CHIP PACKAGE STRUCTURE

A chip package structure includes a substrate, a chip, a light-permeable element, and an adhesive element. The chip is disposed on the substrate. The light-permeable element is disposed above the chip. The adhesive element is connected between the chip and the light-permeable element. The adhesive element surrounds the chip for formation of an accommodating space, and the chip is located in the accommodating space. The adhesive element includes two material layers having complementary visible light absorption spectra, such that the adhesive element is capable of being used to absorb full visible spectrum light.

CROSS-REFERENCE TO RELATED PATENT APPLICATION

This application claims the benefit of priority to Taiwan Patent Application No. 112110809, filed on Mar. 23, 2023. The entire content of the above identified application is incorporated herein by reference.

FIELD OF THE DISCLOSURE

The present disclosure relates to a chip package structure, and more particularly to a chip package structure capable of reducing stray light that enters an image sensing region.

BACKGROUND OF THE DISCLOSURE

In an existing image sensor, when external light (such as visible light) enters the image sensor to form an image, the light passes through a lens before entering the image sensor. Then, most of the light will be received by an image sensing region of a chip. A small portion of the light is incident to surrounding structures of the image sensor (such as an edge of an encapsulation compound or a substrate), and is reflected once or more than once before entering the image sensing region. This small portion of the light is referred to as stray light. The stray light may cause flare and affect the image quality.

Therefore, how to design a chip package structure capable of reducing the probability of the stray light entering the image sensing region has become an important issue in the related art.

SUMMARY OF THE DISCLOSURE

In response to the above-referenced technical inadequacy, the present disclosure provides a chip package structure, which can address an issue of an image quality of an existing image sensor being easily affected by stray light.

In order to solve the above-mentioned problem, one of the technical aspects adopted by the present disclosure is to provide a chip package structure, which includes a substrate, a chip, a light-permeable element, and an adhesive element. The chip is disposed on the substrate. The light-permeable element is disposed above the chip. The adhesive element is connected between the chip and the light-permeable element. The adhesive element surrounds the chip for formation of an accommodating space, and the chip is located at the accommodating space. The adhesive element includes two material layers having complementary visible light absorption spectra, such that the adhesive element is capable of being used to absorb full visible spectrum light.

Therefore, in the chip package structure provided by the present disclosure, through the structural feature of the adhesive element including two material layers and the optical property of the two material layers having complementary visible light absorption spectra, the adhesive element can be used to absorb the full visible spectrum light. Accordingly, the adhesive element can directly absorb the stray light that is incident into the chip package structure, so as to reduce the probability of reflection to the image sensing region and improve the image quality.

DETAILED DESCRIPTION OF THE EXEMPLARY EMBODIMENTS

First Embodiment

Referring toFIG.1,FIG.1is a schematic cross-sectional view of a chip package structure according to a first embodiment of the present disclosure. A first embodiment of the present disclosure provides a chip package structure M, which includes a substrate1, a chip2, a light-permeable element3, and an adhesive element4. The chip2is disposed on the substrate1. The light-permeable element3is disposed above the chip2. The adhesive element4is connected between the chip2and the light-permeable element3, and the chip2and the light-permeable element3are separated from each other. For example, the substrate1is formed of a ceramic, and the light-permeable element3is formed of a transparent glass. However, the present disclosure is not limited thereto. Furthermore, the adhesive element4surrounds the chip2for formation of an accommodating space E, and the chip2is located at the accommodating space E. A plurality of solder balls7can be disposed on a bottom surface of the substrate1. The chip package structure M can be soldered and fixed onto an electronic component (not shown in the figures) through the plurality of solder balls7, such that the chip package structure M is electrically coupled to the electronic component.

For example, the chip2may be an image sensing die (e.g., a complementary metal oxide semiconductor (CMOS) sensing die), and an upper surface20of the chip2has an image sensing region21. External light (such as visible light) can pass through the light-permeable element3, and is received by the image sensing region21of the chip2to form an image. However, the present disclosure is not limited thereto. In addition, the chip package structure M further includes a plurality of metal wires5electrically connected between the chip2and the substrate1. More specifically, one end of each of the metal wires5is connected to a conducting portion2P of the chip2, and another end of each of the metal wires5is connected to a pad1P of the substrate1. Therefore, the substrate1can be electrically coupled to the chip2through the plurality of metal wires5. Here, any of the metal wires5can be formed by normal bonding or reverse bonding, but the present disclosure is not limited thereto.

The chip package structure M can further include an encapsulation compound6. The encapsulation compound6is disposed on the substrate1. The chip2, the adhesive element4, the plurality of metal wires5, and a part of the light-permeable element3are embedded within the encapsulation compound6, and an outer surface of the light-permeable element3that faces outward is exposed from the encapsulation compound6. The encapsulation compound6can be, for example, a liquid compound or a molding compound, but the present disclosure is not limited thereto.

In addition, the adhesive element4includes two different material layers, and the two material layers are stacked up and down. The material of the two material layers is not limited in the present disclosure. Moreover, the two material layers have complementary visible light absorption spectra, such that the adhesive element4is capable of being used to absorb full visible spectrum light ranging from 380 nm to 750 nm.

As shown inFIG.1, in the present disclosure, the two material layers that are stacked up and down can be divided into a first material layer41and a second material layer42, and the first material layer41is stacked above the second material layer42. In another embodiment, the second material layer42can be stacked above the first material layer41. The present disclosure is not limited thereto.

It should be noted that ranges of the light absorption spectra of the first material layer41and the second material layer42are not limited in the present disclosure. For example, the first material layer41can absorb visible light having a wavelength from 300 nm to 600 nm. Alternatively, the reflectance of the first material layer41for the visible light having a wavelength from 300 nm to 600 nm is less than 10%. The second material layer42can absorb visible light having a wavelength from 600 nm to 1,200 nm. Alternatively, the reflectance of the second material layer42for the visible light having a wavelength from 600 nm to 1,200 nm is less than 10%. Therefore, the adhesive element4is capable of absorbing the full visible spectrum of light ranging from 380 nm to 750 nm. In other words, any two material layers that have the complementary visible light absorption spectra and cover the full visible spectrum of light are within the scope of the present disclosure.

Reference is made toFIG.2andFIG.3, which show different configurations of the adhesive element4. The first material layer41has a first surface411and a second surface412that are opposite to each other. The second material layer42also has a first surface421and a second surface422that are opposite to each other. Outlines of the first surface411,421and the second surface412,422can have a planar shape or a jagged shape, but the present disclosure is not limited thereto.

As shown inFIG.1andFIG.2, the outline of the first surface411and the outline of the second surface412of the first material layer41are symmetrical to each other (i.e., both have a planar shape), and the outline of the first surface421and the outline of the second surface422of the second material layer42are symmetrical to each other (i.e., both have a planar shape). Furthermore, an inner surface4S of the adhesive element4is formed by the first surface411of the first material layer41and the first surface421of the second material layer42, and an outer surface of the adhesive element4is formed by the second surface412of the first material layer41and the second surface422of the second material layer42. Therefore, the inner surface4S and the outer surface of the adhesive element4are symmetrical to each other (since only the inner surface4S can be seen fromFIG.2, the outer surface is not marked with a reference sign).

As shown inFIG.1andFIG.3, the outlines of the first surface411and the second surface412of the first material layer41are asymmetric (i.e., the outline of the first surface411has a jagged shape, and the outline of the second surface412has a planar shape). The outlines of the first surface421and the second surface422of the second material layer42are asymmetric (i.e., the outline of the first surface421has a jagged shape, and the outline of the second surface422has a planar shape). Therefore, the inner surface4S and the outer surface of the adhesive element4are asymmetric to each other.

Second Embodiment

Referring toFIG.4andFIG.5,FIG.4is a schematic cross-sectional view of a chip package structure according to a second embodiment of the present disclosure, andFIG.5is a schematic view of an adhesive element according to the second embodiment of the present disclosure. A second embodiment of the present disclosure provides a chip package structure M, which includes a substrate1, a chip2, a light-permeable element3, an adhesive element4, a plurality of metal wires5, and an encapsulation compound6. The chip package structure M of the second embodiment has a structure similar to that of the chip package structure M of the first embodiment, and the similarities therebetween will not be reiterated herein. The main difference between the second embodiment and the first embodiment is that the adhesive element4of the second embodiment can be divided into an inner part and an outer part by having a medium filled therein.

Specifically, the adhesive element4includes an inner adhesive portion4A, an outer adhesive portion4B, and a middle portion4C. Each of the inner adhesive portion4A and the outer adhesive portion4B includes a part of the first material layer41and a part of the second material layer42. The middle portion4C is disposed between the inner adhesive portion4A and the outer adhesive portion4B, and completely separates the inner adhesive portion4A and the outer adhesive portion4B. In other words, the inner adhesive portion4A and the outer adhesive portion4B are separated from and not in contact with each other. It is worth mentioning that the material of the middle portion4C filled between the first material layer41and the second material layer42is different from that of the first material layer41and the second material layer42. For example, the medium of the present embodiment is air. That is, the middle portion4C is an air gap layer. However, the present disclosure is not limited thereto. In addition, the size of each of the inner adhesive portion4A, the outer adhesive portion4B, and the middle portion4C is not limited in the present disclosure.

