JPH0682692B2 - Method for manufacturing semiconductor device - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for manufacturing a semiconductor device of the present invention, and in particular, at least one electrode of a semiconductor element formed on an insulating substrate is drawn out to the back surface through a through hole. The present invention relates to a method for manufacturing a semiconductor device.

[Conventional technology]

In a semiconductor element formed on an insulating substrate, for example, a GaAs field effect transistor (hereinafter referred to as FET), its thickness is, for example, 20 to 30 μm in order to reduce the thermal resistance of the insulating substrate.
In order to reduce the thickness to about m and to reduce the source inductance at high frequencies, a structure is used in which a through hole is opened in the insulating substrate immediately below the source electrode and the source electrode is pulled out from the back side by connecting to the conductor layer on the back side. .

3 (a) to 3 (e) are cross-sectional views of a semiconductor chip shown in the order of steps for explaining a first example of a conventional method for manufacturing a semiconductor device.

In this example, first, as shown in FIG.
After forming the source 3, the gate 4 and the drain 5 on the active layer 2 on the surface of the insulating substrate 1a of μm, the surface of the insulating substrate 1a is covered with the insulating film 6, and the back surface of the insulating substrate 1b is polished to reduce the thickness. 100
After having a thickness of about μm, the surface of the photoresist film 9
Affix to the quartz plate 10 by.

Next, as shown in FIG. 3 (b), the back surface of the insulating substrate 1b is etched by chemical etching or the like to form the insulating substrate 1 having a thickness of about 20 to 30 μm.

Next, as shown in FIG. 3C, a through hole A ′ and a scribe groove B ′ are selectively formed in the insulating substrate 1 by a photolithography method or the like.

Next, as shown in FIG. 3 (d), the conductor layer 1 for plating
After forming 2'on the back surface of the insulating substrate 1, a photoresist film 13 is formed in the scribe groove portion, and a conductor layer 14 'made of Au or the like is formed by plating.

Finally, after removing the photoresist film 13, the semiconductor chip is divided at the scribe line, and the photoresist film 9 is further removed to peel the semiconductor chip from the quartz plate 10.
A semiconductor device including a FET as shown in FIG. 3 (c) can be obtained.

FIG. 4 is a sectional view of a semiconductor chip for explaining a second example of the conventional method for manufacturing a semiconductor device.

In this example, as shown in FIG. 3 (b) in the first example, after forming the through hole A ′ and the scribe groove B ′ in the insulating substrate 1, as shown in FIG. Conductor layer 12 '
First, the back surface is covered with a photoresist film 13 'in which the through holes A'are opened, and then a conductor layer made of Au or the like is formed on the through holes A'by plating, and then the photoresist film 13' is formed. ′ Is removed and the scribe groove portion is removed again to form a conductor layer by plating with Au or the like on the back surface to form a conductor layer 14 ′ on the back surface by plating. In this second example, the conductor layer 14 'on the back surface is formed by the two steps of first forming the conductor layer by plating only on the through-hole portion and then again forming the conductor layer by plating on the entire back surface.
Even if the through hole is narrowed, a conductor layer 14 'can be uniformly plated on that portion.

[Means for solving problems]

A method of manufacturing a semiconductor device according to the present invention comprises a step of forming an insulating film having openings on a surface of the insulating substrate, the insulating film having openings on a first conductor layer having a predetermined pattern formed on the surface of the insulating substrate. Forming a second conductor layer connected to the first conductor layer through the opening on the insulating film, forming a through hole from the back surface to the first conductor layer in the insulating substrate, and The method includes a step of forming a third conductor layer that fills the through hole by plating, and forms a third conductor layer that is connected to the first conductor layer and extends to the back surface of the insulating substrate.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

1A to 1G are cross-sectional views of a semiconductor chip shown in the order of steps for explaining the first embodiment of the present invention.

In this embodiment, first, as shown in FIG.
After the source 3, the gate 4 and the drain are formed on the active layer 2 on the surface of the insulating substrate 1a having a thickness of 400 μm, the insulating film 6 having the openings and the polyimide film 7 are sequentially formed on the source 3.

Next, as shown in Fig. 1 (b), the thickness is about 2000Å
After forming the conductor layer 8 made of a Ti layer and connected to the source 3 through the opening on the polyimide layer 7, the surface of the insulating substrate 1a is attached to the quartz plate 10 via the photoresist film 9.

