1. Field of Invention
The present invention relates to a semiconductor structure and a method for manufacturing the same. More particularly, the present invention relates to a semiconductor structure having high voltage devices, a low voltage device and a middle voltage device arranged on the same chip and a method for manufacturing the same.
2. Description of Related Art
With the development of the new semiconductor manufacturing technology, the system-on-chip which is a single chip possesses many functions attracts a great attention. The driver of the thin film transistor (TFT) crystal display or color supper twisted nematic (CSTN) crystal display generally possesses three kinds of integrated circuits including a signal processor, a gate driver and a source driver. Furthermore, these integrated circuits are located in different chips.
With the decreasing of the product size, the size of the chip is decreased to meet the product specification. Generally, the low voltage device and the middle voltage device are arranged on the same chip. Meanwhile, the high voltage device is located on another chip to decrease the number of the chips in the product so that the low voltage device and the middle voltage device can be prevented from being affected by the intensive electric field generated while the high voltage device is operated.
However, with the enhancing of the power of the product, the number of the chips in the product is increased. Therefore, how to decrease the number of the chips in the product without affecting the functionality of the product becomes the main study task nowadays.
Accordingly, at least one objective of the present invention is to provide a system-on-chip semiconductor structure capable of decreasing the size of the semiconductor device.
At least another objective of the present invention is to provide a system-on-chip semiconductor structure capable of arranging high voltage devices, a middle voltage device and a low voltage device at the same chip.
At least the other objective of the present invention is to provide a method for manufacturing a system-on-chip semiconductor structure capable of forming high voltage devices, a middle voltage device and a low voltage device at the same chip.
To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, the invention provides a system-on-chip semiconductor structure. The system-on-chip semiconductor structure comprises a substrate, a low voltage device, a middle voltage device, at least one high voltage device and a plurality of isolation structures. The substrate has a low voltage circuit region and a high voltage circuit region. The low voltage device is located on the low voltage circuit region of the substrate. The middle voltage device is located on the low voltage circuit region of the substrate. The high voltage device is located on the high voltage circuit region of the substrate. The isolation structures are located in the substrate for isolating the low voltage device, the middle voltage device and the high voltage device from each other.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, an operation voltage of the aforementioned low voltage device is about 0˜3.3 voltage.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, an operation voltage of the aforementioned middle voltage device is about 3.3˜20 voltage.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, an operation voltage of the aforementioned high voltage device is larger than 20 voltages.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, the aforementioned isolation structures include shallow trench isolations.
The present invention further provides a system-on-chip semiconductor structure. The system-on-chip semiconductor structure comprises a substrate, a low voltage device, a middle voltage device, a first high voltage device and a plurality of isolation structures. The substrate has a first conductive type, wherein the substrate comprises a low voltage circuit region, a high voltage circuit region and a first well region with the first conductive type. The low voltage device is located on the low circuit region of the substrate. The middle voltage device is located on the low circuit region of the substrate. The first high voltage device having a second conductive type is located on the high circuit region of the substrate, wherein the high voltage device comprises s first metal-oxide semiconductor transistor with the second conductive type, a deep isolation well region with the second conductive type and an isolation well region with the first conductive type. The first metal-oxide semiconductor transistor is located on the substrate. The deep isolation well region is located in a portion of the substrate under the first metal-oxide semiconductor transistor and the isolation well region is located under the first metal-oxide semiconductor transistor and in the deep isolation well region. The isolation structures are located in the substrate for isolating the low voltage circuit, the middle voltage circuit and the first high voltage device from each other.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, the depth of the aforementioned deep isolation well region is larger than the depth of the aforementioned first well region and larger than the depth of the aforementioned isolation well region.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, the depth of the aforementioned isolation well region is as same as the depth of the aforementioned first well region.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, the system-on-chip semiconductor structure further comprises a second high voltage device with the second conductive type located on the high voltage circuit of the substrate.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, the aforementioned second high voltage device includes a second metal-oxide semiconductor transistor with the second conductive type located on the aforementioned first well region.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, an operation voltage of the second high voltage device is larger than 20 voltages.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, the system-on-chip semiconductor structure further comprises a third high voltage device with the first conductive type located on the substrate.