# US 10,121,755 B1 · Robust chamfer design for seal ring

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- Number: US 10,121,755 B1
- Document ID: US10121755B1
- Status: Granted
- Kind: B1
- Application number: 15/713,687
- Filed: 2017-09-24
- Granted: 2018-11-06
- Earliest claimed: 2017-09-24
- Assignees: Globalfoundries Singapore Pte. Ltd.
- Applicants: GLOBALFOUNDRIES Singapore Pte. Ltd.
- Inventors: Mahesh Bhatkar; Juan Boon Tan; Wanbing Yi
- Web page: https://patentgrep.com/patent/US10121755B1

## CPC

- H10W 72/013: {of die-attach connectors}
- H10W 42/00: Arrangements for protection of devices (arrangements for thermal protection H10W40/00)
- H10W 42/121: {protecting against mechanical damage (H10W76/00, H10W74/00 take precedence)}
- H10W 72/30: Die-attach connectors
- H10W 72/244: {relative to underlying supporting features, e.g. bond pads, RDLs or vias}
- H10W 72/252: {comprising solid metals or solid metalloids, e.g. PbSn, Ag or Cu}
- H10W 72/29: Bond pads specially adapted therefor
- H10W 72/921: {Structures or relative sizes of bond pads}
- H10W 72/922: {Bond pads being integral with underlying chip-level interconnections}
- H10W 72/9223: {with redistribution layers [RDL]}
- H10W 72/923: {Bond pads having multiple stacked layers}
- H10W 72/9415: {relative to the surface, e.g. recessed, protruding}
- H10W 72/952: {comprising metals or metalloids, e.g. PbSn, Ag or Cu}
- H10W 90/724: {between a chip and a stacked insulating package substrate, interposer or RDL}
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

A seal ring structure is disclosed for integrated circuit (IC) packaging. The seal ring includes an inner moisture barrier ring and an outer crack stop ring. Line structures of both the inner and outer rings include chamfered corners. The chamfers of a chamfered corner are devoid of acute angles. No metal line structure for the inner ring is provided at the pad level. The seal ring as described improves the reliability and strength of the structure and hence the seal ring can sustain high stress at the corners of the die during dicing.

## Claims

### Claim 1

A semiconductor device comprising:
a substrate, the substrate includes
a prime region having circuit components,
a seal ring region surrounding the prime region, and
a kerf region;
a back-end-of-line (BEOL) dielectric disposed on the substrate covering the prime region with the circuit components, the seal ring region and the kerf region, the BEOL dielectric includes
a plurality of interlevel dielectric (ILD) levels, an ILD level of the ILD levels includes
a via dielectric level with via contacts,
a metal dielectric level with metal lines,
the metal lines and the via contacts of the ILD levels interconnect the circuit components of the prime region, and
wherein
a bottom ILD level is a first ILD level of the BEOL dielectric,
one or more intermediate ILD levels is disposed above the bottom ILD level, and
a top ILD level is disposed above the intermediate ILD levels, wherein a top metal level of the top ILD level serves as a pad level with pads; and
a seal ring disposed in the BEOL dielectric over the seal ring region of the substrate, the seal ring comprises an inner moisture oxygen barrier (MOB) ring adjacent to the prime region and an outer crack stop (CS) ring adjacent to the kerf region, wherein
the MOB ring includes
MOB metal level metal line structures disposed in metal dielectric levels of the ILD levels except the top metal dielectric level,
MOB via level metal line structures disposed in via dielectric levels of the ILD levels, and
the MOB metal level metal line structures and the MOB via level metal line structures include MOB chamfered corners which are devoid of acute angles, and
the CS ring includes
CS metal level metal line structures disposed in metal dielectric levels of the ILD levels,
CS via level metal line structures disposed in via dielectric levels of the ILD levels, and
the CS metal level metal line structures and the CS via level metal line structures include CS chamfered corners which are devoid of acute angles.

### Claim 2 (depends on 1)

The device of claim 1 wherein the MOB ring includes the via level metal line structures in via dielectric levels of the ILD levels except the top via dielectric level of the top ILD level.

### Claim 3 (depends on 1)

The device of claim 1 wherein the CS chamfered corners each comprises inner and outer chamfers forming a polygonal shape which is devoid of acute angles.

### Claim 4 (depends on 3)

The device of claim 3 wherein the polygonal shape of the chamfer corners comprises a hexagonal shape.

### Claim 5 (depends on 3)

The device of claim 3 wherein a space within the polygonal shaped chamfered corners comprises a marker pattern.

### Claim 6 (depends on 3)

The device of claim 3 wherein a line width of the CS metal level metal line structures is wider than a via width of the CS via level metal line structures.

### Claim 7 (depends on 3)

The device of claim 3 wherein the MOB metal line structures and the MOB via level metal line structures follow a pattern of the CS metal line structures and the CS via level metal line structures.

### Claim 8 (depends on 7)

The device of claim 7 wherein the chamfered corners of the MOB metal line structures and the MOB via line structures are similar to the inner chamfer of the CS chamfered corners.