When the outer adhesive portion4B deteriorates due to the adhesive element4being subject to an external stress, the middle portion4C can protect the inner adhesive portion4A from being affected by the external stress. Therefore, the influence of the external stress on the adhesive element4can be reduced through the structural design of the middle portion4C, and the reliability and structural strength of the adhesive element4can be improved. In addition, when light (i.e., stray light) is incident to the adhesive element4, one part of the light is reflected, and another part of the light passes through the adhesive element4. Through the feature of a refractive index of the middle portion4C being different from that of the inner adhesive portion4A and the outer adhesive portion4B, a path of the light passing through the adhesive element4can be changed, thereby reducing the probability of incidence into the image sensing region21.

As shown inFIG.4, since the middle portion4C completely separates the inner adhesive portion4A from the outer adhesive portion4B, the inner adhesive portion4A is located inside the accommodating space E, and the outer adhesive portion4B is located outside the accommodating space E. When the adhesive element4is subject to the external stress, the outer adhesive portion4B is affected most, and the inner adhesive portion4A can maintain a sufficient structural strength.

Third Embodiment

Referring toFIG.6toFIG.9,FIG.6andFIG.8are schematic cross-sectional views of different configurations of a chip package structure according to a third embodiment of the present disclosure, andFIG.7andFIG.9are schematic views of different configurations of an adhesive element according to the third embodiment of the present disclosure. A third embodiment of the present disclosure provides a chip package structure M, which includes a substrate1, a chip2, a light-permeable element3, an adhesive element4, a plurality of metal wires5, and an encapsulation compound6. The chip package structure M of the third embodiment has a structure similar to that of the chip package structure M of the first embodiment, and the similarities therebetween will not be reiterated herein. The main difference between the third embodiment and the first embodiment is that widths of the first material layer41and the second material layer42are not equal to each other in the third embodiment. Furthermore, a projection area of the first material layer41projected onto the light-permeable element3is not equal to a projection area of the second material layer42projected onto the light-permeable element3.

As shown inFIG.6andFIG.7, the first surface411and the second surface412of the first material layer41have a first width W1therebetween, and the first width W1is a width of the first material layer41. The first surface421and the second surface422of the second material layer42have a second width W2therebetween, and the second width W2is a width of the second material layer42. In the third embodiment, the first width W1is not equal to the second width W2. Specifically, the first width W1is greater than the second width W2. When the first width W1is greater than the second width W2, the projection area of the first material layer41projected onto the light-permeable element3is greater than the projection area of the second material layer42projected onto the light-permeable element3. When the visible light passes through the light-permeable element3and is incident into the accommodating space E, one part of stray light L is absorbed by the first material layer41, and another part of the stray light L is directly reflected by the first material layer41and cannot enter the accommodating space E, thereby reducing the probability of the stray light L being received by the image sensing region21.

On the other hand, as shown inFIG.8andFIG.9, the first width W1can be, for example, smaller than the second width W2. Thus, the projection area of the first material layer41projected onto the light-permeable element3is smaller than the projection area of the second material layer42projected onto the light-permeable element3. When the visible light passes through the light-permeable element3and is incident into the accommodating space E, one part of the stray light L is sequentially absorbed by the second material layer42and the first material layer41, and another part of the stray light L is sequentially reflected by the second material layer42and the first material layer41, thereby keeping the stray light L away from the image sensing region21.

Therefore, by adjusting the structure and the size of each of the first material layer41and the second material layer42, the light (i.e., the stray light L) is reflected away from the image sensing region21, thereby reducing the probability of the stray light L being received by the image sensing region21.

Beneficial Effects of the Embodiments

In conclusion, in the chip package structure M provided by the present disclosure, through the feature of the adhesive element4being a composite structure that includes two material layers and the optical property of the two material layers having complementary visible light absorption spectra, the adhesive element4can be used to absorb the full visible spectrum light. Accordingly, the adhesive element4can directly absorb the stray light that is incident into the chip package structure M, so as to reduce the probability of reflection to the image sensing region21and improve the image quality.

Furthermore, the influence of the external stress on the adhesive element4can be reduced through the structural design of the middle portion4C, and the reliability and structural strength of the adhesive element4can be improved. When the outer adhesive portion4B deteriorates due to the adhesive element4being subject to the external stress, the middle portion4C can protect the inner adhesive portion4A from being affected by the external stress. In addition, through the feature of the refractive index of the middle portion4C being different from that of the inner adhesive portion4A and the outer adhesive portion4B, a path of the stray light L passing through the adhesive element4can be changed, thereby reducing the probability of incidence into the image sensing region21.

Furthermore, by adjusting the structure and the size of each of the first material layer41and the second material layer42, the stray light L is reflected away from the image sensing region21, thereby reducing the probability of the stray light L being received by the image sensing region21.