# US 9,437,524 B2 · Through-silicon via with sidewall air gap

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- Number: US 9,437,524 B2
- Document ID: US9437524B2
- Status: Granted
- Kind: B2
- Application number: 14/514,425
- Filed: 2014-10-15
- Published: 2015-02-26
- Granted: 2016-09-06
- Earliest claimed: 2013-03-15
- Assignees: Globalfoundries Inc.
- Applicants: GLOBALFOUNDRIES Inc.
- Inventors: Shan Gao; Seung Man Choi
- Web page: https://patentgrep.com/patent/US9437524B2

## CPC

- H10W 20/20: Interconnections within wafers or substrates, e.g. through-silicon vias [TSV]
- H10W 20/023: {the interconnections being through-semiconductor vias}
- H10W 20/0245: {comprising use of blind vias during the manufacture}
- H10W 20/0265: {characterised by the sidewall insulation}
- H10W 20/072: {of dielectric parts comprising air gaps}
- H10W 20/46: comprising air gaps
- H10W 72/012: {of bump connectors, dummy bumps or thermal bumps}
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

Embodiments of the present invention provide a novel process integration for air gap formation at the sidewalls for a Through Silicon Via (TSV) structure. The sidewall air gap formation scheme for the TSV structure of disclosed embodiments reduces parasitic capacitance and depletion regions in between the substrate silicon and TSV conductor, and serves to also reduce mechanical stress in silicon substrate surrounding the TSV conductor.

## Claims

### Claim 1

A semiconductor structure comprising:
a bulk silicon substrate;
a through-silicon via formed in the bulk silicon substrate;
a barrier layer disposed adjacent to the through-silicon via;
an air gap disposed adjacent to the barrier layer;
a sealant dielectric layer disposed below the air gap, wherein the sealant dielectric layer seals the air gap; and
a conductor region disposed within the sealant dielectric layer.

### Claim 2 (depends on 1)

The semiconductor structure of claim 1, wherein the air gap is sealed with a sealant dielectric layer selected from the group consisting of: polyimide, benzocyclobutene, and polybenzoxazole.

### Claim 3 (depends on 1)

The semiconductor structure of claim 1, wherein the barrier layer comprises tantalum.

### Claim 4 (depends on 1)

The semiconductor structure of claim 1, further comprising a silicon oxide region disposed above the air gap.

### Claim 5 (depends on 1)

The semiconductor structure of claim 1, wherein the through-silicon via is comprised of copper.

### Claim 6 (depends on 1)

The semiconductor structure of claim 1, wherein the through-silicon via is comprised of tungsten.

### Claim 7 (depends on 1)

The semiconductor structure of claim 1, wherein the sealant dielectric layer comprises epoxy.

### Claim 8 (depends on 1)

The semiconductor structure of claim 1, wherein the sealant dielectric layer comprises polyimide (PI).

### Claim 9 (depends on 1)

The semiconductor structure of claim 1, wherein the sealant dielectric layer comprises benzocyclobutene (BCB).

### Claim 10 (depends on 1)

The semiconductor structure of claim 1 wherein the sealant dielectric layer comprises polybenzoxazole (PBO).

### Claim 11 (depends on 1)

The semiconductor structure of claim 1, further comprising a solder ball attached to the conductor region.