JP2000038579A - Etching gas - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an etching gas which is excellent in etching objects with intricate shapes and enables good etching to be carried out at a high speed by incorporating, into the same, a gas which is for removing certain parts of a film deposited on a substrate and comprises a compd. of the formula: (CF3)2CHOH or the like. SOLUTION: This etching gas contains a gas which is for removing certain parts of a film deposited on a substrate (e.g. a silicon wafer) and is represented by the formula, such as (CF3)2CHOH, and at least one hydrogen-contg. compd. gas (e.g. H2, CH4, NH3, HI, HBr, or HCl) in a ratio of flow rate of the latter gas to the former of 4 or lower. When anisotropic etching is carried out, the gas pressure is pref. 0.01-5 Torr; the gas flow rate, pref. 10-1,000 SCCM; and the gas temp., pref. 400 deg.C or lower. Etching with this etching gas can be conducted under the conditions of plasma etching, reactive plasma etching, microwave etching, etc. The deposit on the substrate is an oxide, nitride, carbide, or the like of B, P, W, Si, T, V or the like. In the formula, X is F, Cl, Br or the like; and R is H, CH2F, CHF2 or the like.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an etching gas suitable for manufacturing semiconductor devices such as LSIs and TFTs.

[0002]

2. Description of the Related Art In a thin film device manufacturing process, an optical device manufacturing process and a super steel material manufacturing process mainly in the semiconductor industry, CVD is used.
Various thin films, thick films, powders, and whiskers have been manufactured by using a method, a sputtering method, a sol-gel method, and an evaporation method. When these are produced, deposits are also formed on the inner wall of the reactor other than on the target on which films, whiskers and powders are to be deposited, jigs carrying the target, and the like. The generation of unnecessary deposits causes the generation of particles, which makes it difficult to produce high quality films, particles, and whiskers, and must be removed as needed. In addition, it is necessary to perform gas etching to partially remove the thin film material in order to form a circuit pattern on various thin film materials constituting a circuit in a semiconductor, a TFT, and the like. Further, in CVM (chemical vapor machining), , Si ingots and the like must be cut by gas etching.

At present, etching for forming a circuit and C
For cleaning of a thin film forming apparatus such as a VD apparatus, CF ₄ ,
Gases such as C ₂ F ₆ , CHF ₃ , SF ₆ and NF ₃ are used, but these have a problem in that they have a high global warming potential. Further, since these are relatively stable gases, CF ₃ radicals and F
In order to generate radicals and the like, high energy is required, and there is a problem that power consumption is large and it is difficult to treat a large amount of unreacted exhaust gas.

[0004]

The present inventors have made intensive studies and have found that a gas comprising a compound represented by the chemical formula (1) has excellent etching ability, and have reached the present invention.

That is, the present invention provides a compound represented by the following chemical formula (1):

[0006]

Embedded image

[0007] It is an object of the present invention to provide an etching gas containing at least one gas composed of a compound consisting of: The etching gas of the present invention is obtained by depositing B, P, W, S on a substrate such as a silicon wafer, metal plate, glass, single crystal, or polycrystal.
i, Ti, V, Nb, Ta, Se, Te, Mo, Re,
It is used as an etching gas for Os, Ir, Sb, Ge, Au, Ag, As, Cr and compounds thereof, specifically, oxides, nitrides, carbides and alloys thereof.

The etching gas of the present invention has been conventionally used
CF_Four, C_TwoF₆, SF₆, NF _ThreeCompared to
Excellent etching accuracy. Also cleaning gas
High compared to supply molecular weight
The feature is that the etching rate can be taken.

The etching method using the gas of the present invention comprises:
It can be performed under various dry etching conditions such as plasma etching, reactive plasma etching, and microwave etching, and these etching gases and He,
An inert gas such as N ₂ or Ar, or HI, HBr,
HCl, CO, NO, O ₂ , CH ₄ , NH ₃ , H ₂ , C ₂ H ₂
It may be used by mixing it with an appropriate gas at an appropriate ratio. In particular, when used as an etching gas, hydrogen, CH ₄ , NH ₃ , HI, and HBr are used for the above-described etching gas used in the present invention in order to reduce the amount of F radicals that promote isotropic etching. It is particularly desirable to use a hydrogen-containing compound gas such as HCl mixed at a flow rate of 4 times or less. Mixing more than 4 times the amount of hydrogen or a hydrogen-containing compound gas is not preferable because the amount of F radicals effective for etching is significantly reduced. The pressure when using, in order to perform anisotropic etching,
The gas pressure is preferably set to 5 Torr or less, but a pressure of 0.01 Torr or less is not preferable because the etching rate is reduced. The gas flow rate used is
The etching is preferably performed at a flow rate of 10 SCCM to 1000 SCCM, depending on the reactor capacity of the etching apparatus and the wafer size. Further, the etching temperature is preferably 400 ° C. or lower. If the temperature is 400 ° C. or higher, the etching tends to progress isotropically, and the required processing accuracy cannot be obtained, and the resist is not preferably etched. .

Further, the etching gas of the present invention is easily decomposed. It can be dissolved in water, an aqueous alkaline solution, or an acidic aqueous solution or can be decomposed by these solutions, and has a low environmental load.

[0011]

Hereinafter, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

Examples 1 to 20 and Comparative Example 1 In Examples 1 to 20, the gas of the present invention was applied to contact hole processing and applied to etching of an interlayer insulating film (SiO ₂ ). The sample used in the present embodiment is obtained by depositing Si on a single crystal silicon wafer 1 as shown in FIG.
An O ₂ interlayer insulating film 2 is formed, and a resist mask 3 having an opening as an SiO ₂ etching mask is formed.

[0013] The wafer is placed in an etching apparatus provided with a power supply for supplying high frequency power of 13.56 MHz,
The processing shape around the resist opening and the ratio of the SiO ₂ etching rate to the resist (resist selectivity) were measured. As an example, etching of SiO ₂ was performed under the following conditions. (Conditions) Reaction gas flow rate: 25 SCCM Ar flow rate: 50 SCCM Gas pressure: 0.2 Torr RF power density: 2.2 W / cm ²

[0014]

[Table 1]

Table 1 shows the obtained results. By using the etching gas of the present invention, a high-speed etching rate can be obtained, and a high selectivity to a resist can be obtained. In addition, it is preferable for the resist to have an etching characteristic with no shoulder drop for the processing for forming a wiring hole with high accuracy, but by using the gas of the present invention, a processed shape without the shoulder drop can be obtained. (Shown in FIG. 1 (b)). In Table 1, a circle of CD loss indicates that there is no shoulder drop, and a triangle indicates that shoulder drop is recognized. As a comparative example, CF ₄ gas was used.

Examples 21 to 26 (CF ₃ ) ₂ CHOCH ₂ F and H ₂ , CH ₄ , NH ₃ , HB
Examples 1 to 20 using a mixed gas of r, HI and HCl
An etching test similar to that described above was performed under the following conditions. As a result, both the selectivity to resist and the CD loss were improved as compared with the case where they were not mixed. The results are shown in Table 2. (Conditions) Reaction gas flow rate: 25 SCCM Hydrogen-containing gas flow rate: 2.5 SCCM Ar flow rate: 50 SCCM Gas pressure: 0.2 Torr RF power density: 2.2 W / cm ²

[0017]

[Table 2]

[0018]

The etching gas of the present invention is excellent in a processed shape and can perform good etching at high speed.

[Brief description of the drawings]

1A is a schematic cross-sectional view of an etching sample used in Examples 1 to 20 and Comparative Example 1, and FIG.
FIG. 3 shows a schematic cross-sectional view after etching.

[Explanation of symbols]

Reference Signs List 1 silicon wafer 2 SiO ₂ interlayer insulating film 3 resist mask

Continued on the front page (72) Inventor Mitsuya Ohashi 2805 Imafukunakadai, Kawagoe-shi, Saitama F-term in the Chemical Research Laboratory, Central Glass Co., Ltd. 5F004 AA02 DA00 DA22 DA23 DA24 DA25 DA26 DA29 DB03 DB08 DB12 DB13

Claims (2)

[Claims] 1. A chemical formula (1) for removing a predetermined portion of a film deposited on a substrate. An etching gas containing a gas comprising a compound represented by the formula: 2. A chemical formula (1) for removing a predetermined portion of a film deposited on a substrate. An etching gas containing a gas consisting of a compound represented by the formula and hydrogen or a hydrogen-containing compound gas.