# US 2019/0006180 A1 · Microassembly of heterogeneous materials

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- Number: US 2019/0006180 A1
- Document ID: US20190006180A1
- Status: Published application
- Kind: A1
- Application number: 16/024,123
- Filed: 2018-06-29
- Published: 2019-01-03
- Earliest claimed: 2017-07-03
- Assignees: The Board of Trustees of the University of Illinois
- Applicants: The Board of Trustees of the University of Illinois
- Inventors: Seok Kim; Zining Yang; Hohyun Keum
- Web page: https://patentgrep.com/patent/US20190006180A1

## CPC

- H10P 76/4085: {characterised by the processes involved to create the masks}
- B41K 3/04: and movable at right angles to the surface to be stamped
- B41K 3/24: for multicolour stamping
- B41K 3/54: Inking devices
- B41K 3/56: using inking pads
- B41K 3/62: Details or accessories
- C09D 11/103: of aldehydes, e.g. phenol-formaldehyde resins
- H10P 50/242: {of Group IV materials}
- H10P 50/73: {using masks for insulating materials}
- H10P: GENERIC PROCESSES OR APPARATUS FOR THE MANUFACTURE OR TREATMENT OF DEVICES COVERED BY CLASS H10
- B41K: STAMPS; STAMPING OR NUMBERING APPARATUS OR DEVICES (marking meat A22C17/10; embossing combined with printing B41F19/00; selective printing mechanisms B41J; embossing decorations or marks B44B5/00; marking or coding completed packages B65B61/26; ticket printing and issuing, fare registering, nonprinting aspects of franking apparatus G07B)
- C09D: COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR (cosmetics A61K; processes for applying liquids or other fluent materials to surfaces, in general, B05D; staining wood B27K5/02; glazes or vitreous enamels C03C; natural resins, French polish, drying-oils, driers, turpentine, per se, C09F; polishing compositions other than French polish, ski waxes C09G; adhesives or use of materials as adhesives C09J; materials for sealing or packing joints or covers C09K3/10; materials for stopping leaks C09K3/12; processes for the electrolytic or electrophoretic production of coatings C25D)

## Abstract

A method for microassembly of heterogeneous materials comprises contacting a stamp with an ink disposed on a donor substrate to form an inked stamp, where the ink is reversibly bound to the stamp. The inked stamp is stamped onto a receiving substrate or onto an object on the receiving substrate, and the stamp is removed, thereby transferring the ink to the receiving substrate. The ink and the receiving substrate or the ink and the object are thermally joined, thereby forming a microassembly of heterogeneous materials. The ink may comprise a first material and the receiving substrate or the object may comprise a second material different from the first material.

## Claims

### Claim 1

A method for microassembly of heterogeneous materials, the method comprising:
contacting a stamp with an ink disposed on a donor substrate to form an inked stamp, where the ink is reversibly bound to the stamp;
stamping the inked stamp onto a receiving substrate or onto an object on the receiving substrate;
removing the stamp, thereby transferring the ink to the receiving substrate; and
thermally joining the ink with the receiving substrate or the object, thereby forming a microassembly of heterogeneous materials.

### Claim 2 (depends on 1)

The method of claim 1, wherein the ink comprises a first material and the receiving substrate or the object comprises a second material different from the first material.

### Claim 3 (depends on 2)

The method of claim 2, wherein the first material comprises SiO2 and the second material is selected from the group consisting of: Si and SU-8.

### Claim 4 (depends on 2)

The method of claim 2, wherein the first material comprises SU-8 and the second material is selected from the group consisting of: SiO2, Si, and Au.

### Claim 5 (depends on 1)

The method of claim 1, further comprising repeating the contacting and stamping to add additional inks to the receiving substrate.

### Claim 6 (depends on 1)

The method of claim 1, wherein the stamp comprises a material with viscoelastic properties.

### Claim 7 (depends on 1)

The method of claim 1, wherein the object comprises a previously deposited ink.

### Claim 8 (depends on 1)

The method of claim 1, wherein the thermal joining comprises a method selected from fusion, eutectic and adhesive bonding.

### Claim 9 (depends on 1)

The method of claim 1, wherein the thermal joining takes place at a temperature in a range from about 150° C. to about 1000° C.

### Claim 10 (depends on 1)

The method of claim 1, wherein no external pressure is applied during the thermal joining.

### Claim 11 (depends on 1)

The method of claim 1, wherein an interface between the ink and the receiving substrate or the ink and the object exhibits a joining strength in a range from about 0.3 J/m2 to about 4.5 J/m2.

### Claim 12 (depends on 1)

The method of claim 1, further comprising fabricating the ink on the donor substrate.

### Claim 13 (depends on 12)

The method of claim 12, wherein the ink comprises a polymer, and wherein the fabricating comprises:
coating a sacrificial layer onto a silicon substrate;
coating a polymeric material on the sacrificial layer and curing to form a polymer layer;
patterning the polymer layer to form a polymeric ink pattern; and
removing the sacrificial layer, thereby forming a polymeric ink for transfer printing.

### Claim 14 (depends on 13)

The method of claim 13, wherein the sacrificial layer comprises polymethylmethacrylate (PMMA), and
wherein the polymeric material comprises an epoxy-based polymer.

### Claim 15 (depends on 13)

The method of claim 13, wherein the polymeric material comprises SU-8, and
wherein the patterning comprises exposing the polymer layer to light through a pattern mask, baking after the exposing, and developing after the baking, thereby forming the polymeric ink pattern.

### Claim 16 (depends on 13)

The method of claim 13, wherein the sacrificial layer is removed by exposure to a solvent.

### Claim 17 (depends on 12)

The method of claim 12, wherein the ink comprises SiO2, and wherein the fabricating comprises:
growing a SiO2 layer on a silicon layer;
patterning the SiO2 layer to form a SiO2 ink pattern on the silicon layer;
patterning the silicon layer to form a silicon pattern laterally surrounding and underlying the SiO2 ink pattern, thereby exposing a buried oxide layer away from the SiO2 ink pattern;
covering the SiO2 ink pattern with photoresist and forming one or more photoresist anchors to the buried oxide layer; and
removing the silicon pattern, thereby forming a SiO2 ink for transfer printing.

### Claim 18 (depends on 17)

The method of claim 17, wherein the patterning of the silicon layer is carried out with a mask pattern larger in lateral dimension than that employed to form the SiO2 ink pattern.

### Claim 19 (depends on 17)

The method of claim 17, wherein the patterning of the silicon layer comprises using reactive ion etching.

### Claim 20 (depends on 17)

The method of claim 17, wherein a silicon-on-insulator wafer comprises the silicon layer and the buried oxide layer.