TWI479646B - Wafer scale image sensor package and optical mechanism including the same - Google Patents

Description

Wafer level image chip package and optomechanical structure containing the same

The present invention relates to a optomechanical structure suitable for wafer level packaging technology. Further, the present invention is directed to a optomechanical structure of an image sensor of a semiconductor structure covered with a transparent material in a wafer level packaging technique.

The current image sensor chip (IC) mainly cuts the die from the wafer and then encapsulates it into a wafer by various packaging methods, such as encapsulation technology such as iDip, LGA or COB. . Such packaging technology is well known to those skilled in the art, and thus will not be described herein.

A wafer fabricated using a similar packaging technique has a common profile that the periphery of the wafer is covered by a black cavity, which is a common wafer form today. For image sensor wafers, this feature blocks ambient ambient stray light, so image sensor wafers can be directly applied to a variety of applications after packaging, for example, in optical mice. The image sensor wafer can be directly fixed and then fixed, and can be used to sense the reflected light of the desktop for optical navigation operations.

However, with the evolution of semiconductor process technology, wafer-level packaging has gradually become a mature technology. In wafer-level packaging technology, a transparent material such as glass or resin (Epoxy) is coated on the bare crystal. The method of forming a package structure; for example, "Chip Scale Package (CSP)" technology, "Through-Silicon Via (TSV)" technology, OPLGA technology, etc., can use transparent glass Or the resin is overlaid on the die for packaging. Therefore, such a packaged wafer does not have a black cavity structure, so that when applied to an image sensor wafer, ambient light may affect the operation of the sensor through transparent glass or resin.

In view of this, the new state light machine and positioning structure for wafer level packaging technology is urgently needed for the image sensing industry.

The object of the present invention is to propose a optomechanical structure and positioning structure suitable for wafer level packaging technology, and is particularly suitable for wafer level image chip packaging. Since the wafer level packaging technology can cover the outer layer of the semiconductor circuit with a transparent material such as glass or resin, the packaged wafer level image chip package surface does not have a black cavity structure and cannot effectively block the surrounding light. Therefore, the present invention provides a optomechanical structure and a positioning structure for fixing a wafer packaged wafer and a optomechanical structure and/or a positioning structure to a substrate, such as a printed circuit board (PCB), while blocking or Absorb the rest of the unnecessary light. For an image sensor wafer that needs to sense light to generate an image signal, the image sensor wafer can be effectively prevented from being affected by ambient light and affecting the final imaging effect.

To achieve the above object, the present invention provides a wafer level image The chip package comprises a die, an intermediate layer and a transparent layer. The die has a sensing surface and the sensing mask has a sensing region. The intermediate layer is disposed outside the sensing area on the sensing surface. The transparent layer is bonded to the die through the intermediate layer, wherein a filter layer is formed on at least a portion of the surface of the transparent layer.

The invention further provides a optomechanical structure comprising a substrate, a wafer level image chip package, a light source, a barrier member and a tight fitting. The wafer level image chip package is attached to a front side of the substrate and has a sensing area. The light source is attached to the front side of the substrate. The barrier encases the wafer level image chip package and has an opening for exposing at least the sensing region of the wafer level image chip package. The fastening member encloses the barrier member for fixing the barrier member to the substrate, wherein the fastening member has a first light transmitting region opposite to the light source and a second light transmitting region opposite to the opening of the barrier member.

The invention further provides an optical mouse structure of an optical mouse, comprising a substrate, a wafer level image chip package, a light source, a barrier member and a tight fitting. The wafer level image chip package and the light source are attached to the substrate. The barrier encases a portion of the wafer level image chip package and surrounds the light source. The tight fitting covers the barrier to secure the barrier to the substrate.

In the optomechanical structure of the embodiment of the present invention, the first light transmitting region is configured to allow light emitted by the light source to penetrate the illuminating device structure to a reflecting surface; the second light transmitting region is provided for the reflecting of the illuminating device structure Surface reflection Light penetrates and reaches the sensing region via the opening of the barrier.

In the optomechanical structure of the embodiment of the present invention, the wafer level image chip package has a sensing surface and a back surface opposite to each other, wherein the wafer level image chip package is attached to the front surface of the substrate through the back surface; The substrate has a circuit configuration on the front side to couple the wafer level image chip package.