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, the third high voltage device comprises a third metal-oxide semiconductor transistor with the first conductive type and a second well region with the second conductive type. The third metal-oxide semiconductor transistor is located on the substrate and the second well region is located under the third metal-oxide semiconductor transistor in the substrate.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, the depth of the second well region is smaller than the depth of the deep isolation region.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, the depth of the second well region is as same as the depth of the first well region.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, an operation voltage of the third high voltage device is larger than 20 voltages.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, the low voltage device and the middle voltage device respectively comprise a complementary metal-oxide semiconductor transistor and a deep well region with the second conductive type. The complementary metal-oxide semiconductor transistor is located on the substrate and the deep well region is located in the substrate under the complementary metal-oxide semiconductor transistor.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, the depth of the deep well region is smaller than the deep isolation well region.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, the depth of the deep well region is as same as the depth of the first well region.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, an operation voltage of the low voltage device is about 0˜3.3 voltage.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, an operation voltage of the middle voltage device is about 3.3˜20 voltage.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, an operation voltage of the first high voltage device is larger than 20 voltages.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, the isolation structures include shallow trench isolations.
The present invention also provides a method for manufacturing a system-on-chip semiconductor structure. The method comprises steps of providing a substrate having a first conductive type, wherein the substrate possesses a low voltage circuit region and a high voltage circuit region. A plurality of isolation structures are formed in the substrate. A first well region having the first conductive type is formed in the substrate. A plurality of high voltage devices are formed on a portion of the substrate between the isolation structures in the high voltage circuit region. A low voltage device and a middle voltage device are formed on a portion of the substrate between the isolation structures in the low voltage circuit region.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, the high voltage devices include a first high voltage device with a second conductive type, a second high voltage device with the second conductive type and a third high voltage device with the first conductive type.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, the method for forming the first high voltage device comprises steps of forming a deep isolation well region having the second conductive type in the substrate, wherein a portion of the first well region is located in the deep isolation well region. Then, a first metal-oxide semiconductor transistor having the second conductive type is formed on the substrate above the deep isolation well region.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, the depth of the deep isolation well region is larger than the depth of the first well region.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, the method for forming the second high voltage device comprises a step of forming a second metal-oxide semiconductor transistor having the second conductive type on the substrate above the first well region.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, the method for forming the third high voltage device comprises steps of forming a second well region having the second conductive type in the substrate and then forming a third metal-oxide semiconductor transistor having the first conductive type on the substrate above the second well region.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, the depth of the second well region is as same as the depth of the first well region.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, the method for forming the low voltage device and the middle voltage device comprises steps of forming a deep well region having the second conductive type in the substrate and then forming a complementary metal-oxide semiconductor transistor on the substrate above the deep well region.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, the depth of the deep well region is as same as the depth of the first well region.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, an operation voltage of the low voltage device is about 0˜3.3 voltage.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, an operation voltage of the middle voltage device is about 3.3˜20 voltage.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, an operation voltage of the high voltage device is larger than 20 voltages.
According to the system-on-chip semiconductor structure described in one embodiment of the present invention, the isolation structures include shallow trench isolations.
In the present invention, the high voltage devices, the middle voltage device and the low voltage device are all arranged in the same chip so that the product size is decreased and the number of the semiconductor devices arranged in a single product can be increased. Hence, the product can possess multiple functions. Furthermore, in the high voltage circuit region of the system-on-chip semiconductor structure, the deep isolation well region with the conductive type different from that of the substrate is used to isolate the high voltage devices from the substrate. Therefore, the high voltage devices can be prevented from being interfered from the substrate. In addition, in the low voltage circuit region of the system-on-chip semiconductor structure, the deep well region with the conductive type different from that of the substrate is used to isolate the low voltage device and the middle voltage device from the high voltage devices. Hence, the low voltage device and the middle voltage can be prevented from being interfered by the intensive electric field generated by the high voltage devices.
