Inner matching capacitance and manufacturing method of rfldmos device

Abstract

The invention discloses an internal matching capacitor of an RFLDMOS device. The internal matching capacitor is an MIM capacitor, the lower plate is connected to the back metal through a plurality of through-silicon holes, the upper plate is led out from the front, and the lower electrode of the MIM capacitor is realized through the back metal. The matching connection between the plate and the drain of the RFLDMOS device, the matching connection between the above-mentioned upper plate of the MIM capacitor and the gate of the RFLDMOS device is realized through the front metal, so that the MIM capacitor and the RFLDMOS device form an internal matching structure. The invention also discloses a manufacturing method of the internal matching capacitance of the RFLDMOS device. The internal matching capacitor of the present invention is realized by using MIM capacitors, which can greatly reduce the parasitic series resistance of the internal matching capacitor, improve the quality factor of the matching capacitor, reduce energy loss under radio frequency, and enable the package of the RFLDMOS device to obtain better output and input resistance and Get better power efficiency.

Description

technical field [0001] The invention relates to the field of manufacturing semiconductor integrated circuits, in particular to an internal matching capacitor applied to a radio frequency laterally diffused metal oxide semiconductor (RFLDMOS) device; the invention also relates to a method for manufacturing the internal matching capacitor of the RFLDMOS device. Background technique [0002] In the RFLDMOS package, in order to be suitable for the RF power amplifier of the 50 ohm impedance system, it is necessary to perform capacitance matching on the input gate terminal and the output drain terminal of the RFLDMOS device to obtain a suitable input and output impedance. Since it is used in the vicinity of 1GHz and higher frequencies, and is suitable for high power applications, the quality factor of the matching capacitor is extremely important. A poor quality factor will seriously affect the working efficiency of the device, increase the loss of power supply energy, and thus in...

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Problems solved by technology

It can be seen from the above that the upper and lower plates of the existing MIM capacitor are all formed on the front side of the silicon substrate, and since the drain of the RFLDMOS device is formed on the back side of the silicon substrate, and the gate is formed on the front side of the silicon substrate, when using the existing When MIM capacitors and RFLDMOS devices are matched and connected, one plate of the MIM capacitor needs to be directly welded to the package flange, so the existing MIM capacitors are not suitable for the application scenario of RFLDMOS device internal matching.

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