Wafer level camera module with snap-in latch

An apparatus includes an image sensor module with a lens stack disposed on the image sensor module. A protective tube is disposed on the image sensor module and encloses the lens stack. The protective tube includes an outer wall having a snap-in latch element disposed thereon. A metal housing encloses the protective tube. The metal housing includes a housing foot and inner wall having an opposite snap-in latch element disposed thereon. The image sensor module is adapted to be secured between the housing foot of the metal housing and the protective tube when the opposite snap-in latch element of the metal housing is engaged with the snap-in latch element of the protective tube.

REFERENCE TO RELATED APPLICATION(S)

This application is related to co-pending application Ser. No. 13/435,649, filed Mar. 30, 2012, entitled “Wafer Level Camera Module With Protective Tube,” and assigned to the Assignee of the present application.

BACKGROUND INFORMATION

1. Field of the Disclosure

The present invention relates generally to image sensors. More specifically, embodiments of the present invention are related to wafer level camera modules.

A wafer level camera module is a camera module that has a small footprint and can be utilized in applications such for example mobile phones, notebook computers, tablet computers, and the like. A wafer level camera module includes optics to focus an image and an image sensor for sensing the image. In order to capture a high quality image, the optics of the camera module typically includes several lenses that are separated by glass wafers and/or spacers. The lenses are stacked in a lens stack. The lens stack is disposed on an image sensor module. The lens stack and the image sensor module are typically enclosed within a metal housing.

There are continuing efforts to reduce production costs and improve yields of the manufacturing and assembly of wafer level camera modules. A consequence of low yields is increased production costs. Accordingly, a wafer level camera module and wafer level camera module assembly method that may increase yields and thus lower production costs is desired. Furthermore, wafer level camera modules having enhanced mechanical strength, improved electromagnetic compatibility (EMC) performance, and reduced stray light related artifacts are desired.

DETAILED DESCRIPTION

Example methods and apparatuses directed to a wafer level camera module with snap-in latch are disclosed. As will be appreciated, a wafer level camera module and wafer level camera module assembly method according to the teachings of the present invention may provide increased yields with reduced production costs. In addition, examples of the disclosed wafer level camera modules further provide enhanced mechanical strength, improved electromagnetic compatibility (EMC) performance, and reduced stray light related artifacts in accordance with the teachings of the present invention.

To illustrate,FIG. 1is a schematic diagram of a typical wafer level camera module20. Wafer level camera module20includes a lens stack22and an image sensor module24in a metal housing26. An interposer28, which is a cap with an aperture, is configured to close metal housing26.

FIG. 2illustrates lens stack22, image sensor module24, metal housing26, and interposer28. As shown, lens stack22includes one or more lenses34on glass wafers32and spacers36. Image sensor module24includes an image sensor die42, a spacer44mounted on the image sensor die, a cover glass46mounted on the spacer, and a plurality of solder balls48mounted to the image sensor die. Metal housing26may include a bent hook-like housing foot52.

FIGS. 3A-3Eillustrate a process for assembling an example wafer level camera module in accordance with the teachings of the present invention.FIG. 3Ashows a lens stack22including one or more lenses34on glass wafers32and spacers36.FIG. 3Bshows lens stack22disposed on an image sensor module24, which includes an image sensor die42, spacers44mounted on the image sensor die, a cover glass46mounted on spacers44, and a plurality of solder balls48mounted to the image sensor die. In other examples, it is appreciated that plurality of solder balls48may be replaced with solder bumps, solder pads, or other electrical connection elements. In one example, glue or an adhesive may be applied between lens stack22and image sensor module24.

In the illustrated example,FIG. 3Cshows a protective tube60disposed on image sensor module24and enclosing lens stack22. As shown, protective tube60includes an outer wall62having a snap-in latch element64disposed thereon. As shown in the depicted example, snap-in latch element64may be a male latch element. In the example, protective tube60includes a cap66with aperture as shown. In one example, cap66includes extension or ledge68.

In the illustrated example,FIG. 3Dshows a metal housing70enclosing protective tube60. As shown in the depicted example, metal housing includes a hook-like housing foot76and an inner wall74having an opposite snap-in latch element72disposed thereon. As shown in the depicted example, opposite snap-in latch element72may be a female latch element. In one example, the image sensor module24is adapted to be secured between housing foot76of metal housing70and protective tube60when opposite snap-in latch element72of metal housing70is engaged with the snap-in latch element64of protective tube60. As shown in the example, snap-in latch element64is a male latch element that includes a protruding part, and opposite snap-in latch element72is a female latch element that includes a recess adapted to accept and engage with the protruding part of the male latch element.

FIG. 3Eillustrates metal housing70enclosing protective tube60with protective tube60being inserted into metal housing70. As such, snap-in latch element64is engaged with opposite snap-in latch element72resulting in image sensor module24being secured between housing foot76and protective tube60. As shown, the inner surface of housing foot76presses against image sensor module24from one side and protective tube60presses image sensor module24from the other side. In this manner, the snap-in latching mechanism between protective tube60and metal housing70secures lens stack22and image sensor module24in accordance with the teachings of the present invention.