It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the invention as claimed.
The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention.
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It should be noticed that, in the present embodiment, the deep isolation well region 108 having the conductive type different from that of the substrate is used to isolate the high voltage device 14 from the substrate 100 so as to prevent the high voltage device 14 from being interfered by the substrate 100. Also, the deep isolation well region 108 can be used as a level shift. Furthermore, the deep isolation well region 106 isolates the high voltage device 14 from other devices in the high voltage circuit region 103 so that the high voltage device 14 can be independently operated.
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It should be noticed that all the high voltage devices 14,16 and 18 can be FDMOS so that the high voltage devices can be operated over 40 voltage without being damaged. Furthermore, the high voltage devices can be used for processing the signals of the gate driver. Additionally, in the embodiment, the positions of the high voltage devices 14, 16 and 18 in the high voltage circuit region 103 can be varied with the demands of the products and are not limited to the configuration shown in the present embodiment.
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It should be noticed that the deep well regions 112 and 118 are located in the substrate 100 under the MOS transistors 10a and 12a respectively. Therefore, the low voltage device 10 and the middle voltage device 12 are individually independent and the low voltage device 10 and the middle voltage device 12 are free from the interference of the high voltage device. Moreover, in the present embodiment, the low voltage device 10 can be used to operate the logic operation in the memory under 2.5 voltage and the middle voltage device 12 can be used to process the signals of the source driver.
It should be noticed that, in the present invention, the high voltage devices, the low voltage device and the middle voltage device are located at the same chip so as to decrease the space occupied by the chip and to decrease the size of the product. Therefore, the configuration of the high voltage devices in the high voltage circuit region can be adjusted with the demands of the products and is not limited to the configuration shown in the present embodiment.
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In this embodiment, the method for forming the high voltage device 24 comprises a step of forming a MOS transistor 24a with the second conductive type on the substrate 200 after the deep isolation well region 206 is formed around the well region 204. The method for forming the high voltage device 26 comprises a step of forming a MOS transistor 26a with the second conductive type on the substrate 200 over the well region 204. The method for forming the high voltage device 28 comprises a step of forming a MOS transistor 28a with the first conductive type on the substrate 200 over the well region 210 after the well region 210 is formed in the substrate 200. The method for forming the low voltage device 20 and the middle voltage device 22 can, for example, comprise a step forming a complementary MOS transistors 20a and 22a on the substrate over the deep well region 212 after the deep well region 212 is formed in the substrate 200. Notably, the depth of the deep isolation well region 206 in the substrate 200 is larger than the depth of each of the well regions 204 and 210 and the deep well regions 212 and 214.
Altogether, in the present invention, the high voltage devices, the middle voltage device and the low voltage device are all arranged in the same system on chip so that the number of the chips in a single product can be decreased and the space occupied by the chips in a single product can be decreased as well. Accordingly, the size of the product is decreased and the number of the semiconductor devices equipped in a single product is increased. Hence, the product can possess multiple functions. Furthermore, in the high voltage circuit region of the system-on-chip semiconductor structure of the present invention, the deep isolation well region with the conductive type different from that of the substrate is used to isolate the high voltage devices from the substrate. Therefore, the high voltage devices can be prevented from being interfered from the substrate. In addition, in the low voltage circuit region of the system-on-chip semiconductor structure, the deep well region with the conductive type different from that of the substrate is used to isolate the low voltage device and the middle voltage device from the high voltage devices. Hence, the low voltage device and the middle voltage can be prevented from being interfered by the intensive electric field generated by the high voltage devices.
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 descriptions, it is intended that the present invention covers modifications and variations of this invention if they fall within the scope of the following claims and their equivalents.