Wire bond interposer package for CMOS image sensor and method of making same

• US 8,432,011 B1
• Filed: 12/06/2011
• Issued: 04/30/2013
• Est. Priority Date: 12/06/2011
• Status: Active Grant

• Current Assignee: Optiz, Inc.
• Original Assignee: Optiz, Inc.
• Inventors: Oganesian, Vage
• Primary Examiner(s): Lee, Kyoung
• Application Number:
  US13/312,826
• Time in Patent Office: 511 Days
• Field of Search: None
• US Class Current: 257/432
• CPC Class Codes: H01L 2224/48471 the other connecting portion not on the bonding area being a ball bond, i.e. wedge-to-ball, reverse stitch
• CPC Class Codes: H01L 2224/73265 Layer and wire connectors
• CPC Class Codes: H01L 2224/83 using a layer connector
• CPC Class Codes: H01L 2224/85 using a wire connector
• CPC Class Codes: H01L 2224/92247 the second connecting process involving a wire connector
• CPC Class Codes: H01L 2224/97 the devices being connected to a common substrate, e.g. interposer, said common substrate being separable into individual assemblies after connecting
• CPC Class Codes: H01L 27/14618 Containers
• CPC Class Codes: H01L 27/14683 Processes or apparatus peculiar to the manufacture or treatment of these devices or parts thereof not peculiar thereto H01L21/00
• CPC Class Codes: H01L 2924/15153 the die mounting substrate comprising a recess for hosting the device
• CPC Class Codes: H01L 2924/15311 being a ball array, e.g. BGA

Abstract

An image sensor package that includes a handler assembly having a crystalline handler with a cavity formed into its first surface. The cavity has a stepped sidewall that defines at least one step surface extending inwardly inside the cavity. A plurality of conductive elements each extend from the step surface(s), through the crystalline handler and to its second surface. A sensor chip is disposed in the cavity and includes a substrate, a plurality of photo detectors formed at its front surface, and a plurality of contact pads formed at its front surface which are electrically coupled to the photo detectors. A plurality of wires each extend between and electrically connect one of the contact pads and one of the conductive elements. A substrate is disposed over the cavity and mounted to the crystalline handler. The substrate is optically transparent to at least one range of light wavelengths.

Claims

1. An image sensor package, comprising:

a handler assembly that includes;

a crystalline handler having opposing first and second surfaces, wherein the crystalline handler includes a cavity formed into the first surface such that the cavity has a stepped sidewall that defines at least one step surface extending inwardly inside the cavity, and

a plurality of conductive elements each extending from the at least one step surface, through the crystalline handler, to the second surface;

a sensor chip disposed in the cavity, wherein the sensor chip includes;

a substrate with front and back opposing surfaces,

a plurality of photo detectors formed at the front surface, and

a plurality of contact pads formed at the front surface which are electrically coupled to the photo detectors;

a plurality of wires each extending between and electrically connecting one of the contact pads and one of the conductive elements; and

a substrate disposed over the cavity and mounted to the crystalline handler, wherein the substrate is optically transparent to at least one range of light wavelengths.

2. The image sensor package of claim 1, further comprising:

a plurality of surface mount interconnects each disposed over the second surface of the crystalline handler, and each electrically connected to one of the conductive elements.

3. The image sensor package of claim 2, wherein for each of the conductive elements:

the conductive element terminates at the at least one step surface in a first conductive pad, wherein one of the wires is connected to the first conductive pad; and

the conductive element terminates at the second surface in a second conductive pad, wherein one of the surface mount interconnects is connected to the second conductive pad;

wherein the first and second conductive pads each have a lateral dimension that is greater than that of the conductive element.

4. The image sensor package of claim 1, wherein the sensor chip further comprises:

a plurality of color filters and microlenses mounted over the photo detectors.

5. The image sensor package of claim 1, wherein the substrate has a surface with a portion thereof that is disposed over the photo detectors and is non-planar.

6. The image sensor package of claim 1, wherein the plurality of conductive elements are insulated from the crystalline handler by a dielectric material.

7. The image sensor package of claim 1, wherein:

the cavity has a first portion disposed higher than the step surface and a second portion disposed lower than the step surface;

the second portion has a lateral dimension that is smaller than that of the first portion; and

the sensor chip is disposed in the second portion.

8. The image sensor package of claim 7, wherein the sensor chip is disposed entirely within the second portion.

9. A method of packaging a sensor chip that includes a substrate with front and back opposing surfaces, a plurality of photo detectors formed at the front surface, and a plurality of contact pads formed at the front surface which are electrically coupled to the photo detectors, the method comprising:

providing a crystalline handler having opposing first and second surfaces;

forming a cavity into the first surface such that the cavity has a stepped sidewall that defines at least one step surface extending inwardly inside the cavity;

forming a plurality of conductive elements each extending from the at least one step surface, through the crystalline handler, to the second surface;

inserting the sensor chip in the cavity;

affixing a plurality of wires between the sensor chip and the plurality of conductive elements such that each of the wires extends between and electrically connects one of the contact pads and one of the conductive elements; and

mounting a substrate to the crystalline handler such that the substrate is disposed over the cavity, wherein the substrate is optically transparent to at least one range of light wavelengths.

