JPS5842255A - Semiconductor mounting substrate having multilayer wiring and manufacture thereof - Google Patents

Abstract

PURPOSE:To obtain high reliable multilayer wiring structure having no crack and pin hole by a method wherein after an insulating film consisting of heat resisting high polymer is covered with a chemically resistive film of photo resist, etc., and patterning is performed, openings are formed by selective etching. CONSTITUTION:After the Toreyneece film 9 of heat resisting high polymer resin on a semiconductor mounting substrate 8 is dried for 60min at 90 deg.C in the nitrogen atmosphere, it is heated for 60min at 180 deg.C, and is heated for 60min at 380 deg.C in succession in the same atmosphere to be hardened. Then aluminum is evaporated on the film 9, and patterning is performed to form the first layer conductor wiring layer 10. The Toreyneece film 11 is formed thereon, it is heated for 60min at 90 deg.C, and for 60min at 180 deg.C in the nitrogen atmosphere, and after it is hardened once, selective etching is performed to remove the film, and the opening parts 12 are formed. The photo resist is removed, and is heated for 30min at 380 deg.C in the nitrogen atmosphere to perform the hardening treatment, and the second layer conductor wiring layer 13 is formed according once more to the process mentioned above.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a semiconductor substrate having multilayer wiring and a method for manufacturing the same.

Semiconductor integrated circuits are constructed by integrating many circuit elements such as transistors, diodes, and resistors in a single semiconductor substrate, so if the necessary wiring is formed on one plane on the surface of the substrate, the wiring becomes long and causes heat waves. However, in some cases, the wiring itself becomes impossible due to crossing, so conventionally, the necessary wiring was formed in multiple layers with an insulating film between the eyebrows. Ceramic substrate for reasons,
Multilayer wiring is formed on a printed circuit board or the like, and semiconductor elements are mounted thereon by 7-lip chip mounting or the like.

The conventional multilayer structure is shown in FIG. 1, with the semiconductor integrated circuit designated as H. That is, in this conventional example,
A silicon dioxide film (2) with connection openings formed at predetermined positions as a protective film is formed on a silicon wafer (1) incorporating semiconductor elements such as transistors and diodes, and a conductive metal such as aluminum is formed on this film. A conductive wiring layer (3) is formed by vapor deposition, patterning, and etching to form a first layer of metal film, and then a silicon dioxide film (4) is formed as an interlayer insulating film by vapor phase growth or high-frequency sputtering. A second conductor wiring layer (5) is similarly formed via the wiring layer (3),
(5) is connected through a connection opening (6).

In such a conventional multilayer wiring structure, a temperature condition of at least 450°C is required to form the silicon dioxide film (4) as an interlayer insulating film between the conductor wiring layers (3) and (5). However, this causes the following problems because minute protrusions such as hillocks are formed on the aluminum forming the underlying wiring layer.

That is, first, the microprotrusions cause a large number of pinholes in the silicon dioxide film (4) deposited thereon, causing a short circuit between the two conductor wiring layers (a) and (5). point LJ), and secondly, due to the temperature conditions, due to the difference in thermal expansion coefficient between the wafer (1), the silicon dioxide films (2), (4), and the conductor wiring layers (3), (5)O. In particular, silicon dioxide film +2>
, (4) becomes a problem when deposited thickly. Thirdly, since the walls of the openings (6) formed in the silicon dioxide films (2) and (4) have a shape close to perpendicular to the wafer (1) K, the conductive metal is deposited sufficiently thickly. There is a problem in that the wiring layers (3) and (5) may break at this part, and fourthly, the conductor wiring layer (
Due to the unevenness of 3), the silicon dioxide film (4) is not sufficiently deposited on the stepped portion (7), and both wiring layers (a),
(5) There is a tendency for short circuits to occur.

Therefore, an object of the present invention is to improve such drawbacks of the conventional multilayer wiring structure and to propose a semiconductor board having multilayer wiring and a method for manufacturing the same. In the present invention, a heat-resistant, thermosetting polymeric material such as polyimide or polyamide is used as the insulating film between the conductive wiring layers, and the heat treatment thereof is controlled.

