JPS63276228A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To prevent the crack of a thin substrate by a method wherein a main surface photo resist coating process for applying a photo resist on the main surface of the substrate is added midway between a main surface electrode forming process and a rear polishing process. CONSTITUTION:Electrodes 2, 3 and 4 are formed on a substrate 1 in a main surface electrode forming process for forming the electrodes on the substrate 1. A photo resist 8 which is used for photo-engraving is applied on the side of the main surface of the substrate 1 by a spinner in a main surface photo resist coating process for applying the photo resist on the side of the main surface. The substrate 1 is adhered on a jig for the exclusive use of adhesion in a rear polishing process for polishing the rear of the substrate and the rear of the substrate 1 is polished. A wax 6 is spread on a glass plate 5 heated to the melting point of the wax 6 in a main surface glass plate adhering process for adhering the glass plate 5 on the main surface, and after the wax 6 is melted, the main surface side of the substrate 1 is adhered on the glass plate 5. Thereby, the crack of the thin substrate is prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method of manufacturing a semiconductor device, and particularly to a step of forming a back electrode of a GaAsFET.

[Conventional technology]

FIGS. 3 and 4 are process explanatory diagrams showing a conventional example of a semiconductor device manufacturing method. FIG. 3 is a side cross-sectional explanatory view of the semiconductor device at each step, FIG. 3(a) is an explanatory view after the main surface electrode forming step, FIG. 3(b) is an explanatory view after the back surface polishing step is completed, In Figure 3, (C) is an explanatory diagram after the process of attaching the main glass plate is completed, Figure 3 (d) is an explanatory diagram after forming the back electrode, and Figure 3 (e) is an explanatory diagram after the process of removing the main glass plate. It is an explanatory diagram.

FIG. 4 is a schematic process explanatory diagram showing each process and its flow.

In Fig. 3, 1 is a semiconductor substrate (hereinafter referred to as a substrate), 2, 3
．． 4 is formed on the substrate in, for example, a source, a drain,
a gate electrode, 5 a glass plate attached to the main surface of the substrate 1;
6 is wax for pasting the glass plate 5 and the semiconductor substrate 1; 7;
is a back electrode formed on the back surface of the substrate 1.

Next, the semiconductor device manufacturing method of this conventional example will be explained in order of manufacturing steps.
An outline will be explained using FIGS. 3 and 4.

First, in the main surface electrode forming step (FIG. 4(4a)), source, drain, and gate electrodes 2, 3.4 are formed on the main surface of the substrate 1 (FIG. 3(a)). .

Next, in the back surface polishing step (FIG. 4(4b)), the back surface of the substrate 1 is polished (FIG. 3(b)). After that, in the main surface glass plate adhesion step (Fig. 4 (4C)), wax 6 is applied on the glass plate 5, and the main surface side of the substrate l is adhered thereon (Fig. 3 (c)). ).

Next, in the back electrode formation step (FIG. 4 (4d)),
The back surface of the substrate l is made into a mirror surface by etching, and the back surface electrode 7 is formed thereon by vapor deposition (FIG. 3(d)). After the formation of the back surface electrode 7, the main surface glass plate, etc. is removed (FIG. 4(4)).
In e)), the glass plate 5 is removed (FIG. 3(e)
).

[Problem that the invention seeks to solve]

As described above, in the conventional example, the thickness of the substrate 1 after the back polishing process is as thin as 100 to 3001 Lm, and the substrate 1, which is extremely brittle like ca AS, is easily broken.
Furthermore, since there are parts of the main surface of the substrate 1 in which the elements come into direct contact with the wax 6, there are problems such as contamination of the elements and reduction in reliability. This invention was made to solve the above-mentioned problems, and aims to prevent the thin substrate l from cracking after the back polishing process and protect the elements formed on the main surface. .

[Means for solving problems]

Therefore, the present invention provides a manufacturing method in which the following steps are sequentially performed: a main surface electrode forming step, a back surface polishing step, a main surface glass plate adhering step, a back surface electrode forming step, and a main surface glass plate removal step. The purpose is to solve the above problem and achieve the objective by adding a main surface photoresist coating step to apply a photoresist to the main surface of the substrate between the main surface electrode forming step and the back surface polishing step. be.

(Function) In the method of manufacturing a semiconductor device according to the present invention, the strength of the substrate is increased and cracking of a thin substrate is prevented by applying a photoresist on the main surface of the substrate.

〔Example〕

Embodiments of the present invention will be described below based on the drawings. FIGS. 1 and 2 are process explanatory diagrams showing an embodiment of the semiconductor manufacturing method of the present invention. FIG. 1 is an explanatory side cross-sectional view of the semiconductor device after each step, FIG. 1(a) is an explanatory view after the main surface electrode forming step, and FIG. Later explanatory diagrams, FIG. 1(C) is an explanatory diagram after the back surface polishing process, FIG. 1(d) is an explanatory diagram after the main surface glass plate adhesion process, and FIG. 1(e) is an explanatory diagram after the back surface electrode formation process. Later explanatory diagram,
FIG. 1(f) is an explanatory diagram after the process of removing the main surface glass plate, etc., and FIG. 2 is an explanatory diagram of each process and its flow. In FIG. with a spinner to a thickness of 2
This is a photoresist used in normal photolithography that is applied to ~3#Lm.