In the wafer level image chip package of the embodiment of the present invention, at least one specific light wavelength filter layer is coated on at least a portion of the surface of the transparent layer and/or the sensing surface of the bare crystal to enable light of a specific wavelength to pass through. For example, infrared light and blue light penetrating filter layer (B+IR filter layer) can pass blue light and infrared light; infrared light penetrates the filter layer (IR filter layer) to pass infrared light.

In the wafer level image chip package of the embodiment of the invention, at least one light reflecting layer is provided, comprising a metal component, coated on the transparent layer and/or at least a part of the surface of the sensing surface of the bare crystal, so that specific light can be The reflective layer reflects and cannot enter the image wafer.

In the optomechanical structure of the embodiment of the invention, a barrier member is provided on the wafer level image chip package, and the barrier member needs to be matched with a tight fitting. The tight fitting is fixed to the substrate and simultaneously fixes the barrier directly. Therefore, when the tight fitting is fixed on the substrate, the tight fitting, the barrier and the wafer level image chip package can maintain a stable relative position, and the blocking member can block the surrounding stray light from entering the wafer.

In the optomechanical structure of the embodiment of the invention, the wafer level image chip package can be directly soldered to the substrate, and then the barrier member is combined on the wafer level image chip package to fix the relative position thereof, and finally the tight fitting is combined to block. The component is fastened to the substrate; thereby, the tight fitting, the barrier and the wafer level image chip package maintain a stable relative position.

In other embodiments, the barrier member itself may be directly fixed to the substrate, and then the tight fitting is attached to the barrier member and fixed to the substrate.

The above and other objects, features, and advantages of the present invention will become more apparent from the accompanying drawings. In the following embodiments and drawings, elements that are not related to the present invention have been omitted and are not shown, and the dimensional relationships between the elements in the drawings are only for easy understanding, and are not intended to limit the actual ratio. .

FIG. 1 is a schematic view showing a wafer level image chip package 1 according to an embodiment of the present invention. The wafer level image chip package 1 comprises a transparent layer 11, a die 13 and an intermediate layer 15; wherein the transparent layer 11 is, for example, a glass layer or a resin layer; the intermediate layer 15 is interposed between the die 13 and The transparent layer 11 has a function of buffering and bonding the transparent layer 11 and the die 13 . The die 13 is a light sensing component, which is a semiconductor circuit structure formed on a wafer; the die 13 has a sensing surface 131 and the sensing mask has a sensing region 132; The sensing area 132 can be located substantially at the center of the sensing surface 131, but is not limited thereto. The intermediate layer 15 is located on the sensing surface 131 outside the sensing region 132. It is of course better to avoid shielding the sensing region 132. The transparent layer 11 has an inner surface 11 _IS facing the die 13, an outer surface 11 _OS opposite the inner surface 11 _IS and a side surface 11 _SS . In the embodiment of the present invention, at least a part of the surface of the transparent layer 11 and/or the sensing surface 131 of the die 13 is formed with a filter layer and/or a light reflecting layer (described in detail later).

In this embodiment, the light reflecting layer may be coated on at least one of the positions 101, 111, 131 and 151; the specific wavelength filter layer may be applied on at least one of the positions 103, 113 and 133; that is, the filter layer Forming on at least a portion of the surface of the inner surface 11 _IS , the outer surface 11 _{OS ,} and the sensing surface 131 of the die 13 , wherein the filter layer is preferably opposite to the sensing region 132 of the die 13 ; the reflective layer It may be formed on at least a part of the surface of the inner surface 11 _IS , the outer surface 11 _OS , the side surface 11 _SS and the sensing surface 131 of the bare crystal 13 . Since the light reflecting layer has a metal component such as chromium or other metal components, it is possible to effectively restrict the light from entering the transparent layer 11 or the bare crystal 13 from the range in which the light reflecting layer is not coated. The specific wavelength filter layer can partially overlap the light reflecting layer without affecting each other's functions. In this embodiment, the positions 103, 113 and 133 can be regarded as one of the effective field of view of the light sensing element, which is preferably opposite to the sensing area 132.

When the reflective layer is formed at a relatively high temperature, the material of the transparent layer 11 needs to select a material that can withstand high temperatures, such as glass. Resins without heat resistance are not applicable.

