A wafer uniformity optimization method for an ICP chamber

Abstract

The application discloses a wafer uniformity optimization method for an ICP chamber, comprising the following steps: S1, continuously monitoring accumulated radio frequency time, and judging the consumption of a focusing ring through the accumulated radio frequency time; when the accumulated radio frequency time exceeds a preset radio frequency time threshold, entering step S2; S2, for different etching process parameters, changing the power of the outer coil and the inner coil of the inductive coupling coil through adjusting the power distribution of the source radio frequency, so that the edge region and the center region of the wafer obtain different plasma density distribution, and the change of the plasma sheath layer of the edge region of the wafer caused by the consumption of the focusing ring is compensated. The application can autonomously adjust the I / O power distribution set by the process menu, compensate the change of the plasma sheath layer distribution and morphology of the edge region of the wafer caused by the consumption of the focusing ring, and maintain the uniformity stability.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of ICP etching, and particularly relates to a wafer uniformity optimization method for an ICP chamber. BACKGROUND

[0002] In a semiconductor integrated circuit manufacturing process, etching is one of the most important procedures, and among them, plasma etching is one of the commonly used etching methods. Plasma etching devices for semiconductor device processing / processing mainly include capacitively coupled plasma (CCP) etching devices, inductively coupled plasma (ICP) etching devices, and electron cyclotron resonance plasma (ECR) etching devices. The ICP etching device can be used for etching and processing various metal or non-metal film layer structures, and is particularly suitable for processing / processing 300mm large-size wafers.

[0003] An ICP equipment schematic diagram is shown in Figure 1 Generally, etching occurs in a vacuum reaction chamber, an electrostatic chucking chuck is placed on a pedestal in the middle of the vacuum reaction chamber, and a wafer is located on the upper surface of the electrostatic chucking chuck. Generally, a source radio frequency is connected to a gas inlet device at the top of the device, and the high-frequency radio frequency power output by the source radio frequency power supply is used to ignite and provide plasma density; a bias radio frequency is connected to the electrostatic chucking chuck and the pedestal on which it is placed, and the low-frequency radio frequency power output by the bias radio frequency power supply is used to provide plasma energy and incident angle. Generally, a focus ring is installed around the periphery of the wafer to change the distribution and morphology of the plasma sheath in the edge region of the wafer.

[0004] However, since the focus ring is retained in the plasma filled with etching gas for a long time, the material on the upper surface of the focus ring will be consumed after a certain time of plasma processing, and the height will decrease accordingly. The decrease in the height of the focus ring will seriously affect the distribution and morphology of the plasma sheath in the edge region of the wafer, and the edge tilting phenomenon (as shown in Figure 2 ) will occur, so that the etching rate and direction of the edge region of the wafer are different from those of the central region, which reduces the uniformity of the wafer and seriously affects the yield of the chip.

[0005] In the prior art, the edge tilting can only be solved by raising the focus ring or replacing a new focus ring to improve the uniformity of the wafer. However, the focus ring lifting structure is relatively complex, and it is difficult to add this configuration design in the limited lower electrode space, which has high cost and only a few manufacturers choose to use it. In addition, the focus ring is usually made of materials such as SiC, which has a high cost, and frequent replacement of new focus rings will greatly increase the cost of the etching device, which is not a long-term solution.

[0006] The invention with publication number CN102800547A discloses a modulatable focusing ring and a method for adjusting the plasma processor using the focusing ring. The focusing ring is connected with a temperature adjusting device, and an impedance adjusting material of conductor or non-conductor is doped in the focusing ring. The temperature of the focusing ring is adjusted by the temperature adjusting device, and the impedance of the focusing ring changes with the temperature by using the characteristic that the impedance of the impedance adjusting material changes with the temperature. The impedance of the focusing ring is adjusted, so as to adjust the density distribution of the plasma on the wafer edge and the focusing ring, realize the uniformization of the density distribution of the plasma on the wafer surface, and improve the process quality of wafer etching. The invention needs to add the impedance adjusting material in the focusing ring and also needs to install the temperature adjusting device, which has high design difficulty.

[0007] The invention with publication number CN113838730A discloses a gas shielding ring, a plasma processing device and a method for adjusting polymer distribution. The gas shielding ring is used to guide the reaction gas to flow to the outer ring exhaust area of the plasma confinement ring, so as to balance the difference of the generated polymers in the center and the edge of the cavity, thereby reducing the overall morphology and absolute diameter difference of the etched sample. The invention needs to combine the gas shielding ring to guide the reaction gas, which has a complex structure.

