Critically aligned optical MEMS dies for large packaged substrate arrays and method of manufacture

• US 20020145185A1
• Filed: 04/09/2001
• Published: 10/10/2002
• Est. Priority Date: 04/09/2001
• Status: Active Grant

• Current Assignee: Analog Devices, Inc.
• Original Assignee: Axiowave Networks, Inc.
• Inventors: Shrauger, Vernon
• Granted Patent: US 6,531,767 B2
• Time in Patent Office: Days
• US Class Current: 257/678
• CPC Class Codes: G02B 6/4232 using the surface tension of fluid solder to align the elements, e.g. solder bump techniques flip-chip mounting techniques in assembly of semiconductor devices H01L24/81
• CPC Class Codes: G02B 6/4251 Sealed packages G02B6/4248 takes precedence
• CPC Class Codes: G02B 6/4259 of the transparent type
• CPC Class Codes: G02B 6/426 mounting, engaging or coupling of the package to a board, a frame or a panel
• CPC Class Codes: G02B 6/428 containing printed circuit boards [PCB]
• CPC Class Codes: H01L 2224/0401 Bonding areas specifically adapted for bump connectors, e.g. under bump metallisation [UBM]
• CPC Class Codes: H01L 2224/16225 the item being non-metallic, e.g. insulating substrate with or without metallisation
• CPC Class Codes: H01L 2224/48472 the other connecting portion not on the bonding area also being a wedge bond, i.e. wedge-to-wedge
• CPC Class Codes: H01L 2224/73204 the bump connector being embedded into the layer connector
• CPC Class Codes: H01L 23/15 Ceramic or glass substrates H01L23/142, H01L23/145, H01L23/147 take precedence
• 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 2924/00014 the subject-matter covered by the group, the symbol of which is combined with the symbol of this group, being disclosed without further technical details
• CPC Class Codes: H01L 2924/10253 Silicon [Si]
• CPC Class Codes: H01L 2924/19107 off-chip wires
• CPC Class Codes: H01L 31/0203 Containers; Encapsulations , e.g. encapsulation of photodiodesfor photovoltaic devices H01L31/048; for organic photosensitive devices H10K30/80

Abstract

A novel array of optically and electrically interacting optical MEMS dies physically and electrically integrally attached upon an optically transmissive preferably (transparent) printed circuit substrate that is monolithically formed with one or more optical components, such as lenses, for providing fixed optical path alignment and interaction therebetween, and with provision for the integration also of active optical components such as lasers and photodiodes and the like.

Claims

1. An assembled array of optically and electrically interacting optical MEMS dies physically and electrically integrally attached upon a light-transmissive substrate carrying a pattern of printed electrical circuit interconnections for operating the dies;

the light-transmissive substrate being integrated monolithically with optical components to provide accurate and fixed optical alignment of the MEMS and the optical components optically interacting therewith.

2. The assembled array of claim 1 wherein the optical components comprise lenses and the optical MEMS dies carry electrical signal-controllable mirrors, and said fixed optical alignment enables the lenses integrated in the light-transmissive substrate to focus light onto the MEMS mirrors along fixed optical paths for optically addressing the array.

3. The assembled array of claim 2 wherein the MEMS dies are provided with metalization between the mirrors, and are flip-chip solder-bonded in inverted position to conductive posts provided in the printed circuit of the substrate, with sufficient clearance between the substrate and the mirrors to avoid interference with the operation of the mirrors.

4. The assembled array of claim 3 wherein the lenses are integrally formed on the bottom surface of the substrate, enabling optical readout of the MEMS in reflection from the bottom surface.

5. The assembled array of claim 3 wherein a patterned optical blocking layer is applied to the substrate in areas surrounding said conductive posts.

6. The assembled array of claim 3 wherein the backside of the substrate is provided with a solid annular peripheral metalized region solder-attachable as to an external pin or ball grid array package housing.

7. The assembled array of claim 6 wherein a package housing is provided receiving the assembled array bonded therewithin with the substrate electrically connected to package pads disposed annularly within the housing.

8. The assembled array of claim 7 wherein the upper side of the substrate is provided with peripheral conductive pads connected internally of the package housing with said package pads as by wirebonding.

9. The assembled array of claim 7 wherein the upper side or the bottom of the package housing is apertured or windowed to enable the transmission of optical readout light for the array mounted within the package.

10. The assembled array of claim 9 wherein the packaged housing is sealed and the medium therewithin is environmentally controlled.

33. The assembled array of claim 3 wherein the substrate is selected from the group of materials consisting of silicon, gallium phosphide, sapphire, a glass composite and quartz, and the MEMS dies are silicon-based.

