Method of fabricating micro electro mechanical system structure which can be vacuum-packed at wafer level
First Claim
1. A method of fabricating a micro electro mechanical system (MEMS) structure which can be vacuum-packaged at the wafer level, the method comprising the steps of:
- i. forming a signal line on a first wafer;
ii. bonding a second wafer to the first wafer to form a multilayered stack;
iii. forming a MEMS structure in a vacuum area of the first wafer in a vacuum state;
iv. forming a structure in a third wafer to have space corresponding to the vacuum area of the MEMS structure; and
v. bonding the third wafer to a surface of the first wafer in a vacuum state.
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Abstract
A method of fabricating a micro electromechanical system (MEMS) structure which can be vacuum-packaged at the wafer level is provided. The method includes the steps of forming a multilayered stack including a signal line on a first wafer; bonding a second wafer to the multilayered stack; polishing the first wafer to a predetermined thickness; forming a MEMS structure in a vacuum area of the first wafer and a pad outside the vacuum area, the MEMS structure and the pad being connected to the signal line; forming a structure in a third wafer to have space corresponding to the vacuum area of the MEMS structure; and bonding the third wafer to the polished surface of the first wafer in a vacuum state. For protection of the structure and maintaining a vacuum level required for operation, the fabricated structure is vacuum-packaged at the wafer level, thereby improving the yield of fabrication. In addition, since a special vacuum packaging process is not necessary, the fabrication can be simplified.
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Citations
17 Claims
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1. A method of fabricating a micro electro mechanical system (MEMS) structure which can be vacuum-packaged at the wafer level, the method comprising the steps of:
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i. forming a signal line on a first wafer;
ii. bonding a second wafer to the first wafer to form a multilayered stack;
iii. forming a MEMS structure in a vacuum area of the first wafer in a vacuum state;
iv. forming a structure in a third wafer to have space corresponding to the vacuum area of the MEMS structure; and
v. bonding the third wafer to a surface of the first wafer in a vacuum state. - View Dependent Claims (2, 3, 4, 5, 6, 7, 15)
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8. A method of fabricating a micro electro mechanical system (MEMS) structure which can be vacuum-packaged at the wafer level, the method comprising the steps of:
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i. forming a poly silicon layer having a predetermined pattern for a signal line on the sacrificial layer;
ii. forming a poly silicon layer having a predetermined pattern for a signal line on the sacrificial layer;
iii. forming an insulation layer on the poly silicon layer;
iv. bonding a second wafer to the insulation wafer;
v. forming a MEMS structure comprising a resonant plate and a frame supporting the resonant plate in a vacuum area of the first wafer and a pad outside the vacuum area, the MEMS structure and the pad being connected to the signal line;
vi. forming a structure in a third wafer to have space corresponding to the vacuum area of the MEMS structure; and
vii. bonding the third wafer to the polished surface of the first wafer in a vacuum state. - View Dependent Claims (9, 10, 11, 12, 13, 14, 16, 17)
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Specification