TW200827485A - Method for etching metal - Google Patents

Abstract

A method for etching metal is provided. The method includes the following steps: providing a substrate; forming a metal layer on the substrate; forming an Al2O3 layer on the metal layer; patterning the Al2O3 layer; and etching the metal layer by using the patterned Al2O3 layer as a mask.

Description

200827485 IX. Description of the Invention: TECHNICAL FIELD OF THE INVENTION The present invention relates to a semiconductor process method, and more particularly to a semiconductor process for metal etching. [Prior Art]

With the development of industrial technology, the spatial scale of semiconductor manufacturing has also been gradually reduced to meet the needs of increasingly complex ultra-large integrated circuits (Sink & Scale Integration (ULSI)). The resolution of the lithography technique defines the minimum line width of the semiconductor component, and the thickness of the fine layer affects the resolution of the desired pattern. The wire resist layer (4) is too large in width, and may cause serious resolution due to certain optical effects such as interference. Therefore, as the threshold is slightly reduced, the light_thickness also needs to decrease. Due to the residual selection between the photoresist and the metal, it is necessary to have a photoresist having a sufficient thickness. However, when etching the metal, the selectivity is small (generally about 1.6), which is sufficient to resist the surname of the residual agent. In order to reduce the gold in the margin, it is therefore necessary to provide a metal etching method, which is required for the thickness of the photoresist layer. SUMMARY OF THE INVENTION In view of the problems of the prior art, the present invention provides a side method of reducing the thickness of a desired photoresist layer. ’,

4NTC/06022TW : 93156TW 200827485 Yu Γ 之 - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - ; and Ming ^ for the curtain, 働j metal layer. i U layer

Alumina Layer According to another aspect of the present invention, the method of treating an oxygen layer with the same layer comprises the steps of: forming a photoresist layer over the oxidized layer; forming a photoresist layer with an exposure process; and closing the photoresist The layer is a mask, and according to still another aspect of the invention, the metal layer is |g or the thickness thereof is between 7000A and 10000A, the thickness of the oxide layer is between 3〇〇A and 700A, and the thickness of the photoresist layer. Less than 1200 a. Other aspects of the invention will be set forth in part in the description which follows. The various aspects of the invention can be solved and achieved by means of the elements and combinations (s) specified in the appended claims. The above general description and the following detailed description are for illustrative purposes only and are not intended to limit the invention. [Embodiment] The present invention provides a metal etching method which can effectively reduce the required photoresist thickness. In order to make the description of the present invention more detailed and complete, reference is made to the following description in conjunction with the drawings of Figures 1 to 3. However, as described in the following examples

4NTC/06022TW: 93156TW 6 200827485 The present invention is not intended to limit the scope of the present invention. ▲The various layers (4) established in the grade of the defeated party can be purely processed by the method known to the skilled artisan, such as deposition » /'^(chemical vapor deposition) or atomic layer deposition (at〇miC layer Qing-(u^)). Referring to Figure 1, the method of the present invention comprises providing a substrate 100 that can be used with any suitable semiconductor substrate or conventional lithographic wafer, or any suitable substrate that requires metal etching during the fabrication of the i-body circuit. . Then, the buffer layer 110 is formed on the substrate 100. The material of the buffer layer 110 can be, for example, not limited to titanium, and has a thickness of about 4 intrusions. Next, a metal layer 12 is formed on the buffer layer 110. The material of the metal layer 12 can be, for example, aluminum or copper, but not limited thereto, and the thickness thereof can be determined according to the design requirements of the subsequent processes. In one embodiment of the invention, the metal layer 120 has a thickness of from about 7 Å to about 10,000 Å, preferably 8500 Å. Thereafter, a barrier layer 13 is formed on the metal layer 120. The barrier layer 13 is known to those skilled in the art; a titanium layer, a titanium nitride layer, or a titanium or titanium nitride layer. The composite layer is on the metal layer 12' wherein the titanium nitride layer is about 400 and the titanium layer is about 5 〇a. It should be noted that although the barrier layer 13 is exemplified by titanium, titanium nitride or a combination thereof, the material of the barrier layer 130 may be selected according to different needs. Further, titanium, titanium nitride or titanium/titanium nitride may be formed by sputtering or deposition, or a titanium layer may be transformed by a nitridation step to form a nitrided 4NTC/06022TW:93]56tw 200827485 titanium layer. Next, an aluminum oxide (Al2〇3) layer 140 is deposited as a hard tantalum having a thickness of about 10,000 Å, preferably 5 Å. 4 The cold cloth-photoresist layer 150 is on the oxidized inscription layer (10), wherein the thickness of the soil is generally less than 1200 Α.

Next, referring to Fig. 2, the photoresist layer 15G' is patterned by a pattern transfer technique such as exposure development to define a desired side region. Thereafter, the photoresist layer 15G is used as a mask, and (10) the inscription layer 14 () is oxidized to transfer the pattern of the photoresist reed 150 to the oxidized underlayer 14A. It should be noted here that when the 2150 ® case is transferred to the oxidized layer 140, the photoresist layer 150 may simultaneously eliminate or detract. Next, the etched _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ Meng ^ invention - in the embodiment, the metal layer (10) and the buffer layer 11 〇 rhyme j is dry _, _ gas such as ^ job and 2t genus (such as Ming or copper) and Pei (4) choose to report higher ( About: ) Drying therefore turns Al2〇3 as a hard mask on the metal side, which is thick and can also reduce the thickness of the photoresist, and improve the exposure and development of the second yang. In addition, the 'A!2〇3 and the metal also have Good point production, this will not increase the risk of mistakes in the process. Further, the above-mentioned examples are used to describe the present invention, and the method and the gentleman of the present invention may be modified and changed without departing from the essence of the invention. Two sides =

4NTC/06022TW: 93156TW 8 200827485 is not limited to the description of the specific embodiments above, and the scope of the present invention is intended to cover all such modifications and variations as to the true spirit and scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS Figures 1 through 3 illustrate cross-sectional views of a process for fabricating a trench structure in accordance with the method of the present invention. • [Main component symbol description] 100 Substrate 110 Buffer layer 120 Metal layer 130 Barrier layer 140 Alumina layer 150 Photoresist layer 4NTC/06022TW : 93156TW 9

Claims (1)

200827485 X. Patent application scope: 1. A metal surname method comprising the steps of: providing a substrate; forming a metal layer on the substrate; forming an aluminum oxide layer on the metal layer; patterning the aluminum oxide The layer; and the 5 layer of the patterned oxide layer as the mask 'rice engraved the metal layer. 2. The method of claim 1, wherein the step of patterning the aluminum oxide layer comprises forming a photoresist layer over the aluminum oxide layer; patterning the photoresist layer by an exposure and development process; and using the pattern The photoresist layer is a mask that etches the aluminum oxide layer. 3. The method of claim 1, wherein the metal layer is aluminum or copper. 4. The method of claim 1, wherein the aluminum oxide layer has a thickness of from 3 to 700. 5. The method of claim 1, wherein the metal layer has a thickness of from 10,000 to 10,000. 6. The method of claim 1, further comprising the steps of: forming a titanium layer over the metal layer; and 4NTC/06022TW: 93156TW 10 200827485 forming a titanium nitride layer over the titanium layer. 7. The method of claim 1, wherein the photoresist layer has a thickness of less than 1200 Å. 8. The method of claim 1, wherein the step of etching the metal layer is dry etching using a gas containing one of CHF3 and Cl2. 4NTC/06022TW : 93156TW 11