JPH0355833A - Manufacture of semiconductor device - Google Patents

Abstract

PURPOSE:To easily eliminate reaction product which is generated by dry etching and attaches to the inside of a through hole, by a method wherein the etching process for forming a through hole is constituted of the following; a process for dry etching an insulating layer, and a post treatment process for dipping and eliminating the reaction product generated by dry etching while using a specified solution. CONSTITUTION:A semiconductor substrate has a laminated film on the surface, which film is composed of a lower wiring pattern metal layer 2 composed of aluminum and/or its alloy and an insulating film 3 formed on the layer 2. After said substrate is etched and a through hole 5 is formed in the insulating film 3, an upper wiring pattern metal layer 7 is formed. When a semiconductor device is formed by electrically connecting the lower wiring pattern metal layer 2 and the upper wiring pattern metal layer 7 via the through hole 5, the above etching is constituted of the following; a process for dry-etching the insulating film 3, and a post-treatment process wherein solution selected from hydrofluoric acid, etchant, and warm water is used and reaction product generated by dry etching is dipped and eliminated. Thereby a semiconductor device wherein the resistance between metal-metal is stabilized can be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to a method of manufacturing a semiconductor device. More specifically, the present invention relates to a method of manufacturing a semiconductor device suitable for LSI manufacturing technology using multilayer wiring.

(Example) Conventional technology Normally, a semiconductor device is manufactured by having a metal layer such as aluminum or its alloy for a wiring pattern on a semiconductor substrate via an insulating layer. The active layer provided on the semiconductor substrate and the metal layer are electrically connected through contact holes formed at the positions by etching.

Furthermore, in the manufacture of LSIs, wiring is made into a multilayer structure in order to reduce the chip area. The multilayer wiring is constructed by laminating a plurality of wiring metal layers and a glabella insulating layer for insulating between these metal layers on a semiconductor substrate. In such multilayer wiring, there are through holes (holes) that penetrate the insulating layer at predetermined positions and provide conduction between the metal layers above and below the insulating layer, and holes that provide conduction between the metal layer and the active layer of the semiconductor substrate as described above. A hole (contact hole) is provided.

As mentioned above, the formation of contact holes, through holes, etc. is performed using a reactive gas such as CHP. This is done by a dry etching method in which the insulating layer is etched using CF4 or a gas obtained by adding ON to CF4.

(c) Problems to be Solved by the Invention However, in the above-mentioned dry etching, a compound of the etching gas and aluminum or its alloy aluminum forming the wiring pattern metal layer is generated, and this creates a problem in the formed through hole. Particularly, it adheres to the aluminum surface exposed at the inner bottom of the through hole.

The reaction products of conventional dry etching are
O, organic matter removal using plasma and organic cleaning have been used to remove the above-mentioned adhering reaction products, but these removal methods cannot completely remove them, so contact etching may increase contact resistance. This makes it difficult to control the line width in fine pattern formation using multilayer resists.

The present invention has been made in view of the above situation, and it is possible to easily remove reaction products generated by dry etching when forming a through hole in an insulating layer and adhere to the inside of the through hole using a specific solution. The present invention aims to provide a method for manufacturing a semiconductor device that includes processing.

(2) Means for Solving the Problems Thus, according to the present invention, a semiconductor having on its surface a laminated film comprising a lower wiring pattern metal layer made of aluminum and/or its alloy and an insulating layer formed on the layer. After etching the substrate to form a through hole in the insulating layer,
An upper wiring pattern metal layer is provided on the insulating layer, and the lower wiring pattern metal layer and the upper wiring pattern metal layer are electrically connected through the through hole to form a semiconductor device. A semiconductor characterized by comprising a step of dry etching, and a post-treatment step of removing reaction products generated in the dry etching by immersion using a solution selected from hydrofluoric acid, silox etchant, and hot water. A method of fabricating a device is provided.

The present invention can be seen as a method for manufacturing semiconductor devices in which a wet etching step using a specific solution is inserted after the normal dry etching step for forming through holes.

In the method of this invention, the following solutions may be used in the post-treatment of dry etching. namely, hydrofluoric acid (HF), Cyrox etchant, and hot water. These are used alone.