[0008] The invention with publication number CN113496862A discloses a plasma reactor and a radio frequency power distribution adjusting method thereof. The coupling ring is used to make the radio frequency of the plasma reactor adjustable and reduce the arc discharge. The invention dynamically and precisely adjusts the radio frequency power distribution of the low frequency radio frequency power in the center and the edge area of the substrate by the coupling ring, so that more low frequency radio frequency power is delivered to the focusing ring at the edge of the substrate, thereby changing the height of the sheath layer at the focusing ring, improving the uniformity of the substrate processing process, and reducing the arc discharge phenomenon. The invention requires that the focusing ring is made of conductor material or semiconductor material, and the bottom is coated with a conductive layer. Such structure cannot be used in metal, poly and other ICP etching systems. Moreover, the invention is similar to the power distribution design of bias radio frequency, which has an impact on the structure of the electrostatic chuck, facility, filter, HV and cooling, and has a complex structure.

[0009] In view of the above problems, a new adjusting method needs to be developed to more effectively solve the edge tilting phenomenon caused by the consumption of the upper surface of the focusing ring and improve the uniformity of the wafer. SUMMARY

[0010] The technical problem solved by the application is: in view of the technical problem of poor wafer uniformity caused by the edge tilting phenomenon due to the consumption of the upper surface of the focus ring, the application provides a wafer uniformity optimization method for an ICP chamber, when the RFH exceeds the pre-set threshold, the I / O power distribution set in the process menu is automatically adjusted according to the existing RFH time length, the plasma density at the center and edge of the wafer is changed, the change of the plasma sheath distribution and morphology in the edge region of the wafer caused by the consumption of the focus ring is compensated, and the uniformity is finally maintained stable.

[0011] Technical scheme

[0012] A wafer uniformity optimization method for an ICP chamber, the chamber top of the ICP chamber is provided with a coupling window, the upper part of the coupling window is placed with an inductive coupling coil, the inductive coupling coil includes an outer coil and an inner coil, the outer coil and the inner coil are connected with a source radio frequency matcher through a power distribution box, and energy is provided by a source radio frequency power supply;

[0013] The optimization method comprises the following steps:

[0014] S1, continuously monitor the cumulative radio frequency time, judge the consumption of the focus ring through the cumulative radio frequency time, and when the cumulative radio frequency time exceeds a pre-set radio frequency time threshold, enter step S2;

[0015] S2, for different etching process parameters, the power distribution of the source radio frequency is adjusted, the power of the outer coil and the inner coil of the inductive coupling coil is changed, different plasma density distributions are obtained in the edge region and the center region of the wafer, and the change of the plasma sheath in the edge region of the wafer caused by the consumption of the focus ring is compensated.

[0016] Further, in step S1, the calculation process of the radio frequency time threshold comprises the following steps:

[0017] S11, a mathematical model between the cumulative radio frequency time and the consumption of the focus ring is constructed:

[0018] FR=RFH×k1+a;

[0019] In the formula, FR is the consumption of the focus ring, RFH is the cumulative radio frequency time, k1 and a are parameter factors, which are fitted according to the collected historical production data;

[0020] S12, the performance of wafer uniformity is numerically processed and normalized to obtain the uniformity value of the wafer, and a mathematical model between the uniformity value of the wafer and the consumption of the focus ring is constructed;

[0021] NU=FR×k2+b;

[0022] In the formula, NU is the uniformity value of the wafer; k2 and b are parameter factors, which are fitted according to the collected historical production data;

[0023] S13, two mathematical models are integrated to obtain:

[0024] RFH = [(NU-b) / k2-a] / k1;

[0025] S14, according to the limit value NU of the wafer uniformity * The RF time threshold value RFH is calculated * .

