Method for dynamically etching sheet metal and forming metal wire

Abstract

The invention relates to a method for dynamically etching a metal layer to form a metal line, wherein the metal layer is deposited on a wafer, and the metal layer has a photoresist that has been photoetched and developed with a metal line pattern, and the method includes the first step 1. The second and third stages of etching. The third stage of etching when the existing etching forms the metal line adopts the etching for a fixed time, which easily causes the problem of under-etching or over-etching of the metal layer. The method of the present invention first performs a first-stage etching for a fixed time, and then performs a second-stage etching that controls the etching end point according to the metal content in the etching tail gas, and then extracts the time of the second-stage etching, and then The third-stage etching time is calculated according to the second-stage etching time, and finally the third-stage etching is performed according to the third-stage etching time. By adopting the method of the present invention, the etching time of the third stage etching can be determined according to the time of the second etching stage, so as to avoid under-etching or over-etching of the metal layer.

Description

Technical field [0001] The invention relates to the field of semiconductor manufacturing, in particular to a method for dynamically etching a metal layer to form a metal wire. Background technique [0002] In the field of semiconductor manufacturing, after the semiconductor device is manufactured, it is necessary to connect the semiconductor device through a metal wire to form a chip with a certain function. When making the metal line, a metal layer is first deposited on the wafer, then a pattern of the metal line is photoetched on the metal layer, and finally the metal line is formed by etching. See figure 1 , Showing a schematic diagram of the structure of the metal layer 1. As shown in the figure, the metal layer 1 is deposited on the wafer 2, and the metal layer 1 is left with a photoresist 3 that has been etched and developed with a metal line pattern, and the metal layer 1 It includes the first titanium nitride layer 10, the aluminum copper alloy layer 11, the second titan...

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Problems solved by technology

[0004] However, since the distribution of the metal lines is not uniform, and there are differences in the structure and thickness of the metal layers, the etching of the fixed time in the third stage just etches the first titanium nitride layer 10 at the lowermost end of the metal layer 1. The probability of etching clean is extremely small, or the first titanium nitride layer 10 will not be etched clean, or over-etching will occur and damage the semiconductor device in the wafer 2 under the metal layer 1

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