# US 8,739,390 B2 · Method for microcontact printing of MEMS

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- Number: US 8,739,390 B2
- Document ID: US8739390B2
- Status: Granted
- Kind: B2
- Application number: 12/636,757
- Filed: 2009-12-13
- Published: 2010-07-29
- Granted: 2014-06-03
- Earliest claimed: 2008-12-16
- Assignees: Massachusetts Institute of Technology
- Applicants: Vladimir Bulovic; Corinne Evelyn Packard; Jennifer Jong-Hua Yu; Apoorva Murarka; LeeAnn Kim
- Inventors: Vladimir Bulovic; Corinne Evelyn Packard; Jennifer Jong-Hua Yu; Apoorva Murarka; LeeAnn Kim
- Web page: https://patentgrep.com/patent/US8739390B2

## CPC

- B81C 1/0046: {using stamping, e.g. imprinting (nanoimprinting for making etch masks G03F7/0002)}
- B81B 2201/042: Micromirrors, not used as optical switches
- B81C 2201/0185: Printing, e.g. microcontact printing
- Y10T 29/43: Electric condenser making
- Y10T 29/435: Solid dielectric type
- Y10T 29/49002: Electrical device making
- Y10T 29/4902: Electromagnet, transformer or inductor
- Y10T 29/49105: Switch making
- Y10T 156/1168: Gripping and pulling work apart during delaminating
- B81C: PROCESSES OR APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OR TREATMENT OF MICROSTRUCTURAL DEVICES OR SYSTEMS (making microcapsules or microballoons B01J13/02; processes or apparatus specially adapted for the manufacture or treatment of piezoelectric, electrostrictive or magnetostrictive elements per se H10N30/01)
- B81B: MICROSTRUCTURAL DEVICES OR SYSTEMS, e.g. MICROMECHANICAL DEVICES (piezoelectric, electrostrictive or magnetostrictive elements per se H10N30/00, H10N35/00)
- Y10T: TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION

## Abstract

The embodiments disclosed herein are directed to fabrication methods useful for creating MEMS via microcontact printing by using small organic molecule release layers. The disclose method enables transfer of a continuous metal film onto a discontinuous platform to form a variable capacitor array. The variable capacitor array can produce mechanical motion under the application of a voltage. The methods disclosed herein eliminate masking and other traditional MEMS fabrication methodology. The methods disclosed herein can be used to form a substantially transparent MEMS having a PDMS layer interposed between an electrode and a graphene diaphragm.

## Claims

### Claim 1

A method for micro-contact printing of a MEMS structure, the method comprising:
providing a MEMS structure having a plurality of ridges;
providing a support structure having a substrate for supporting a release layer and a conducting layer;
bringing the MEMS structure into conformal contact with the support structure; and
rapidly peeling the MEMS structure from the support structure so as to delaminate substantially all of the conducting layer metal layer from the support structure;
wherein the peeling velocity is in the range is about 3 m/sec or more and wherein the metal layer forms a suspended membrane at a gap between a pair of the plurality of ridges.

### Claim 2 (depends on 1)

The method of claim 1, wherein the peeling velocity is about 5 m/sec.

### Claim 3 (depends on 1)

The method of claim 1, wherein the step of providing the MEMS structure further comprises: forming a layer of indium tin oxide oxide (ITO) over a substrate; depositing an elastomeric layer over the ITO layer; and forming the plurality of ridges in the elastomeric layer.

### Claim 4 (depends on 3)

The method of claim 3, wherein the elastomeric layer is poly(dimethylsiloxane) (PDMS).

### Claim 5 (depends on 1)

The method of claim 1, wherein the step of providing the MEMS structure further comprises: (i) spin casting PDMS and curing agent at a weight ratio of about 10:1 in a mold; (ii) forming an ITO-coating glass substrate; (iii) adjoining the cured PDMS to the substrate so as to interpose the ITO coating between the glass and the cured PDMS; and (iv) removing the mold from the cured PDMS.

### Claim 6 (depends on 5)

The method of claim 5, wherein the PDMS includes a plurality of ridges in which adjacent ridges are separated by a gap of about 10-50 nm.

### Claim 7 (depends on 5)

The method of claim 5, wherein the PDMS includes a plurality of ridges in which adjacent ridges are separated by a gap of about 1-50 μm.

### Claim 8 (depends on 1)

The method of claim 1, wherein the step of providing a support structure further comprises depositing a van der Waal bonded organic film.

### Claim 9 (depends on 8)

The method of claim 8, wherein the van der Waals bonded organic film defines a molecular thin film.

### Claim 10 (depends on 8)

The method of claim 8, wherein the step of providing a support structure further comprises depositing a TPD layer over a molded substrate to achieve a discontinuous film with a plurality of raised portions for defining the desired pattern and evaporating the metal layer over the TPD layer to form a discontinuous metal film.

### Claim 11 (depends on 8)

The method of claim 8, wherein the van-der-Waals bonded organic film is N,N′-diphenyl-N-N′-bis(3-methylphenyl)-(1,1′-biphenyl)-4,4′-diamine (TPD).

### Claim 12 (depends on 8)

The method of claim 8, wherein the step of providing a support structure further comprises: depositing a layer of TPD over the substrate; evaporating the metal layer over the TPD layer by shadow masking.

### Claim 13 (depends on 1)

The method of claim 1, wherein the metal layer is selected from the group consisting of gold, silver, and other thermally evaporated metals.

### Claim 14 (depends on 1)

The method of claim 1, wherein the MEMS structure defines a capacitor array.

### Claim 15 (depends on 1)

The method of claim 1, wherein the conductive layer is selected from the group consisting of a metal, a conducting metal oxide or a doped polymer.