# US 2026/0076247 A1 · Manufacturing method of connecting structure and package structure

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- Number: US 2026/0076247 A1
- Document ID: US20260076247A1
- Status: Published application
- Kind: A1
- Application number: 19/390,671
- Filed: 2025-11-17
- Published: 2026-03-12
- Earliest claimed: 2021-04-15
- Assignees: Taiwan Semiconductor Manufacturing Company, Ltd.
- Applicants: Taiwan Semiconductor Manufacturing Company, Ltd.
- Inventors: Tsung-Fu Tsai; Jian-Yang He; Ying-Ching Shih; Szu-Wei Lu
- Web page: https://patentgrep.com/patent/US20260076247A1

## CPC

- H10P 72/74: {using temporarily an auxiliary support}
- H10W 72/20: Bump connectors, e.g. solder bumps or copper pillars; Dummy bumps; Thermal bumps
- H10W 72/012: {of bump connectors, dummy bumps or thermal bumps}
- H10W 72/072: {of bump connectors}
- H10P 72/7416: {used during dicing or grinding}
- H10P 72/7424: {used as a support during the manufacture of self-supporting substrates}
- H10W 70/095: {of vias therein}
- H10W 70/611: {for connecting multiple chips together}
- H10W 70/635: {Through-vias}
- H10W 70/685: comprising multiple insulating layers
- H10W 70/698: Semiconductor materials that are electrically insulating, e.g. undoped silicon
- H10W 72/01235: {by plating, e.g. electroless plating or electroplating}
- H10W 72/01255: {by using masks}
- H10W 72/01257: {by reflowing}
- H10W 72/019: {of bond pads}
- H10W 72/01953: {by etching}
- H10W 72/0198: {batch processes}
- H10W 72/07207: {Temporary substrates, e.g. removable substrates}
- H10W 72/07236: {Soldering or alloying}
- H10W 72/073: {of die-attach connectors}
- H10W 72/222: {Multilayered bumps, e.g. a coating on top and side surfaces of a bump core}
- H10W 72/223: {characterised by the structure of the outermost layers, e.g. multilayered coatings}
- H10W 72/241: {Dispositions, e.g. layouts}
- 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 74/014: {using batch processing}
- H10W 74/019: {using temporary auxiliary substrates (H10W74/017 takes precedence)}
- H10W 74/142: {the encapsulations exposing the passive side of the semiconductor body}
- H10W 74/15: on active surfaces of flip-chip devices, e.g. underfills
- H10W 90/701: {characterised by the relative positions of pads or connectors relative to package parts}
- H10W 90/724: {between a chip and a stacked insulating package substrate, interposer or RDL}
- H10W 90/734: {between a chip and a stacked insulating package substrate, interposer or RDL}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

A structure including a substrate having a conductive pad and a connecting structure disposed on the conductive pad and electrically connected to the conductive pad. The connecting structure includes a first metallic layer disposed on the conductive pad, a first intermetallic compound layer disposed on the first metallic layer, a second intermetallic compound layer disposed on the first intermetallic compound layer and a second metallic layer disposed on the second intermetallic compound layer. The first metallic layer comprises copper. The first intermetallic compound layer comprises a first intermetallic compound. The second intermetallic compound layer comprises a second intermetallic compound different from the first intermetallic compound. The second metallic layer comprises tin. The first intermetallic compound contains copper, tin and one of nickel and cobalt.

## Claims

### Claim 1

A method for forming a connecting structure, comprising:
forming a seed layer covering a conductive pad formed in a substrate;
forming a mask layer with an opening corresponding to the conductive pad over the substrate;
forming a first metal layer on the seed layer in the opening of the mask layer, wherein the first metal layer comprises copper;
forming a second metal layer on the first metal layer, wherein the second metal layer comprises tin;
forming a third metal layer on the second metal layer, wherein the third metal layer comprises nickel or cobalt;
forming a fourth metal layer on the third metal layer, wherein the fourth metal layer comprises tin;
removing the mask layer and removing the seed layer; and
performing a thermal process to form a connecting structure, comprising:
forming a first intermetallic compound layer and a second intermetallic compound layer between the first metal layer and the fourth metal layer; and
turning the first metal layer into a first metallic layer and turning the fourth metal layer into a fourth metallic layer,
wherein the first intermetallic compound layer comprises a layer of a first intermetallic compound and metallic particles that are distributed within the layer of the first intermetallic compound and are nonexistent on surfaces of the layer of the first intermetallic compound.

### Claim 2 (depends on 1)

The method of claim 1, wherein the second intermetallic compound layer comprises a second intermetallic compound that is different from the first intermetallic compound.

### Claim 3 (depends on 1)

The method of claim 1, wherein the second metal layer further comprises silver.

### Claim 4 (depends on 3)

The method of claim 3, wherein the metallic particles are silver compound particles containing tin and silver.

### Claim 5 (depends on 4)

The method of claim 4, wherein the first intermetallic compound contains a Cu—Ni—Sn intermetallic compound.

### Claim 6 (depends on 5)

The method of claim 5, wherein the second intermetallic compound includes a Ni—Sn intermetallic compound or a Cu—Ni—Sn intermetallic compound different from the Cu—Ni—Sn intermetallic compound contained in the first intermetallic compound.

### Claim 7 (depends on 3)

The method of claim 3, wherein the connecting structure is formed with a third metallic layer between the first intermetallic compound layer and the second intermetallic compound layer, and the third metallic layer comprises nickel.

### Claim 8 (depends on 7)

The method of claim 7, wherein the second intermetallic compound includes a Ni—Sn intermetallic compound.

### Claim 9

A method for forming a connecting structure, comprising:
forming a conductive pad in a substrate and exposed from the substrate;
forming a mask layer over the substrate and with an opening exposing the conductive pad;
forming a first metal layer over the conductive pad and in the opening of the mask layer, wherein the first metal layer comprises copper;
forming a second metal layer on the first metal layer in the opening, wherein the second metal layer comprises tin;
forming a third metal layer on the second metal layer in the opening, wherein the third metal layer comprises nickel or cobalt;
forming a fourth metal layer on the third metal layer in the opening, wherein the fourth metal layer comprises tin;
removing the mask layer; and
performing a thermal process to form a connecting structure, comprising:
heating and turning the first metal layer into a first metallic layer;
heating and turning the fourth metal layer into a fourth metallic layer; and
forming a first intermetallic compound layer and a second intermetallic compound layer between the first metallic layer and the fourth metallic layer.

### Claim 10 (depends on 9)

The method of claim 9, wherein the second metal layer further comprises silver.

### Claim 11 (depends on 10)

The method of claim 10, wherein forming the first intermetallic compound layer includes forming a layer of a first intermetallic compound with silver compound particles formed within the layer of the first intermetallic compound layer and unexposed from surfaces of the layer of the first intermetallic compound, and the silver compound particles include an Ag—Sn compound.

### Claim 12 (depends on 9)

The method of claim 9, wherein the first intermetallic compound layer contains a Cu—Ni—Sn intermetallic compound, and the second intermetallic compound layer contains a Ni—Sn intermetallic compound.

### Claim 13 (depends on 9)

The method of claim 9, wherein the first intermetallic compound layer and the second intermetallic compound layer contain different Cu—Ni—Sn intermetallic compounds, and the Cu—Ni—Sn intermetallic compound contained in the second intermetallic compound layer has a nickel content higher than a nickel content of the Cu—Ni—Sn intermetallic compound contained in the first intermetallic compound layer.

### Claim 14 (depends on 9)

The method of claim 9, wherein the first intermetallic compound layer and the second intermetallic compound layer contain different Cu—Co—Sn intermetallic compounds, and the Cu—Co—Sn intermetallic compound contained in the second intermetallic compound layer has a cobalt content higher than a cobalt content of the Cu—Co—Sn intermetallic compound contained in the first intermetallic compound layer.

### Claim 15 (depends on 9)

The method of claim 9, wherein the connecting structure is formed with a third metallic layer between the first intermetallic compound layer and the second intermetallic compound layer, and the third metallic layer comprises nickel.

### Claim 16

A method, comprising:
forming a conductive pad in a substrate and exposed from the substrate;
forming a connecting structure on the conductive pad, comprising:
forming a mask layer over the substrate and with an opening exposing the conductive pad;
forming a first metal layer over the conductive pad and in the opening of the mask layer, wherein the first metal layer comprises copper;
forming a second metal layer on the first metal layer in the opening, wherein the second metal layer comprises tin and silver;
forming a third metal layer on the second metal layer in the opening, wherein the third metal layer comprises nickel or cobalt;
forming a fourth metal layer on the third metal layer in the opening, wherein the fourth metal layer comprises tin;
removing the mask layer; and
performing a thermal process to form the connecting structure by turning the first metal layer into a first metallic layer, the fourth metal layer into a fourth metallic layer and forming a first intermetallic compound layer and a second intermetallic compound layer between the first metallic layer and the fourth metallic layer;
providing a die having a connector thereon; and
performing a bonding process to connect the connector with the connecting structure to form a connected structure.

### Claim 17 (depends on 16)

The method of claim 16, further comprising:
forming an underfill between the die and the substrate and surrounding the connected structure; and
forming an encapsulating material covering the die and the underfill.

### Claim 18 (depends on 16)

The method of claim 16, wherein forming the first intermetallic compound layer includes forming a layer of a first intermetallic compound with silver compound particles formed within the layer of the first intermetallic compound layer and unexposed from surfaces of the layer of the first intermetallic compound.

### Claim 19 (depends on 16)

The method of claim 16, wherein the first intermetallic compound layer and the second intermetallic compound layer contain different Cu—Ni—Sn intermetallic compounds.

### Claim 20 (depends on 16)

The method of claim 16, wherein the first intermetallic compound layer and the second intermetallic compound layer contain different Cu—Co—Sn intermetallic compounds.