The specific wavelength filter layer is used to enable light of a specific wavelength, for example, infrared light and blue light penetrating filter layer (B+IR filter layer) to pass blue light and infrared light, and infrared light penetrates the filter layer. (IR filter layer) allows infrared light to pass. As the wafer 1 is designed differently, different filter layers can be used; for example, an optical mouse using a blue light source can use a B+IR filter layer; and in an optical mouse using invisible light, The IR filter layer is available.

Some specific optical wavelength filter layers are soft, and are not suitable for coating on the outermost layer of the wafer level image chip package 1, that is, it is not suitable for coating at the position 133 to prevent the filter layer from being damaged or scratched. At this time, the filter layer is preferably formed on the inner surface 11 _{IS of the} transparent layer 11 or directly applied to the sensing surface 131 of the bare crystal 13 .

The filter layer and the light-reflecting layer can be matched with the design of the optical machine and the sensing element, and are coated at different positions to promote the overall reflection and absorption effect of the whole design, for example, the filter layer can be coated at positions 103 and 113 at the same time. .

In another embodiment, when the light to be received is visible light, the IR filter layer can be used to absorb and block the visible light, and the IR filter layer can be applied to the position formed by the reflective layer in the previous embodiment. That is, at least one of the positions 101, 111, 131, and 151 serves as an absorbing layer. Since the IR filter layer can absorb visible light, only the area not covered by the IR filter layer can allow visible light. To achieve the purpose of effectively limiting the passage of visible light. In other words, the formation of the light reflecting layer or the absorbing layer on the sensing surface 131 of the transparent layer 11 and the bare crystal 13 is determined according to the operational characteristics of the light sensing element.

2 is a schematic view showing the structure of the optical machine according to the embodiment of the present invention; wherein the wafer level image chip package 21 (hereinafter referred to as the wafer 21) is a sensing wafer that has been wafer level packaged, and can be utilized as shown in FIG. The method is formed; that is, the wafer 21 includes a die 13 and a transparent layer 11 are bonded to each other via an intermediate layer 15. Figure 2 is a schematic view of the optomechanical structure applied to an optical mouse, and therefore also includes a light source 25 that emits light through the tight fitting 24 to a reflecting surface S, and the reflected light passes through the tight fitting 24 Arrived at the wafer 21.

In detail, the optomechanical structure of the embodiment includes a substrate 22, a wafer level image chip package 21, a light source 25, a barrier member 23, and a tight fitting 24. The wafer 21 is attached to one of the front faces 22S of the substrate 22 and has a sensing region 132 (as shown in FIG. 1). The light source 25 is attached to the front surface 22S of the substrate 22 and emits light in a direction away from the front surface 22S. The barrier member 23 covers a portion of the wafer 21, for example, having an opening 232 for exposing at least the sensing region 132 of the wafer 21. The fastening member 24 covers the barrier member 23 for fixing the barrier member 23 to the substrate 22; wherein the fastening member 24 preferably has a first light transmitting region 241 opposite to the light source 25 and a second light transmitting region. 242 relative to the barrier 23 of the opening 232. The first light-transmitting region 241 is configured such that the light emitted by the light source 25 passes through the light-emitting device structure to the reflective surface S; the second light-transmitting region 242 passes through the light-transmitting structure and the reflected light of the reflective surface S penetrates and passes through The opening 232 of the barrier member 23 reaches the sensing region 132 of the die 13 .

The optomechanical structure of the present embodiment is usually disposed in a casing 3, such as a mouse casing. The casing 3 can be placed on a reflecting surface S for a user to operate and the casing 3 has a bottom hole 30. The light emitted from the light source 25 illuminates the reflecting surface S through the first light transmitting region 241 and the bottom hole 30. The reflected light (including stray light) of the reflecting surface S passes through the bottom hole 30 and passes through the second transparent region 242 and the opening 232 to reach the sensing region 132 of the wafer 21.