[0026] Further, in step S2, for different etching process parameters, by adjusting the power distribution of the source radio frequency, the power of the outer coil and the inner coil of the inductive coupling coil is changed, so that the wafer edge region and the center region obtain different plasma density distribution, and the process of compensating the change of the plasma sheath of the wafer edge region caused by the consumption of the focusing ring includes the following steps:

[0027] S21, the power distribution setting value of the source radio frequency is X and Y, X and Y are positive integers, X represents the capacitance value of the inner coil, Y represents the capacitance value of the outer coil, and the sum of X and Y is a certain value;

[0028] S22, a mathematical model between the cumulative radio frequency time and the wafer uniformity is constructed:

[0029] NU1 = (RFH×k1+a)×k2+b

[0030] In the formula, NU1 is the uniformity of the wafer under the same power distribution setting value, RFH is the cumulative radio frequency time; k1, k2, a, and b are parameter factors, which are fitted according to the collected historical production data;

[0031] S23, a mathematical model between the power distribution setting value of the source radio frequency and the wafer uniformity is constructed:

[0032] NU2 = X 2 ×c-X×d+e

[0033] In the formula, NU2 is the uniformity value of the wafer in the similar radio frequency time; X is the power distribution setting value of the source radio frequency; c, d, and e are parameter factors, which are fitted according to the collected historical production data;

[0034] S24, according to the preset period ΔRFH, the change amount ΔNU1 of NU1 is calculated:

[0035] ΔNU1 = (ΔRFH×k1+a)×k2+b

[0036] Let the change amount of NU2 in the same period be ΔNU2, and a mathematical model between ΔNU1 and ΔNU2 is constructed:

[0037] ΔNU2-(ΔNU1×k3+f)=0

[0038] The conversion is obtained as:

[0039] ΔNU2=ΔNU1×k3+f

[0040] In the formula, k3, f are parameter factors, which are fitted according to the collected historical production data;

[0041] S25, ΔNU2 obtained by conversion is substituted into the mathematical model between the power distribution setting value of the source radio frequency and the wafer uniformity, and the following is obtained:

[0042]

[0043] In the formula, is the performance value of wafer uniformity before compensation;

[0044] Two solutions X1 and X2 are calculated, and the integer values [X1] and [X2] are obtained; for different etching processes, [X1] or [X2] is automatically selected and used by the system.

[0045] Further, the fixed value is 180.

[0046] Further, the optimization method comprises the following steps:

[0047] The uniformity of the wafer is monitored regularly, a curve graph of uniformity changing with time is drawn, and the optimization effect is evaluated.

[0048] The application also relates to an ICP chamber, which comprises a vacuum reaction chamber, an electrostatic chuck, a protection ring, a focusing ring, a coupling window, an inductive coupling coil, a power distribution box, a source radio frequency matcher, a source radio frequency power supply and a processor.

[0049] The electrostatic chuck is placed on the middle base of the vacuum reaction chamber, the protection ring is arranged on the side of the electrostatic chuck, and the edge of the electrostatic chuck is provided with the focusing ring.

[0050] The top of the vacuum reaction chamber is provided with the coupling window, the inductive coupling coil is arranged on the upper part of the coupling window, the inductive coupling coil is divided into an outer coil and an inner coil, and the outer coil and the inner coil are connected with the source radio frequency matcher through the power distribution box; and the source radio frequency power supply provides energy.

[0051] The processor continuously monitors the accumulated radio frequency time, determines the consumption of the focus ring through the accumulated radio frequency time, and when the accumulated radio frequency time exceeds a preset radio frequency time threshold, the processor adjusts the power distribution of the source radio frequency, changes the power of the outer coil and the inner coil of the inductive coupling coil, so that the edge region and the center region of the wafer obtain different plasma density distributions, and compensate for the change of the plasma sheath layer of the edge region of the wafer caused by the consumption of the focus ring.

[0052] Further, the calculation process of the radio frequency time threshold comprises the following steps:

[0053] S11, a mathematical model between the accumulated radio frequency time and the consumption of the focus ring is constructed:

[0054] FR=RFH×k1+a;

[0055] In the formula, FR is the consumption of the focus ring; RFH is the accumulated radio frequency time; k1 and a are parameter factors, which are fitted according to the collected historical production data;

[0056] S12, the performance of wafer uniformity is numerically processed and normalized to obtain a wafer uniformity value, and a mathematical model between the wafer uniformity value and the consumption of the focus ring is constructed;

[0057] NU=FR×k2+b;

[0058] In the formula, NU is the wafer uniformity value; k2 and b are parameter factors, which are fitted according to the collected historical production data;

[0059] S13, two mathematical models are integrated to obtain:

[0060] RFH= [(NU-b) / k2-a] / k1;

[0061] S14, according to the limit value NU of wafer uniformity * The radio frequency time threshold RFH is calculated * .

