# US 2014/0191392 A1 · Post-Passivation Interconnect Structure and Methods for Forming the Same

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- Number: US 2014/0191392 A1
- Document ID: US20140191392A1
- Status: Published application
- Kind: A1
- Application number: 13/737,177
- Filed: 2013-01-09
- Published: 2014-07-10
- Earliest claimed: 2013-01-09
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Inventors: Chia-Wei Tu; Yian-Liang Kuo; Wei-Lun Hsieh; Tsung-Fu Tsai
- Web page: https://patentgrep.com/patent/US20140191392A1

## CPC

- H10W 90/701: {characterised by the relative positions of pads or connectors relative to package parts}
- H10W 20/081: {by forming openings in the dielectric parts}
- H10W 20/096: {by contacting with gases, liquids or plasmas}
- H10W 20/48: Insulating materials thereof
- H10W 74/147: {the encapsulations being multilayered}
- H10W 20/49: Adaptable interconnections, e.g. fuses or antifuses
- H10W 72/01257: {by reflowing}
- H10W 72/0198: {batch processes}
- H10W 72/07251: {characterised by changes in properties of the bump connectors during connecting}
- H10W 72/20: Bump connectors, e.g. solder bumps or copper pillars; Dummy bumps; Thermal bumps
- H10W 72/252: {comprising solid metals or solid metalloids, e.g. PbSn, Ag or Cu}
- H10W 72/255: {of outermost layers of multilayered bumps, e.g. material of a coating}
- H10W 72/29: Bond pads specially adapted therefor
- H10W 72/9415: {relative to the surface, e.g. recessed, protruding}
- H10W 72/942: {relative to underlying supporting features, e.g. bond pads, RDLs or vias}
- H10W 72/952: {comprising metals or metalloids, e.g. PbSn, Ag or Cu}
- H10W 72/983: {Reinforcing structures, e.g. collars}
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

A method includes forming a polymer layer over a passivation layer, wherein the passivation layer further comprises a portion over a metal pad. The polymer layer is patterned to form an opening in the polymer layer, wherein exposed surfaces of the polymer layer have a first roughness. A surface treatment is performed to increase a roughness of the polymer layer to a second roughness greater than the first roughness. A metallic feature is formed over the exposed surface of the polymer layer.

## Claims

### Claim 1

A method comprising:
forming a polymer layer over a passivation layer, wherein the passivation layer further comprises a portion over a metal pad;
patterning the polymer layer to form an opening in the polymer layer, wherein exposed surfaces of the polymer layer have a first roughness;
performing a surface treatment to increase a roughness of the polymer layer to a second roughness greater than the first roughness; and
forming a metallic feature over the exposed surface of the polymer layer.

### Claim 2 (depends on 1)

The method of claim 1, wherein the surface treatment comprises sputtering the exposed surfaces of the polymer layer.

### Claim 3 (depends on 1)

The method of claim 1, wherein the surface treatment is performed using a plasma of nitrogen.

### Claim 4 (depends on 1)

The method of claim 1 further comprising, after patterning the polymer layer and before the surface treatment, performing an ashing step on the exposed surfaces of the polymer layer.

### Claim 5 (depends on 4)

The method of claim 4, wherein the ashing step is performed using a plasma of an oxygen-containing gas.

### Claim 6 (depends on 1)

The method of claim 1, wherein the surface treatment is configured to make the second roughness to be greater than four times the first roughness.

### Claim 7 (depends on 1)

The method of claim 1, wherein the step of forming the metallic feature comprises:
blanket forming a seed layer over and contacting the exposed surfaces of the polymer layer and an exposed surface of the metal pad;
forming and patterning a mask layer over the seed layer;
depositing a metallic material over the seed layer and in an opening in the mask layer; and
removing the mask layer and portions of the seed layer covered by the mask layer, wherein a remaining portion of the metallic material and an underlying portion of the seed layer form the metallic feature.

### Claim 8

A method comprising:
forming a passivation layer over a metal pad;
patterning the passivation layer to expose a portion of the metal pad;
forming a first polymer layer over the passivation layer and the metal pad;
patterning the first polymer layer to form an opening in the first polymer layer, wherein a portion of the metal pad is revealed through the opening;
performing a surface treatment on exposed surfaces of the first polymer layer, wherein the surface treatment comprises sputtering; and
forming a Post-Passivation Interconnect (PPI) over the exposed surfaces of the first polymer layer.

### Claim 9 (depends on 8)

The method of claim 8 further comprising, before the surface treatment and after the step of patterning the first polymer layer, performing an ashing step on the exposed surfaces of the first polymer layer.

### Claim 10 (depends on 9)

The method of claim 9, wherein the step of ashing is performed for a duration greater than about 25 seconds.

### Claim 11 (depends on 8)

The method of claim 8 further comprising:
forming a second polymer layer over the PPI and the passivation layer;
forming a Under-Bump Metallurgy (UBM) extending into the second polymer layer; and
forming a connector over the UBM and electrically coupled to the metal pad.

### Claim 12 (depends on 8)

The method of claim 8, wherein the sputtering is performed using a plasma of nitrogen (N2).

### Claim 13 (depends on 8)

The method of claim 8 further comprising, before the surface treatment and after patterning the first polymer layer, curing the patterned first polymer layer.

### Claim 14 (depends on 8)

The method of claim 8, wherein the sputtering is performed until a roughness of the exposed surfaces of the first polymer layer is increased to greater than about four times an additional roughness of the first polymer layer before the sputtering is performed.

### Claim 15

A device comprising:
a passivation layer over a metal pad;
a first polymer layer over the passivation layer; and
a Post-Passivation Interconnect (PPI) over and contacting top surfaces of the first polymer layer, wherein the PPI comprises a first portion over the first polymer layer, and a second portion in the first polymer layer, and wherein a surface of the first polymer layer contacting the PPI has a roughness greater than about 20 nm.

### Claim 16 (depends on 15)

The device of claim 15, wherein the first polymer layer comprises polyimide.

### Claim 17 (depends on 15)

The device of claim 15 further comprising:
a second polymer layer over the PPI and the passivation layer, wherein a roughness of the second polymer layer is smaller than about 10 nm;
an Under-Bump Metallurgy (UBM) extending into the second polymer layer; and
a connector over the UBM and electrically coupled to the metal pad.

### Claim 18 (depends on 17)

The device of claim 17, wherein the first polymer layer and the second polymer layer are formed of a same material.

### Claim 19 (depends on 15)

The device of claim 15, wherein the passivation layer has a k value greater than about 3.9, and wherein the device further comprises a plurality of low-k dielectric layers underlying the passivation layer and the metal pad.

### Claim 20 (depends on 15)

The device of claim 15, wherein the surface of the first polymer layer contacting the PPI comprises a first portion contacting the first portion of the PPI, and a second portion contacting the second portion of the PPI.