JPH04120760A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To easily liberate a gaseous substance generated from a green sheet, especially reactive products evaporating in a molten state by providing through- holes or grooves in a flat surface at least of loading plate of a jig for firing consisting of a loading plate having a flat surface pressing the green sheet. CONSTITUTION:A green sheet 6 consisting of aluminium nitride powder is placed on the flat-ground surface of a supporting board 5 consisting of, for instance, boron nitride to press the green sheet 6, by a loading plate 1. The green sheet 6 in this state is fired in the atmosphere of gas nitride at 1800 deg.C for about 9 hours. Further, the green sheet 6 is that where several to ten and several single green sheets of about 0.3mm consisting by containing a Ca compound as firing assistant auxiliaries, polyvinyl butylar as a binder, further ethanol as a solvent, are laminated followed by being pressed. Vapor of molten sintering assistant auxiliaries and reactive products generated from the green sheet 6 in firing is easily liberated into the atmosphere through the through-holes 2 or the grooves 3 so as not to influence the surface condition and warping.

Description

[Detailed Description of the Invention] [Summary] The present invention relates to a method for manufacturing a substrate or package on which a semiconductor device is mounted, and in particular to a jig used in a firing process in manufacturing a substrate or package made of AIN.

The purpose is to improve the flatness of the substrate or package.

The green sheet is pressed between a support plate having a flat surface on which the formed green sheet is placed, and a support plate having a flat surface in contact with the green sheet placed on the support plate. a load plate, and at least the load plate has at least a through hole passing through the plate or a groove provided parallel to the flat surface and having one end open on at least one side edge of the plate. It consists of using a firing jig with a plurality of one side.

[Industrial Field of Application] The present invention relates to a method for manufacturing a substrate or cage on which a semiconductor device is mounted, and in particular, a method for manufacturing a substrate or cage on which a semiconductor device is mounted.
This invention relates to a jig used in the firing process of a substrate or Tsuma Nokeshi made by sintering powder.

It replaces alumina, which has traditionally been used mainly for substrates mounting semiconductor devices or packages for encapsulating them, to improve their heat dissipation.

Those constructed using AIN, which has a lower thermal conductivity, have come to be used.

(Prior art) The manufacturing process of a substrate or bar cage made of AIN is as follows:
Basically, it is the same as in the case of alumina.

That is, a slurry prepared by mixing ^IN powder with a sintering aid, a plasticizer, a binder, and a solvent is kneaded and processed into a green sheet by the so-called doctor blade method. This green sheet is punched out to a predetermined size, and a large number of vias (through holes) are formed therein. After filling these vias with conductor paste, a predetermined conductor pattern is printed on the surface of the green sheet. After stacking a predetermined number of such green sheets, 10
The package is completed by firing at a temperature of several hundred degrees.

[Problem to be solved by the invention] However, in the case of AIN packages, the firing temperature is 1600 to 190℃ compared to alumina packages etc.
Since the temperature is as high as 0°C and it is necessary to perform firing in a nitrogen gas atmosphere, the atmosphere control conditions are strict. This is because the presence of oxygen in the firing atmosphere will oxidize the AIN powder particles, so it is necessary to use a non-oxidizing atmosphere such as nitrogen gas.

In addition, in order to accelerate the sintering of the AIN powder, a sintering aid consisting of a calcium compound or a yttrium compound is added to the green sheet, but this sintering aid is left in a molten state during the firing of the green sheet. It evaporates and escapes from the sintered body. Furthermore, 1-graphite is generally used as a heater for the 1-calcining furnace, but when carbon generated from high-temperature graphite comes into contact with AIN, carbide is generated and good sintering is not performed. Therefore, in controlling the atmosphere, it is necessary to consider prevention of such carbon pollution.

