JP3134093B2 - Method of forming platinum pattern - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a platinum pattern by etching.

[0002]

2. Description of the Related Art In recent years, while a gas is being pumped from a nozzle hole into a gas passage by a pump, a gas flow is generated straight toward a heat wire pair formed of a heat-sensitive resistance element provided in the gas passage. In a gas rate sensor that is configured to electrically detect a deflection state of a gas flow when an external angular velocity is applied by a heat wire pair,
The nozzle holes and gas passages are formed by etching the semiconductor substrate by micromachining, and platinum, which is the material of the heat wire, is formed on the surface of the bridge formed in the gas passages by vapor deposition or the like. A pattern has been developed in which a pair of heat wires is formed in a pattern by etching the platinum layer using a mask (JP-A-3-29858).
Reference).

Conventionally, to form a platinum pattern, FIG.
As shown in FIG. 5, after a platinum layer 2 is formed on a pattern forming surface 1, a mask 4 such as a resist is directly applied on the platinum layer 2 as shown in FIG.
Predetermined patterning is performed by dry etching using E or the like.

[0004]

The problem to be solved is that when an etching process is performed by directly applying a mask 4 on the platinum layer 2, as shown in FIG. 2 grows along the end face of the mask 4 from the upper end face of the etch, and the sidewall 5 is formed. As shown in FIG. 6, when the mask 4 is removed after the etching process, the sidewall 5 Is to remain.

[0005]

SUMMARY OF THE INVENTION The present invention provides a method for forming a platinum film so that a sidewall formed on an end face of a mask due to the growth of a reaction product during etching does not remain on the platinum pattern when the mask is removed. After forming a buffer layer made of a material having an etching rate higher than that of platinum on the layer, a mask is applied on the buffer layer to etch the platinum layer and the buffer layer. The growth from the upper end of the etch face is prevented.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In a method for forming a platinum pattern according to the present invention, as shown in FIG.
And a buffer layer 3 made of a material such as SiN having a higher etching rate than platinum is formed to a thickness of about 500 nm on the platinum layer 2 by vapor deposition or sputtering. A second step of forming a platinum layer 2 by applying a mask 4 such as a resist on the buffer layer 3 as shown in FIG.
And a third step of the buffer layer 3 is dry-etched, as shown in FIG. 3, the etching after the etching
And a fourth step of removing the mask 4 together with the reaction product .

According to the present invention, when the etching is performed on the platinum layer 2 with the mask 4 interposed therebetween via the buffer layer 3, as shown in FIG. also proceed faster because the high etching rate etching, the state recessed than the etch end surface of the platinum layer 2.

Therefore, the side wall 5 is formed by growing the product of the etching reaction from the lower part of the end face of the mask 4 along the end face without growing from the upper part of the etch end face of the platinum layer 2.

Therefore, the side wall 5 formed on the end face of the mask 4 is completely separated from the etch end face of the platinum layer 2, and as shown in FIG. 3, when the mask 4 is removed after the etching process. The sidewalls 5 are also removed, so that a platinum pattern having a sharp edge can be obtained.

[0010]

As described above, in the method of forming a platinum pattern according to the present invention, a buffer layer made of a material having a higher etching rate than platinum is formed on a platinum layer, and a mask is formed on the buffer layer. the platinum layer and the buffer layer by dry etching Te, Ba than platinum layer
The etching of the buffer layer proceeds quickly, and the etch end of the platinum layer
By being recessed from the surface, a reaction product at the time of etching can be prevented from growing from above the etch end face of the platinum layer, and the sidewall formed on the mask end face by the product can be used as a mask. There is an advantage that a platinum pattern having a sharp edge shape can be easily obtained by being removed with removal and not remaining on the platinum pattern.

[Brief description of the drawings]

FIG. 1 is a front sectional view showing a state in which a platinum layer, a buffer layer, and a mask are formed on a pattern formation surface according to the present invention.

FIG. 2 is a front sectional view showing an etched state of a platinum layer and a buffer layer according to the present invention.

FIG. 3 is a front sectional view showing a state where a mask is removed after etching according to the present invention;

FIG. 4 is a front sectional view showing a state where a platinum layer and a mask are formed on a conventional pattern forming surface.

FIG. 5 is a front sectional view showing a conventional state of etching a platinum layer and a buffer layer.

FIG. 6 is a front sectional view showing a state in which a mask is removed after etching according to the related art.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pattern formation surface 2 Platinum layer 3 Buffer layer 4 Mask 5 Side wall

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Takashi Hosoi 1-4-1 Chuo, Wako-shi, Saitama Pref. Honda Technical Research Institute Co., Ltd. (56) References JP 4-162429 (JP, A) JP 62-222658 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) H01L 21/302 H01L 21/3205-21/3213 H01L 21/768

Claims (1)

(57) [Claims] 1. A first method for forming a platinum layer on a pattern forming surface.
A second step of forming a buffer layer made of a material having an etching rate higher than that of platinum on the platinum layer, and a third step of dry- etching the platinum layer and the buffer layer using a mask on the buffer layer. And a fourth step of removing the mask together with a reaction product at the time of etching after etching .