[0062] Further, for different etching process parameters, the power distribution of the source radio frequency is adjusted, the power of the outer coil and the inner coil of the inductive coupling coil is changed, so that the edge region and the center region of the wafer obtain different plasma density distributions, and the change of the plasma sheath layer of the edge region of the wafer caused by the consumption of the focus ring is compensated.

[0063] S21, the power distribution setting value of the source radio frequency is X and Y, X and Y are positive integers, X represents the capacitance value of the inner coil, Y represents the capacitance value of the outer coil, and the sum of X and Y is a certain value;

[0064] S22, a mathematical model between the cumulative radio frequency time and the wafer uniformity is constructed:

[0065] NU1=(RFH×k1+a)×k2+b

[0066] In the formula, NU1 is the wafer uniformity under the same power distribution setting value, RFH is the cumulative radio frequency time; k1, k2, a, b are parameter factors, which are obtained by fitting the collected historical production data;

[0067] S23, a mathematical model between the power distribution setting value of the source radio frequency and the wafer uniformity is constructed:

[0068] NU2=X 2 ×c-X×d+e

[0069] In the formula, NU2 is the wafer uniformity in the similar radio frequency time; X is the power distribution setting value of the source radio frequency; c, d, e are parameter factors, which are obtained by fitting the collected historical production data;

[0070] S24, the change amount ΔNU1 of NU1 is calculated according to the preset period ΔRFH:

[0071] ΔNU1=(ΔRFH×k1+a)×k2+b

[0072] Let the change amount of NU2 in the same period be ΔNU2, and a mathematical model between ΔNU1 and ΔNU2 is constructed:

[0073] ΔNU2-(ΔNU1×k3+f)=0

[0074] It is converted to:

[0075] ΔNU2=ΔNU1×k3+f

[0076] In the formula, k3, f are parameter factors, which are obtained by fitting the collected historical production data;

[0077] S25, the converted ΔNU2 is substituted into the mathematical model between the power distribution setting value of the source radio frequency and the wafer uniformity, and the following is obtained:

[0078]

[0079] In the formula, is the performance value of the wafer uniformity before compensation;

[0080] Two solutions X1 and X2 are calculated, and [X1] and [X2] are obtained by rounding; for different etching processes, [X1] or [X2] is automatically selected and used by the system.

[0081] Further, the fixed value is 180.

[0082] The present application also relates to an ICP apparatus comprising the ICP chamber as described above.

[0083] Advantages:

[0084] The wafer uniformity optimization method for the ICP chamber of the present application, when the RFH exceeds the preset threshold, adjusts the I / O power distribution set by the process menu according to the existing RFH duration, changes the plasma density at the center and edge of the wafer, compensates for the changes in the plasma sheath distribution and morphology at the edge region of the wafer caused by the consumption of the focus ring, and finally maintains the stability of the uniformity. BRIEF DESCRIPTION OF DRAWINGS

[0085] Figure 1 It is a schematic diagram of the existing ICP equipment;

[0086] Figure 2 It is a schematic diagram of the edge tilting phenomenon;

[0087] Figure 3 It is a structural diagram of the inductively coupled coil of the embodiment of the present application;

[0088] Figure 4 It is a schematic diagram of the running logic of Process I / O Tuning;

[0089] Figure 5 It is a schematic diagram of the relationship between the radio frequency time and the focus ring consumption;

[0090] Figure 6 It is a schematic diagram of the relationship between the focus ring consumption and the uniformity;

[0091] Figure 7 It is a schematic diagram of the relationship between the inner and outer coil power distribution and the uniformity;

[0092] Figure 8 It is a schematic diagram of the uniformity comparison results before and after the application of Process I / O Tuning. DETAILED DESCRIPTION

[0093] The following examples enable those skilled in the art to more fully understand the present application, but in no way limit the present application.

[0094] The embodiment of the present application relates to a wafer uniformity optimization method for an ICP chamber, the chamber top of the ICP chamber is provided with a coupling window, the upper part of the coupling window is placed with an inductively coupled coil, the inductively coupled coil comprises an outer coil and an inner coil, the outer coil and the inner coil are connected with a source radio frequency matcher through a power distribution box, and energy is provided by a source radio frequency power supply.