10. The method of claim 9, further comprising:

forming a plurality of surface mount interconnects each disposed over the second surface of the crystalline handler, and each electrically connected to one of the conductive elements.

11. The method of claim 10, wherein each of the plurality of conductive elements is formed such that:

the conductive element terminates at the at least one step surface in a first conductive pad, wherein one of the wires is connected to the first conductive pad; and

the conductive element terminates at the second surface in a second conductive pad, wherein one of the surface mount interconnects is connected to the second conductive pad;

wherein the first and second conductive pads each have a lateral dimension that is greater than that of the conductive element.

12. The method of claim 9, wherein the substrate has a surface with a portion thereof that is disposed over the photo detectors and is non-planar.

13. The method of claim 9, further comprising:

forming a dielectric material between the plurality of conductive elements and the crystalline handler.

14. The method of claim 9, wherein the forming of the cavity comprises:

forming a first portion of the cavity into the first surface, wherein the first portion has a first lateral dimension and a bottom surface;

forming a second portion of the cavity into the bottom surface of the first portion, wherein the second portion has a second lateral dimension that is smaller than the first lateral dimension, wherein at least one portion of the bottom surface remains after the second portion is formed and which constitutes the at least one step surface.

15. The method of claim 14, wherein the inserting the sensor chip in the cavity includes inserting the sensor chip in the second portion of the cavity.

16. The method of claim 14, wherein the inserting the sensor chip in the cavity includes inserting the sensor chip entirely within the second portion of the cavity.

17. The method of claim 9, wherein the forming of each of the conductive elements comprises:

forming a hole that extends from the at least one step surface to the second surface;

forming an insulation material along a sidewall of the hole; and

depositing conductive material in the hole.

18. A method of forming a plurality of image sensor packages, comprising:

providing a crystalline handler having opposing first and second surfaces;

forming a plurality of cavities into the first surface such that each of the cavities has a stepped sidewall that defines at least one step surface extending inwardly inside the cavity;

for each of the cavities, forming a plurality of conductive elements each extending from the at least one step surface, through the crystalline handler, to the second surface;

inserting a sensor chip in each of the cavities, wherein each of the sensor chips includes;

a substrate with front and back opposing surfaces,

a plurality of photo detectors formed at the front surface, and

a plurality of contact pads formed at the front surface which are electrically coupled to the photo detectors;

for each of the respective sensor chips and cavities, affixing a plurality of wires between the sensor chip and the plurality of conductive elements such that each of the wires extends between and electrically connects one of the contact pads and one of the conductive elements;

mounting a substrate to the crystalline handler such that the substrate is disposed over the cavities, wherein the substrate is optically transparent to at least one range of light wavelengths; and

cutting the crystalline handler and substrate to form separate packages each including one of the cavities and one of the sensor chips therein.

19. The method of claim 18, further comprising:

forming a plurality of surface mount interconnects each disposed over the second surface of the crystalline handler, and each electrically connected to one of the conductive elements.

20. The method of claim 18, wherein portions of the substrate top surface disposed over the sensor chips are non-planar, wherein the substrate has a surface with portions thereof that each is disposed over one of the photo detectors and is non-planar.

21. The method of claim 18, wherein for each of the cavities, each of the plurality of conductive elements is formed such that:

the conductive element terminates at the at least one step surface in a first conductive pad, wherein one of the wires is connected to the first conductive pad; and

the conductive element terminates at the second surface in a second conductive pad, wherein one of the surface mount interconnects is connected to the second conductive pad;

wherein the first and second conductive pads each have a lateral dimension that is greater than that of the conductive element.

22. The method of claim 18, further comprising:

forming a dielectric material between the plurality of conductive elements and the crystalline handler.

23. The method of claim 18, wherein the forming of each of the cavities comprises:

forming a first portion of the cavity into the first surface, wherein the first portion has a first lateral dimension and a bottom surface;

forming a second portion of the cavity into the bottom surface of the first portion, wherein the second portion has a second lateral dimension that is smaller than the first lateral dimension, and wherein at least one portion of the bottom surface remains after the second portion is formed and which constitutes the at least one step surface.

24. The method of claim 23, wherein the inserting the sensor chips in the cavities includes inserting the sensor chips in the second portions of the cavities.

25. The method of claim 23, wherein the inserting the sensor chips in the cavities includes inserting the sensor chips entirely within the second portions of the cavities.

26. The method of claim 18, wherein for each of the cavities, the forming of each of the conductive elements comprises:

forming a hole that extends from the at least one step surface to the second surface; and

forming an insulation material along a sidewall of the hole; and

depositing conductive material in the hole.