This type of polymer material is heat resistant, thermosetting, chemical resistant, and chemically stable; Regarding polymer resin films, there has been no means for forming etched openings with good controllability to establish electrical continuity between conductive wiring layers. Therefore, in this invention, the wiring structure is improved by particularly devising the heat curing process.

Hereinafter, one embodiment of the present invention will be described in detail. First, the processability of the polymer resin film, which is closely related to the improvement of the wiring structure, will be described from the viewpoint of heat treatment in particular.

As is well known, a thermosetting polymer resin film is formed by partially curing uncured resin by heat treatment, and this treatment has the purpose of 2':). One method is to evaporate the solvent contained in the resin, and the other method is to cause a dehydration reaction in the resin existing in a polyamic state to form polyimide. If this heat treatment is not carried out properly, the following problems will occur regarding the workability of the resulting resin film. In other words, if heat treatment is performed at low temperatures (below 80°C), a uniform film cannot be formed, and as a result, in many cases, the etching rate of the film increases, resulting in excessive etching of the openings and poor controllability. There is a disadvantage in that the heat treatment is carried out at high temperature (400℃).
℃ or higher), water generation due to solvent evaporation or imidization causes bubbles to form in the film and unevenness to the surface. The same thing happens when the device is heated to a certain temperature (in the case of TRENICE, the solvent is dN-N' dimethylacetamide, the boiling point is 163°C), and as a result, the processability of the coating is reduced, and in many cases, the opening part is Sharp edges or corners, cross-sectional shapes, etc. (turning performance will deteriorate).

Figure 3 shows the curing time dependence of the etching rate of the F-lenice coating, using the curing temperature ltT as a parameter.
A mixture of IIj and 400 wLl of ethylenediamine was used to maintain a constant temperature of 20°C. It can also be seen from FIG. 3 that when the heat treatment temperature is high, the etching rate becomes significantly slow. As mentioned above, this decrease in etching speed causes the edges of the openings, sharp corners, and poor cross-sectional shape, as well as a decrease in workability.Furthermore, when the heat treatment time is shortened, the solvent evaporates insufficiently. As a result, the uniformity of the coating deteriorated, and processability was similarly reduced.

As described above, there are various problems with heat treatment of polymer resin films, so when manufacturing semiconductor substrates with multilayer wiring covered with an insulating film made of heat-resistant polymer resin,
It is necessary to take these points into consideration when determining the manufacturing method.

Next, a detailed description will be given based on an embodiment shown in FIG. 2, focusing in particular on selective processing means for an insulating coating made of a heat-resistant polymer resin.

First, a 30-inch ceramic substrate (8
) [manufactured by Kyoto Ceramic Co., Ltd.], washed in a normal manner, and placed on this substrate (8) a heat-resistant polymer resin, Trenice (resin content 17-2, viscosity 1.000 cp) (manufactured by Toyo Rayon Co., Ltd.). , semiconductor grade] for 60 seconds), and then immediately dried in a nitrogen atmosphere at 90°C for 60 minutes to evaporate most of the solvent (N-N'-dimethylacetamide), and then dried in the same atmosphere. At 180"060 minutes, Tsui f380'o.

Heat and cure for 60 minutes. The thickness of the coating (9) thus obtained was approximately 6 pm.

Next, aluminum is vapor-deposited on the coating (9) of the substrate (8) by a conventional method, and this is similarly patterned into a predetermined wiring pattern by a conventional photolithography method to a thickness of approximately 0.7 mm. A first conductive wiring layer (11) is formed.Before this, a trenice film (11) similar to that described above is applied.
11) was formed by a spin coating method (rotation speed 4.00 rpm, rotation time 60 seconds), and similarly coated at 90°C in a nitrogen atmosphere.
, heated for 60 minutes at 180" o and heated for 60 minutes to once cure to obtain a film of about 3 μm thickness. Furthermore, on top of this, a photoresist OMB '83 [negative type manufactured by Tokyo Ohka Co., Ltd., viscosity lo cp ) was used to form a predetermined pattern by a well-known photolithography method, and the required portions of the trenise film a1) were covered with this photoresist with a thickness of about 0.55 mm, and then hydrazine 100 and ethylenediamine 1
00- (solution temperature: 20°C) for about 3 minutes to selectively remove exposed portions of the trenise film to form openings (lIJ). After removal, the layer structure is cured by heating at 380° C. for 30 minutes in a nitrogen atmosphere, and a second conductive wiring layer is formed by the above procedure again. A semiconductor circuit board with a wiring layer of

