KR0126655B1 - Metalizing method of semiconductor device - Google Patents

Abstract

A forming method of metal wires is provided to improve an yield. The method comprises the steps of: depositing a metal layer(2) on a silicon substrate(1); removing a native oxide formed on the metal layer(2); sequentially depositing a lower photo-resist(3), a middle layer(4) and an upper photo-resist; forming an upper PR pattern(5) by exposing and developing; forming a middle-layer pattern(11) using the upper PR pattern(5) as a mask; forming a lower PR pattern(9) using the middle-layer pattern(11) as a mask and forming a metal wire(20) by etching the exposed metal layer(2) using the lower PR pattern(9) as a mask. Thereby, it is possible to easily form metal wires having a high yield.

Description

Metal wiring formation method

1A to 1C are cross-sectional views showing a metal wiring forming process according to the prior art.

2A and 2C are cross-sectional views showing a metal wiring forming process according to the present invention.

* Explanation of symbols for main parts of the drawings

1 Insulation film 2,17 Metal layer

3: lower photosensitive film 4: intermediate layer

5: upper photoresist pattern 7: natural oxide film

9,13: lower layer photoresist pattern 11,19: middle layer pattern

15: Lifted lower layer photoresist pattern 20: Metal wiring

The present invention relates to a method for forming metal wiring, a solution containing fluorine to remove the natural oxide film on the upper metal layer during the pattern formation by a metal tri-layer photoresist (TLR: tri-layer-resist, hereinafter referred to as TLR) process After the treatment and the solvent treatment, and after the HMDS treatment, the TLR is deposited to suppress the lifting of the lower photoresist film, thereby improving the yield of the device.

In the prior art, a metal layer is formed on an oxide film, and then a metal layer is formed, and then a lower photoresist film used in a TLR process is applied to the metal layer after HMDS (Hxa-Methyl-Di-Silazane). After applying the intermediate layer and the upper photosensitive film, an upper photosensitive film pattern is formed by lithography. Then, a TLR etching process is performed. In the etching process, the intermediate layer is removed using 100: 1 and bOE (buffer oxide ecthant, hereinafter referred to as bOE). At this time, the native oxide film on the top of the metal layer is lifted to lower the yield of the device.

Problems caused by the prior art will be described in detail with reference to FIGS. La to lc.

FIG. 1A is a structure in which an insulating film 1, for example, an oxide film is formed on the silicon substrate 10, and a metal layer 2, for example, Ti, TiN, an al alloy, and a coating reflecting film TiN is deposited thereon. It is a cross-sectional view showing that a TLR formed of a lower photosensitive film 3, an intermediate layer 4, and an upper photosensitive film (not shown) is applied to the upper layer, and the upper photosensitive film pattern 5 is formed by an exposure and development process. Here, it should be noted that the upper photosensitive layer 3 is applied to the top of the metal layer 2 in a state where TiN is oxidized in the air and the natural oxide film 7 is grown. The natural oxide film 7 reacts with oxygen in the air. The growth thickness depends on the time it takes. In order to improve the adhesion of the lower layer photosensitive film 3, the metal layer 2 is subjected to an HMDS treatment, and then the lower layer photosensitive film 3 is applied. In this case, as the intermediate layer 4, SG (SOG: spin on glass, hereinafter referred to as SOG) is used.

1B illustrates the intermediate layer pattern 11 formed by etching the intermediate layer 4 using the upper layer photoresist pattern 5 as the mask, and then exposing the lower layer photosensitive layer 3 exposed using the intermediate layer pattern 11 as a mask. Is a cross-sectional view showing that the lower photosensitive film pattern 9 is formed by etching.

FIG. 1C is a cross-sectional view showing the removal of the intermediate layer pattern 11 by a wet method. Simultaneously removing the intermediate layer pattern 11 using a BOE of 100: 1 simultaneously with the exposed natural oxide film 7 Where the natural oxide film 7 is thickly removed, the natural oxide film 7 is pitted and the lower photoresist pattern 9 is lifted.

