Patent Application
20170088417
Field of Invention
The present invention relates to an electronic device and a manufacturing method of the electronic device.
Description of Related Art
With the development of science and technology, electronic products are required to have more functions. In order to meet the requirements of multi-functions for an electronic product, different semiconductor chips and electrical components have to be disposed on a printed circuit board of the electronic product. However, when the number of the components is desired to be increased, the volume of the electronic product has to be increased, and thus the electronic product fails to satisfy product miniaturization requirements. In order to meet the product miniaturization requirements, in general, a semiconductor chip and a micro electro mechanical system (MEMS) device may be integrated as an electronic device with the MEMS device. As a result, not only the space for accommodating the printed circuit board can be reduced for further reducing the volume of the electronic product, but also the electronic product can retain its multi-functions.
After the MEMS device and the semiconductor chip are combined, a cavity is formed between the MEMS device and the semiconductor chip, and the cavity is in a vacuum state. The electrical component (e.g., an accelerometer or a gyroscope) of the MEMS device is corresponding to the cavity in position. However, when the cavity is in a vacuum state, the electrical component may not have good performance. Because the process capability is limited, pressure in the cavity between the MEMS device and the semiconductor chip cannot be adjusted and controlled. For example, an accelerometer in a 1 atm environment has better performance than in a vacuum environment.
An aspect of the present invention is to provide an electronic device.
According to an embodiment of the present invention, an electronic device includes an image sensor and a MEMS device. The image sensor has a device layer. The MEMS device is located on the image sensor and includes a MEMS element, a cap element, and a cover layer. The MEMS element is located on the device layer, such that a first cavity is formed between the MEMS element and the image sensor. The MEMS element has plural hollow regions. The cap element is located on a surface of the MEMS element facing away from the device layer, such that a second cavity is formed between the cap element and the MEMS element. The cap element has an opening that communicates with the second cavity. The first cavity communicates with the second cavity through the hollow regions. The cover layer is located on a surface of the cap element facing away from the MEMS element and is located in the opening of the cap element.
Another aspect of the present invention is to provide a manufacturing method of an electronic device.
According to an embodiment of the present invention, a manufacturing method of an electronic device includes the following steps. A cap element is bonded to a MEMS element to form a MEMS device. The MEMS device is bonded to an image sensor, and a first cavity between the MEMS element and the image sensor communicates with a second cavity between the cap element and the MEMS element through hollow regions of the MEMS element. An opening is formed in the cap element, and the opening communicates with the second cavity. A cover layer is formed on a surface of the cap element facing away from the MEMS element and in the opening of the cap element.
In the aforementioned embodiment of the present invention, because the cap element has the opening that communicates with the second cavity and the first cavity communicates with the second cavity through the hollow regions, the first and second cavities may communicate with outside of the electronic device after the opening of the cap element is formed and before the cover layer is formed. Hence, the pressure of each of the first cavity and the second cavity is increased to about 1 atm from a vacuum state. After the cover layer is formed in the opening of the cap element, the pressure of the first cavity and the second cavity may be maintained about 1 atm. As a result, the performance for some electrical components (e.g., an accelerometer) in the cap element may be improved.
It is to be understood that both the foregoing general description and the following detailed description are by examples, and are intended to provide further explanation of the invention as claimed.
The invention can be more fully understood by reading the following detailed description of the embodiments, with reference made to the accompanying drawings as follows:
Reference will now be made in detail to the present embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.
The cap element 124 is located on a surface of the MEMS element 122 facing away from the device layer 112, such that a second cavity 134 is formed between the cap element 124 and the MEMS element 122. The first cavity 132 communicates with the second cavity 134 through the hollow regions 121 of the MEMS element 122. The cap element 124 has an opening 123 that communicates with the second cavity 134. The cover layer 126 is located on a surface of the cap element 124 facing away from the MEMS element 122 and is located in the opening 123 of the cap element 124.
In this embodiment, the cover layer 126 may be a solder mask, but the present invention is not limited in this regard. The cap element 124 may include an accelerometer, a gyroscope, or a combination thereof. For example, in
Since the cap element 124 has the opening 123 that communicates with the second cavity 134 and the first cavity 132 communicates with the second cavity 134 through the hollow regions 121 of the MEMS element 122, the first and second cavities 132, 134 may communicate with outside of the electronic device 100 after the opening 123 of the cap element 124 is formed and before the cover layer 126 is formed. Hence, the pressure of each of the first cavity 132 and the second cavity 134 is increased to about 1 atmosphere (atm) from a vacuum state. After the cover layer 126 is formed in the opening 123 of the cap element 124, the pressure of the first cavity 132 and the second cavity 134 may be maintained at about 1 atm. In this text, the term “about” may refer to a variation of 10% from an indicated value. As a result, the performance for some electrical components (e.g., an accelerometer) in the cap element 124 may be improved.
In another embodiment, after the opening 123 of the cap element 124 is formed, the pressure of the first cavity 132 and the second cavity 134 may be controlled and adjusted through the opening 123 of the cap element 124, for example, by withdrawing air out or pumping air in. After the adjustment of the pressure is completed, the cover layer 126 is formed to block the opening 123, such that the first cavity 132 and the second cavity 134 maintain an adjusted pressure. In other words, in the electronic device 100 of the present invention, designers may adjust and control the pressure of the first cavity 132 and the second cavity 134 in accordance with the type of the electrical component of the cap element 124 to improve the performance of the electrical component of the cap element 124.
The cover layer 126 in the opening 123 of the cap element 124 has a bottom surface that faces the second cavity 134. The bottom surface of the cover layer 126 may be a flat surface (as shown by a solid-line bottom surface of
In this embodiment, the cap element 124 further includes a static electricity eliminating layer 125 that is located on the surface of the cap element 124 facing away from the MEMS element 122. The static electricity eliminating layer 125 may be used for grounding to eliminate the static electricity of the electronic device 100. The static electricity eliminating layer 125 may be made of a material including an aluminum-copper alloy, but the present invention is not limited in this regard.
Furthermore, the image sensor 110 has a first bonding layer 114, and the first bonding layer 114 is located on a surface of the device layer 112 facing the MEMS element 122. The MEMS element 122 has a second bonding layer 128 that is electrically connected to the first bonding layer 114. In this embodiment, the first bonding layer 114 may be made of a material including aluminum, and the second bonding layer 128 may be made of a material including germanium, but the present invention is not limited in this regard. In addition, the MEMS device 120 may further include an isolation layer 127 that is disposed between the MEMS element 122 and the cap element 124.
Moreover, the manufacturing method of the electronic device may further include forming a static electricity eliminating layer on the surface of the cap element facing away from the MEMS element.
Through the aforementioned manufacturing method, the electronic device 100 shown in
It is noted that the connection relationships and the materials of the aforementioned elements will not be described again in the following description. In the following description, other types of electronic devices will be described.
The stop layer 131 is located in the opening 123 of the cap element 124 and has through holes 133. After the opening 123 of the cap element 124 is formed and before the cover layer 126 is formed, although the stop layer 131 is present between the second cavity 134 and the opening 123 of the cap element 124, the first cavity 132 and second cavity 134 may still communicate with outside of the electronic device 100b through the through holes 133 of the stop layer 131, such that users may adjust and control the pressure of the first and second cavities 132, 134. In addition, in this embodiment, the cover layer 126 is a solder mask. The isolation layer 129 is located on the surface of the cap element 124 facing away from the MEMS element 122, a sidewall of the cap element 124 surrounding the opening 123, and the stop layer 131. A static electricity eliminating layer 125a is located on the isolation layer 129. The static electricity eliminating layer 125a may be made of a material including an aluminum-copper alloy. The stop layer 131 may provide a supporting force to the isolation layer 129 and the static electricity eliminating layer 125a, such that the isolation layer 129 and the static electricity eliminating layer 125a may extend into the opening 123.
The manufacturing method of the electronic device 100b further includes the following steps beside steps S1-S4 of
Although the present invention has been described in considerable detail with reference to certain embodiments thereof, other embodiments are possible. Therefore, the spirit and scope of the appended claims should not be limited to the description of the embodiments contained herein.
It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention covers modifications and variations of this invention provided they fall within the scope of the following claims.
This application claims priority to U.S. provisional Application Ser. No. 62/234,465, filed Sep. 29, 2015, which is herein incorporated by reference.
| Number | Date | Country | |
|---|---|---|---|
| 62234465 | Sep 2015 | US |
