# US 7,466,022 B2 · Wafer-level seal for non-silicon-based devices

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- Number: US 7,466,022 B2
- Document ID: US7466022B2
- Status: Granted
- Kind: B2
- Application number: 11/041,857
- Filed: 2005-01-24
- Published: 2005-08-04
- Granted: 2008-12-16
- Earliest claimed: 2002-08-28
- Assignees: Silicon Light Machines Corporation
- Inventors: Gregory D. Miller; Mike Bruner
- Web page: https://patentgrep.com/patent/US7466022B2

## CPC

- B81C 1/00293: {maintaining a controlled atmosphere with processes not provided for in B81C1/00285}
- H03H 3/08: for the manufacture of resonators or networks using surface acoustic waves
- H03H 9/02921: {Measures for preventing electric discharge due to pyroelectricity}
- H03H 9/02984: {Protection measures against damaging}
- H03H 9/1092: {the enclosure being defined by a cover cap mounted on an element forming part of the surface acoustic wave [SAW] device on the side of the IDT's}
- B81C 2203/0136: Growing or depositing of a covering layer
- Y10T 29/42: Piezoelectric device making
- Y10T 29/49005: Acoustic transducer
- Y10T 29/49011: Commutator or slip ring assembly
- Y10T 29/4908: Acoustic transducer
- Y10T 29/49126: Assembling bases
- B81C: PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS (making microcapsules or microballoons B01J13/02; processes or apparatus specially adapted for the manufacture or treatment of piezoelectric, electrostrictive or magnetostrictive elements per se H10N30/01)
- H03H: IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS (waveguides, resonators, lines or other devices of the waveguide type H01P)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

One embodiment disclosed relates to a method for sealing an active area of a non-silicon-based device on a wafer. The method includes providing a sacrificial material over at least the active area of the non-silicon-based device, depositing a seal coating over the wafer so that the seal coating covers the sacrificial material, and replacing the sacrificial material with a target atmosphere. Another embodiment disclosed relates to a non-silicon-based device sealed at the wafer level (i.e. prior to separation of the die from the wafer). The device includes an active area to be protected, a contact area, and a lithographically-formed structure sealing at least the active area and leaving at least a portion of the contact area exposed.

## Claims

### Claim 1

A non-silicon-based device sealed at the wafer level, the device comprising:
an active area to be protected on a SAW device;
a contact area on a substrate; and
a continuous structure sealing at least the active area and leaving at least a portion of the contact area exposed,
wherein the continuous structure comprises vertical and horizontal portions which are integral to the continuous structure, further wherein a sealed pocket is formed under the horizontal portion, and further wherein the horizontal portion includes an indented area above the active area a target gas sealed between the continuous structure and the substrate.

### Claim 2 (depends on 1)

The device of claim 1, wherein the continuous structure comprises a glassy material.

### Claim 3 (depends on 1)

The device of claim 1, wherein the non-silicon-based device is fabricated on the substrate from a group of substrates consisting of lithium tantalate, lithium niobate, and quartz.

### Claim 4 (depends on 3)

The device of claim 3, wherein the sealed pocket is hermetically sealed.

### Claim 5

A lithographically-fabricated non-silicon-based device, the non-silicon-based SAW device comprising:
a non-silicon substrate for the non-silicon-based SAW device;
an active area of the non-silicon-based SAW device that is atmospherically sensitive; and
a wafer-level means for sealing the active area of the non-silicon-based SAW device, a target gas sealed between the wafer-level means and the non-silicon-based substrate
wherein the wafer-level means for sealing the active area has a thermal coefficient of expansion mismatch with the non-silicon substrate so as to induce a strain in the non-silicon substrate.

### Claim 6 (depends on 5)

The device of claim 5, wherein the non-silicon substrate comprises lithium tantalite.

### Claim 7 (depends on 5)

The device of claim 5, wherein the non-silicon substrate comprises lithium niobate.

### Claim 8 (depends on 5)

The device of claim 5, wherein the non-silicon substrate comprises quartz.

### Claim 9 (depends on 5)

The device of claim 5, wherein the wafer-level means for sealing comprises a layer of glassy material.

### Claim 10 (depends on 5)

The device of claim 5, wherein the wafer-level means for sealing comprises a continuous glassy structure with vertical and horizontal portions that are integral to the structure.