The semiconductor device substrate obtained in this manner has flat surfaces of the film (9) and αυ formed on each, and therefore, the conductor wiring layers a, which intersect through the film (11),
(There is almost no level difference in the part a◆ of 13, so there is no chance of wiring breakage due to the level difference.Also, even if the polymer resin coating has the same coefficient of thermal expansion as the conductive material, Since it sufficiently absorbs the internal stress caused by the difference, it does not cause cracks in practical use.Furthermore, it has sufficient insulation and heat resistance, making it a highly reliable wiring structure. is obtained.

In the above embodiment, a ceramic substrate was used as the semiconductor substrate, but it may be a printed circuit board, a glass substrate, etc. In addition to TRENICE, PIQ (manufactured by Hitachi Chemical Co., Ltd.) may be used as an insulating coating made of a heat-resistant polymer. %t PYLA
Polyimide resins such as LIN (manufactured by Du-Pon Co., Ltd.) and polyamide zeta resins such as HI-600 (manufactured by Hitachi Chemical) can be used.

In the above embodiments, the structure of the semiconductor circuit board having multilayer wiring was made with two layers of wiring conductors, but as can be easily expected from a technical standpoint, it is possible to have multilayer wiring with more than one layer. Similarly, forming the first conductive wiring layer directly on the semiconductor container or directly on the insulating film can be selected as appropriate depending on the flatness of the substrate surface and other factors.

Further, in the above example, the thickness of the insulating film made of heat-resistant polymer between the conductor wiring layers is 3 μm, but the thickness can be selected as appropriate based on the dielectric breakdown strength, the size of the opening formed in the insulating film, etc. This coating thickness is determined by the resin viscosity,
It can be easily controlled by adjusting the spinner rotation speed, etc.

In addition to aluminum, gold, molybdenum, nickel, and steel are also used as materials for conductor wiring layers.

A combination of two or more of platinum, titanium, etc. may be used as an alloy, or a multilayer film of two or more of these materials has better mechanical strength and thermal stability than aluminum alone.

As detailed above, according to the present invention, an insulating film made of a heat-resistant polymer such as polyimide or polyamide-imide is used, and this insulating film is patterned and coated with a chemical-resistant film such as photoresist, and then selectively Since the opening is etched in the opening, it is possible to control the inclination angle of the insulating film at the opening, and it is also possible to eliminate disconnections at the stepped portions of the upper and lower conductor wiring layers that are connected through this opening. Because it can absorb internal stress caused by wiring, a highly reliable multilayer wiring structure can be constructed without cracks or pinholes.Furthermore, the insulating coating can be formed by papermaking using well-known photolithography technology, so conventional equipment can be used as is. It has features such as being able to

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing a semiconductor substrate with a multi-layer wiring structure made by a conventional method, FIG. 2 is a cross-sectional view showing a semiconductor substrate with a multi-layer wiring structure to which an embodiment of the method of the present invention is applied, and FIG. 3 is a heat-resistant FIG. 2 is an explanatory diagram showing the workability of an insulating coating made of a synthetic polymer. (8) Ceramic substrate, (91, (Jυ...
・Insulating coating, Q(1, Q3...conductor wiring layer, oz.
···Aperture. Agent Makoto Kuzuno - (#1 is one person) Figure 1 Figure 2 Figure 3 Kanatomo Haana

Claims (1)

[Claims] (1) A multilayer structure characterized in that conductor wiring layers are formed in multiple layers on a substrate via an insulating film made of a heat-resistant polymer, and each of these conductor wiring layers is connected through an opening formed in the insulating film. A semiconductor board with wiring. (A step of forming a first insulating film made of a heat-resistant polymer on the sword substrate, and a step of forming a first conductive wiring layer in a predetermined pattern O on at least a portion of this tenth insulating film,
forming a second insulating film made of a heat-resistant polymer on the first conductor wiring layer; selectively forming an O opening in the second insulating film for connection between the conductors; and forming a 20th conductor wiring layer having a predetermined pattern, at least a portion of which is present on the second insulating film, including the opening. Method.