JPH0637070A - Manufacture of semiconductor device and semiconductor element - Google Patents

Abstract

PURPOSE:To restrain a second layer as much as possible from being formed discontinuously on a first layer which is etched to steps. CONSTITUTION:In a semiconductor element manufacturing method wherein a part of a first layer 7 laminated on a semiconductor substrate 1 is etched to steps and a second layer 10 is laminated thereafter, a second etching treatment is performed wherein an upper surface part of the first layer 7 and a side part of the step-etched part are etched simultaneously after a first etching treatment wherein the first layer 7 is etched to steps.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a semiconductor device in which a part of a first layer laminated on a semiconductor substrate is stepwise etched and then a second layer is laminated.

[0002]

2. Description of the Related Art In such a semiconductor device manufacturing method, the first layer is generally etched by covering a non-etched portion of the first layer which is left unetched with a resist or the like and RI.
After etching by dry etching such as E or wet etching using an etching solution, the resist and the like are removed. As a result, the portions removed by etching and the portions not etched were stepwise. In this etching process, since sharp edges are formed at the corners of the stepped portion, the second layer to be laminated next becomes discontinuous at this stepped portion, and a uniform layer cannot be formed. was there. If the second layer is formed discontinuously, for example, if the second layer is a layer forming an electrode, uniform current cannot be obtained over the entire surface of the second layer, resulting in a defective product. However, there is a problem in that the manufacturing yield of semiconductor devices is reduced. For this reason, conventionally, a method of forming the stepped portion in a tapered shape to suppress the generation of the discontinuous portion of the second layer has been considered (Japanese Patent Laid-Open No. 3-278433).
(See the official gazette).

[0003]

However, in the above-mentioned prior art, sharp edges formed at the corners of the stepped portion still remain, and therefore, especially when the second layer is made thinner, the second layer is also used. The layers may be discontinuous,
The manufacturing yield may decrease. The present invention has been made in view of the above circumstances, and an object thereof is to provide a semiconductor element manufacturing method and a semiconductor element capable of suppressing the formation of the second layer in a discontinuous state as much as possible. It is in.

[0004]

A method of manufacturing a semiconductor device according to the present invention comprises a step of etching a part of a first layer laminated on a semiconductor substrate in a stepwise manner, and then laminating a second layer. The first feature is that the etching treatment is performed in the first
After the first etching process, which etches the layers stepwise,
The second etching process is performed to simultaneously etch the upper surface portion of the first layer and the side surface portion of the stepwise etched portion. A second feature is to limit the embodiment of the first feature, wherein the first etching treatment is performed on the first layer with the non-etched portion of the first layer covered with an etching stopper film. This is an etching process, and the second etching process is a process of etching the first layer with the etching stopper film removed.

Further, in the semiconductor element of the present invention, the first layer on the semiconductor substrate is laminated so that a part thereof has a penetrating portion penetrating in the layer thickness direction, and the first layer is formed on the first layer. A second layer is laminated so as to cover the upper surface of the first part and the inside of the through part, and the characteristic configuration is that the continuous part of the upper surface of the first layer and the inner surface of the through part has a protruding curved surface shape. It is in the point that is formed.

[0006]

According to the first feature of the method for manufacturing a semiconductor element of the present invention, when a part of the first layer laminated on the semiconductor substrate is stepwise etched, the first layer is first stepped. A first etching process for etching is performed. At the stage where the first etching process is performed, the side surface of the step-etched portion is vertical or nearly vertical, and a sharp edge is formed at the corner of the step-shaped portion. ing. And after the first etching process,
Second etching is performed to simultaneously etch the upper surface portion of the first layer and the side surface portion of the stepwise etched portion.
When this second etching process is performed, sharp edges are removed at the corners of the stepped portion, and the stepped portion is tapered so that the inclination changes smoothly. By laminating the second layer on the thus-etched material, it is possible to suppress the second layer from being formed in a discontinuous state at the corners of the stepped portion as much as possible.

