Plasma etching method of reducing generation of fine dust

Abstract

Being suitable for forming trench in substrate, the method includes steps: carrying out first etching step for the substrate under first etching condition; carrying out second etching step for the substrate under second etching condition; carrying out a conversion step between the first etching step and second etching step in order to adjust one of environmental parameters such as pressure condition in reaction chamber, gas flow, source power of plasma or temperature of reaction chamber; moreover, making variance of environmental parameters between etching step and conversion step be les than 15úÑ in order to maintain stabilized environment for reaction, and to avoid dropping off fine dust. Afterwards, when cleaning step of oxygen plasma is carried out, pressure in reaction chamber is raised to 40mTorr -80mTorr so as to prevent generation of spheroidal defect.

Description

technical field [0001] The invention relates to a plasma etching method, in particular to a plasma etching method which reduces dust generation and is suitable for making a shallow trench isolation structure (Shallow Trench Isolation, STI). Background technique [0002] In the semiconductor process, etching is mainly used for pattern transfer application. The general practice is to cooperate with the lithography process (lithography). First, a layer of photoresist is coated on the substrate, and then the pattern on the mask is patterned on the photoresist by an exposure process, and then the unexposed photoresist is removed with a developer , the patterned photoresist is then used as an etching mask, and an appropriate wet or dry etching technique is selected to remove part of the substrate, and finally the patterned photoresist is removed, and the The pattern on the mask is transferred to the substrate. [0003] The etching process in the semiconductor process mainly ado...

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Problems solved by technology

However, if Figure 1B As shown, ball type defects (ball type defect) 140 will still be found on the fabricated trench 120, thereby affecting the conduction properties of the circuit 130.

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