In the method of the present invention, the removal treatment using the solution includes:
When the above-mentioned hydrofluoric acid is used, the concentration thereof is about 1% or less and the treatment is carried out within 30 seconds. If the concentration is higher than 1% or the treatment time is longer than 30 seconds, aluminum will be etched.

When using the above Pyrox etchant, first the Pyrox etchant is CH3COOH:NH. F:
The solution is a mixture of H and O in a ratio of 2:1:2, and is a well-known etchant such as PSG. This is preferable since it has a selective ratio with aluminum, but the treatment time with this solution is within 10 seconds. 1
If the processing time is longer than 0 seconds, the SiOz-based insulating layer will be etched. It can also be removed with warm water. In this case, the processing time varies somewhat depending on the temperature of the hot water. For example, at 60° C., the processing time is within 2 minutes, and at i00° C., the processing time is within 1 minute.

If the processing time at this temperature is long, peeling or blistering of the insulating layer will occur, causing defects in the semiconductor device.

In the method of this invention, methods and apparatuses known in the art can be used as they are, except for the step of removing reaction products generated during dry etching.

(E) Effect According to the present invention, in the process of manufacturing a semiconductor device, aluminum compounds generated when forming through holes by dry etching adhere to the inside of the formed through holes, but after the etching, hydrofluoric acid When the aluminum compound adhering to the metal layer made of aluminum and/or its alloy exposed on the side walls and bottom of the insulating layer inside the through hole is selectively removed by immersion treatment in a solution selected from , Syrox etchant and hot water. It will be removed.

The present invention will be explained in detail with reference to Examples below. Riko's invention is not limited.

(f) Example FIG. 1 is a process diagram showing an example of the method of the present invention.

After forming a lower wiring pattern (2) using an aluminum alloy by a lithography method on an insulating film (BPSG) (1) provided on a semiconductor substrate, a glabellar insulating film (SiOt) ( 3) is formed by plasma CVD to cover the above wiring pattern (Fig. 1(a)).
).

Next, a photoresist (4) is applied onto the wiring pattern (2), and a contact hole forming mask is formed by exposure and development. Next, a contact hole (5) is formed in this by reactive ion etching (RIE) using C H F s or CF 4 gas, or a gas in which O is added to these gases. At this time, these etching gases and aluminum react with each other, and a reaction product (6) is deposited inside the contact hole (FIG. 2(b)).

When the semiconductor substrate obtained above is immersed in any of the solutions shown in the table below for a predetermined period of time, only the reaction product (6) is selectively removed ((C) in the same figure).

After the above immersion, the resist of the semiconductor substrate was washed with O, plasma,
The contact hole (5) formed above is removed by chemical stripper and organic cleaning using Guiflon, acetone or isopropyl alcohol.
An upper wiring pattern (7) made of aluminum alloy is formed on the interlayer insulating layer (3) containing contact holes (5).
) to establish conduction between the lower wiring pattern (2) and the upper wiring pattern (7) ((d) in the same figure).

Through the above steps, a semiconductor device with stable metal-to-metal resistance was obtained.

(G) Effects of the Invention According to the present invention, in a method for manufacturing a semiconductor device, only deposits can be removed without changing the shape of aluminum or the insulating film. Therefore, stable metal-to-metal resistance can be obtained, while the controllability of the multilayer resist process can be improved.

[Brief explanation of drawings]

FIG. 1 is a process explanatory diagram of an embodiment of the method of the present invention. l... Insulating film 2... Lower wiring pattern, 3... Plasma Sin. , 4... Photoresist, 5... Contact hole, 6... Reaction product 7... Upper wiring pattern. 1st stroke~1 (d)

Claims (1)

[Claims] 1. A semiconductor substrate having a laminated film on its surface consisting of a lower wiring pattern metal layer made of aluminum and/or its alloy and an insulating layer formed on the layer is etched to form the insulating layer. After forming a through hole, an upper wiring pattern metal layer is provided in the insulating layer, and the lower wiring pattern metal layer and the upper wiring pattern metal layer are electrically connected through the through hole to form a semiconductor device, The etching comprises a step of dry etching the insulating layer, and a post-treatment step of removing reaction products generated in the dry etching by immersion using a solution selected from hydrofluoric acid, Cyrox etchant, and hot water. A method for manufacturing a semiconductor device, characterized in that: