# US 12,009,286 B2 · Methods of forming packaged semiconductor devices and leadframes for semiconductor device packages

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- Number: US 12,009,286 B2
- Document ID: US12009286B2
- Status: Granted
- Kind: B2
- Application number: 17/504,284
- Filed: 2021-10-18
- Published: 2023-04-20
- Granted: 2024-06-11
- Earliest claimed: 2021-10-18
- Assignees: MACOM Technology Solutions Holdings, Inc.
- Applicants: MACOM Technology Solutions Holdings, Inc.
- Inventors: Soon Lee Liew; Eng Wah Woo; Alexander Komposch
- Web page: https://patentgrep.com/patent/US12009286B2

## CPC

- H10W 70/048: {Mechanical treatments, e.g. punching, cutting, deforming or cold welding}
- H10W 70/421: {Shapes or dispositions}
- H10W 20/20: Interconnections within wafers or substrates, e.g. through-silicon vias [TSV]
- H10W 70/424: {Cross-sectional shapes (H10W70/481 takes precedence)}
- H10W 70/438: {of side rails, e.g. having holes}
- H10W 74/014: {using batch processing}
- H10W 74/111: {the semiconductor body being completely enclosed}
- H10W 74/134: {the encapsulations being in grooves in the semiconductor body}
- H10W 70/042: {Etching}
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

A method of forming a packaged semiconductor device according to some embodiments includes providing a leadframe blank including a first package blank, a second package blank and a tie bar between the first package blank and the second package blank, forming a recessed cavity in the tie bar, and separating the first and second package blanks by sawing through the leadframe blank along the tie bar.

## Claims

### Claim 1

A method of forming a packaged semiconductor device, comprising:
providing a leadframe blank including a first package blank, a second package blank and a tie bar between the first package blank and the second package blank, each package blank comprising a die attach pad and a lead, wherein the leads of the first and second package blanks are attached to the tie bar;
forming a recessed cavity in the tie bar; and
separating the first and second package blanks along the tie bar,
wherein each package blank comprises a plurality of leads attached to the tie bar at respective attachment points, the method further comprising forming a plurality of recessed cavities in the tie bar at the attachment points.

### Claim 2 (depends on 1)

The method of claim 1, wherein forming the recessed cavity in the tie bar comprises etching the tie bar.

### Claim 3 (depends on 2)

The method of claim 2, wherein etching the tie bar comprises etching the tie bar at the attachment point to form the recessed cavity in the tie bar at the attachment point.

### Claim 4 (depends on 2)

The method of claim 2, wherein etching the tie bar at the attachment point comprises:
forming a mask on the leadframe blank;
forming an opening in the mask above the attachment point; and
isotropically etching the leadframe through the opening in the mask.

### Claim 5 (depends on 1)

The method of claim 1, wherein forming the recessed cavity in the tie bar comprises stamping or punching the leadframe blank.

### Claim 6 (depends on 1)

The method of claim 1, further comprising:
molding first and second package bodies onto the first and second package blanks prior to separating the first and second package blanks.

### Claim 7 (depends on 1)

The method of claim 1, further comprising:
mounting first and second semiconductor devices on the first and second die attach pads.

### Claim 8 (depends on 1)

The method of claim 1, wherein the leadframe blank comprises a plurality of package blanks arranged in a two dimensional grid and connected to a plurality of tie bars arranged in saw streets between adjacent ones of the package blanks.

### Claim 9 (depends on 1)

The method of claim 1, wherein the recessed cavity is formed on a same side of the leadframe blank as die attach surfaces of the die attach pads.

### Claim 10 (depends on 1)

The method of claim 1, wherein the recessed cavity has a depth of about 25% to 75% of a thickness of the leadframe blank.

### Claim 11 (depends on 1)

The method of claim 1, wherein the recessed cavity is formed in a top surface of the leadframe, the method further comprising forming a mold retention feature in a bottom surface of the leadframe opposite the top surface.

### Claim 12 (depends on 1)

The method of claim 1, wherein the recessed cavity has an area greater than about 0.1 mm2.

### Claim 13 (depends on 1)

The method of claim 1, wherein the recessed cavity has a width greater than about 0.3 mm.

### Claim 14

A method of forming a packaged semiconductor device, comprising:
providing a leadframe blank including a first package blank, a second package blank and a tie bar between the first package blank and the second package blank;
forming a recessed cavity in the tie bar; and
separating the first and second package blanks along the tie bar,
wherein separating the first and second package blanks along the tie bar comprises sawing through the leadframe blank along the tie bar.

### Claim 15 (depends on 1)

The method of claim 1, wherein separating the first and second package blanks along the tie bar comprises sawing through the leadframe blank along the tie bar.