In the drawings, the same or equivalent components as those in the conventional example are represented by the same reference numerals, and redundant explanation thereof will be omitted.

Next, the manufacturing method of the present invention will be explained in more detail in the order of steps with reference to FIGS. 1 and 2, partially overlapping the conventional example.

First, in the main surface electrode forming step (FIG. 2(2a)) in which electrodes are formed on the substrate 1, the electrodes 2, 3.4 are formed on the substrate 1 (FIG. 1(a)).

After that, in the main surface photoresist coating step (Fig. 2 (2b'')) in which photoresist is applied to the main surface side, a photoresist 8, which is used in ordinary photolithography, is applied to the main surface side of the substrate 1 using a spinner. Coat to a thickness of 2 to 3 #Lm (Fig. 1(b)).

Next, a back surface polishing step (Fig. 2 (2c)) is performed to polish the back surface.
), polish the back side of the substrate 1 to a thickness of about 100 to 300 m using Sanada's 9hfi and 41cm polishing method. After polishing, remove the thinned substrate 1 from the jig (first
Figure (C)).

Next, in the main surface glass plate adhesion step (FIG. 2 (2d)) in which a glass plate is attached to the main surface, wax 6 is applied on the glass plate 5 heated to the melting point of the wax 6.
After melting, the main surface side of the substrate 1 is attached to the glass plate 5 (FIG. 1(d)).

After that, a back electrode formation step (second
In FIG. 2e), the back surface of the substrate 1 attached to the glass plate 5 is etched to give it a mirror finish, and the back electrode 7 is formed thereon by vapor deposition (FIG. 1e).

After that, in the main glass plate etc. removal step in FIG. 2 (2f) in which the main glass plate 5 etc. are removed, the substrate 1 is removed from the glass plate 5, the wax 6 is removed by cleaning, and finally the photoresist 8 is peeled off. (Fig. 1(f)).

As described above, according to the present embodiment, after applying the photoresist 8 to the main surface of the substrate 1, it is polished thinly and is attached to the glass plate 5 with wax 6, so that cracking of the substrate 1 can be prevented. At the same time, the elements on the substrate 1 can be protected from contamination by the wax 6 and the like.

〔Effect of the invention〕

As described above, according to the present invention, each of the steps of forming an electrode on the main surface of a semiconductor substrate, polishing the back surface, attaching the main surface glass plate, forming a back electrode, and removing the main surface glass plate, etc. A semiconductor manufacturing method in which steps are performed sequentially, and a main surface photoresist coating step of applying a photoresist to the main surface of the substrate is added between the main surface electrode forming step and the back surface polishing step. This has the effect of preventing cracking of the substrate 1 and protecting the elements on the substrate 1 from being contaminated by wax or the like.

[Brief explanation of drawings]

FIG. 1 is a side cross-sectional explanatory view of a semiconductor device in each step of a manufacturing method according to an embodiment of the present invention, and FIG. 1(a)
is an explanatory diagram after the main surface electrode forming process, FIG. 1(b) is an explanatory diagram after the main surface photoresist coating process, FIG. 1(C) is an explanatory diagram after the back surface polishing process, FIG. 1(d) 1(e) is an explanatory diagram after the process of attaching the main surface glass plate, FIG. 1(e) is an explanatory diagram after forming the back electrode, and FIG. 2 is a schematic process explanatory diagram showing each process and its flow in FIG. 1, and FIG.
Figure 3 (a) is an explanatory diagram after the main surface electrode formation process, Figure 3 (b)
) is an explanatory diagram after the back surface polishing process, FIG. 3(C) is an explanatory diagram after the main surface glass plate adhesion process, FIG. 3(d) is an explanatory diagram after the back surface electrode formation, and FIG. 3(e) is an explanatory diagram after the back surface polishing process. 4 is an explanatory view after the main surface glass plate removal process, and FIG. 4 is a schematic process explanatory view showing each process of FIG. 3 and its flow. 1... Semiconductor substrate 2.3.4... Electrode 5... Glass plate 7... Back electrode 8... Photoresist

Claims (2)

[Claims] (1) Main surface electrode formation step of forming electrodes on a semiconductor substrate, back surface polishing step of polishing the back surface of the substrate, main surface glass plate attaching step of attaching a glass plate to the main surface of the substrate with wax, back surface of the substrate A method for structuring a semiconductor device, comprising sequentially performing a back electrode forming step of forming a back electrode after mirror polishing a substrate, and a main glass plate removing step of removing a main glass plate of the substrate, the method comprising: 1. A method for manufacturing a semiconductor device, characterized in that a main surface photoresist coating step of applying a photoresist to the main surface of the substrate is added between the electrode forming step and the back surface polishing step. (2) The semiconductor according to claim 1, wherein the main surface photoresist coating step is a step of applying a photolithographic photoresist to a film thickness of 2 to 3 μm on the main surface of the semiconductor substrate. Method of manufacturing the device.