# US 8,785,326 B2 · Methods of separating solid state transducers from substrates and associated devices and systems

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- Number: US 8,785,326 B2
- Document ID: US8785326B2
- Status: Granted
- Kind: B2
- Application number: 13/482,856
- Filed: 2012-05-29
- Published: 2013-12-05
- Granted: 2014-07-22
- Earliest claimed: 2012-05-29
- Assignees: Micron Technology, Inc.
- Applicants: Martin F. Schubert; Ming Zhang; Lifang Xu
- Inventors: Martin F. Schubert; Ming Zhang; Lifang Xu
- Web page: https://patentgrep.com/patent/US8785326B2

## CPC

- H10H 20/018: {Bonding of wafers}
- H10H: INORGANIC LIGHT-EMITTING SEMICONDUCTOR DEVICES HAVING POTENTIAL BARRIERS

## Abstract

Wafer-level processing of wafer assemblies with transducers is described herein. A method in accordance with some embodiments includes forming a solid state transducer device by forming one or more trenches to define solid state radiation transducers. An etching media is delivered in to the trenches to release the transducers from a growth substrate used to fabricate the transducers. A pad can hold the radiation transducers and promote distribution of the etching media through the trenches to underetch and release the transducers.

## Claims

### Claim 1

A method of forming a solid state transducer device, the method comprising:
forming at least one trench through a semiconductor material, the trench forming a boundary between individual transducers; and
delivering an etching media through the trench and underetching material at an interface between a growth substrate and the individual transducers such that the individual transducers are separated from the growth substrate.

### Claim 2 (depends on 1)

The method of claim 1, further comprising holding the individual transducers using a transducer support member before delivering the etching media into the trench, and wherein the plurality of individual transducers are positioned between the transducer support member and the growth substrate while delivering the etching media into the trench.

### Claim 3 (depends on 1)

The method of claim 1 wherein a sacrificial material is between the growth substrate and the individual transducers, and the method further comprises removing the sacrificial material using the etching media until the plurality of individual transducers are separated from the growth substrate.

### Claim 4 (depends on 3)

The method of claim 3, further comprising removing at least a portion of a portion of the sacrificial material positioned directly between one of the individual transducers and a base of the growth substrate to separate the individual transducer from the growth substrate.

### Claim 5 (depends on 1)

The method of claim 1, further comprising underetching substantially an entire periphery of at least one of the individual transducers at the same time.

### Claim 6 (depends on 1)

The method of claim 1 wherein delivering the etching media includes delivering the etching media though a transducer support member extending across and holding the plurality of individual transducers.

### Claim 7 (depends on 6)

The method of claim 6, further comprising forming pads of the transducer support member on the respective individual transducers and forming links of the transducer support member to couple the pads together.

### Claim 8 (depends on 7)

The method of claim 7 wherein forming the links includes at least partially filling sections of the trenches such that the links extend across the trenches and between the pads.

### Claim 9 (depends on 6)

The method of claim 6 wherein the transducer support member is an etch resistant transducer support member having openings through which the etching media flows to enter the trench.

### Claim 10 (depends on 1)

The method of claim 1 wherein delivering the etching media includes delivering the etching media through a transducer support member extending across and coupled to the plurality of individual transducers via an adhesive.

### Claim 11 (depends on 10)

The method of claim 10 wherein the transducer support member is porous and comprises an etch resistant material.

### Claim 12 (depends on 1)

The method of claim 1 wherein forming the at least one trench includes forming a network of interconnected trenches extending across the growth substrate.

### Claim 13 (depends on 1)

The method of claim 1, further comprising forming at least one of the individual transducers having a first semiconductor material, a second semiconductor material, and an active region between the first semiconductor material and the second semiconductor material.

### Claim 14 (depends on 13)

The method of claim 13, further comprising:
forming a first contact electrically coupled to the first semiconductor material; and
forming a second contact electrically coupled to the second semiconductor material.

### Claim 15 (depends on 1)

The method of claim 1 wherein at least one of the individual transducers is a light-emitting diode.

### Claim 16 (depends on 1)

The method of claim 1, further comprising forming one or more protective materials on a sidewall of one the individual transducers before delivering the etching media through the trench.

### Claim 17 (depends on 16)

The method of claim 16 wherein forming the one or more protective materials includes:
forming an insulating material on the sidewall of the individual transducer; and
forming a transducer support member such that a sidewall covering of the transducer support member overlays the insulating material.

### Claim 18

A method of forming a light-emitting device (LED), the method comprising:
forming a LED on a growth substrate, the LED comprising a first semiconductor material, a second semiconductor material, and an active region;
forming at least one trench through the LED to a sacrificial material over the growth substrate and between individual transducers of the LED; and
delivering an etching media through the trench to an interface between the individual transducers and the growth substrate.

### Claim 19 (depends on 18)

The method of claim 18, further comprising removing a portion of the growth substrate contacting the individual transducers using the etching media.

### Claim 20 (depends on 18)

The method of claim 18, further comprising forming a support member that physically couples the LEDs together before releasing the LEDs from the growth substrate.

### Claim 21 (depends on 20)

The method of claim 20 wherein forming the support member includes forming pads on respective individual transducers and links connecting the pads together.

### Claim 22 (depends on 18)

The method of claim 18, further comprising adhering a support member to the individual transducers before delivering the etching media, and delivering the etching media comprises passing the etching media through the support member and to the trench between the individual transducers.

### Claim 23 (depends on 18)

The method of claim 18 wherein the individual transducers include a first transducer and a second transducer, the method further comprising:
forming a first insulating material on a first sidewall of the first transducer;
forming a first sidewall covering of the support member on the first insulating material;
forming a second insulating material on a second sidewall of the second transducer; and
forming a second sidewall covering of the support member on the second insulating layer such that an exposed portion of the growth substrate is positioned between the first sidewall covering and the second sidewall covering.

### Claim 24 (depends on 23)

The method of claim 23 wherein at least one of the first sidewall covering and the second sidewall covering comprises an etch resistant material.

### Claim 25 (depends on 18)

The method of claim 18, further comprising underetching substantially an entire length of a periphery of at least one of the individual transducers at the same time.

### Claim 26 (depends on 18)

The method of claim 18, further comprising simultaneously underetching a plurality of the individual transducers.

### Claim 27 (depends on 18)

The method of claim 18, further comprising separating the individual transducers from the growth substrate while an etch resistant support member holds the individual transducers.

### Claim 28

A method of forming a solid state transducer, comprising:
providing a growth substrate and a transducer structure on the growth substrate, the transducer structure having a first semiconductor material, a second semiconductor material, and an active region between the first and second semiconductor materials, the transducer structure including a plurality of individual transducers separated by at least one trench; and
underetching between the growth substrate and the individual transducers from the trench between the individual transducers toward a center region of the individual transducers.

### Claim 29 (depends on 28)

The method of claim 28 wherein the at least one trench surrounds most of a periphery of the individual transducers.

### Claim 30 (depends on 28)

The method of claim 28, further comprising a support structure holding the individual transducers, the support structure including pads on the individual transducers and a plurality of links, wherein the plurality of links separate portions of the at least one trench and connect the pads together.