

The purpose of the present invention is to eliminate the drawbacks in the hot press process of green sheets, and to provide a method for producing glass ceramic multilayer wiring boards that are free from defects such as blistering. To provide a green sheet lamination technology that prevents air bubbles from being trapped between green sheets and has good adhesion.

[Summary of the invention]

In contrast to conventional thermocompression bonding of green sheets, in which heating and pressing were carried out simultaneously, the present invention separates these processes and performs them in two steps (see Fig. 1).

First, after stacking the green sheets, in order to remove the gaps (air bubbles) that were inadvertently introduced between the sheets, they are placed under reduced pressure (~10-2 Torr) and pressed (pressurized) at room temperature. Here, inadvertently trapped air bubbles are degassed under reduced pressure below atmospheric pressure.

Subsequently, when the sheets are pressurized in this deaerated state, the adhesive surfaces of the sheets are crushed into small pieces. This is because the green sheet is still raw, and the glass-ceramic powder causes some fluidity due to pressure.

In this way, a temporarily bonded state with no gaps or bubbles is created on the adhesive surfaces of the sheets. This is the first method according to the present invention.
This is the condition. That is, under reduced pressure (~10-2 Torr
, ) and at room temperature (~50℃ or less) -? [The first condition is crimping. At this time, the reason why the pressure must be reduced at room temperature is as follows. In other words, glass-ceramic green sheets are made by molding the powder into a flexible material.
In order to impart properties, polyvinyl butyral, butylphthalbutyl glycote, etc. are used as organic binders, and trichlorethylene and butyl alcohol are used as solvents. Therefore, it is heated from the beginning (120~1
When the pressure is reduced at 30° C.), the effect of lowering the boiling point of these substances accelerates their volatilization, making the degassing operation less meaningful. In particular, the drying temperature when producing the green sheet is 11
Heating under reduced pressure above 0 to 120°C has a negative effect on the degassed multilayer sheet.

Next, while applying pressure (approximately 5 kg/crd) to the multilayer green sheet temporarily bonded at room temperature and reduced pressure, heat is gradually applied, and when the temperature rises to around 50'' to 80°C, the pressure is reduced (~ 10-2 Torr, ) loosen the condition,
Return to atmospheric pressure. However, heating is continued and pressure is applied for 10 to 20 minutes at a predetermined temperature (120 to 130°C). This is the second condition of the present invention. The fully adhered multilayer green sheets are cooled to room temperature, and the bubble-free green sheet lamination method according to the present invention is completed.

[Embodiments of the invention]

Examples of the present invention are shown below.

Example 1 Example 1 was conducted to more clearly demonstrate the effects of the present invention.

(1) Method for producing green sheet The green sheet of Toshis Ceramics used in this example was produced in the following manner.

Sing 55.7 (same below wt0%), &Us 2
4.9%Ba010.8%Alto, 5.8%01
To 100 y of raw material powder obtained by adding 40 wt.% of crystalline 81α to a low melting point glass containing small amounts of LO, Na, and 0, organic substances were added in the following proportions and mixed for 6 hours in a ball mill.

Resin content - polyvinyl butyral 7.6g Plasticizer dibutyl phthalbutyl glycol 2.5.9 Solvent = trichlorethylene 30cc tetrochlorethylene 8.5
cc! ]-butyl alcohol 11.4 cc The slip thus obtained was doctor bladed to a width of 250 m.
It was molded into a green sheet with a thickness of 0.2 m and a thickness of 0.2 m. The drying temperature at this time was 120'C.

Since this green sheet remains flexible, it is cut into appropriate lengths while remaining adhered to the Mylar film used to form the sheet. Next, we selected a sheet with no defects (such as bores) from among these sheets and cut it into a 105m+++ square.
Now peel off the mylar film. In this way, a large number of green sheets were prepared.

Next, using 30 of these green sheets, a lamination experiment was conducted under the following three conditions in order to compare the effects of the present invention with those of the conventional method.

(2) Lamination method of green sheets (al) Lamination method according to the present invention After stacking the green sheets one by one sidewise, they are set in a hot press equipped with a vacuum container.Next, the pressure is reduced using a rotary pump (5 x 10 'Torr,) (
, c) 501c9/cut <7) Pressure was applied for about 5 minutes.

Next, while maintaining this state, gradually increase the temperature to about 60℃.
When the temperature reached ℃, the vacuum pump was stopped and the leak valve was gradually opened to return the pressure to atmospheric pressure. At this time the temperature is 80°
Reach C. Thereafter, heating was further continued and pressure was applied at a predetermined temperature of 125° C. for 10 minutes. Next, after cooling to 100°C, the multilayered green sheet was taken out and cooled to room temperature. In this way, 10 green sheets (10 sets) laminated in multiple layers were obtained.

(b) Lamination method using conventional method In order to compare with the lamination method of the present invention described above, 30 green sheets were used as a conventional method under the following conditions (see Figure 2).
10 pieces (10 sets) were stacked.

After sequentially stacking the 105 m2 sheets prepared in (1) one by one, the sheets were set in the hot press apparatus used in the experiment in (a) above. At this time, the hot press was already at 125℃.
Set the temperature to the specified temperature. Next, it was pressed for 20 minutes at a sokg/cyst pressure under atmospheric pressure without evacuation.

After cooling this to 100℃ for 4'4, the sample was taken out.
Cooled to room temperature.

In addition, in order to see the effects of temporary crimping under reduced pressure in cold (room temperature), which is the first condition of the present invention, and heating crimping (125 ° C.) under atmospheric pressure, which is the second condition, the above (b) ) and under reduced pressure (5X 10
'Torr, ) was carried out (reference comparison method).

As described above, multilayer green sheets laminated using six different methods were heated at 850°C and 111°C. As a result of firing in air, the occurrence of blisters in the fired multilayer substrates was as shown in Table 1.

Example 2 Using 30 green sheets prepared in Example 1 (1), wiring necessary for a multilayer wiring board was printed on each using M conductor paste.

This was laminated under pressure using (a) of Example 1, that is, the lamination method according to the present invention, and then fired in air at 830° C. for 1 h. Using this method, a total of five glass-ceramic multilayer wiring boards (five sets) were manufactured over a period of about one month, and all products were able to be manufactured without blistering.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an example of the profile of the green sheet lamination method according to the present invention, and FIG. 2 is a diagram showing an example of the profile of the green sheet lamination method according to the conventional method.

Claims (1)

[Claims] A glass-ceramic multilayer wiring board characterized in that a multilayered green sheet is temporarily crimped in a pressure reducer lower than atmospheric pressure, and then the green sheet is crimped while being heated to 100 to 140°C under atmospheric pressure. Lamination method.