On the other hand, in the above-described firing process, a green sheet shrinks, which causes warping. For this reason, firing is generally performed by pressing the green sheet with a flat load plate, but in the case of AIN packages, the firing atmosphere control conditions described above affect not only the sintering state but also the warpage. occurs. When we investigated this issue, we found that calcium aluminate is produced when a trace amount of alumina (thth) contained in AIN reacts with the sintering aid during sintering, and it is difficult to evaporate it. It was found that the flatness of the sintered body deteriorated. For example, if the load plate used in the firing process comes into close contact with the green sheet and prevents the evaporation of the reaction products, complex undulations will occur on the surface of the sintered body.

Accordingly, one aspect of the present invention reduces warpage of the sintered body by facilitating the escape of reaction products generated in the above-mentioned firing process from the green sheet.

It is an object of the present invention to provide a ceramic substrate or package having good shape and dimensional accuracy.

[Means for Solving the Problems] The above object is to provide a jig for manufacturing a substrate or package on which a semiconductor device is mounted by molding and firing a green sheet containing ceramic powder. A support plate having a flat surface on which the green sheet is placed, and a support plate having a flat surface in contact with the green sheet placed on the support plate for pressing the green sheet. and a load plate, at least the load plate.

Using a baking jig provided with at least one of a plurality of through holes penetrating the plate or grooves provided parallel to the flat surface and having one end open on at least one side edge of the plate. The method for manufacturing a semiconductor device according to the present invention is characterized in that it includes a step of firing the green sheet using a method of manufacturing a semiconductor device. This is achieved by the method for manufacturing a semiconductor device according to the present invention.

[Function] When firing a green sheet made of AIN powder, the firing jig is composed of a support plate having a flat surface on which the green sheet is placed and a load plate having a flat surface pressing the green sheet. By providing through holes or grooves in at least the flat surface of the load plate, gaseous substances generated from the green sheet, particularly the reaction products that evaporate in a molten state, can easily escape. This reduces warpage and surface waviness of the sintered body, that is, the ceramic package, and provides a ceramic package with good shape and dimensional accuracy.

〔Example〕

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 is a structural explanatory diagram of an embodiment of the present invention. For example, the vertical and horizontal dimensions are 130mm x 130n+m, and the thickness is 5m.
A load plate 1 made of a 1II+ boron nitride (BN) sintered body and having one surface polished flat is penetrated in the thickness direction. A large number of through holes 2 each having a diameter of about 10 m are formed in the vertical and horizontal directions at a pitch of about 13 a+m.

Fig. 2 is a structural explanatory diagram of another embodiment of the present invention.
A load plate 1 is made of III11 boron nitride (BN) sintered body and has one surface polished to a flat surface. On one surface of the load plate 1, a number of grooves 3 each having a width and depth of about 7 mm + 3 mm are formed at a pitch of about 13 mm. . Although the figure shows an example in which the grooves 3 are formed only in one direction, the grooves 3 may be formed so as to intersect in the vertical and horizontal directions;
The firing is carried out using the load plate 1 shown in FIG.

A green sheet 6 made of AIN powder is placed, and the green sheet 6 is pressed by a load plate 1, for example, shown in FIG. The green sheet 6 in this state is fired at 1800° C. for about 9 hours in a nitrogen gas atmosphere.

The green sheets 6 are a number of single green sheets each having a thickness of about 0.3 mm and containing a Ca compound (for example, CaC0+) as a firing aid, polyvinyl butyral (PVB) as a binder, and ethanol as a solvent. ~10 sheets were laminated and then pressed. Vias and conductor patterns (not shown) are formed in each of the single green sheets as described above.

The gaseous substances generated from the green sheet 6 during the above firing, that is, the molten sintering aid and its reaction products (
Since the vapor of calcium aluminate, etc. easily escapes into the atmosphere through the through holes 2 or grooves 3, it does not affect the surface condition or warpage of the sintered body. Note that the support substrate 5 in FIG. 3 may be replaced by the load plate l shown in FIG. 1 or 2.
The green sheets 6 may be placed on these flat surfaces by using similar materials, and the escape of the gaseous substance is further promoted.