Next, as shown in FIG. 1 (c), the source 3 is formed on the insulating substrate 1 whose thickness is about 30 μm by polishing the back surface.
A through hole A reaching up to and a scribe groove B for dividing into semiconductor chips are formed.

Next, as shown in FIG. 1D, the through hole is filled with a conductor layer 11 made of Au and connected to the source 3 by plating.

Next, as shown in FIG. 1 (e), a conductor for plating consisting of a Ti layer having a thickness of 500Å and an Au layer having a thickness of 2000Å connected to the source 3 via the conductor layer 11 on the back surface of the insulating substrate 1. After forming the layer 12 and forming the photoresist film 13 in the scribe groove portion, the conductor layer 14 having a thickness of 50 μm is formed by Au plating.

Next, as shown in FIG. 1 (f), after removing the photoresist film 13 in the scribe groove portion, it is divided into semiconductor chips at the scribe line portion, and the photoresist film 9 is dissolved and removed to dissolve the quartz plate 10. The semiconductor chip is separated from.

Finally, the conductor layer 8 made of a Ti layer is removed with a hydrofluoric acid-sulfuric acid-based etching solution, and then the polyimide film is removed with an aqueous solution of hydrazine to obtain a semiconductor device including a GaAs FET shown in FIG. 1 (g).

FIG. 2 is a sectional view of a semiconductor chip for explaining the second embodiment of the present invention.

In the second embodiment, as shown in FIG. 2, a polyimide layer 7 is not formed on the insulating film 6 and a conductor layer 8 made of a Ti layer having a thickness of about 2000Å is directly formed on the insulating film 6 and then a photoresist is formed. The surface of the insulating substrate 1a is attached to the quartz plate 10 by the film 9.

Thereafter, the same steps as those in the first embodiment are carried out, and the process shown in FIG.
A semiconductor device including the GaAs FET shown in can be obtained.

However, since the polyimide film 7 is not provided in the second embodiment, the surface of the insulating film 6 below is also slightly etched when the conductor layer 8 made of the Ti layer is removed with a hydrofluoric acid-sulfuric acid based etching solution. Since the step of forming the polyimide film 7 is unnecessary, the manufacturing process is shortened as compared with the first embodiment.

In the embodiment of the present invention, the conductor layer 8 connected to the source 3 is also used.
Although a Ti layer is used as the above, of course, a transparent conductor layer such as conductive glass may be used.

〔The invention's effect〕

As described above, in the present invention, by forming a conductor layer in a state of filling a through hole from the back surface of the insulating substrate to the front surface, and flattening the back surface of the insulating substrate, particularly the through hole portion, There is an effect that the conductor layer composed of the plated layer can be uniformly formed.

[Brief description of drawings]

1 (a) to 1 (g) are sectional views of a semiconductor chip shown in the order of steps for explaining the first embodiment of the present invention, and FIG. 2 is for explaining the second embodiment of the present invention. 3A to 3E are sectional views of the semiconductor chip shown in the order of steps for explaining the first example of the conventional method for manufacturing a semiconductor device, and FIG. FIG. 9 is a cross-sectional view of a semiconductor chip for explaining a second example of the method for manufacturing the semiconductor device of FIG. 1, 1a ... Insulating substrate, 2 ... Active layer, 3 ... Source, 4
... gate, 5 ... drain, 6 ... insulating film, 7 ... polyimide film, 8 ... conductor layer, 9 ... photoresist film, 10
...... Quartz plate, 11,12,12 '... Conductor layer, 13,13' ... Photoresist film, 14,14 '... Conductor layer, A, A' ... Through hole, B,
B '... scribe groove.

Claims (1)

[Claims] 1. A step of forming, on the surface of the insulating substrate, an insulating film having openings on the first conductor layer having a predetermined pattern formed on the surface of the insulating substrate. A step of forming a second conductor layer connected to the first conductor layer through an opening, a step of forming a through hole from the back surface to the first conductor layer in the insulating substrate, and a step of plating the through hole Filling the third conductor layer to a height substantially flush with the back surface of the insulative substrate to form a conductor layer for extraction from the first conductor layer to the back surface of the insulative substrate. A method of manufacturing a semiconductor device, comprising: