# US 8,569,167 B2 · Methods for forming a semiconductor structure

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- Number: US 8,569,167 B2
- Document ID: US8569167B2
- Status: Granted
- Kind: B2
- Application number: 13/074,852
- Filed: 2011-03-29
- Published: 2012-10-04
- Granted: 2013-10-29
- Earliest claimed: 2011-03-29
- Assignees: Micron Technology, Inc.
- Applicants: Jaspreet S. Ghandi; Don L. Yates; Yangyang Sun
- Inventors: Jaspreet S. Ghandi; Don L. Yates; Yangyang Sun
- Web page: https://patentgrep.com/patent/US8569167B2

## CPC

- H10W 90/701: {characterised by the relative positions of pads or connectors relative to package parts}
- H10W 72/00: Interconnections or connectors in packages
- H10W 74/137: {the encapsulations being directly on the semiconductor body (H10W74/134 takes precedence)}
- H10W 74/47: comprising organic materials, e.g. plastics or resins
- H10W 20/081: {by forming openings in the dielectric parts}
- H10W 20/082: {the openings being tapered via holes}
- H10W 20/097: {by thermally treating}
- H10W 72/01935: {by plating, e.g. electroless plating or electroplating}
- H10W 72/01955: {by using masks}
- H10W 72/227: {Multiple bumps having different sizes}
- H10W 72/241: {Dispositions, e.g. layouts}
- 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 72/923: {Bond pads having multiple stacked layers}
- H10W 72/926: {Multiple bond pads having different sizes}
- 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: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

Methods of forming a Ni material on a bond pad are disclosed. The methods include forming a dielectric material over a bond pad, forming an opening within the dielectric material to expose the bond pad, curing the dielectric material to form a surface of the dielectric material having a steep curvilinear profile, and forming a nickel material over the at least one bond pad. The dielectric material having a steep curvilinear profile may be formed by altering at least one of a curing process of the dielectric material and a thickness of the dielectric material. The dielectric material may be used to form a relatively thick Ni material on bond pads smaller than about 50 μm. Semiconductor structures formed by such methods are also disclosed.

## Claims

### Claim 1

A method of forming a semiconductor structure, the method comprising:
forming a dielectric material over at least one bond pad;
forming at least one opening within the dielectric material to expose the at least one bond pad;
curing the dielectric material comprising the at least one opening, the curing forming a surface of the dielectric material having a steep curvilinear profile; and
forming a nickel material over the at least one bond pad.

### Claim 2 (depends on 1)

The method of claim 1, wherein curing the dielectric material comprising the at least one opening comprises:
heating the dielectric material comprising the at least one opening to a first temperature less than or equal to a glass transition temperature of the dielectric material; and
heating the dielectric material comprising the at least one opening to a second temperature greater than the glass transition temperature of the dielectric material.

### Claim 3 (depends on 2)

The method of claim 2, wherein heating the dielectric material comprising the at least one opening to a first temperature less than or equal to a glass transition temperature of the dielectric material comprises heating the dielectric material comprising the at least one opening for about one hour.

### Claim 4 (depends on 2)

The method of claim 2, wherein heating the dielectric material comprising the at least one opening to a second temperature greater than the glass transition temperature of the dielectric material comprises heating the dielectric material comprising the at least one opening for about two hours.

### Claim 5 (depends on 1)

The method of claim 1, wherein forming a dielectric material over at least one bond pad comprises forming the dielectric material at least about 10 μm thick.

### Claim 6 (depends on 1)

The method of claim 1, wherein forming a dielectric material over at least one bond pad comprises forming a positive tone polyimide over the at least one bond pad.

### Claim 7 (depends on 1)

The method of claim 1, wherein forming a dielectric material over at least one bond pad comprises forming the dielectric material over the at least one bond pad having a cross-section dimension of less than about 50 μm.

### Claim 8 (depends on 1)

The method of claim 1, wherein forming a nickel material over the at least one bond pad comprises forming the nickel material at least about 4 μm thick.

### Claim 9 (depends on 1)

The method of claim 1, wherein forming a dielectric material over at least one bond pad comprises forming a photosensitive dielectric material having a glass transition temperature (Tg) of from about 50° C to about 250° C over the at least one bond pad.

### Claim 10 (depends on 1)

The method of claim 1, wherein curing the dielectric material comprising the at least one opening, the curing forming a surface of the dielectric material having a steep curvilinear profile comprises changing sidewalls of the dielectric material from a substantially vertical profile to a substantially rounded profile.

### Claim 11 (depends on 1)

The method of claim 1, wherein curing the dielectric material comprising the at least one opening, the curing forming a surface of the dielectric material having a steep curvilinear profile comprises forming the surface of the dielectric material having a hemispherical cross-section.

### Claim 12 (depends on 1)

The method of claim 1, wherein curing the dielectric material comprising the at least one opening, the curing forming a surface of the dielectric material having a steep curvilinear profile comprises forming an angle of greater than about 30° and less than about 90° between a line tangent to a curvilinear surface of the dielectric material and an exposed surface of an adjacent bond pad.

### Claim 13

A method of forming a semiconductor structure, the method comprising:
forming a dielectric material over at least one bond pad, the dielectric material comprising a photosensitive polyimide material;
removing at least one portion of the dielectric material to expose at least a portion of the at least one bond pad;
heating the dielectric material to a first temperature after removing the at least one portion of the dielectric material, the first temperature less than or equal to a glass transition temperature of the dielectric material;
heating the dielectric material to a second temperature after heating the dielectric material to the first temperature, the second temperature greater than the glass transition temperature of the dielectric material; and
plating a nickel material on the at least one bond pad.

### Claim 14 (depends on 13)

The method of claim 13, wherein removing at least one portion of the dielectric material to expose at least a portion of the at least one bond pad comprises exposing the at least one bond pad through openings in the dielectric material, the openings defined by substantially vertical sidewalls of the dielectric material.

### Claim 15 (depends on 13)

The method of claim 13, wherein heating the dielectric material to a first temperature after removing the at least one portion of the dielectric material and heating the dielectric material to a second temperature after heating the dielectric material to the first temperature comprises forming a steep curvilinear profile in the dielectric material.

### Claim 16 (depends on 13)

The method of claim 13, wherein forming a dielectric material over at least one bond pad comprises forming a dielectric material having a thickness of at least about two times a thickness of the nickel material.

### Claim 17 (depends on 13)

The method of claim 13, wherein forming a dielectric material over at least one bond pad comprises forming at least two external bond pads, at least one of the external bond pads having a cross-sectional dimension less than about 50 μm and another of the at least one external bond pads having a cross-sectional dimension of greater than or equal to about 100 μm.

### Claim 18 (depends on 13)

The method of claim 13, wherein heating the dielectric material to a first temperature after removing the at least one portion of the dielectric material comprises crosslinking only a surface of the dielectric material.