Wafer-level through-wafer packaging process for mems and mems package produced thereby
First Claim
1. A method for packaging a MEMS device comprising:
- providing a first substrate having a functional element and metal leads thereon and a second SO substrate having at least one recessed cavity in a first silicon portion thereof with metal connectors therein;
bonding a surface of the first substrate to a non-recessed surface of the first silicon portion of the second SOI substrate and bonding the metal leads of the first substrate to respective metal connectors of the second SOI substrate to enclose and seal the functional element of the first substrate within the recessed cavity of the second SOI substrate; and
forming metal pads on each of the metal connectors of the second SOI substrate through the second SOI substrate for feeding electrical signals to and from the functional element of the first substrate sealed in the cavity of the second SOI substrate through the metal leads, the connectors and the pads.
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Accused Products
Abstract
A wafer-level packaging process for MEMS applications, and a MEMS package produced thereby, in which a SOI wafer is bonded to a MEMS wafer and the electrical feed-throughs are made through the SOI wafer. The method includes providing a first substrate having the functional element thereon connected to at least one metal lead, and providing a second SOI substrate having a recessed cavity in a silicon portion thereof with metal connectors formed in the recessed cavity. The non-recessed surfaces of the SOI substrate are bonded to the first substrate to form a hermetically sealed cavity. Within the cavity, the metal leads are bonded to respective metal connectors. Prior to bonding, the recessed cavity has a depth that is greater than the thickness of the functional element and less than the combined thickness of the metal leads and their respective metal connectors. After bonding, silicon from the SOI substrate is removed to expose the buried oxide portion of the SOI substrate. Metal pads are then formed through the SOI substrate to the metal connectors within the cavity. Wire bond pads are thereby connected to the functional element without opening the cavity to the environment. Electrical signals may then be fed through the SOI wafer to the metal connectors, metal leads and the functional element.
65 Citations
50 Claims
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1. A method for packaging a MEMS device comprising:
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providing a first substrate having a functional element and metal leads thereon and a second SO substrate having at least one recessed cavity in a first silicon portion thereof with metal connectors therein;
bonding a surface of the first substrate to a non-recessed surface of the first silicon portion of the second SOI substrate and bonding the metal leads of the first substrate to respective metal connectors of the second SOI substrate to enclose and seal the functional element of the first substrate within the recessed cavity of the second SOI substrate; and
forming metal pads on each of the metal connectors of the second SOI substrate through the second SOI substrate for feeding electrical signals to and from the functional element of the first substrate sealed in the cavity of the second SOI substrate through the metal leads, the connectors and the pads. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19)
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20. A method for packaging a MEMS device comprising:
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providing a first substrate and a second substrate, the second substrate comprising an SOI wafer having a first silicon portion, a second silicon portion and an oxide portion therebetween;
forming a functional element on a surface of the first substrate;
forming at least two metal leads on the surface of the first substrate, wherein at least one of the metal leads connects to the functional element;
etching at least one recessed cavity in the first silicon portion of the second substrate;
forming at least two metal connectors in the at least one recessed cavity for connecting to a respective metal lead on the surface of the first substrate wherein the recessed cavity is etched to a depth greater than the thickness of the functional element and less than the combined thickness of the metal connectors and respective metal leads;
bonding the surface of the first substrate to a non-recessed surface of the first silicon portion and bonding each metal connector to the respective metal lead thereby sealing the functional element in the at least one recessed cavity;
removing the second silicon portion of the second substrate thereby exposing the oxide portion;
etching a via through the oxide portion and the first silicon portion over each metal connector to expose at least a portion of each metal connector; and
forming a metal pad on the exposed portion of each metal connector in the via. - View Dependent Claims (21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36)
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37. A MEMS package comprising:
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a first wafer having at least one functional element and at least two metal leads thereon, at least one of the two metal leads being connected to the functional element;
a second wafer having a silicon portion, a silicon oxide portion, at least one recessed cavity in the silicon portion, and at least two metal connectors in the recessed cavities;
a first bond between a non-recessed surface of the silicon portion of the second wafer and the first wafer wherein the at least one recessed cavity is hermetically sealed thereby, and wherein the functional element and connected metal lead of the first wafer are enclosed within the at least one recessed cavity of the second wafer and hermetically sealed therein, and wherein the depth of the recessed cavity is greater than the thickness of the functional element; and
a second bond between each of the at least two metal connectors of the second wafer and a respective one of the at least two metal leads of the first wafer;
a metal pad connected to each metal connector of the second wafer through the silicon oxide portion and silicon portion. - View Dependent Claims (38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50)
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Specification