In this embodiment, most of the area of the wafer 21 is covered by the barrier member 23. Therefore, the light can only reach the wafer 21 through the partial opening 232 of the barrier member 23 above the wafer 21 to block unnecessary light from entering the wafer 21. . In one embodiment, the blocking member 23 can also be disposed around the light source 25 to prevent the light emitted by the light source 25 from scattering around the housing 3. In this case, the blocking member 23 can further have a light transmission hole 231 for the light source 25. The emitted light is emitted from the barrier member 23. The shape of the barrier member 23 is designed to fit the wafer 21 and the light source 25 while being able to be tightly coupled to the tight fitting 24. When the tight fitting 24 is fixed to the substrate 22, the barrier 23, the wafer 21, and the light source 25 can be maintained in a stable relative position. It can be understood that if the barrier 23 can The wafer 21 is well shielded, and the barrier 23 may not surround the light source 25.

In the embodiment of the present invention, the tight fitting 24 can be fastened to the substrate 22 through the structure of the cantilever beam. Therefore, the substrate 22 needs to be hollowed out in advance so that the cantilever beam can be engaged through the hole, and the size of the hole needs to accommodate the cantilever beam. However, it does not need to fit tightly to the cantilever beam. Further, if the horizontal plane of the wafer 21 represents the horizontal plane, by the bonding of the barrier member 23 to the wafer 21, the barrier member and the wafer 21 can be maintained in a stable horizontal relative position, and the fastening member 24 is fixed to the substrate 22 due to The barrier member 23 can be tightly coupled to the tight fitting member 24, so that the tight fitting member 24, the barrier member 23 and the wafer 21 can maintain a stable vertical relative position on a vertical plane perpendicular to the horizontal plane.

As can be seen from FIG. 2, the tight fitting 24 is provided with a light guiding structure at a portion of the opening 232 of the blocking member 23 (ie, the second light transmitting region 242) and the front of the light source 25 (ie, the first light transmitting region 241). In this embodiment, the light guiding structure in front of the light source 25 is mainly configured to enable the light emitted by the light source 25 to be bent toward the reflecting surface S, and the light guiding structure at the front end of the wafer 21 mainly concentrates the reflected light from the reflecting surface S; That is, the first light transmitting region 241 and the second light transmitting region 242 may be, for example, a lens structure. It can be understood that the direction of travel of light shown in FIG. 2 is merely illustrative.

In Fig. 2, in order to show the relationship between the constituent elements, it is presented in a similar exploded view. In fact, the tight fitting 24 and the blocking member 23 and/or the blocking member 23 and the wafer 21 are designed to be mutually compatible. The wafers 21 are closely adhered to maintain a fixed relative position of the barrier member 23 and the wafer 21 through the tight fittings 24 (as shown in FIG. 3); wherein the wafer 21 can be joined to the substrate 22 by solder balls or bumps. Alternatively, the barrier member 23 can be made of a opaque colored material, such as a black barrier.

The substrate 22 in the foregoing embodiment may be a rigid substrate such as a printed circuit board for bonding and fixing the tight fittings 24, and the front surface 22S of the substrate 22 has a circuit layout for electrically connecting with the wafer 21. In addition, the tight fitting 24 can be combined with the substrate 22 by other bonding means, such as by screwing the tight fitting 24 and the substrate 22 to maintain a stable relative position between the components. In other embodiments, the barrier member 23 itself may be directly fixed to the substrate 22, and then the tight fitting 24 is attached to the barrier member 23 and fixed to the substrate 22.

In summary, the optomechanical structure of the present invention can position the wafer level image chip package at a preset position, and in the application of the image sensing application technology, can block or absorb the light around the image sensing component, so that The image sensing system works smoothly. In this way, the optomechanical and positioning structure input device of the present invention can be applied to wafers of wafer level packaging.

The present invention has been disclosed in the foregoing embodiments, and is not intended to limit the present invention. Any of the ordinary skill in the art to which the invention pertains can be modified and modified without departing from the spirit and scope of the invention. . Therefore, the scope of the invention is defined by the scope of the appended claims.

1‧‧‧ Wafer-level image chip packaging

11‧‧‧ transparent layer

11IS‧‧‧ inner surface of transparent layer

11OS‧‧‧ outside surface of transparent layer

11 _SS ‧‧‧Side side of transparent layer

13‧‧‧Bare crystal

131‧‧‧Sense surface

132‧‧‧Sensing area

15‧‧‧Intermediate

101, 111, 131, 151‧‧‧ reflective layer

103, 113, 133‧‧ ‧ filter layer

21‧‧‧ Wafer-level image chip packaging

22‧‧‧Substrate

22S‧‧‧ substrate front

23‧‧‧Resist

232‧‧‧Opening

231‧‧‧Light hole

24‧‧‧ Close fittings

241‧‧‧First light transmission area

242‧‧‧Second light transmission area

25‧‧‧Light source

3‧‧‧Shell

30‧‧‧ bottom hole

S‧‧‧reflecting surface

FIG. 1 is a schematic view showing a wafer level image chip package of an embodiment of the present invention.

