# US 2020/0395293 A1 · Large via buffer

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- Number: US 2020/0395293 A1
- Document ID: US20200395293A1
- Status: Published application
- Kind: A1
- Application number: 16/440,012
- Filed: 2019-06-13
- Published: 2020-12-17
- Earliest claimed: 2019-06-13
- Assignees: International Business Machines Corporation
- Applicants: International Business Machines Corporation
- Inventors: YANN MIGNOT; HSUEH-CHUNG CHEN; JUNLI WANG; CHI-CHUN LIU; MARY CLAIRE SILVESTRE
- Web page: https://patentgrep.com/patent/US20200395293A1

## CPC

- H10W 20/42: Vias, e.g. via plugs
- H10W 20/056: {by filling conductive material into holes, grooves or trenches}
- H10W 20/074: {of dielectric parts comprising thin functional dielectric layers, e.g. dielectric etch-stop, barrier, capping or liner layers}
- H10W 20/081: {by forming openings in the dielectric parts}
- H10W 20/087: {involving multiple stacked pre-patterned masks}
- H10W 20/47: comprising two or more dielectric layers having different properties, e.g. different dielectric constants
- H10W 20/063: {by forming conductive members before forming protective insulating material}
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

An interconnect structure is provided. The interconnect structure includes a first metallization layer, an insulating layer and a second metallization layer. The first metallization layer includes, at an uppermost surface thereof, a first body formed of first dielectric material, first metallic elements and buffer elements formed of second dielectric material adjacent the first metallic elements. The insulating layer is disposed on the uppermost surface of the first metallization layer and defines apertures located at the first metallic elements and the corresponding buffer elements. The second metallization layer is disposed on the insulating layer and includes a second body formed of first dielectric material and second metallic elements located at the apertures and extending through the apertures to contact the corresponding first metallic elements and the corresponding buffer elements.

## Claims

### Claim 1

An interconnect structure comprising:
a first metallization layer comprising, at an uppermost surface thereof, a first body formed of first dielectric material, first metallic elements and buffer elements formed of second dielectric material adjacent the first metallic elements;
an insulating layer disposed on the uppermost surface of the first metallization layer and defining apertures located at the first metallic elements and the corresponding buffer elements; and
a second metallization layer disposed on the insulating layer and comprising a second body formed of first dielectric material and second metallic elements located at the apertures and extending through the apertures to contact the corresponding first metallic elements and the corresponding buffer elements.

### Claim 2 (depends on 1)

The interconnect structure according to claim 1, wherein respective surface areas of the second metallic elements are less than a combined surface area of the corresponding first metallic elements and the corresponding buffer elements.

### Claim 3 (depends on 1)

The interconnect structure according to claim 1, wherein:
the first metallization layer comprises additional first metallic elements; and
the second metallization layer comprises additional second metallic elements.

### Claim 4 (depends on 3)

The interconnect structure according to claim 3, wherein each first metallic element is insulated from an adjacent first metallic element or an adjacent additional first metallic element by a buffer element or a combination of a buffer element and a corresponding portion of the first body.

### Claim 5 (depends on 3)

The interconnect structure according to claim 3, wherein the insulating layer defines additional apertures through which the additional second metallic elements contact the corresponding first metallic elements and the corresponding additional first metallic elements.

### Claim 6 (depends on 3)

The interconnect structure according to claim 3, wherein a pattern of the first metallic elements and the additional first metallic elements is distinct from a pattern of the second metallic elements and the additional second metallic elements.

### Claim 7 (depends on 1)

The interconnect structure according to claim 1, wherein one or more of the buffer elements surround uppermost portions of one or more first metallic elements.

### Claim 8 (depends on 1)

The interconnect structure according to claim 1, wherein the first dielectric material comprises ultra low-k dielectric, the second dielectric material is different from the ULK, and the insulating layer comprises nitride.

### Claim 9

A method of fabricating an interconnect structure, the method comprising:
forming a first metallization layer to comprise, at an uppermost surface thereof, a first body formed of first dielectric material, first metallic elements and buffer elements formed of second dielectric material adjacent the first metallic elements;
disposing an insulating layer on the uppermost surface of the first metallization layer;
defining apertures in the insulating layer at locations of the first metallic elements and the corresponding buffer elements; and
disposing, on the insulating layer, a second metallization layer comprising a second body formed of first dielectric material and second metallic elements located at the apertures and extending through the apertures to contact the corresponding first metallic elements and the corresponding buffer elements.

### Claim 10 (depends on 9)

The method according to claim 9, wherein respective surface areas of the second metallic elements are less than a combined surface area of the corresponding first metallic elements and the corresponding buffer elements.

### Claim 11 (depends on 9)

The method according to claim 9, wherein:
the first metallization layer comprises additional first metallic elements; and
the second metallization layer comprises additional second metallic elements.

### Claim 12 (depends on 11)

The method according to claim 11, wherein each first metallic element is insulated from an adjacent first metallic element or an adjacent additional first metallic element by a buffer element or a combination of a buffer element and a corresponding portion of the first body.

### Claim 13 (depends on 11)

The method according to claim 11, wherein the insulating layer defines additional apertures through which the additional second metallic elements contact the corresponding first metallic elements and the corresponding additional first metallic elements.

### Claim 14 (depends on 11)

The method according to claim 11, wherein a pattern of the first metallic elements and the additional first metallic elements is distinct from a pattern of the second metallic elements and the additional second metallic elements.

### Claim 15 (depends on 9)

The method according to claim 9, wherein one or more of the buffer elements surround uppermost portions of one or more first metallic elements.

### Claim 16 (depends on 9)

The method according to claim 9, wherein the first dielectric material comprises ultra low-k dielectric, the second dielectric material is different from the ultra low-k dielectric and the insulating layer comprises nitride.

### Claim 17

A method of fabricating an interconnect structure, the method comprising:
assembling a stack of at least a first metallization layer and an insulating layer;
etching the stack to expose uppermost portions of first metallic elements of the first metallization layer;
surrounding the uppermost portions of the first metallic elements with buffer elements;
rebuilding etched portions of the insulating layer;
forming a second metallization layer on the insulating layer;
etching vias through the second metallization layer and the insulating layer to expose the first metallic elements and the buffer elements; and
filling the vias with conductive material to form second metallic elements in contact with the first metallic elements and the buffer elements.

### Claim 18 (depends on 17)

The method according to claim 17, wherein respective surface areas of the second metallic elements are less than a combined surface area of the corresponding first metallic elements and the corresponding buffer elements.

### Claim 19 (depends on 17)

The method according to claim 17, wherein a material of the buffer elements differs from a dielectric material of the first and second metallization layers.

### Claim 20 (depends on 19)

The method according to claim 19, wherein the etching is selective to the dielectric material of the first and second metallization layers.