Patterning of antistiction films for electromechanical systems devices

• US 8,445,390 B1
• Filed: 11/10/2011
• Issued: 05/21/2013
• Est. Priority Date: 11/10/2011
• Status: Expired due to Fees

• Current Assignee: Snaptrack Incorporated (Qualcomm, Inc.)
• Original Assignee: Qualcomm MEMS Technologies Incorporated (Qualcomm, Inc.)
• Inventors: Sasagawa, Teruo
• Primary Examiner(s): Sarkar, Asok K
• Application Number:
  US13/294,114
• Publication Number:
  US 20130120414A1
• Time in Patent Office: 558 Days
• Field of Search: 257/E21.218, 257/E21.347, 257/E21.475, 257/E21.517, 438/694, 438/706, 438/707, 438/709, 438/710
• US Class Current: 438/707
• CPC Class Codes: B81C 1/00269 Bonding of solid lids or wafers to the substrate
• CPC Class Codes: B81C 1/00492 Processes for surface micromachining not provided for in groups B81C1/0046 - B81C1/00484
• CPC Class Codes: B81C 2201/0143 Focussed beam, i.e. laser, ion or e-beam
• CPC Class Codes: B81C 2203/019 characterised by the material or arrangement of seals between parts

Abstract

A laser absorption layer is first selectively formed in a seal pattern region surrounding an array of electromechanical systems elements, followed by depositing an antistiction layer as a blanket layer over the substrate and the laser absorption layer. The antistiction layer is then selectively removed from the seal pattern using a laser. An epoxy sealing material is provided in the seal pattern where the antistiction layer was removed and a backplate is sealed to the substrate using epoxy.

Claims

1. A method for selectively removing an antistiction layer in an electromechanical systems apparatus, comprising:

providing a substrate having a device with a patterned laser absorption layer surrounding the device in a seal pattern;

depositing an antistiction layer as a blanket layer over the substrate and over the laser absorption layer after providing the substrate with the patterned laser absorption layer;

selectively removing the antistiction layer from the seal pattern using a laser; and

sealing the device with epoxy in regions where the antistiction layer was removed.

2. The method of claim 1, wherein providing comprises selectively forming the patterned laser absorption layer in the seal pattern region surrounding the device.

3. The method of claim 1, wherein selectively removing the antistiction layer includes selectively removing the laser absorption layer using the laser.

4. The method of claim 3, wherein the laser absorption layer and overlying portions of the antistiction layer are removed using less than 10 pulses of the laser.

5. The method of claim 4, wherein the laser absorption layer and overlying portions of the antistiction layer are removed using less than 3 pulses of the laser.

6. The method of claim 1, wherein the laser absorption layer is a photodefinable polymer.

7. The method of claim 1, further including providing a blocker layer between the laser absorption layer and an underlying metal feature, the blocker layer configured to protect the metal feature from laser damage during the selectively removing.

8. The method of claim 1, wherein the laser absorption layer has a thickness and material configured to absorb the wavelength of the laser such that the laser ablates the laser absorption layer to remove the antistiction layer.

9. The method of claim 1, wherein the laser absorption layer is directly under the antistiction layer.

10. The method of claim 1, wherein depositing the antistiction layer comprises depositing an atomic layer deposition (ALD) layer and forming a self-assembled monolayer (SAM) over the ALD layer.

11. The method of claim 10, wherein a total thickness of the antistiction layer is less than about 110 Å

.

12. The method of claim 11, wherein the ALD layer includes aluminum oxide.

13. The method of claim 11, wherein the SAM layer includes a layer of an organic monomer with a hydrophobic end and a hydrophilic end.

14. The method of claim 1, wherein the laser includes at least one of:

Excimer lasers, solid state lasers, gas lasers, and metal vapor lasers.

15. The method of claim 1, wherein the laser has a wavelength of less than about 400 nm.

16. The method of claim 1, further including providing an inert atmosphere to the apparatus during selectively removing with the laser.

17. The method of claim 1, wherein the device includes an array of interferometric modulators, and the laser absorption layer and the epoxy are formed in regions where the antistiction layer is removed.