FIG. 4 shows a case where the present invention is applied to a firing jig used for manufacturing a ceramic pancage having a cavity. In this case, the green sheet 60 consists of a base part 61, an intermediate part 62, and a lid part 63, as shown in FIG. 6A, and is made by laminating and pressing individual green sheets corresponding to each of these parts.

The intermediate portion 62 is provided with an opening 6° serving as a cavity into which the semiconductor device is fitted, and a conductor pattern 7 is printed on the upper surface thereof. The lid part 63 is.

An opening is provided in which a heat sink (not shown) that will be thermally connected to the semiconductor device later is attached, and a part of the conductor pattern 7 formed on the surface of the intermediate portion 62 is exposed within this opening. . A metallized pattern 8 for soldering the heat sink is printed on the surface of the lid 63 around the opening.

FIG. 4(b) is a structural diagram of the load plate 10 used for firing the green sheet 60, and this will be explained in comparison with FIG. 4(a). For example, the load plate 10 made of a boron nitride (BN) sintered body has a base 61 surface exposed within an opening 6° provided in an intermediate portion 62, and an intermediate portion exposed within an opening provided in a lid portion 63. In order to press against the 62 surface, projections 11 and 12 are provided which fit into these openings. The flat surface around the projection 12 presses the surface of the lid 63 on which the metallized pattern 8 is formed. The vertical, horizontal and height dimensions of the projections 11 and 12 are the same as those of the green sheet 60 in the firing process.
It is determined by taking into account the shrinkage of about 20%.

The protrusions 11 and 12 have through holes 20 passing through the load plate 10, and the flat surface around the protrusions 12 has grooves 30.
is provided. As a result, even in the case of a ceramic package having a cavity, gaseous substances generated from the green sheet 60 during the firing process, especially the vapor of the molten sintering aid, can escape.

This is because it is promoted through these through holes 20 and grooves 30.

There is no influence on the surface condition or warpage of the sintered body.

In addition, in the above firing, the support substrate on which the green sea) 60 is placed is a flat-polished boron nitride (BN).
), but it goes without saying that it is effective to use a plate similar to the load plate 1 shown in FIG. 1 or 2. Also.

In the above embodiment, the firing of a ceramic package was explained as an example, but it is equally effective to apply the load plate and support substrate of the structure shown in FIG. 1 or 2 to the firing of a ceramic substrate. .

〔Effect of the invention〕

According to the present invention, it is possible to manufacture a ceramic substrate or package made of a material such as AIN that needs to be fired in a non-oxidizing atmosphere with high shape and dimensional accuracy and with good reproducibility.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are structural explanatory diagrams of an embodiment of the present invention. FIG. 3 is an explanatory diagram of an example of the use of the firing jig of the present invention, and FIG. 4 is an explanatory diagram of its application to a ceramic package having a cavity. In fig. l and 10 are load plates 1, 2 and 20 are through holes. 3 and 30 are grooves, and 5 is a support substrate. 6 and 60 are green sheets with 6° openings, and 7 is a conductor pattern. 8 is a metallized pattern. 11 and 12 are protrusions, and 61 is a base. 62 is an intermediate portion, and 63 is a lid portion.

Claims (2)

[Claims] (1) A jig for manufacturing a substrate or package on which a semiconductor device is mounted by molding and firing a green sheet containing ceramic powder, and a flat surface on which the molded green sheet is placed. and a load plate having a flat surface in contact with the green sheet placed on the support plate for pressing the green sheet between the support plate and the load plate. The firing jig is provided with at least one of a plurality of through holes penetrating the plate or grooves provided parallel to the flat surface and having one end open at at least one edge of the plate. A method for manufacturing a semiconductor device, comprising the step of firing the green sheet using a tool. (2) the ceramic powder is made of aluminum nitride;
2. The method of manufacturing a semiconductor device according to claim 1, wherein the support plate and the load plate are made of boron nitride.