# US 12,009,256 B2 · Redistribution lines with protection layers and method forming same

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- Number: US 12,009,256 B2
- Document ID: US12009256B2
- Status: Granted
- Kind: B2
- Application number: 18/338,095
- Filed: 2023-06-20
- Published: 2023-11-02
- Granted: 2024-06-11
- Earliest claimed: 2020-05-27
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Taiwan Semiconductor Manufacturing Co., Ltd.
- Inventors: Ming-Da Cheng; Wen-Hsiung Lu; Chin Wei Kang; Yung-Han Chuang; Lung-Kai Mao; Yung-Sheng Lin
- Web page: https://patentgrep.com/patent/US12009256B2

## CPC

- H10W 20/063: {by forming conductive members before forming protective insulating material}
- H10W 20/039: {also covering sidewalls of the conductive structures}
- H10W 20/042: {the barrier, adhesion or liner layers being seed or nucleation layers}
- H10W 20/081: {by forming openings in the dielectric parts}
- H10W 72/20: Bump connectors, e.g. solder bumps or copper pillars; Dummy bumps; Thermal bumps
- H10W 72/30: Die-attach connectors
- H10W 72/90: Bond pads, in general
- H10W 70/05: of insulating or insulated package substrates, or of interposers, or of redistribution layers (manufacture or treatment of leadframes H10W70/04)
- H10W 70/60: Insulating or insulated package substrates; Interposers; Redistribution layers (leadframes H10W70/40)
- H10W 70/65: Shapes or dispositions of interconnections
- H10W 70/66: Conductive materials thereof
- H10W 72/019: {of bond pads}
- H10W 72/29: Bond pads specially adapted therefor
- 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: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

A method includes forming a metal seed layer over a first conductive feature of a wafer, forming a patterned photo resist on the metal seed layer, forming a second conductive feature in an opening in the patterned photo resist, and heating the wafer to generate a gap between the second conductive feature and the patterned photo resist. A protection layer is plated on the second conductive feature. The method further includes removing the patterned photo resist, and etching the metal seed layer.

## Claims

### Claim 1

A device comprising:
a first dielectric layer;
a redistribution line comprising a portion over the first dielectric layer, wherein the redistribution line comprises:
a metal seed layer;
a conductive feature over the metal seed layer, wherein the metal seed layer extends laterally beyond respective edges of the conductive feature; and
a protection layer comprising:
a top portion over and contacting a first top surface of the conductive feature, wherein the top portion also extends laterally beyond the respective edges of the conductive feature; and
a second dielectric layer extending on a sidewall and a second top surface of the redistribution line.

### Claim 2 (depends on 1)

The device of claim 1, wherein the protection layer further comprises a sidewall portion on a sidewall of the conductive feature, wherein the sidewall portion is joined with the top portion of the protection layer.

### Claim 3 (depends on 2)

The device of claim 2, wherein the sidewall portion of the protection layer is further joined to a top surface of the metal seed layer.

### Claim 4 (depends on 3)

The device of claim 3, wherein an outer sidewall of the sidewall portion of the protection layer is vertically aligned to an outer edge of the metal seed layer.

### Claim 5 (depends on 1)

The device of claim 1, wherein the second dielectric layer contacts the top portion of the protection layer to form a horizontal interface.

### Claim 6 (depends on 1)

The device of claim 1, wherein the second dielectric layer is fully separated from the conductive feature by the protection layer.

### Claim 7 (depends on 1)

The device of claim 1, wherein the conductive feature comprises copper, and the protection layer comprises a metal selected from the group consisting of Ni, Sn, Ag, Cr, Ti, Pt, and alloys thereof.

### Claim 8 (depends on 1)

The device of claim 1 further comprising a via over and electrically coupling to the redistribution line, wherein the via penetrates through the second dielectric layer to contact a third top surface of the top portion of the protection layer.

### Claim 9 (depends on 1)

The device of claim 1 further comprising a via over and electrically coupling to the redistribution line, wherein the via penetrates through the second dielectric layer and the top portion of the protection layer to contact the conductive feature.

### Claim 10

A device comprising:
a passivation layer;
a redistribution line comprising a via portion extending into the passivation layer, and a line portion over and joining to the via portion, wherein the line portion comprises:
a seed layer over the passivation layer, wherein the seed layer comprises first outer edges;
a conductive material over the seed layer, wherein the conductive material comprises second outer edges; and
a protection layer comprising:
a top portion over and contacting the conductive material, wherein the top portion of the protection layer comprise third outer edges vertically offset from respective ones of the second outer edges; and
a sidewall portion directly contacting one of the second outer edges of the conductive material; and
a first dielectric layer on the first sidewall portion and the top portion of the protection layer.

### Claim 11 (depends on 10)

The device of claim 10, wherein the third outer edges of the top portion of the protection layer are also vertically offset from respective underlying ones of the first outer edges.

### Claim 12 (depends on 10)

The device of claim 10, wherein the second outer edges are vertically aligned to respective underlying ones of the first outer edges.

### Claim 13 (depends on 10)

The device of claim 10, wherein the top portion of the protection layer comprises an overhang portion extending beyond the respective ones of the second outer edges.

### Claim 14 (depends on 13)

The device of claim 13, wherein the first dielectric layer comprises a portion contacting a bottom surface of the overhang portion to form an interface.

### Claim 15 (depends on 10)

The device of claim 10, wherein the protection layer further comprises a sidewall portion contacting an upper part of one of the second outer edges of the conductive material.

### Claim 16 (depends on 15)

The device of claim 15, wherein the first dielectric layer contacts a bottom part of the one of the second outer edges of the conductive material.

### Claim 17

A device comprising:
a first dielectric layer;
a redistribution line comprising a portion over the first dielectric layer, wherein the redistribution line comprises:
a metal seed layer;
a conductive feature over the metal seed layer, wherein the metal seed layer extends laterally beyond respective edges of the first conductive feature; and
a protection layer comprising:
a top portion over and contacting a first top surface of the conductive feature, wherein the top portion also extends laterally beyond the respective edges of the conductive feature; and
a sidewall portion contacting a sidewall of the conductive feature to form a vertical interface; and
a second dielectric layer contacting the redistribution line.

### Claim 18 (depends on 17)

The device of claim 17, wherein the sidewall portion of the protection layer overlaps a part of the metal seed layer.

### Claim 19 (depends on 17)

The device of claim 17, wherein the sidewall portion of the protection layer has a bottommost end higher than a topmost surface of the metal seed layer.

### Claim 20 (depends on 17)

The device of claim 17 further comprising an under-bump metallurgy over and contacting the redistribution line.