Preparation method of N-trap high-voltage gate driving chip for directly driving power device

Abstract

The invention discloses a preparation method of an N-trap high-voltage gate driving chip for directly driving a power device. A high-voltage side driving control module and a low-voltage side driving control module are separated through a way of directly injecting N-type impurities on a polished silicon wafer, through a trap pushing way and by adopting a high-pressure junction isolation technology; and a capacitive voltage divider is formed by utilizing two layers of polysilicons by forming an RESURF (Reducing Surface Electric Field) area on a PN (Positive Negative) junction surface on the basis of PN junction isolation of the conventional CMOS (Complementary Metal Oxide Semiconductor) tube technology, the electric field distribution on the PN junction surface is effectively changed, the high-voltage isolation of a high-voltage LDMOS (Laterally Diffused Metal Oxide Semiconductor) tube is formed, and a high-voltage N-type LDMOS tube is prepared and obtained by forming a P-BODY area. Compared with the conventional LDMOS tube, the voltage resistance requirement with the voltage being more than 700V can be achieved by adding an RESURF area structure and a double-layer polysilicon capacitance structure; and simultaneously, the working procedure of the preparation method is simple and compact, the cost is lower, and a high-voltage gate driving circuit device which is used for directly driving the power device can be formed by only 14 structural layers.

Description

technical field [0001] The invention relates to a preparation process of a semiconductor chip, in particular to a preparation method of an N-well high-voltage gate drive chip used to directly drive a power device. Background technique [0002] High-voltage gate drive chips are also called power integrated circuits (PIC, POWER INTERGARTED CIRCUIT), which is the product of the combination of power electronic device technology and microelectronic technology, and is a key component of mechatronics. High-voltage grid driver chips have a wide range of applications, such as electronic ballasts, motor drives, dimming, inverter circuits, various power modules, and so on. [0003] The power module is made by integrating the power device and its drive circuit, protection circuit, interface circuit and other peripheral circuits on one or several chips. As the application of power modules becomes more and more extensive, power modules gradually develop from simple trigger functions to m...

AI Technical Summary

Problems solved by technology

In the high-voltage gate drive chip, the low-voltage side drive control module works under the normal voltage as the control signal part; the high-voltage side drive control module mainly includes the high-voltage control signal part, which controls the high-voltage side gate signal; and the level shift module considers the The low-voltage side control signal is transmitted to the high-voltage side control area. Therefore, when implementing these functions, the following three aspects are mainly considered: one is the isolation of the high-voltage side drive control module and the low-voltage side drive control module. From the perspective of process technology, High-voltage isolation technology is mainly divided into three types: PN junction isolation, dielectric isolation and self-isolation. The self-isolation process is the simplest, but the leakage current is large; the cost of dielectric isolation is high, the process is complicated, and it is difficult to realize; the advantage of PN junction isolation technology is that the process is simple. , low cost, so in the conventional CMOS process, most of the PN junction isolation technology is used, but according to the basic principle of PN junction breakdown, the voltage breakdown point is generally not at the planar junction, but occurs on the surface of the junction, so that the PN junction advances Breakdown, resulting in failure to meet the design requirements, resulting in the inability to achieve a high voltage of hundreds of volts or even tens of volts in the conventional CMOS process; the second is to realize the high-voltage device (ie, LDMOS tube) of the high-voltage side drive control module, which requires On the basis of conventional CMOS device technology, N-type LDMOS devices are formed by increasing the RESURF region (that is, the reduced surface electric field region) and the P-BODY region; the third is to use N-well technology on polished silicon wafers to achieve the required high withstand voltage

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