34. An optical MEMS system or architecture incorporating therein one or more of the packaged assembled arrays of claim 9.

35. An optical MEMS system or architecture as claimed in claim 34 wherein a first of said packaged assembled arrays is positioned to receive collimated ingress fiber bundle light signals and reflect the same to a mirror for redirection to a second of said packaged assembled arrays positioned to receive the light signals and reflect them to an egress collimated fiber bundle to provide optical cross-connection between the fiber bundles.

11. An optical and electrical MEMS device physically and electrically integrally attached upon an optically transmissive substrate carrying a pattern of printed electrical circuit interconnections for the device, the light-transmissive substrate being integrated monolithically with an optical component to provide fixed optical alignment of the MEMS device and the optical component.

12. The device as claimed in claim 11 wherein the optical component is a passive optical element.

13. The device as claimed in claim 12 wherein the optical element is selected from the group consisting of lenses, diffractive optical elements, phase elements, masks, mirrors and polarizers.

14. The device as claimed in claim 11 wherein the optical component is an active optical element.

15. The device as claimed in claim 14 wherein the optical element is selected from the group consisting of light sources, and sensors including lasers and photodiodes.

16. The device as claimed in claim 14 wherein the optical element is integrated onto or into said light-transmissive substrate.

18. The device as claimed in claim 17 wherein the active optical component is selected from the group consisting of light sources, and sensors including lasers, VCSELs and photodetectors.

19. The device as claimed in claim 17 wherein the active optical device is carried by the MEMS device.

20. The device as claimed in claim 17 wherein a passive optical device is integrated into said substrate.

17. An optical and electrical MEMS device physically and electrically integrally attached upon an optically transmissive substrate carrying a pattern of printed electrical circuit interconnections for the device, the light-transmissive substrate being integrated monolithically with an active optical component integrated onto or into the MEMS device or the light-transmissive substrate, and optically cooperative with the light-transmissive substrate as integrated with the MEMS device.

21. A method for enabling the precision assembly of optical MEMS arrays to a single substrate without substantial restriction on the size or layout of the substrate, that comprises, custom-forming a plurality of MEMS dies each carrying electrical signal-controllable mirrors;

forming a light transmissive substrate of desired size to accommodate the plurality of MEMS dies, and monolithically integrating into the light-transmissive substrate, optical components useful for light-path interfacing with the MEMS dies;

providing integral printed electrical circuit interconnections on the substrate for operation of the mirrors of the dies;

physically and electrically integrally attaching dies along and upon the single optically transmissive substrate and with electrical connection to the printed circuit, thereby to provide also for the accurate and fixed optical alignment of the MEMS dies and the optical components optically interacting therewith, enabling the focusing of light onto the MEMS mirrors along fixed optical paths for optically addressing the array and without requiring adjustments.

22. The method of assembling an array of optically and electrically interacting optical MEMS dies, that comprises, physically and electrically integrally attaching the dies in a predetermined order or pattern along and upon a light-transmissive substrate carrying a pattern of printed electrical circuit interconnections for the dies;

and monolithically integrating into the substrate, optical components for interacting light with the dies and to provide accurate and fixed optical alignment of the MEMS and the optical components optically interacting therewith.

23. The method of claim 22 wherein said optical components are passive and/or active optical elements.

24. The method of claim 23 wherein said optical components are active optical elements such as lasers and photodiodes and they are integratable onto or into said dies.

25. The method of claim 22 wherein the optical components comprise lenses and the optical MEMS dies carry electrical signal-controllable mirrors, and focusing light by said lenses along fixed optical paths for optically addressing the array.

26. The method of claim 25 wherein the MEMS dies are provided with metalization between the mirrors;

and flip-chip solder-bonding conductive posts provided in the printed circuit of the substrate, leaving sufficient clearance between the substrate and the mirrors to avoid interference with the operation of the mirrors.

27. The method of claim 25 wherein the lenses are integrally formed on the top or bottom surface of the substrate, enabling optical readout of the MEMS in reflection from the bottom surface.

28. The method of claim 26 wherein a patterned optical blocking layer is applied to the substrate in areas surrounding said conductive posts.

29. The method of claim 25 wherein the backside of the substrate is provided with a solid annular peripheral metalized region solder-attachable as to an external pin or ball grid array package housing.

30. The method of claim 29 wherein a package housing is provided and the assembled array is bonded therewithin with the substrate electrically connected to package pads disposed annularly within the housing.

31. The method of claim 30 wherein the top of the substrate is provided with peripheral conductive pads, and wirebonding the conductive pads internally of the packaged housing to said package pads.

32. The method of claim 30 wherein the top or bottom of the package housing is apertured or windowed, and optical readout light for the array mounted within the package is transmitted therethrough.