[0095] The optimization method comprises the following steps:

[0096] S1, continuously monitor the cumulative radio frequency time, and determine the consumption of the focus ring through the cumulative radio frequency time; when the cumulative radio frequency time exceeds a pre-set radio frequency time threshold, step S2 is entered.

[0097] S2, for different etching process parameters, the power distribution of the source radio frequency is adjusted, the power of the outer coil and the inner coil of the inductive coupling coil is changed, so that the edge region and the center region of the wafer obtain different plasma density distribution, and the change of the plasma sheath layer of the edge region of the wafer caused by the consumption of the focus ring is compensated.

[0098] In this embodiment, the power distribution of the source radio frequency is adjusted, the power of the inner and outer inductive coils is changed, the edge and the center obtain different plasma density, the change of the plasma sheath layer of the edge region of the wafer caused by the consumption of the focus ring is compensated, the edge tilting phenomenon is improved, and the overall uniformity is improved. The adjustment amount of the power distribution of the source radio frequency is determined according to the radio frequency time (RFH) length of the focus ring in the chamber, and the compensation is dynamically adjusted to maintain the uniformity stability for a long time.

[0099] The structure diagram of the ICP device with an inductive coupling coil of the present application is shown in Figure 3 The middle base of the vacuum reaction chamber 10 is provided with an electrostatic chuck 20, the side of the electrostatic chuck 20 is provided with a protection ring 30, the edge of the electrostatic chuck 20 is provided with a focus ring 40, the top of the chamber is provided with a coupling window 50, the upper part of the coupling window 50 is provided with an inductive coupling coil 100, the inductive coupling coil 100 is divided into an outer coil 110 and an inner coil 120, the inner and outer coils are connected with a source radio frequency matcher 220 through a power distribution box 230, and energy is provided by a source radio frequency power supply 210. The wafer uniformity optimization method for the ICP chamber disclosed in the present application can be integrated into a function (Process I / O Tuning), which is run in the background through software. The running logic of the function is shown in Figure 4 .

[0100] The function (Process I / O Tuning) for improving uniformity disclosed in the present application judges the degree of consumption of the focus ring through continuous monitoring of the radio frequency time (RFH), which is the starting condition for enabling the function. When it is found that the RFH exceeds the pre-set threshold, the function starts to be enabled. According to the existing RFH length, the I / O power distribution set in the process menu is automatically adjusted according to the pre-set algorithm, the plasma density of the center and the edge of the wafer is changed, the change of the plasma sheath distribution and morphology of the edge region of the wafer caused by the consumption of the focus ring is compensated, and the uniformity stability is finally maintained.

[0101] The function of improving uniformity (Process I / O Tuning) disclosed in the present application is supported by a large amount of experimental data. According to the following three rules, the optimal uniformity performance is maintained by self-adjustment according to the actual situation.

[0102] (1) The radio frequency time is proportional to the consumption of the focus ring, and the rule is summarized as shown in Figure 5 .

[0103] (2) The consumption of the focus ring is proportional to the performance of the uniformity, and the uniformity continues to deteriorate in the process of being consumed, as shown in Figure 6 .

[0104] (3) The power distribution of the inner and outer inductively coupled coils and the performance of the uniformity form a "V" type distribution, and the optimal uniformity performance is shown under the optimal power distribution parameters, as shown in Figure 7 .

[0105] Exemplarily, in step S1, the calculation process of the radio frequency time threshold value includes the following steps:

[0106] S11, a mathematical model between the cumulative radio frequency time and the consumption of the focus ring is constructed:

[0107] FR=RFH×k1+a;

[0108] In the formula, FR is the consumption of the focus ring; RFH is the cumulative radio frequency time; k1 and a are parameter factors, which are fitted according to the collected historical production data.

[0109] S12, the performance of the wafer uniformity is numerically processed and normalized to obtain the wafer uniformity value, and a mathematical model between the wafer uniformity value and the consumption of the focus ring is constructed:

[0110] NU=FR×k2+b;

[0111] In the formula, NU is the wafer uniformity value; k2 and b are parameter factors, which are fitted according to the collected historical production data.

[0112] S13, two mathematical models are integrated to obtain:

[0113] RFH= [(NU-b) / k2-a] / k1;

[0114] S14, according to the limit value NU * of the wafer uniformity, the radio frequency time threshold value RFH * is calculated.