According to the second feature, first, the first etching process is performed on the first layer with the non-etched portion covered with the etching stopper film. At the stage of performing the first etching process, the non-etched portion covered with the etching stopper film remains without being etched, and the portion not covered with the etching stopper film is etched, resulting in the etching stopper. A step is formed between the portion covered with the film and the portion not covered with the film, which results in stepwise etching. A sharp edge is formed at the corner of the stepped portion of this stepwise etched portion. And the first
After the etching process of, the etching stop film is removed,
A second etching process is performed. In the second etching process, the etching stop film is removed, so that the first etching process is performed.
In this etching process, the upper surface portion of the first layer that was not etched and the side surface portion that was stepwise etched were simultaneously etched, and as a result, sharp edges were removed at the corners of the stepped portion. The stepped portion has a tapered shape in which the inclination changes smoothly. By laminating the second layer on the thus-etched product, it is possible to suppress the second layer from being formed in a discontinuous state at the corners of the stepped portion as much as possible.

Further, according to the characteristic structure of the semiconductor element of the present invention, since the continuous portion of the upper surface of the first layer and the inner surface of the penetrating portion is formed in a projecting curved surface, the upper portion of the first layer is The laminated state of the second layer laminated so as to cover the upper surface of the first layer and the inside of the penetrating portion depends on the thickness of the layer laminated on the continuous portion between the upper surface of the first layer and the inner surface of the penetrating portion. However, the layers are laminated without becoming so thin as compared with the layer thicknesses laminated on other portions. Therefore, even if the laminated layer thickness of the entire second layer varies, it is possible to form the second layer in a discontinuous state on the continuous portion between the upper surface of the first layer and the inner surface of the through portion. The element structure can be suppressed.

[0009]

The first aspect of the method for manufacturing a semiconductor device of the present invention is as follows.
According to the feature, the second feature, or the feature configuration of the semiconductor element of the present invention, it is possible to suppress the formation of the second layer in a discontinuous state as described above, and thus the semiconductor element It is possible to suppress the decrease in the manufacturing yield of the device as much as possible.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment in which the present invention is applied to a manufacturing process of a semiconductor laser device will be described with reference to the drawings. In the element cross-sectional views in each step of the manufacturing process of the semiconductor laser element shown in FIGS. 1 to 6, first, as shown in FIG. 1, M on a wafer-shaped n-type GaAs substrate 1 as a semiconductor substrate,
The n-type GaAs buffer layer 2, the n-type AlGaAs cladding layer 3, and the undoped AlG are formed by the crystal growth method such as the BE method.
The aAs active layer 4, the p-type AlGaAs clad layer 5, and the p-type GaAs cap layer 6 are sequentially laminated, and the SiO ₂ insulating film 7 as the first layer laminated on the semiconductor substrate 1 is further formed by the CVD method or the sputtering method. Etc. to form a film.

Then, as shown in FIG. 2, SiO₂Insulation film 7
Stripped pattern on top of the layer as an etching stop film.
A dist film 8 is formed. Stripe the resist film 8
The work to remove is performed by photolithography the uniformly applied resist film.
It may be removed by etching using Ruffy's technique. This
The resist film 8 is formed by using a hydrofluoric acid-based etchant.
Soaking in SiO2 solution ₂First etch for insulating film 7
Perform processing. This first etching process is completed
And, as shown in FIG.₂Insulating film 7 resist film
The striped part not covered by 8 penetrates in the layer thickness direction.
The through portion P is formed by being removed by etching while passing through.
It In the penetration portion P, SiO₂The insulating film 7 has a stepped shape.
Is being touched.

Next, the resist film 8 is removed by etching, and the SiO ₂ insulating film 7 is subjected to a second etching treatment by immersing it again in a hydrofluoric acid-based etching solution. The etching time at this time is considerably shorter than that of the first etching process. Further, instead of shortening the etching time, the concentration of the etching solution may be reduced. When this second etching process is completed, the SiO ₂ insulating film 7 is wholly etched as shown in FIG. FIG. 6 shows changes in the cross-sectional shape of the stepwise etched portion of the SiO ₂ insulating film 7 before and after the second etching treatment. In FIG. 6, the shape of the SiO ₂ insulating film 7 changes from the state before etching shown by the solid line to the state after etching shown by the dotted line B. By the second etching process,
The sharp edges of the corners of the stepwise etched portion of the SiO ₂ insulating film 7 are removed to form a taper shape in which the inclination changes smoothly. That is, the connecting portion between the upper surface of the SiO ₂ insulating film 7 and the inner surface of the penetrating portion P has a protruding curved surface shape.