### Claim 9

A method of forming a semiconductor device comprising:
providing a substrate, the substrate is prepared with
a prime region having circuit components,
a seal ring region surrounding the prime region, and
a kerf region;
forming a back-end-of-line (BEOL) dielectric disposed the substrate covering the sprime region with the circuit components, the seal ring region and the kerf region, the BEOL dielectric includes
a plurality of interlevel dielectric (ILD) levels, an ILD level of the ILD levels includes
a via dielectric level with via contacts,
a metal dielectric level with metal lines,
the metal lines and the via contacts of the ILD levels interconnect the circuit components of the prime region, and
wherein
a bottom ILD level is a first ILD level of the BEOL dielectric,
one or more intermediate ILD levels is disposed above the bottom ILD level, and
a top ILD level is disposed above the intermediate ILD levels, wherein a top metal level of the top ILD level serves as a pad level with pads; and
forming a seal ring in the BEOL dielectric over the seal ring region of the substrate along with forming metal lines and via contacts, the seal ring comprises an inner moisture oxygen barrier (MOB) ring adjacent to the prime region and an outer crack stop (CS) ring adjacent to the kerf region, wherein
the MOB ring includes
MOB metal level metal line structures disposed in metal dielectric levels of the ILD levels except the top metal dielectric level,
MOB via level metal line structures disposed in via dielectric levels of the ILD levels, and
the MOB metal level metal line structures and the MOB via level metal line structures include MOB chamfered corners which are devoid of acute angles, and
the CS ring includes
CS metal level metal line structures disposed in metal dielectric levels of the ILD levels,
CS via level metal line structures disposed in via dielectric levels of the ILD levels, and
the CS metal level metal line structures and the CS via level metal line structures include CS chamfered corners which are devoid of acute angles.

### Claim 10 (depends on 9)

The method of claim 9 wherein the MOB ring includes the via level metal line structures in via dielectric levels of the ILD levels except the top via dielectric level of the top ILD level.

### Claim 11 (depends on 9)

The method of claim 9 wherein the CS chamfered corners each comprises inner and outer chamfers forming a polygonal shape which is devoid of acute angles.

### Claim 12 (depends on 11)

The method of claim 11 wherein the polygonal shape of the chamfer corners comprises a hexagonal shape.

### Claim 13 (depends on 11)

The method of claim 11 wherein a space within the polygonal shaped chamfered corners comprises a marker pattern.

### Claim 14 (depends on 11)

The method of claim 11 wherein a line width of the CS metal level metal line structures is wider than a via width of the CS via level metal line structures.

### Claim 15 (depends on 11)

The method of claim 11 wherein the MOB metal line structures and the MOB via level metal line structures follow a pattern of the CS metal line structures and the CS via level metal line structures.

### Claim 16 (depends on 15)

The method of claim 15 wherein the chamfered corners of the MOB metal line structures and the MOB via line structures are similar to the inner chamfer of the CS chamfered corners.

### Claim 17

A semiconductor device comprising:
a substrate, the substrate includes
a prime region having circuit components,
a seal ring region surrounding the prime region, and
a kerf region;
a back-end-of-line (BEOL) dielectric disposed on the substrate covering the prime region with the circuit components, the seal ring region and the kerf region, the BEOL dielectric includes
a plurality of interlevel dielectric (ILD) levels, an ILD level of the ILD levels includes
a via dielectric level with via contacts,
a metal dielectric level with metal lines,
the metal lines and the via contacts of the ILD levels interconnect the circuit components of the prime region, and
wherein
a bottom ILD level is a first ILD level of the BEOL dielectric,
one or more intermediate ILD levels is disposed above the bottom ILD level, and
a top ILD level is disposed above the intermediate ILD levels, wherein a top metal level of the top ILD level serves as a pad level with pads; and
a seal ring disposed in the BEOL dielectric over the seal ring region of the substrate, the seal ring comprises an inner moisture oxygen barrier (MOB) ring adjacent to the prime region and an outer crack stop (CS) ring adjacent to the kerf region, wherein
the MOB ring includes
MOB metal level metal line structures disposed in metal dielectric levels of the ILD levels,
MOB via level metal line structures disposed in via dielectric levels of the ILD levels, and
the MOB metal level metal line structures and the MOB via level metal line structures include MOB chamfered corners which are devoid of acute angles, and
the CS ring includes
CS metal level metal line structures disposed in metal dielectric levels of the ILD levels,
CS via level metal line structures disposed in via dielectric levels of the ILD levels, and
the CS metal level metal line structures and the CS via level metal line structures include CS chamfered corners which are devoid of acute angles.

### Claim 18 (depends on 17)

The device of claim 17 wherein the CS chamfered corners each comprise inner and outer chamfers forming a polygonal shape which is devoid of acute angles.

### Claim 19 (depends on 18)

The device of claim 18 wherein the polygonal shape of the chamfer corners comprises a hexagonal shape.

### Claim 20 (depends on 18)

The device of claim 18 wherein a space within the polygonal shaped chamfered corners comprises a marker pattern.