Method of protecting microfabricated devices with protective caps

• US 7,001,793 B2
• Filed: 03/04/2004
• Issued: 02/21/2006
• Est. Priority Date: 01/10/2001
• Status: Expired due to Term

• Current Assignee: Nytell Software LLC (Intellectual Ventures LLC)
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Silverbrook, Kia
• Primary Examiner(s): Baumeister, B. William
• Assistant Examiner(s): Anya, Igwe U.
• Application Number:
  US10/791,840
• Publication Number:
  US 20040171186A1
• Time in Patent Office: 719 Days
• Field of Search: 438/51, 438/106, 438/113, 438/200, 438/202, 438/22
• US Class Current: 438/51
• CPC Class Codes: B29C 2035/0822 using IR radiation
• CPC Class Codes: B29C 2043/503 using ejector pins, rods
• CPC Class Codes: B29C 33/0022 Multi-cavity moulds B29C33/301 takes precedence
• CPC Class Codes: B29C 43/36 Moulds for making articles of definite length, i.e. discrete articles
• CPC Class Codes: B81C 1/00333 Aspects relating to packaging of MEMS devices, not covered by groups B81C1/00269 - B81C1/00325
• CPC Class Codes: B81C 1/00904 Multistep processes for the separation of wafers into individual elements not provided for in groups B81C1/00873 - B81C1/00896
• CPC Class Codes: B81C 2201/034 Moulding
• CPC Class Codes: B81C 2203/0109 Bonding an individual cap on the substrate
• CPC Class Codes: B81C 2203/0127 Using a carrier for applying a plurality of packaging lids to the system wafer
• CPC Class Codes: H01L 21/4803 Insulating or insulated parts, e.g. mountings, containers, diamond heatsinks H01L21/4846 takes precedence; printed circuit boards H05K1/00
• CPC Class Codes: H01L 23/04 characterised by the shape of the container or parts, e.g. caps, walls
• CPC Class Codes: H01L 2924/00 Indexing scheme for arrangements or methods for connecting or disconnecting semiconductor or solid-state bodies as covered by H01L24/00
• CPC Class Codes: H01L 2924/0002 Not covered by any one of groups H01L24/00, H01L24/00 and H01L2224/00
• CPC Class Codes: H01L 2924/16235 Connecting to a semiconductor or solid-state bodies, i.e. cap-to-chip

Abstract

A method of using protective caps (160) applied to a first side of a wafer (150) in the production of microfabricated devices (152), such as micro-electro-mechanical systems (MEMS) devices. One cap (160) covers each microfabricated device or group respectively, such that a gap remains between adjacent protective caps. One or more etches are applied to the gaps between the caps to remove material and separate the wafer into separate units.

Claims

1. A method including:

a) providing a wafer having a plurality of microfabricated devices and a plurality of bond pads formed thereon;

b) applying a plurality of substantially hollow caps to a first side of the wafer, the caps positioned such that, in plan view, each cap overlays part or all of at least one microfabricated device and such that said bond pads are exposed;

c) applying a plurality of hollow caps to a second side of the wafer, the caps positioned such that, in plan view, the caps provide a mask to said bond pads; and

d) applying one or more etches to the wafer from the second side toward the first side to etch away at least some of the material between the peripheries of said caps to separate the wafer into separate units.

2. The method of claim 1 wherein each cap is joined to any adjacent cap by a thin layer of material extending between the periphery of each of the caps.

3. The method of claim 2 wherein the one or more etches are applied such that the layer of material adjoining adjacent caps is removed.

4. The method of claim 3 wherein the layer of material adjoining adjacent caps is removed by an oxygen etch.

5. The method of claim 1 wherein in plan view, each of the first plurality of caps overlays all or part of one or more microfabricated devices;

and, in plan view, each of the second plurality of caps cover the corresponding first cap.