MANUFACTURING METHOD AND STRUCTURE FOR WAFER LEVEL IMAGE SENSOR MODULE WITH FIXED FOCAL LENGTH

• US 20110279815A1
• Filed: 11/17/2010
• Published: 11/17/2011
• Est. Priority Date: 05/17/2010
• Status: Active Grant

• Current Assignee: Tong Hsing Electronic Industries, Ltd.
• Original Assignee: Kingpak Technology Inc.
• Inventors: Hsin, Chung-Hsien, Tu, Hsiu-Wen, Chen, Ming-Hui, Chen, Han-Hsing
• Granted Patent: US 8,440,488 B2
• Time in Patent Office: Days
• US Class Current: 356/213
• CPC Class Codes: H01L 27/14618 Containers
• CPC Class Codes: H01L 27/14625 Optical elements or arrangements associated with the device
• CPC Class Codes: H01L 27/14634 Assemblies, i.e. Hybrid structures
• CPC Class Codes: H01L 27/14685 Process for coatings or optical elements
• CPC Class Codes: H01L 27/1469 Assemblies, i.e. hybrid integration
• 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 31/0203 Containers; Encapsulations , e.g. encapsulation of photodiodesfor photovoltaic devices H01L31/048; for organic photosensitive devices H10K30/80
• CPC Class Codes: H01L 31/0232 Optical elements or arrangements associated with the device H01L31/0236 takes precedence; for photovoltaic cells H01L31/054; for photovoltaic modules H02S40/20

Abstract

This present invention discloses a manufacturing method and structure for a wafer level image sensor module with fixed focal length. The method includes the following steps. First, a silicon wafer comprising several image sensor chips having a photosensitive area and a lens module array wafer comprising several wafer level lens modules with fixed focal length are provided. Next, the image sensor chips and the wafer level lens modules are sorted in grades according to the different quality grades. According to the sorting results, each of the wafer level lens modules is assigned to be situated above the image sensor chip that has the same grade. At the same time, each of the wafer level lens modules is directed to face the photosensitive area of each image sensor chip. Finally, in the packaging process, the wafer level lens module is surrounded by an encapsulation material.

Claims

1. A manufacturing method for a wafer level image sensor module with fixed focal length, comprising steps of:

providing a silicon wafer including a plurality of image sensor chips wherein each said image sensor chip has a photosensitive area;

providing a lens module array wafer that includes a plurality of wafer level lens modules, wherein each said wafer level lens module has a fixed focal length;

sorting the image sensor chips and the wafer level lens modules in grades according to different quality grades;

according to the sorting results, assigning each said wafer level lens module to be situated above the image sensor chip that has the same grade and making each said wafer level lens module aligned with a respective said photosensitive area; and

performing a packaging process by applying an encapsulation material onto a first surface of the silicon wafer, and making the encapsulation material surround the wafer level lens modules.

2. The manufacturing method of claim 1, wherein the silicon wafer is a through-silicon via (TSV) wafer that has a second surface formed with a re-distribution layer and a plurality of solder ball pads.

3. The manufacturing method of claim 1, wherein the step of performing the packaging process comprises steps of:

providing a dam along a periphery of the first surface to form a circular structure; and

dispensing the encapsulation material into the dam such that the encapsulation material surrounds the wafer level lens modules but does not cover upper edges of the wafer level lens modules.

4. The manufacturing method of claim 3, wherein the encapsulation material is a liquid compound.

5. The manufacturing method of claim 1, wherein the step of performing the packaging process comprises steps of:

placing the silicon wafer having the wafer level lens modules into a mold;

introducing the encapsulation material into a mold cavity of the mold, such that the encapsulation material surrounds the wafer level lens modules but does not cover upper edges of the wafer level lens modules; and

after transfer molding the encapsulation material, opening the mold and performing a post mold cure process to cure the encapsulation material.

6. The manufacturing method of claim 5, wherein the encapsulation material is a mold compound.

7. The manufacturing method of claim 5, wherein the mold comprises an upper mold member and a lower mold member, the upper mold member abutting against the upper edges of the wafer level lens modules and the lower mold member abutting against a second surface of the silicon wafer.

8. The manufacturing method of claim 7, wherein the upper mold member has a vacuum absorbed buffer layer for abutting against the upper edges of the wafer level lens modules.

9. The manufacturing method of claim 1, further comprising, after the step of performing the packaging process, steps of:

placing solder balls on a second surface of the silicon wafer; and

cutting the silicon wafer to form a plurality of said wafer level image sensor modules.

10. A structure for a wafer level image sensor module with fixed focal length, comprising:

an image sensor chip including a plurality of photosensitive elements that are situated in a photosensitive area on a first surface of the image sensor chip;

a plurality of first contacts provided on the first surface and electrically connected to the photosensitive elements; and

a plurality of conducting channels passing through the image sensor chip and having one end electrically connected to the first contacts;

a wafer level lens module correspondingly situated above the photosensitive area and having a fixed focal length; and

an encapsulation material situated on the first surface and surrounding the wafer level lens module.

11. The structure of claim 10, wherein the image sensor chip further comprises a plurality of solder ball pads situated on a second surface of the image sensor chip and electrically connected to the conducting channel.

12. The structure of claim 10, wherein the image sensor chip further comprises a ball grid array situated on a second surface of the image sensor chip and electrically connected to a plurality of solder ball pads on the second surface so as to be electrically connected to the conducting channel.

13. The structure of claim 10, wherein the first contacts surround outside the photosensitive area.

14. The structure of claim 10, wherein the encapsulation material is a mold compound or a liquid compound.