JPH0737846A - Rinsing liquid used after resist removal, semiconductor device and manufacture thereof - Google Patents

Abstract

PURPOSE:To neutralize an alkaline component mixed in a rinsing liquid from a resist release solution, and to prevent a wiring material from being corroded, by a method wherein the rinsing liquid consisting of water-soluble lower monohydric alcohol and an organic or inorganic acid or an organic or inorganic acid and water is used. CONSTITUTION:First, a CVD oxide film 2 forms on an Si substrate 1. A TiW layer 3, a CVD-W layer 4 and an Al-Si-Cu layer 5 form in order on the film 2, a P-type photoresist is applied on the layer 5, and exposed, and a mask consisting of the P-type photoresist 6 is made to form. Then, a conductive layer on a region not covered with the mask is removed by etching, and most of the resist 6 is removed by an ashing. At this time, resist residues 7 are left on the surface of the patterned conductive layer or the like, but these residues are removed using a release solution. Then, a semiconductor device is rinsed with a rinsing liquid consisting of isopropylalcohol containing an acetic acid of 0.333mol/liter, and thereafter, washed with water.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a rinse liquid used after resist stripping with an alkaline resist stripping liquid used in the process of manufacturing a semiconductor device. This rinse liquid is an excellent rinse liquid that does not cause corrosion of the wiring material such as Al-Si-Cu which is often used as the wiring material for high density integrated circuits.

[0002]

BACKGROUND ART In the process of manufacturing a semiconductor device, after forming a required photoresist mask, etching is performed to form a wiring pattern, and then an unnecessary resist layer including the resist layer on the wiring pattern is resisted. It is necessary to perform a rinse treatment of removing with a stripping solution, washing with a rinse solution, and washing with water.

In this case, an acidic or alkaline resist stripping solution is used as the stripping solution used for stripping the resist. As a typical acidic resist stripping solution, a stripping solution prepared by mixing an alkylbenzene sulfonic acid with a phenol compound, a chlorine-based solvent, an aromatic hydrocarbon, etc. is commercially available and used. However, it has a problem that pit-like corrosion occurs on the surface of a wiring material such as Al—Si—Cu which is often used in high-density integrated circuits due to alkylbenzene sulfonic acid. In addition, it is also a problem that it contains a highly toxic phenol compound and a chlorine-based solvent that causes environmental pollution. As a typical alkaline resist stripping solution, a stripping solution consisting of an organic alkali and various organic solvents is commercially available and used, and this alkaline resist stripping solution has low toxicity and influence on environmental pollution. Since it is small, it has been widely used in recent years. However, even in the alkaline resist stripping solution, as in the case of the above acidic resist stripping solution, although the resist stripping property is good, pit-like pits on the surface of the wiring material such as Al-Si-Cu due to the alkaline component. It has a problem to be solved that corrosion occurs.

[0004]

DISCLOSURE OF THE INVENTION The present inventors have found that Al-Si- which is generated in a stripping process using an alkaline resist stripping solution.
In order to solve the problem of the occurrence of pit-like corrosion on the surface of wiring materials such as Cu, the mechanism of the occurrence of corrosion was studied. As a result of such corrosion, the alkaline component mixed in the rinse liquid was peeled from the alkaline resist stripping solution. After confirming the fact that it occurs due to dissociation and dissociation during the washing step performed at the end of the step, and as a result of intensive research on a method for preventing such corrosion, (a) a water-soluble monovalent lower alcohol And an organic or inorganic acid, or (b)
By using a non-corrosive rinse liquid for a substrate, which comprises a water-soluble monohydric lower alcohol and an organic or inorganic acid and water, or (c) an organic or inorganic acid and water It has been found that the occurrence of such corrosion can be completely prevented. The present invention has been completed based on such findings.

That is, the present invention is a rinse liquid used after resist stripping with an alkaline resist stripper, which comprises (a) a water-soluble monohydric lower alcohol and an organic or inorganic acid, or (b) a water-soluble one. A non-corrosive rinse liquid for a substrate, which comprises a monohydric lower alcohol and an organic or inorganic acid and water, or (c) an organic or inorganic acid and water. Furthermore, the present invention provides a semiconductor device manufacturing method including a rinse step using such a rinse liquid, and a semiconductor device manufactured by the manufacturing method. By using the rinse liquid according to the present invention, the alkaline components mixed in the rinse liquid from the alkaline resist stripping liquid are neutralized, and the dissociation of the alkaline components during washing with water is completely suppressed.
Corrosion of wiring materials such as Si-Cu is prevented. Therefore, the rinse liquid according to the present invention is an excellent one that enables the production of high-precision and high-density circuit wiring. The present invention will be described in detail below.

Examples of the water-soluble monohydric lower alcohol used in the rinse liquid according to the present invention include isopropyl alcohol, n-propyl alcohol, ethanol, methanol and the like. These can be used alone or in combination of two or more.

Examples of the organic or inorganic acid used in the rinse liquid according to the present invention include acetic acid, sulfuric acid, nitric acid, oxalic acid, benzoic acid, dodecylbenzenesulfonic acid, or an aqueous solution thereof. The blending amount of these acids is an amount capable of neutralizing the alkaline components mixed from the alkaline resist stripping solution, and if an acid having a strong acidity is contained more than necessary, the acid will corrode the wiring material at the time of rinsing. The compounding amount is an amount suitable for each use. The amount of water in the rinse liquid is usually 50% of that of the rinse liquid.
An appropriate amount is less than 10% by weight, and an amount of 50% by weight or more is likely to cause dissociation of alkaline components mixed in the rinse solution, which tends to easily corrode wiring materials such as Al-Si-Cu in the rinse solution.

