JPH04306830A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To make a contact hole excellent for multilayer wiring by a method wherein the reactive products produced in the contact hole making step of a semiconductor are removed by using hydrogen fluoride and an organic amine base solvent. CONSTITUTION:The first layer Al wirings 11 are formed on a semiconductor substrate 10 and then an SiO2 film as an interlayer insulating film 12 is deposited on the wirings 11, next, the whole surface is coated with multilayer resist films 13 and later openings are formed reaching the lowermost layer resist film 131. At this time, the products produced in the etching step of the lowermost layer resist film 131 are removed using hydrogen fluoride. Next, contact holes 16 are made in the SiO2 film as the interlayer insulating film 12 for the mutual connection of the first layer Al and the second layer Al so as to remove the lowermost layer resist film 131 by dry-etching step. At this time, the reactive products 17 remained in the contact holes 16 are removed using an organic amine base solvent.

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 having interconnections between aluminum wires in a semiconductor integrated circuit using multilayer wires.

0002

2. Description of the Related Art A conventional method for manufacturing a semiconductor device using multilayer wiring is shown in FIG. Conventionally, as shown in FIG.
, an intermediate layer resist 42 and an upper layer resist 43)
(b) forming an opening pattern 5 of a multilayer resist on the silicon oxide film on this Al wiring 2; and (c) forming a contact 6 for interconnection with the second layer Al wiring. (d) exposing the aluminum wiring layer by anisotropic dry etching the silicon oxide film based on the opening pattern of the bottom layer resist of the multilayer resist; (d) dry etching the bottom layer resist with oxygen plasma; Semiconductor devices have been manufactured using a process of removing by etching.

When the contact 6 is formed by this method, reaction products 7 from the reactive ion etching at the time of opening the contact remain inside the contact hole, which may cause the contact diameter to become small or the second layer Al wiring to be disconnected. This may cause problems with electrical continuity, or may cause poor connection between Al wirings.

[0004] Therefore, it is necessary to remove reaction products caused by reactive ion etching when opening contacts. However, when O2/N2 plasma is used for resist processing only in step (d), as in the case where the resist is a single layer, the products generated in this step can be removed with an organic amine solvent. However, in the case of a multilayer resist, if O2/N2 plasma is used for resist formation and opening in the step (b), organic amine solvents are used because reaction products are generated in the step (b) as well. Since it is difficult to remove all of these products, conventionally these products have not been removed, resulting in the problems described above.

[0005]

[Problems to be Solved by the Invention] The present invention aims to prevent reaction products generated during reactive ion etching during contact opening into contact holes when a multilayer resist is used in the manufacturing process of a semiconductor device using multilayer wiring. remove the
The purpose is to ensure interconnection of Al wiring.

[0006]

[Means for Solving the Problems] The present invention includes a step of sequentially providing an aluminum wiring layer, a silicon oxide film, and a multilayer resist on a semiconductor device, and forming an opening pattern of the multilayer resist on the silicon oxide film on the aluminum wiring layer. and exposing the aluminum wiring layer by anisotropic dry etching the silicon oxide film based on the opening pattern of the bottom resist of the multilayer resist.
In the method for manufacturing a semiconductor device, which sequentially includes steps of removing the bottom resist layer by dry etching using oxygen plasma, the bottom resist film is immersed in hydrogen fluoride before performing anisotropic dry etching of the silicon oxide film. and a step of immersing the lowermost resist film in an organic amine solvent after removing it by dry etching using oxidation plasma.

[0007]

[Embodiment] An embodiment of the present invention will be described with reference to FIG. First, a first layer Al wiring 11 is formed on the semiconductor device 10,
A SiO2 interlayer insulating film 12 of 10,000 Å is deposited thereon by plasma chemical vapor deposition or normal pressure chemical vapor deposition, and a three-layer resist 13 for electron beam direct writing is further applied (Fig. 2(a) ) reference).

Next, the upper resist 133 is patterned using an electron beam, the intermediate layer 132 is patterned using the upper resist as a mask, and the lower resist 131 is etched using O2/N2 plasma using the intermediate layer 132 as a mask. At this time, the upper layer resist is removed,
The intermediate resist layer 132 is exposed (see FIG. 2(b))
.

The reaction product produced in this step is removed by immersing it in a 2:1 mixture of hydrogen fluoride and acetic acid for 5 seconds. Further, at this time, the SiO2 interlayer insulating film 12 is etched isotropically to form a taper 18, as shown in FIG. 2(c).

Thereafter, using the lower resist 131 as a mask, the interlayer insulating film 12 is etched by reactive ion etching (anisotropic dry etching) to open a contact hole 16. The lower resist 131 is O2/N2
Although it is removed by plasma, etching products 17 remain in the contact holes (see Figure 2(d)), so they are removed using a mixed solution of monoethanolamine (70%) and dimethyl sulfoxide (30%). A positive resist stripping solution is used to remove the product by immersing it at 120° C. for 10 minutes.

[0011]

[Effects of the Invention] By carrying out the method for manufacturing a semiconductor device of the present invention, residues at the bottom of the contact hole and its surroundings are removed, so that there are no disconnections in the second layer Al wiring or defects in the first layer A.
Contact breakage failures between the aluminum layer and the second layer of aluminum will no longer occur. Furthermore, since the contact is immersed in a hydrogen fluoride mixture after forming the opening pattern in the lower resist layer, a tapered shape is formed in the upper layer of the contact, which improves the contact hole coverage of the second Al wiring and improves the semiconductor device. Improves yield and reliability.

[Brief explanation of drawings]

[Figure 1] Cross-sectional view of a semiconductor in a conventional semiconductor manufacturing process

[Fig. 2] Cross-sectional view of a semiconductor in the semiconductor manufacturing process according to the present invention

[Explanation of symbols]

1 Semiconductor device 2 First layer aluminum 3 Interlayer insulation film 4 Multilayer resist 6 Contact hole 7 Etching product 10 Semiconductor device 11 First layer aluminum 12 SiO2 interlayer insulation film 13 3-layer resist 131 Lower layer resist 132 Intermediate layer resist 133 Upper layer resist 16 Contact hole 17 Etching products 18 Taper

Claims (1)

[Claims] 1. (a) Sequentially providing an aluminum wiring layer, a silicon oxide film, and a multilayer resist on a semiconductor device; (b) forming an opening pattern in the multilayer resist on the silicon oxide film on the aluminum wiring layer. process and
(c) exposing the aluminum wiring layer by anisotropic dry etching the silicon oxide film based on the opening pattern of the bottom resist layer of the multilayer resist;
d) A method for manufacturing a semiconductor device which sequentially includes steps of removing the bottom layer resist by dry etching using oxygen plasma, wherein (e) prior to performing anisotropic dry etching of the silicon oxide film, the bottom layer resist is removed. Manufacturing a semiconductor device, comprising: immersing it in a mixed solution of hydrogen chloride; and (f) removing the lowermost resist layer by dry etching with oxygen plasma, and then immersing it in an organic amine solvent. Method.