Microcap wafer-level package with vias
First Claim
1. A method of manufacturing a wafer package comprising:
- providing a first wafer, a second wafer, and a micro device;
forming a bonding pad and a peripheral pad on said first wafer, said peripheral pad encompassing said bonding pad;
forming a seal on said second wafer, said seal configured to match said peripheral pad;
forming a well in said second wafer;
forming a conductor in said well integral with said second wafer;
bonding said first and said second wafers together using said seal to form a hermetically sealed volume therebetween, said second wafer positionable with said conductor in conductive contact with said bonding pad, and said micro device disposed in said hermetically sealed volume and connected to said bonding pad; and
removing a portion of said second wafer whereby said conductor is exposed outside said hermetically sealed volume.
14 Assignments
0 Petitions
Accused Products
Abstract
A microcap wafer-level package is provided in which a micro device is connected to bonding pads on a base wafer. A peripheral pad on the base wafer encompasses the bonding pads and the micro device. A cap wafer is processed to form wells of a predetermined depth in the cap wafer. A conductive material is made integral with the walls of the wells in the cap wafer. The cap wafer has contacts and a peripheral gasket formed thereon where the contacts are capable of being aligned with the bonding pads on the base wafer, and the gasket matches the peripheral pad on the base wafer. The cap wafer is then placed over the base wafer so as to bond the contact and gasket to the pads and form a hermetically sealed volume within the peripheral gasket. The cap wafer is thinned to form a “microcap”. The microcap is thinned below the predetermined depth until the semiconductor dopant is exposed to become conductive vias through the cap wafer to outside the hermetically sealed volume.
237 Citations
20 Claims
-
1. A method of manufacturing a wafer package comprising:
-
providing a first wafer, a second wafer, and a micro device;
forming a bonding pad and a peripheral pad on said first wafer, said peripheral pad encompassing said bonding pad;
forming a seal on said second wafer, said seal configured to match said peripheral pad;
forming a well in said second wafer;
forming a conductor in said well integral with said second wafer;
bonding said first and said second wafers together using said seal to form a hermetically sealed volume therebetween, said second wafer positionable with said conductor in conductive contact with said bonding pad, and said micro device disposed in said hermetically sealed volume and connected to said bonding pad; and
removing a portion of said second wafer whereby said conductor is exposed outside said hermetically sealed volume. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
depositing said conductor therein by a semiconductor deposition process whereby said conductor is integral with the wall of said well.
-
-
3. The method of manufacturing a wafer package as claimed in claim 1 wherein forming said conductor in said well includes:
-
depositing a barrier layer on said second wafer around said well; and
diffusing a dopant in said well.
-
-
4. The method of manufacturing a wafer package as claimed in claim 1 wherein forming said conductor in said well includes:
-
depositing a barrier layer on said second wafer around said well;
diffusing a dopant in said well;
depositing a semiconductor material in said well;
annealing said second wafer whereby said dopant is diffused into said cap wafer and into said semiconductor material; and
removing said barrier layer.
-
-
5. The method of manufacturing a wafer package as claimed in claim 1 wherein forming said conductor in said well includes:
-
depositing a dopant-containing insulator in said well; and
annealing said second wafer whereby dopant diffuses from said dopant-containing insulator.
-
-
6. The method of manufacturing a wafer package as claimed in claim 1 wherein forming said conductor in said well includes:
-
depositing a dopant-containing insulator layer in said well;
depositing a semiconductor material over said dopant-containing insulator layer in said well;
annealing said second wafer whereby dopant diffuses from said dopant-containing insulator into said cap wafer and into said semiconductor material.
-
-
7. The method of manufacturing a wafer package as claimed in claim 1 wherein forming said first and said second seals includes:
-
forming a seed layer on said second wafer;
photolithographically processing said seed layer to leave a seal-patterned photoresist thereon;
depositing said seals on said seed layer using said seal-patterned photoresist;
removing said seal-patterned photoresist; and
selectively removing said seed layer to connect to said conductor.
-
-
8. The method of manufacturing a wafer package as claimed in claim 1 including:
-
depositing an outside bonding pad on said conductor exposed outside said hermetically sealed volume;
placing said wafer package in a micro device utilizing system; and
bonding conductors between said wafer packaging utilizing device and said outside bonding pad.
-
-
9. The method of manufacturing a wafer package as claimed in claim 1 including:
defining a recess in one of said wafers whereby a tall micro device can be accommodated.
