# US 11,309,237 B2 · Semiconductor package with wettable slot structures

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- Number: US 11,309,237 B2
- Document ID: US11309237B2
- Status: Granted
- Kind: B2
- Application number: 16/586,643
- Filed: 2019-09-27
- Published: 2021-04-01
- Granted: 2022-04-19
- Earliest claimed: 2019-09-27
- Assignees: STMicroelectronics S.r.l.; STMicroelectronics (Malta) Ltd
- Applicants: STMICROELECTRONICS S.r.l.; Stmicroelectronics (Malta) Ltd
- Inventors: Marco Del Sarto; Alex Gritti; Pierpaolo Recanatini; Michael Borg
- Web page: https://patentgrep.com/patent/US11309237B2

## CPC

- H10W 70/65: Shapes or dispositions of interconnections
- H10W 70/657: {on sidewalls or bottom surfaces of the package substrates, interposers or redistribution layers}
- H10W 70/685: comprising multiple insulating layers
- H10W 70/69: Insulating materials thereof
- H10W 74/114: {by a substrate and the encapsulations}
- H10W 74/131: {the semiconductor body being only partially enclosed}
- H10W 74/014: {using batch processing}
- H10W: GENERIC PACKAGES, INTERCONNECTIONS, CONNECTORS OR OTHER CONSTRUCTIONAL DETAILS OF DEVICES COVERED BY CLASS H10

## Abstract

The present disclosure is directed to a semiconductor package including a substrate having a lower surface with a plurality of slot structures. The plurality of slot structures are multi-layer structures that encourage the formation of solder joints. The semiconductor package is desirable for high reliability applications in which each solder joint termination should be checked by visual systems to ensure a proper electrical connection has been made.

## Claims

### Claim 1

A substrate, comprising:
a plurality of slot structures positioned along a perimeter of the substrate, each of the plurality of slot structures including:
a first conductive layer;
a first support layer;
a second conductive layer, the first support layer positioned between the first conductive layer and the second conductive layer;
a second support layer;
a third conductive layer on the second support layer, the second support layer positioned between the second conductive layer and the third conductive layer; and
a slot extending into an edge portion of the first support layer, the slot having a base that is the second conductive layer and a sidewall that is the first support layer, a continuous portion of the first conductive layer being on the edge portion of the first support layer, the base, and the sidewall; and
a pillar extending from the continuous portion of the first conductive layer that is on the edge portion of the first support layer, through the first support layer, and to the second conductive layer.

### Claim 2 (depends on 1)

The substrate of claim 1 wherein the pillar is positioned lateral to the sidewall of the slot.

### Claim 3 (depends on 1)

The substrate of claim 1 wherein the pillar is made of a conductive material.

### Claim 4 (depends on 1)

The substrate of claim 1, further comprising:
a first conductive plating on the first conductive layer, the first conductive plating being spaced from the edge portion of the first support layer, the base, and the sidewall by the first conductive layer.

### Claim 5 (depends on 1)

The substrate of claim 1, further comprising:
a protective layer that is positioned on at least three sides of each of the plurality of slot structures.

### Claim 6 (depends on 5)

The substrate of claim 5 wherein the protective layer physically contacts the first support layer.

### Claim 7 (depends on 4)

The substrate of claim 4, further comprising:
a second conductive plating on the first conductive plating, the second conductive plating being spaced from the edge portion of the first support layer, the base, and the sidewall by the first conductive layer and the first conductive plating.

### Claim 8 (depends on 1)

The substrate of claim 1, further comprising:
a protective layer, the third conductive layer being positioned between the second support layer and the protective layer.

### Claim 9 (depends on 1)

The substrate of claim 1 wherein the edge portion is positioned along a perimeter of the first support layer.

### Claim 10

A substrate, comprising:
a plurality of slots;
a first conductive layer;
a first support layer, the plurality of slots extending into edge portions of the first support layer, the first support layer forming sidewalls of the plurality of slots;
a second conductive layer spaced from the first conductive layer by the first support layer, the second conductive layer forming bases of the plurality of slots, portions of the first conductive layer being on the edge portions of the first support layer, the sidewalls of the plurality of slots, and the bases of the plurality of slots;
a plurality of pillars, each of the portions of the first conductive layer being spaced from the second conductive layer by a respective pillar of the plurality of pillars;
a second support layer; and
a third conductive layer spaced from the second conductive layer by the second support layer.

### Claim 11 (depends on 10)

The substrate of claim 10 wherein the first conductive layer includes a plurality of conductive lines.

### Claim 12 (depends on 10)

The substrate of claim 10 wherein the third conductive layer includes a plurality of conductive lines and a plurality of contact pads.

### Claim 13 (depends on 10)

The substrate of claim 10 wherein the plurality of slots are positioned along a perimeter of the substrate.

### Claim 14

A package, comprising:
a substrate having a first side and a second side opposite the first side, the substrate including a plurality of slot structures positioned along a perimeter of the substrate on the second side, each of the plurality of slot structures including:
a planar surface;
a slot extending into an edge portion of the planar surface, the slot having a base and a sidewall, the planar surface being positioned along three sides of the slot;
a conductive layer on the edge portion of the planar surface, the base, and the sidewall; and
a pillar directly underlying a portion of the conductive layer that is on the edge portion of the planar surface; and
a die on the first side of the substrate.

### Claim 15 (depends on 14)

The package of claim 14 wherein the substrate includes a protective layer on the second side of the substrate, the protective layer being positioned along the three sides of the slot of each of the plurality of slot structures.

### Claim 16 (depends on 15)

The package of claim 15 wherein the planar surface, the base, and the sidewall of each of the plurality of slot structures are left uncovered by the protective layer.

### Claim 17 (depends on 14)

The package of claim 14 wherein the substrate includes electrical connections that electrically couple the die to the plurality of slot structures.

### Claim 18 (depends on 17)

The package of claim 17 wherein the electrical connections include a plurality of conductive lines on the first side of the substrate.

### Claim 19 (depends on 17)

The package of claim 17 wherein the plurality of slot structures are positioned on four sides of the substrate.