After the second etching treatment, as shown in FIG. 5, an n-side electrode 9 is formed on the n-type GaAs substrate 1 side and a p-side electrode 10 is formed on the SiO ₂ insulating film 7 side as a second layer. still,
This semiconductor laser device in a wafer state is to be separated in parallel with the stripe-shaped portion of the SiO ₂ insulating film 7 at the position of the dotted line A in FIG. 5, and cleaved in parallel with the cross section shown in FIG. Are separated into individual elements.

In the semiconductor laser device manufactured as described above, since the p-side electrode 10 is connected without interruption in the stepwise etched portion of the SiO ₂ insulating film 7, the p-side electrode 10 is connected. Even if a wire such as an Au wire is connected to the upper portion of the portion where the SiO ₂ insulating film 7 remains, the current injected from the p-side electrode 10 is applied to the portion of the SiO ₂ insulating film 7 that is removed in a stripe shape. Pass through the active layer 4
And contributes to laser emission.

[Other Embodiments] Other embodiments will be listed below. In the above-described embodiment, both the first etching process and the second etching process for the first layer 7 are performed by wet etching using an etching solution.
Either or both of the etching process and the second etching process may be performed by dry etching such as RIE.

[0016]

In the above embodiments, the present invention is applied to the semiconductor laser device or the manufacturing process thereof, but it can be applied to other semiconductor devices such as IC of Si or GaAs or the manufacturing process thereof.

In the above embodiment, the first layer is the SiO ₂ insulating film 7 and the second layer is the p-side electrode 10.
Either the layer or the second layer, or both of them are semiconductor layers.

It should be noted that reference numerals are given in the claims for convenience of comparison with the drawings, but the present invention is not limited to the configurations of the accompanying drawings by the entry.

[Brief description of drawings]

FIG. 1 is a diagram showing a part of a manufacturing process of a semiconductor laser device according to an embodiment of the present invention.

FIG. 2 is a diagram showing a part of a manufacturing process of a semiconductor laser device according to an embodiment of the present invention.

FIG. 3 is a diagram showing a part of a manufacturing process of a semiconductor laser device according to an embodiment of the present invention.

FIG. 4 is a diagram showing a part of a manufacturing process of a semiconductor laser device according to an embodiment of the present invention.

FIG. 5 is a diagram showing a part of a manufacturing process of a semiconductor laser device according to an embodiment of the present invention.

FIG. 6 is a partial enlarged view in a manufacturing process of a semiconductor laser device according to an embodiment of the present invention.

[Explanation of symbols]

 1 Semiconductor Substrate 7 First Layer 10 Second Layer

Claims (3)

[Claims] 1. A method for manufacturing a semiconductor device, comprising a step of etching a part of a first layer (7) laminated on a semiconductor substrate (1) and then laminating a second layer (10), After the first etching process of etching the first layer (7) stepwise, the upper surface portion of the first layer (7) and the side surface portion of the stepped portion are etched. A method of manufacturing a semiconductor device, which comprises performing a second etching process of etching at the same time. 2. The first etching process is the first etching process.
A process of etching the first layer (7) with the non-etched portion of the layer covered with an etching stop film (8),
The method of manufacturing a semiconductor device according to claim 1, wherein the second etching process is a process of etching the first layer (7) with the etching stopper film (8) removed. 3. The first layer (7) on the semiconductor substrate (1) comprises:
It is laminated so that a part of it has a penetrating part (P) penetrating in the layer thickness direction, and the upper surface of the first layer (7) and the inside of the penetrating part (P) are covered with it. Second layer (1
0) is a laminated semiconductor device, wherein the continuous portion of the upper surface of the first layer (7) and the inner surface of the penetrating portion (P) is formed into a protruding curved surface.