JPS5897834A - Manufacture of semicondutor device - Google Patents

Abstract

PURPOSE:To eliminate the deposite of glass on an excess part, even when glass passivation is performed, and give no bad influences to later processes by a method wherein an electrodeposition mask is formed by applying a liquid Si compound on the substrate surface, and next heat treatment is performed. CONSTITUTION:Using the N type substrate, a base diffused layer 1 and an emitter diffused layer 2 are formed on the main surface side of the N<->-ON-N<+> substrate. Next, the electrodeposition mask is formed by a spin application method. Thereafter, a heat treatment is performed in N2+O2 atmosphere at 800 deg.C for 30min rsulting in the formation of the electrodepsotion mask 3 1.2mu thick. Succeedingly, the mesa groove part of the electrodeposition mask 3 is removed by a PEP i.e. photoetching process. Then, in a state of resist deposite, a mesa groove is formed by a blade, the crush layer of the mesa groove is removed by a chemical etching, etc., and accordingly a mesa groove 4 is formed. Thereafter, the P-N junction is exposed by exfoliating the resist. Glass powder is electrodeposited and rinced, and thereafter a heat treatment is performed resulting in glass calcination. Thereafter, an electrode formation, etc. are performed, and thus the pellet of a glass passivation power transistor is completed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method of manufacturing a semiconductor device, and more particularly to a method of manufacturing a glass-bashy power transistor.

Electrophoresis is generally used as a β-lase attachment method for seed transistors. This is done by placing a substrate masked with a 1'810 m thick insulating film, excluding the part to which the glass is to be attached, facing an electrode, and submerging it in a glass liquid containing glass powder dissolved in an alcoholic solvent, so that the glass powder becomes positively charged. 810 on the substrate by applying a negative voltage to the substrate.

Glass powder is electrophoretically deposited on areas where there is no mask.

However, according to this electrophoresis method, 8
10! If there are bottle holes in the membrane, glass will also adhere to those areas.

A similar thing occurs when there is a step 810 in the membrane. Figure 7 shows this, in which a pace diffusion layer I and an emitter diffusion layer Jt' are formed on the main surface side of the substrate, and the bonding surface between the base and emitter has a step difference with respect to the main surface of the substrate. 810 is electrodeposited on the main surface of the semiconductor substrate on which the protective film J is provided (see the same figure) by low-temperature vapor phase growth of the OVD cape, the pupillary protective film 3 is formed. A step break J occurs at the step part between the main surface of the substrate and the main surface of the substrate (see figure (b). When glass basing is applied to this part, glass deposits 7 are formed even in the part of the stepped roof where glass should not be attached.

This glass deposit 7 is more attached than the crow on the mesa! Since the zero product is small and electric field concentration occurs, it is much higher than the swell of the crow in the mesa groove, reaching around 100μ.

Such glass protrusions cause trouble in the PIF mask alignment process to be performed later. In other words, if the height of the glass is greater than the gap length between the glass mask and the substrate, it will damage the glass mask and shorten its lifespan.
When connected, the board does not move at all, making mask alignment impossible for some boards.

The present invention was developed in view of the above-mentioned points, and is a method for manufacturing semiconductor devices that can achieve good glassy cleaning by forming an electrodeposition mask by applying a masking agent using a spin coating method and then performing heat treatment. This is what we provide.

An embodiment of the present invention will be explained below with reference to FIG.

The IJJ diagram shows the glassy basis error process in the present invention as the first
It is shown in correspondence with the figure.

For example, assuming that an N-type substrate is used, a pace diffusion layer l and an emitter diffusion layer are formed on the main surface side of the N-on-N substrate by a well-known technique. With this step, a step of about /jμ is formed on the surface of the substrate (FIG. 6(a)). Next, an electrospring mask is formed by spin coating. For example, 810. Liquid silica of $% g, t is applied by operating a spinner at 300 rpm for 〃 seconds,
After that yt + O**W! An electrodeposition mask J having a thickness of 1.2μ is formed by heat treatment at 100°C for 30 minutes in 1 atmosphere (see figure (b)).The mesa grooves of the electrodeposition mask J are then formed using PEP, that is, photolithography. Remove the part ((0) in the same figure)
').

Next, Regis) 1 - Form a mesa groove with a blade in the adhered state, and create a fractured layer of the mesa groove! It is removed by chemical etching etc. to form a mesa.

This ridge resist is peeled off to make a PM bond (same button), and a voltage of 300 V is applied for -minutes in a ZnO-based glass liquid to electrodeposit glass powder, and the rinse process is completed.
The glass is fired by heat treatment in a furnace at 0 to 00°C.

After forming 11 electrodes, a pellet of a glass passive bass power transistor is completed.

The present invention, as described above, involves applying a liquid silicon compound to the surface of a substrate and then heat-treating it! Because it forms an adhesive mask, even if glass is applied, glass will not adhere to unnecessary areas and will not cause any negative effects on subsequent processes. This means that the method of the present invention is extremely superior when considering the drawbacks of applying a steam oxide film as an electrodeposition mask since the heat treatment temperature is limited.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing the conventional glass bathing process.
W&C diagrams are diagrams showing the same steps in the method of the present invention. l...Base diffusion layer, J...Emitter diffusion layer, 3.
...Retentive film, Tei...electrodeposition mask, I...step break in electrodeposition mask, T...mesa groove, γ...glass deposits. Applicant's agent Kiyomi Inomata 2 Figure 3 ↓

Claims (1)

[Claims] 1. A step of applying an @-shaped electrodeposition masking agent to the main surface of a semiconductor substrate by the Subi Y1111 cloth method and then heat-treating it to a predetermined portion of the electrodeposition mask; A semiconductor with a process of attaching glass powder by electrophoresis through a mask and firing it! jl' manufacturing method. In the method described in claim aIJ/xj4,
The liquid electrodeposition masking agent is made by dissolving a silicon compound in alcohol, and is used in a certain semiconductor device manufacturing method.