Fig. 2 is a view showing the structure of a optomechanical machine according to an embodiment of the present invention and an optical mouse using the optomechanical structure.

Fig. 3 is a view showing another embodiment of the optomechanical structure of the embodiment of the present invention and an optical mouse using the optomechanical structure.

21‧‧‧ Wafer-level image chip packaging

22‧‧‧Substrate

22S‧‧‧ substrate front

23‧‧‧Resist

232‧‧‧Opening

231‧‧‧Light hole

24‧‧‧ Close fittings

241‧‧‧First light transmission area

242‧‧‧Second light transmission area

25‧‧‧Light source

3‧‧‧Shell

30‧‧‧ bottom hole

S‧‧‧reflecting surface

Claims (16)

A wafer level image chip package comprising: a bare crystal having a sensing surface, the sensing mask having a sensing region, wherein the sensing region of the bare crystal forms a filter layer; an intermediate layer, And disposed on the sensing surface outside the sensing region; and a transparent layer through which the intermediate layer is bonded to the bare crystal. The wafer level image chip package of claim 1, wherein at least a portion of the transparent layer is formed with another filter layer on the surface. The wafer level image chip package of claim 2, wherein the transparent layer has an inner surface facing the bare crystal and an outer surface opposite to the inner surface, and the other filter layer is formed on the inner surface and the outer surface At least one of the surfaces. A wafer level image chip package according to any one of claims 2 to 3, wherein the filter layer and the other filter layer are an infrared light transmission filter layer or an infrared light and blue light transmission filter. Light layer. The wafer level image chip package of claim 1 , wherein a reflective layer is formed on at least a portion of the surface of the transparent layer and/or the sensing surface of the die. The wafer level image chip package according to claim 1 , wherein the transparent layer is a glass layer or a resin layer. An optical machine structure comprising: a substrate having a front surface; a wafer-level image chip package attached to the front surface of the substrate and including a die having a sensing region, wherein a photosensitive layer is formed on the sensing region of the die; a light source is attached to a front surface of the substrate; a barrier member covering the wafer level image chip package; and having an opening for exposing at least the sensing region of the wafer level image chip package; and a tight fitting package The barrier member is configured to fix the barrier member to the substrate, wherein the fastening member has a first light transmitting region opposite to the light source and a second light transmitting region opposite to the opening of the barrier member. According to the optomechanical structure of claim 7, wherein the optomechanical structure is applied to an optical mouse. According to the optomechanical structure of claim 7, wherein the first light transmitting region and the second light transmitting region are a lens structure. The optomechanical structure according to claim 7 of the patent application, wherein the barrier member is made of an opaque material. The optomechanical structure according to claim 7 , wherein the wafer level image chip package further comprises a transparent layer combined with the bare crystal via an intermediate layer, and at least a portion of the transparent layer is formed with another filter layer Relative to the sensing area. The optomechanical structure of claim 11, wherein the transparent layer has an inner surface facing the bare crystal and an outer surface opposite the inner surface, and the other filter layer is formed on the inner surface and the outer surface at least One of them. The optomechanical structure according to any one of claims 11 to 12, wherein the filter layer and the other filter layer are an infrared light penetrating filter layer or an infrared light and blue light penetrating filter layer. An optical mouse optical machine structure comprising: a substrate; a wafer level image chip package attached to the substrate and comprising a die, wherein a filter layer is formed on one of the sensing regions of the die a light source attached to the substrate; a barrier covering a portion of the wafer level image chip package surrounding the light source; and a tight fitting covering the barrier member for fixing the barrier member Substrate. The optomechanical structure according to claim 14 , wherein the wafer level image chip package further comprises a transparent layer combined with the bare layer via an intermediate layer, and at least a portion of the transparent layer is formed with another filter layer . The optomechanical structure of claim 14 or 15, wherein a reflective layer is formed on at least a portion of the surface of the transparent layer and/or the sensing surface of the die.