After the process, the exposed metal layer 2 is etched to form metal wiring. At this time, the metal wiring is not formed where the lower photoresist pattern 9 is lifted.

Therefore, in the present invention, since the above problem occurs because the natural oxide film is removed together when the intermediate layer pattern is removed on the upper surface of the metal surface, the lower photosensitive film generated when the intermediate layer is removed by performing a surface treatment to remove the natural oxide film before applying the lower photosensitive film. The purpose is to produce a device having a high yield by forming a metal wiring by solving the lifting of.

Features of the present invention for achieving the above object, the process of depositing a metal layer on top of the silicon substrate, the process of removing the natural oxide film grown when the metal layer is exposed to the atmospheric layer, and the lower photosensitive film, the intermediate layer and the upper layer on the metal layer Forming a lower layer photoresist pattern by laminating a photoresist layer, forming an upper photoresist pattern by an exposure and development process, forming an intermediate layer pattern using the upper photoresist pattern as a mask, and etching the exposed lower layer photoresist underneath; And etching the exposed metal layer using the lower photoresist pattern as a mask to form metal wiring.

Hereinafter, a metal wiring forming method according to the present invention will be described in detail with reference to the accompanying drawings.

2A and 2C are cross-sectional views showing a metal wiring forming process according to an embodiment of the present invention.

In FIG. 2A, an oxide film 1 and a metal layer 2 are deposited on the silicon substrate 10, and a TLR formed of a lower photosensitive film 3, an intermediate layer 4, and an upper photosensitive film is coated on the upper surface of the silicon substrate 10, and exposed and developed. It is sectional drawing which shows that the upper photosensitive film pattern 5 was formed by the process. At this time, the metal layer (2) is a Ti, TiN, al alloy and TiN is laminated with a coating reflection film, and includes fluorine (F) before applying the lower photosensitive film (3) on the metal layer (2) of 100: 1 BOE is used to remove the remaining natural oxide film (not shown) by growing in the air on top of the coating reflective film on the upper part of the metal layer 2 by a wet method, and remaining natural oxide film or foreign material such as ACT-690C or ACT It is removed by washing with a CMI solvent, and then treated with HMDS to increase the adhesion of the lower layer photoresist film, and then the lower layer photoresist film 3 is applied. At this time, the solvent treatment process is carried out in two steps of 80 ℃ (20 ') and 50 ℃ (5'). As the intermediate layer 4, SOG is used.

In FIG. 2B, an intermediate layer pattern 11 is formed using the upper photoresist pattern 5 as a mask, and a lower layer photoresist pattern 3 is formed by dry etching the lower photosensitive layer 3 using the intermediate layer pattern 11 as a mask. It is sectional drawing which showed.

In FIG. 2C, the intermediate layer pattern 1l is removed by a wet method, and the exposed metal layer 2 is etched using the lower layer photoresist pattern 9 as a mask to form a metal wiring 20, and then the upper layer photoresist pattern ( 9 is a cross-sectional view showing the removal.

According to the present invention described above, by removing the natural oxide film grown on the upper metal layer, which causes the lifting of the lower layer photoresist pattern, before applying the TLR, it is possible to prevent the occurrence of the lower layer photoresist pattern to form a normal pattern. .

Claims (2)

A method of forming a metal wiring, comprising: depositing a metal layer on an upper surface of a silicon substrate; removing a natural oxide film grown when the metal layer is exposed to air; and removing a foreign substance from a BOE solution; After the HMDS treatment, a lower photoresist film, an intermediate layer, and an upper photoresist film are laminated on the metal layer, and an upper photoresist film pattern is formed by an exposure and development process, and an intermediate layer pattern is formed by using the upper photoresist film pattern as a mask. And forming a lower layer photoresist pattern by etching the exposed lower layer photoresist film below, and forming a metal wiring by etching the exposed metal layer using the lower layer photoresist pattern as a mask. The method of claim 1, wherein the metal layer has a stacked structure of Ti, TiN, Al, and TiN.