JPH04302142A - Manufactuer of semiconductor device - Google Patents

Abstract

PURPOSE:To remove the deposite produced during the reactive ion etching of a resist film by a multilayer resist method or similar one. CONSTITUTION:The deposit 8 produced on the sidewall of a resist pattern 7 during reactive ion etching is removed by an aqueous solution of ammonium fluoride and acetic acid. Accordingly, the deposite can be efficiently removed causing no damage to the underneath aluminum based substrate.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a method for manufacturing a semiconductor device, and more specifically, the present invention relates to a method for manufacturing a semiconductor device, and more specifically, in pattern formation in a dry development process on an aluminum-based substrate, the formation of a pattern during oxygen-based (O2/CO2) reactive ion etching of a resist. The present invention relates to a method for removing deposits.

0002

[Prior art and problems to be solved by the invention] Conventionally,
Multilayer resist methods and silylation methods are used to form patterns on aluminum-based substrates containing silicon. A resist film is previously formed on the aluminum-based substrate during pattern formation on the aluminum-based substrate, but when patterning this resist film by oxygen-based (O2/CO2) reactive ion etching, deposits are deposited on the side walls of the resist pattern. It was inevitable that it would stick to the surface. This deposit is caused by sputtering of aluminum on the substrate by incident ions, and this deposit is estimated to be a compound consisting of aluminum, oxygen, and carbon. When it comes to leaving this deposit on the sidewalls of the resist pattern,
The aluminum-based substrate is etched while the line width controllability is deteriorated, and a residue is generated during etching. Therefore, it is necessary to remove the deposits, but conventionally a dilute hydrofluoric acid aqueous solution has been used, but in this case it damages the aluminum-based substrate itself and is not effective. The present invention provides a method for manufacturing a semiconductor device in which deposits can be efficiently removed without damaging an aluminum-based substrate.

0003

Means and Effects for Solving the Problems The present invention provides a method for removing an aluminum substrate having a resist film on its upper surface using a predetermined pattern of the resist film, in which the resist film is removed in the presence or absence of carbon dioxide gas. Then, the deposits generated by the above-mentioned reactive ion etching method remaining on the side walls of the predetermined pattern are removed with an aqueous solution of ammonium fluoride and acetic acid. This method of manufacturing a semiconductor device comprises thereafter etching the aluminum-based substrate to form a pattern thereof. As the aluminum-based substrate in this invention, an aluminum substrate containing silicon is preferred. The reactive ion etching method (RIE) in this invention
The reactive ions used in this method are usually O2 gas and CO
A mixture of two gases is often used, or O2 gas alone is often used. As the etching conditions (gas amount, temperature) using O2 gas and CO2 gas, known conditions can be applied. This RIE method is used to form a resist pattern used as a mask when etching an aluminum-based substrate. At this time, the height H of the resist pattern 7 is 1.0 to 0.20 μm, and the maximum thickness D of the deposit 8 is estimated to be at most 0.05 to 0.0 μm.
．． It is 20 μm. In the method of this invention, the above deposits are removed with an aqueous solution of ammonium fluoride and acetic acid. Although the concentrations of ammonium fluoride and acetic acid in the aqueous solution are not particularly limited, it is preferable that the aqueous solution contains about 20% ammonium fluoride and about 40% acetic acid. The treatment time for this aqueous solution is, for example, 5 to 30 seconds. As the treatment method, any of a dipping method, a spray paddle method, etc. can be used. Here, in the spray paddle method, as shown in FIG. 6, a wafer including an aluminum-based substrate 1 is stored in a spin cup 18 while being supported by a chuck 19, and the aqueous solution 16 is sprayed from a spray nozzle 20 provided above. This method involves spraying the liquid onto the wafer.

[0004] An embodiment of the present invention will be explained. A pattern forming method using a multilayer resist method will be explained. First, as shown in FIG. 9, 2.
A lower resist film (9) with a thickness of 0 μm is laminated and then baked. Next, an SOG film (10) is applied to a thickness of 1500 Å and then baked, followed by an upper resist film (11) with a thickness of 1.10 μm. After coating, perform baking (see Figure 9).
, perform exposure and development to form an upper resist pattern (12) (Fig. 10), and use this as a mask to perform SOG by RIE.
Remove the membrane (10) (see Figure 11). Next, using the SOG pattern (13) as a mask, the lower resist film (9) is dry etched under O2/CO2 to remove the pattern (
7) (see Figure 1). At this time, the height H is 2.0
A deposit 8 with a maximum width D of 0.10 μm is generated on the sidewall of a resist pattern of μm (see FIGS. 4 and 1).
. Next, as shown in Figure 5, by the immersion method, the volume ratio was
:CH3COOH:H2O=1:2:2 aqueous solution treatment allowed the deposits to be completely removed from the side walls (see FIG. 2). At this time, as shown in FIG. 5, as an apparatus for the immersion method, an etching container 15 containing the aqueous solution 16 is used.
The wafer containing the substrate 1 was placed on the carrier 17 and placed in the container 15 for 5 to 30 seconds. After removing the deposits, the Al substrate 1 is etched to have a width W as shown in FIG.
An Al pattern 21 having a thickness of 0.8 μm was formed. In this way, in this example, the volume 8 on the side wall of the resist pattern 7 is prevented from being etched by the aqueous solution, unlike when immersed in hydrofluoric acid, and the Al/substrate is not etched.
(i) It can be completely removed without any residue or pattern deterioration. Furthermore, (ii) the shape shown in FIG. 7 can be formed without producing an undercut portion 22 as shown in FIG. 8 at the interface between the Al substrate 1 and the resist pattern 7, and (iii) the Al substrate is not damaged. It has the effect of not being there.

[0005]

As described above, according to the present invention, N is effective for removing deposits generated during reactive ion etching of a resist film in a multilayer resist method or silylation method.
Since this was carried out using an H4F/CH3COOH aqueous solution, complete removal was possible and good results were obtained.

[Brief explanation of drawings]

FIG. 1 is a configuration explanatory diagram showing one step of a manufacturing process in a first embodiment of the present invention.

FIG. 2 is a configuration explanatory diagram showing one step of the manufacturing process in the above embodiment.

FIG. 3 is a configuration explanatory diagram showing one step of the manufacturing process in the above embodiment.

FIG. 4 is an explanatory diagram of the main part configuration for explaining the removal of deposits in the above embodiment.

FIG. 5 is a configuration explanatory diagram for explaining one method used in the first embodiment.

FIG. 6 is a configuration explanatory diagram showing a second embodiment of the invention.

FIG. 7 is a configuration explanatory diagram showing a preferred step in the above two embodiments of the present invention.

FIG. 8 is a configuration explanatory diagram showing one unfavorable step in the above two embodiments of the present invention.

FIG. 9 is a configuration explanatory diagram showing the first step in the manufacturing process of the first embodiment.

FIG. 10 is a configuration explanatory diagram showing the second step in the manufacturing process of the first embodiment.

FIG. 11 is a configuration explanatory diagram showing the third step in the manufacturing process of the first embodiment.

[Explanation of symbols]

1 Al substrate 9 Lower resist (resist film) 7 Resist pattern of lower resist (predetermined pattern of resist film) 8 Deposit 16 Aqueous solution of ammonium fluoride and acetic acid 21 A
l pattern

Claims (1)

[Claims] 1. When removing an aluminum-based substrate having a resist film on its upper surface using a predetermined pattern of the resist film, the resist film is removed using reactive ions using oxygen gas in the presence or absence of carbon dioxide gas. removing it in a predetermined pattern by etching, and then removing the deposits generated by the above-mentioned reactive ion etching method remaining on the sidewalls of the predetermined pattern with an aqueous solution of ammonium fluoride and acetic acid,
A method of manufacturing a semiconductor device, comprising: thereafter etching the aluminum-based substrate to form a pattern thereof.