JPH06275580A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To remove a polymeric etching product generated at the time of etching a polysilicon film with a chlorine gas. CONSTITUTION:After etching a polysilicon film 2, a polymeric etching product 4 generated at the time of etching the film 2 is changed to a water-soluble substance in the dry etching plasma atmosphere of a fluorocarbon gas by dry- etching a silicon oxide film of about 5-10Angstrom in thickness with the fluorocarbon gas and the water-soluble substance is removed by wet cleaning.

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 using polysilicon wiring.

[0002]

2. Description of the Related Art A conventional technique will be described with reference to the drawings. 2A to 2D are cross-sectional views in order of steps of a conventional semiconductor device. FIG. 2A shows a polysilicon film 2 formed on a base insulating film 1 on the surface of a semiconductor device, and a resist film 3 is patterned by a photolithography method. FIG. 2B shows a dry process using chlorine gas. The polysilicon film 2 is etched by an etching method until the surface of the base insulating film 1 is exposed. During this etching, the polymeric etching product 4 adheres to the side wall of the resist film 3. In FIG. 2C, the resist film 3 is ashed by plasma treatment using oxygen gas. FIG. 2D shows a semiconductor device whose surface has been cleaned by wet cleaning. As a conventional technique, the method of manufacturing a semiconductor device as described above has been known.

[0003]

However, in the conventional manufacturing method, the polymer-like etching product 4 generated during the etching of the polysilicon film 2 using chlorine gas remains even after the wet cleaning, which causes a particle contamination source. However, it has a drawback that the coating property of the upper layer film is adversely affected.

[0004]

In order to solve the above-mentioned problems, the present invention uses a fluorocarbon gas for 5 to 1 after etching the polysilicon film 2 using chlorine gas.
A step of dry etching a silicon oxide film of about 0Å is added.

[0005]

By using the manufacturing method as described above, the polymer-like etching product 4 attached at the time of etching
Is altered by the reaction with the fluorocarbon radicals and fluorine radicals contained in the plasma, and can be stripped by the subsequent wet cleaning. Further, since the similar effect is also present in the wet type dilute hydrofluoric acid cleaning, the polymer-like etching product 4 contains a silicon-silicon and a silicon-oxygen bond, and the fluorocarbon radical and the fluorine It is considered that the substance became water-soluble by being fluorinated by contact with radicals.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. 1A to 1E are cross-sectional views in order of steps of a semiconductor device showing an embodiment of the present invention. Figure 1 (a)
A polysilicon film 2 is formed on the base insulating film 1 on the surface of the semiconductor device.
Is formed and the resist film 3 is patterned by photolithography. In FIG. 1B, the polysilicon film 2 is etched by a dry etching method using chlorine gas until the surface of the base insulating film 1 is exposed. is there. During this etching, the polymeric etching product 4 adheres to the side wall of the resist film 3. In FIG. 1 (c), a pressure of 450 mtorr and an oxygen flow rate of 1000 scc are obtained by a RIE type single-plate dry etching apparatus.
m, the CF4 gas flow rate is 10 sccm, and the power is 1000 W, and plasma processing is performed for 1 minute. During this plasma treatment, the polymer-like etching product 4 is altered and becomes water-soluble. Further, the silicon oxide film of about 10 Å is etched during this plasma treatment. FIG. 1 (d) shows the resist film 3 ashed by plasma treatment with oxygen gas, and FIG. 1 (e) shows the polymeric etching product 4 peeled off by wet cleaning. In the above-described examples, the polymer-like etching product 4 generated during the etching of the polysilicon film 2 using chlorine gas is exposed to CF ₃ radicals and F radicals, and becomes water-soluble. It can be peeled off by the wet cleaning process of 1 (e). Further, in FIG. 1 (c), instead of the oxide film etching conditions using CF ₄ + O _2, the same effect can be obtained with the oxide film etching conditions of CF ₄ + H ₂ and C ₂ F ₆ + O _2.

[0007]

As described above, according to the present invention, after the etching of the polysilicon film using chlorine gas,
By dry-etching a silicon oxide film of about 10Å using fluorocarbon gas, the polymer-like etching product generated during the etching of the polysilicon film becomes water-soluble in the fluorocarbon gas dry etching plasma atmosphere. It has the effect of changing the quality and allowing it to be peeled off by a wet cleaning process.

[Brief description of drawings]

1A to 1C are cross-sectional views in order of steps of a semiconductor device showing an embodiment of the present invention.

2A to 2D are cross-sectional views in order of steps of a conventional semiconductor device.

[Explanation of symbols]

 1 Base Insulating Film 2 Polysilicon Film 3 Resist Film 4 Polymeric Etching Product

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location 7514-4M H01L 21/88 M

Claims (1)

[Claims] 1. A step of forming a polysilicon wiring of a semiconductor device, a step of patterning a resist on the polysilicon film by a photolithography method, and a step of etching the polysilicon film by a dry etching method using chlorine gas. A semiconductor including a step of etching a silicon oxide film of about 5 to 10 Å by a dry etching method using a fluorocarbon gas, a step of ashing the resist film by a plasma treatment with oxygen gas, and a wet cleaning step. Device manufacturing method.