EP-4411784-B1 - SEMICONDUCTOR PROCESS DEVICE AND IMPEDANCE MATCHING METHOD THEREFOR

EP4411784B1EP 4411784 B1EP4411784 B1EP 4411784B1EP-4411784-B1

Inventors

LI, WENQING
WEI, GANG
YANG, JING
JIANG, Shuqi
ZHANG, DI

Dates

Publication Date: 20260506
Application Date: 20220928

Claims (10)

An impedance matching method applied to semiconductor processing equipment comprising: a processing preparation step (S102) including obtaining currently stored impedance-matching data corresponding to a processing ignition step, the impedance-matching data including a parameter adjustment position corresponding to a parameter adjustable device in an impedance-matching device of the semiconductor processing equipment, and adjusting the parameter adjustable device based on the parameter adjustment position, wherein for a semiconductor processing that is performed multiple times, the currently stored impedance-matching data is a value that is updated multiple times; and the processing ignition step (S104) including applying radio frequency (RF) power to a processing chamber of the semiconductor processing equipment through the impedance-matching device, performing impedance matching through the impedance-matching device, and determining a current parameter adjustment position of the parameter adjustable device when impedance is matched, and updating the impedance-matching data based on the current parameter adjustment position.
The method according to claim 1, wherein an operation mode of the impedance-matching device includes an automatic matching mode and a non-automatic matching mode; in the processing preparation step (S102), the impedance-matching device is set to the non-automatic matching mode; and in the processing ignition step (104), the impedance-matching device is set to the automatic matching mode.
The method according to claim 1, wherein the parameter adjustment position includes a first parameter adjustment position, a parameter correction value, and a second parameter adjustment position, wherein the second parameter adjustment position is a sum of the first parameter adjustment position and the parameter correction value; and adjusting the parameter adjustable device based on the parameter adjustment positions includes: adjusting the parameter adjustable device based on the second parameter adjustment position.
The method according to claim 3, wherein updating the impedance-matching data based on the current parameter adjustment position includes: updating the first parameter adjustment position based on the current parameter adjustment position; and updating the second parameter adjustment position based on the updated first parameter adjustment position and the parameter correction value.
The method according to claim 3 or 4, wherein the parameter adjustment position further includes a predetermined parameter matching value; the second parameter adjustment position is a sum of the first parameter adjustment position, the predetermined parameter matching value, and the parameter correction value; after adjusting the parameter adjustable device according to the second parameter adjustment position, impedance matching information of the impedance-matching device satisfies a predetermined condition; the impedance matching information includes at least one of a total impedance matching time length, or a difference in impedance matching time lengths corresponding to processing ignition steps; and the predetermined condition includes at least one of the total impedance matching time length being shortest, or the difference in the impedance matching time lengths corresponding to the processing ignition steps being minimum.
The method according to claim 5, further comprising: determining a plurality of to-be-filtered parameter matching values corresponding to the parameter adjustable device; adjusting the parameter adjustment position of the parameter adjustable device according to the second parameter adjustment position corresponding to the plurality of to-be-filtered parameter matching values; each time after adjusting the parameter adjustment position of the parameter adjustable device, performing ignition once and determining the impedance matching time lengths corresponding to the to-be-filtered parameter matching values; and determining a to-be-filtered parameter matching value corresponding to the impedance matching time length that meets the predetermined condition as the predetermined parameter matching value according to the plurality of impedance matching time lengths.
The method according to claim 1, wherein the parameter adjustable device includes an adjustable capacitor and/or an adjustable inductor.
A semiconductor processing equipment comprising a radio frequency (RF) power source (310), an impedance-matching device (320), and a processing chamber (330), wherein: the RF power source (310) is configured to apply RF power to the processing chamber (330) of the semiconductor processing equipment through the impedance-matching device (320); and the impedance-matching device (320) includes a controller (321) and a parameter adjustable device (322), the controller (321) being configured to, in a processing preparation step, obtain currently stored impedance-matching data corresponding to a processing ignition step, the impedance-matching data including a parameter adjustment position corresponding to the parameter adjustable device (322) in the impedance-matching device (320) of the semiconductor processing equipment, adjust the parameter adjustable device (322) based on the parameter adjustment position, wherein for a semiconductor processing that is performed multiple times, the currently stored impedance-matching data is a value that is updated multiple times, and in a processing ignition step, when applying the RF power to the processing chamber (330) of the semiconductor processing equipment through the impedance-matching device (320), adjust the parameter adjustable device (322) to achieve impedance matching, determine a current parameter adjustment position of the parameter adjustable device (322) when impedance is matched, and update the impedance-matching data based on the current parameter adjustment position.
The semiconductor processing equipment according to claim 8, wherein an operation mode of the impedance-matching device (320) includes an automatic matching mode and a non-automatic matching mode; the controller (321) is further configured to, in the processing preparation step, set the impedance-matching device (320) to the non-automatic matching mode, and in the processing ignition step, set the impedance-matching device (320) to the automatic matching mode.
The semiconductor processing equipment according to claim 8, wherein the parameter adjustment position includes a first parameter adjustment position, a parameter correction value, and a second parameter adjustment position, wherein the second parameter adjustment position is a sum of the first parameter adjustment position and the parameter correction value; and the controller (321) is further configured to adjust the parameter-adjustable device (322) based on the second parameter adjustment position.