Other components may be added to the rinse liquid according to the present invention. Examples of these other components include surfactants for lowering the surface tension or for preventing reattachment of the resist to the substrate. In addition, sugars can be added.

Hereinafter, examples of the present invention will be listed together with comparative examples. Table 1 shows the evaluation results of the number of pits generated by corrosion with an optical microscope.

Examples and Comparative Examples The compositions of the stripping solution and the rinsing solution used in the examples are shown in Table 1. A two-layer film of TiW (lower layer) / Al-Si-Cu (upper layer) was formed on a silicon wafer, and a positive photoresist was applied so as to have a film thickness of 1.8 μm. It was then prebaked in an oven at 90 ° C for 10 minutes. After resist patterning, post-baking is performed at 140 ° C. for 30 minutes to remove each alkaline resist stripping solution.
The wafer was immersed at 100 ° C. for 10 minutes. After stripping the resist, each rinse solution was rinsed for 3 minutes, washed with water for 3 minutes and dried, and the number of pits generated by corrosion was evaluated using an optical microscope. The results are shown in Table 1.

[0011]

[Table 1]

[0012]

[Table 2] Note: DMSO: Dimethyl sulfoxide MEA: Monoethanolamine DMI: 1,3-Dimethyl-2-imidazolidinone IPA: Isopropyl alcohol MeOH: Methyl alcohol EtOH: Ethyl alcohol

In the examples using the rinse solution according to the present invention (Examples 1 to 13), corrosion of Al--Si--Cu was not observed, whereas in the case of the conventional product (Comparative Examples 1 to 1).
In 3), it was confirmed that significant corrosion occurred.

Example 14 Next, an example of manufacturing a semiconductor device to which the rinse liquid according to the present invention is applied will be described with reference to FIGS.

First, a CV which is an insulating film is formed on the Si substrate 1.
The D oxide film 2 is formed. A TiW layer 3 which is a first-layer metal film, a CVD-W layer 4 which is a second-layer metal film, and an Al-Si-Cu layer 5 which is a third-layer metal film are sequentially formed thereon (see FIG. 1). . The thickness of the CVD oxide film 2 is 4500Å,
The first layer metal film 3 is 600 Å and the second layer metal film 4 is 5000
Å, the third layer metal film 5 is 8000 Å. Also Al-S
As the i-Cu layer 5, one having a Si content of 1% by weight, a Cu content of 0.5% by weight was used.

Al-Si-Cu layer 5 which is the third metal film
Applying positive photoresist 6 on top (coating)
Then, it is exposed to light to form a mask of a positive photoresist (see FIG. 2). The positive photoresist 6 is mainly composed of a novolac resin and has a film thickness of 180.
It is 00Å. Further, after forming a positive photoresist mask, baking was performed at 140 ° C. for 30 minutes.

Next, the conductive layer in the region not covered with the mask (non-mask region) is removed by etching, and then the positive photoresist acting as the mask is removed by ashing for the most part (FIG. 3). At this time, the resist residue 7 remains on the patterned conductive layer surface or the like, but this is removed with dimethylsulfoxide / monoethanolamine / 1,3-dimethyl-2-imidazolidinone = 70/25/5 (% by weight) Remove with liquid. Then, the substrate is rinsed with a rinse liquid made of isopropyl alcohol containing 0.333 mol / l of acetic acid and then washed with water.

The rinse solution according to the present invention has a high cleaning ability and does not corrode the Al-Si-Cu layer of the wiring material. As can be seen from the results shown in Table 1, Al
The number of pits generated by corrosion on the surface of the -Si-Cu layer clearly shows that the rinse liquid according to the present invention is excellent. Since each of the components used in the rinse liquid according to the present invention has no danger to the human body in handling, the rinse liquid is extremely useful.

[Brief description of drawings]

FIG. 1 is a cross-sectional view schematically showing each layer on a semiconductor substrate in a manufacturing process of a semiconductor device.

FIG. 2 is a cross-sectional view schematically showing each layer on a semiconductor substrate in a manufacturing process of a semiconductor device.

FIG. 3 is a cross-sectional view schematically showing each layer on a semiconductor substrate in a manufacturing process of a semiconductor device.

FIG. 4 is a cross-sectional view schematically showing each layer on a semiconductor substrate in a manufacturing process of a semiconductor device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Si substrate 2 CVD oxide film 3 1st layer metal film 4 2nd layer metal film 5 3rd layer metal film 6 Positive photoresist 7 Resist residue

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masao Miyazaki 1-7-1 Inari, Soka City, Saitama Prefecture, Central Research Laboratory, Kanto Chemical Co., Inc. (72) Inventor Kiyoto Mori 1-7-1 Inari, Soka City, Saitama Prefecture Kanto Chemical Co., Ltd. Central Research Laboratory

Claims (3)

[Claims] 1. A rinsing liquid used after resist stripping with an alkaline resist stripping liquid, comprising (a) a water-soluble monovalent lower alcohol and an organic or inorganic acid, or (b) a water-soluble monovalent lower. A non-corrosive rinse liquid for a substrate, which comprises alcohol and an organic or inorganic acid and water, or (c) an organic or inorganic acid and water. 2. A step of forming a conductive layer made of an aluminum base containing at least copper in a predetermined region on a semiconductor substrate, and forming a required mask on the conductive layer using a resist to form a mask in the non-mask region. A method of manufacturing a semiconductor device, comprising: a step of etching a conductive layer; a step of removing the mask-formed resist from the conductive layer with an alkaline resist remover; and a rinse step using the rinse solution according to claim 1. 3. A semiconductor device manufactured by the manufacturing method according to claim 2.