It is appreciated that protective tube60engaged with metal housing70as described better secures and aligns lens stack22and image sensor module24. Thus, the utilization of protective tube60with metal housing70as described increases the yields and in turn, reduces overall production costs. Protective tube60also enhances the mechanical strength, improves electromagnetic compatibility (EMC) performance, and prevents stray light related artifacts in accordance with the teachings of the present invention.

In one example, glue or a first adhesive23may be applied between lens stack22and image sensor module24, as shown inFIG. 3B. In addition, a second adhesive25may be applied between the inner surface of housing foot76and image sensor module24, and a third adhesive27may be applied between protective tube60and image sensor module24, as shown in the example depicted inFIG. 3E.

FIG. 4illustrates another example wafer level camera module in accordance with the teachings of the present invention. It is noted that the example wafer level camera module illustrated inFIG. 4shares many similarities with the example wafer level camera module illustrated inFIGS. 3A-3E. However, a difference is that the example wafer level camera module illustrated inFIG. 4shows cap66of protective tube60without a ledge68, as illustrated in the example wafer level camera module shown inFIGS. 3A-3E.

It is noted that in various examples, a male latch element for snap-in latch element64of protective tube60may be implemented using a variety of different shapes including for example a triangular shaped snap-in latch element64as shown inFIG. 3C,FIG. 3E,FIG. 4andFIG. 5A, or for example a hemisphere shaped snap-in latch element82as shown inFIG. 5BandFIG. 5C. In addition, a female latch element for opposite snap-in latch element72of metal housing70may be implemented using a variety of different shapes including for example a flat shaped opposite snap-in latch element72as shown inFIG. 3D,FIG. 3E,FIG. 4andFIG. 5B, or for example a slope shaped opposite snap-in latch element84as shown inFIG. 5AandFIG. 5C. It is appreciated that other combinations of shapes are also possible so long as snap-in latch element64engages with opposite snap-in latch element72to secure image sensor module24in accordance with the teachings of the present invention.

In an assembly process of one example, each component, including the lens stack, the image sensor module, the protective tube, and the metal housing, may all be singulated and assembled individually as shown and described with respect toFIGS. 3A-3Efor explanation purposes. In another example, the components may be assembled in wafer level as shown in the example below with respect toFIGS. 6A-6I. It is appreciated that althoughFIGS. 6A-6Iillustrate three units of wafer level camera modules for explanation purposes, there may be hundreds or thousands units on a wafer in accordance with the teachings of the present invention.

To illustrate,FIGS. 6A-6Ishow an example assembly process in wafer level using the reconstruction of components in wafer level after singulation, in accordance with the teachings of the present invention.FIG. 6Ashows that image sensor modules102are singulated after they are fabricated in wafer level.FIG. 6Bshows that the singulated image sensor modules102are reconstructed or rearranged back in wafer level by mounting them on a substrate or a tape104.FIG. 6Cshows that lens stacks106are singulated after they are fabricated in wafer level, and disposed on image sensor modules102. Glue or an adhesive may be applied between lens stacks106and image sensor modules102.FIG. 6Dshows that the fabricated protective tubes108are reconstructed in wafer level by mounting them on a substrate or a tape110. FIG.6E shows protective tubes108disposed on image sensor modules102.FIG. 6Fshows the substrate or tape104mounting image sensor modules102being removed.FIG. 6Gshows that the fabricated metal housings112including housing feet113are reconstructed in wafer level by mounting them on a substrate or a tape114.FIG. 6Hshows that protective tubes108are inserted into metal housings112such that the snap-in latch elements are engaged.FIG. 6Ishows substrate or tape114mounting metal housings112and substrate or tape104mounting protective tubes108being removed. Metal housings112enclose protective tubes108.

In one example, glue or an adhesive may be applied between the inner surface of housing feet113of metal housings112and image sensor modules102, and between protective tubes108and image sensor modules102.

In various examples, some components may not necessarily be singulated in the order represented above byFIGS. 6A-6Ifor explanation purposes. For instance, in one example, image sensor modules102may not be singulated until the step shown inFIG. 6E. Other arrangements of singulation and reconstruction are possible, including the reconstruction of lens stacks106in wafer level in accordance with the teachings of the present invention.

It is to be understood that the cross-section of lens stacks, protective tubes and metal housings illustrated in the above described figures can be circular, square, rectangular or other shapes. To illustrate,FIGS. 7A-7Care cross-section illustrations of various examples along line A-A′ of the example depicted inFIG. 3E. As shown,FIG. 7Aillustrates a cross-section of lens stack22, protective tube60and metal housing70having a circular shape.FIG. 7Billustrates a cross-section of lens stack22, protective tube60and metal housing70having a square shape.FIG. 7Cillustrates a cross-section of lens stack22, protective tube60and metal housing70having a rectangular shape.

In the examples shown in the previous figures, there is a gap between lens stack22and cap66of protective tube60. In other examples, it is appreciated that there may be no gap between lens stack22and cap66of protective tube60(not shown) in accordance with the teachings of the present invention.