Description

TECHNICAL FIELD The present disclosure generally relates to the semiconductor technology field and, more particularly, to semiconductor processing equipment and an impedance-matching method. BACKGROUND The inductive-coupled plasma source is applied in etching, thin film deposition, and ion injection doping of the manufacturing field of semiconductor process equipment. The plasma reaction chamber includes an inductive coupling coil and an electrostatic chuck. In the etching field, the main principle of the inductive-coupled plasma source is as follows. RF current flows through the inductive coupling coil to generate an electromagnetic field inside the reaction chamber. The electromagnetic field excites the gas introduced into the reaction chamber to generate plasma. A bias voltage source controls the energy of ion bombardment to accelerate the plasma to reach the wafer and realize etching. The wafer is fixed on the electrostatic chuck by electrostatic adsorption. In a typical radio frequency (RF) discharge plasma generation system, an output impedance of the RF power source is generally 50 ohms, while an equivalent impedance of the plasma reaction chamber is generally not 50 ohms. Moreover, under different processing conditions, the equivalent impedance of the plasma reaction chamber varies. According to the transmission line theory, when the output impedance of the RF power source is different from the load impedance (i.e., the equivalent impedance of the plasma reaction chamber), loss occurs in the RF power source output power, and the output efficiency cannot reach the maximum. Thus, energy is wasted, damage can be made to the RF power source, and even safety problems such as fire caused by local excessive heat can be caused. Additionally, since the value of the load impedance is related to the processing conditions for generating the plasma, in a process of using the inductively coupled plasma source, an impedance-matching device configured to automatically adjust the load impedance needs to be arranged between the RF power source and the plasma reaction chamber. The impedance-matching device can control and change the actual value of a parameter adjustable device (such as an adjustable capacitor) through a sensor and a control system inside the impedance-matching device according to the actual impedance of the plasma reaction chamber under different processing conditions. Thus, the load impedance is adjusted to 50 ohms to realize the impedance matching to avoid the above problems. The existing impedance-matching device typically works as follows. The sensor inside the impedance-matching device monitors the current impedance value of the circuit in real-time. When the energy from the RF power source is transmitted to the impedance-matching device, the impedance-matching device controls the capacitance value of the adjustable capacitor under a preset algorithm in the impedance-matching device according to the current impedance value and phase provided by the sensor in real-time. Thus, the impedance value of the impedance-matching device and the plasma reaction chamber can be adjusted to 50 ohms to realize the impedance matching. With this operation manner, the impedance matching can be closely related to the initial capacitance value of the adjustable capacitor. If the initial capacitance value of the adjustable capacitor is not set appropriately, the impedance matching may not be realized, and the impedance matching efficiency can be low. Moreover, since internal consumable devices in the plasma reaction chamber gradually wear out during use, the impedance value can change continuously under the same processing condition. Thus, when the initial capacitance value of the adjustable capacitor is fixed, the impedance-matching process can gradually be inconsistent, which causes the impedance-matching efficiency to be lower and lower. Known existing impedance matching systems and methods are disclosed in CN 112 259 433 A, KR 102 240 306 B1, US 2017/345621 A1 and US 5 982 099 A. SUMMARY The purpose of the present disclosure is to provide semiconductor processing equipment and an impedance-matching method to solve the problem of low impedance-matching efficiency in the existing semiconductor processing process. Therefore, according to the invention, there is provided an impedance matching method according to claim 1 and a semiconductor processing equipment according to claim 8. Preferred other inventive embodiments are disclosed in the dependent claims. To solve the above technical problem, embodiments of the present disclosure can be implemented as follows. On an aspect, embodiments of the present disclosure provide an impedance-matching method applied to semiconductor processing equipment. The method includes: a processing preparation step including obtaining currently stored impedance-matching data corresponding to a processing ignition step, the impedance-matching data including a parameter adjustment positi