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US 6,645,875 B2Granted
Method of processing metal and method of manufacturing semiconductor device using the metal
AssigneeDenso Corporation
InventorsMakoto Ohkawa, Takayuki Sugisaka, Shuichi Ito, Hiroshi Tanaka
Life of this patent
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Abstract
When a barrier metal disposed on a thin film resistor material is wet-etched to expose the underlying thin film resistor material as a thin film resistor, the wet etching is performed at first and second steps. The first step is performed using H2O2/NH4OH solution, and is stopped before the thin film resistor material is exposed. Then, the second step is performed using H2O2/H2O solution until the thin film resistor material is exposed with a desired length, thereby forming the thin film resistor.
Claims8
A method for processing metal, comprising:
- preparing a first metal;
- layering a second metal on the first metal, the second metal having an ionization different from that of the first metal;
- and
- wet-etching the second metal so that the first metal underlying the second metal is exposed, wherein:
- the wet-etching is performed at first and second etching steps respectively using a first etching solution having a first electrical conductivity and a second etching solution having a second electrical conductivity smaller than the first electrical conductivity;
- and
- the first etching step is performed using the first etching solution before the second etching step is performed using the second etching solution.
4 more elements
A method of processing metal, comprising:
- preparing a first metallic layer;
- forming a second metallic layer on the first metallic layer, the first metallic layer and the second metallic layer having ionization tendencies different from each other;
- and
- removing a region of the second metallic layer by wet etching using an etching solution to exposed the first metallic layer underlying the region, wherein:
- an electrical conductivity of the etching solution is decreased at a later part of the wet etching to be smaller than an initial value of the electrical conductivity at an early part of the wet etching;
- and
- the first metallic layer is exposed to the etching solution at the later part of the wet etching.
4 more elements
Dependencies are inferred from the claim text.