-
10. The method of manufacturing a wafer package as claimed in claim 1 including:
forming a semiconductor device in one of said wafers.
-
11. A method of manufacturing a wafer package comprising:
-
providing a base wafer, a cap wafer, and a micro device;
forming a bonding pad and a peripheral pad on said base wafer, said peripheral pad encompassing said bonding pad;
forming a well of a predetermined depth in said cap wafer in a position positionable over said bonding pad;
forming a conductor integral with said cap wafer in said well;
forming a contact and a seal on said cap wafer, said contact connected to said conductor and configured to align with said bonding pad, and said seal encompassing said contact and substantially matching said peripheral pad;
bonding said base wafer and said cap wafer together using said seal to bond to said peripheral pad to form a hermetically sealed volume therein, said cap wafer positionable with said contact bonded to said bonding pad, and one of said wafers having said micro device associated therewith disposed in said hermetically sealed volume between said seal and connected to said bonding pad; and
removing a portion of said cap wafer until the thickness of said cap wafer is less than the predetermined depth of said well whereby a conductive via is formed in contact with said bonding pad on said base wafer. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
depositing a metal by a semiconductor process in said well.
-
-
13. The method of manufacturing a wafer package as claimed in claim 11 wherein forming said conductor in said well includes:
-
depositing a barrier layer on said cap wafer around said well;
diffusing a semiconductor dopant in said well by a process selected from a group consisting of gas-source, liquid-source, and solid-source diffusion whereby said semiconductor dopant is integral with the wall of said well; and
removing said barrier layer.
-
-
14. The method of manufacturing a wafer package as claimed in claim 11 wherein forming said conductor in said well includes:
-
depositing a barrier layer on said cap wafer around said well;
diffusing a semiconductor dopant selected from a group consisting of Group III and Group V elements in said well by a process selected from a group consisting of gas-source, liquid-source, and solid-source diffusion whereby said semiconductor dopant is integral with the wall of said well;
depositing polysilicon in said well;
annealing said cap wafer whereby said semiconductor dopant diffuses into said cap wafer and into said polysilicon; and
removing said barrier layer.
-
-
15. The method of manufacturing a wafer package as claimed in claim 11 wherein forming said conductor in said well includes:
-
depositing a glass containing a semiconductor dopant selected from a group consisting of Group III and Group V elements in said well; and
annealing said cap wafer whereby said semiconductor dopant diffuses from said glass.
-
-
16. The method of manufacturing a wafer package as claimed in claim 11 wherein forming said conductor in said well includes:
-
depositing a layer of glass containing a semiconductor dopant selected from a group consisting of Group III and Group V elements in said well;
depositing a polysilicon over said layer of glass in said well;
annealing said cap wafer whereby said semiconductor dopant diffuses from said glass into said cap wafer and into said polysilicon.
-
-
17. The method of manufacturing a wafer package as claimed in claim 11 wherein:
-
forming said first and said second seals on said cap wafer includes;
sputtering a seed layer on said cap wafer;
photolithographically processing said seed layer to leave a seal-patterned thick photoresist thereon;
depositing said seals on said seed layer using said seal-patterned thick photoresist;
removing said seal-patterned thick photoresist; and
removing said seed layer formerly under said seal-patterned thick photoresist; and
forming said bonding pad and said peripheral pad on said base wafer includes;
sputtering a seed layer on said base wafer;
photolithographically processing said seed layer to leave a bonding pad and peripheral pad patterned photoresist thereon;
depositing said bonding pad and said peripheral pad on said seed layer using said bonding pad and peripheral pad patterned photoresist;
removing said bonding pad and peripheral pad patterned photoresist; and
removing said seed layer formerly under said bonding pad and peripheral pad patterned thick photoresist.
-
-
18. The method of manufacturing a wafer package as claimed in claim 11 including:
-
depositing an outside bonding pad on said conductor exposed outside said hermetically sealed volume;
placing said wafer package in a micro device utilizing system; and
bonding conductors between said wafer packaging utilizing device and said outside bonding pad.
-
-
19. The method of manufacturing a wafer package as claimed in claim 11 including:
defining a recess in said cap wafer whereby a tall micro device can be accommodated.
-
20. The method of manufacturing a wafer package as claimed in claim 11 including:
forming a semiconductor device in one of said wafers.
Specification