Mechanism for etching a silicon layer in a plasma processing chamber to form deep openings
AssigneeLam Research Corporation
InventorDarrell McReynolds
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Abstract
A method of etching a silicon layer in a plasma etching reactor to form an ultra deep opening is disclosed. The method includes the steps of providing a semiconductor substrate including the silicon layer into the plasma etching reactor and flowing an etching gas that includes an oxygen reactant gas, a helium gas, and an inert bombardment-enhancing gas into the plasma etching reactor. The method further includes striking a plasma using the etchant gas chemistry, and then providing an additive gas having SF6 into the plasma etching reactor subsequent to striking the plasma. The method continues with etching an opening at least partially through the silicon layer using this plasma.
Claims5
A method of etching a silicon layer in an inductively coupled plasma etching reactor to form an ultra deep trench, said ultra deep trench having an etch depth of at least 10 μm, said method comprising:
- providing a semiconductor substrate into said inductively coupled plasma etching reactor, said semiconductor substrate including said silicon layer;
- flowing an etchant gas chemistry consisting essentially of a helium gas, an O2 gas, and an argon gas into said inductively coupled plasma etching reactor;
- striking a plasma using said etchant gas chemistry;
- providing an SF6 gas into said inductively coupled plasma etching reactor subsequent to said striking said plasma, wherein a flow ratio of said helium gas to said SF6 gas is about 350% to about 550%, a flow ratio of O2 to said SF6 gas is about 60% to about 90%, and a flow ratio of said argon gas to said SF6 gas is about 350% to about 550%;
- and
- etching said ultra deep trench at least partially through said silicon layer.
Dependencies are inferred from the claim text.