[0115] In step S2, for different etching process parameters, by adjusting the power distribution of the source radio frequency, the power of the outer coil and the inner coil of the inductive coupling coil is changed, so that the wafer edge region and the center region obtain different plasma density distribution, and the process of compensating the change of the plasma sheath of the wafer edge region caused by the consumption of the focusing ring includes the following steps:

[0116] S21, set the power distribution setting value of the source radio frequency as X and Y, X and Y are positive integers, X represents the capacitance value of the inner coil, and Y represents the capacitance value of the outer coil, since the total capacitance value of the source radio frequency is unchanged, the sum of X and Y is certain. For example, the certain value is 180, that is, X+Y=180. At this time, the power distribution setting value of the source radio frequency can also be written as: X / (180-X).

[0117] S22, a mathematical model between cumulative radio frequency time and wafer uniformity is constructed:

[0118] NU1=(RFH×k1+a)×k2+b

[0119] In the formula, NU1 is the uniformity of the wafer under the same power distribution setting value, RFH is the cumulative radio frequency time; k1, k2, a, b are parameter factors, which are fitted according to the collected historical production data;

[0120] S23, a mathematical model between the power distribution setting value of the source radio frequency and the wafer uniformity is constructed:

[0121] NU2=X 2 ×c-X×d+e

[0122] In the formula, NU2 is the uniformity of the wafer in the similar radio frequency time; X is the power distribution setting value of the source radio frequency; c, d, e are parameter factors, which are fitted according to the collected historical production data;

[0123] S24, according to the preset period ΔRFH, the uniformity of the wafer is compensated once. The compensation process is:

[0124] The change amount ΔNU1 of NU1 is calculated:

[0125] ΔNU1=(ΔRFH×k1+a)×k2+b.

[0126] Let the change amount of NU2 in the same period be ΔNU2, in order to compensate ΔNU1, NU2 is required to change, and a mathematical model between ΔNU1 and ΔNU2 is constructed:

[0127] ΔNU2-(ΔNU1×k3+f)=0.

[0128] Transformed as:

[0129] ΔNU2 = ΔNU1 * k3 + f;

[0130] In the formula, k3 and f are parameter factors, which are fitted according to the collected historical production data;

[0131] S25, the converted ΔNU2 is substituted into the mathematical model between the power distribution setting value of the source radio frequency and the wafer uniformity to obtain:

[0132]

[0133] In the formula, is the performance value of the wafer uniformity before compensation, which is recorded by the system and can be checked and corrected by relevant personnel;

[0134] Two solutions X1 and X2 are calculated, and [X1] and [X2] are obtained by rounding. For different etching processes, [X1] or [X2] is automatically selected for use, and relevant personnel can check and correct it.

[0135] Through testing, in an application example, the uniformity is improved by 0.5%, as shown in Figure 8 .

[0136] The optimization method used in this embodiment is continuously optimized according to the continuous expansion of the collected data. Optimization methods with the same idea but different algorithms are also within the protection scope of this patent. The present application can be applied to the etching process of various metal or non-metal film layers, and each process corresponds to different adjustment parameters and algorithms, which will not be described here.

Claims

1. A method for wafer uniformity optimization for an ICP chamber, the method comprising: The ICP chamber has a coupling window at the top, and an inductive coupling coil is placed on the upper part of the coupling window. The inductive coupling coil includes an outer coil and an inner coil. The outer coil and the inner coil are connected to the source RF matching unit through a power distribution box and are powered by the source RF power supply. The optimization method includes the following steps: S1: Continuously monitor the cumulative radio frequency time and determine the consumption of the focusing ring based on the cumulative radio frequency time; when the cumulative radio frequency time exceeds the preset radio frequency time threshold, proceed to step S2. S2, for different etching process parameters, by adjusting the power distribution of the source radio frequency, the power of the outer coil and inner coil of the inductive coupling coil is changed, so that the edge region and the center region of the wafer obtain different plasma density distributions, compensating for the changes in the plasma sheath layer in the edge region of the wafer caused by the consumption of the focusing ring; In step S1, the calculation process of the radio frequency time threshold includes the following steps: S11, Construct a mathematical model relating the cumulative RF time to the consumption of the focusing ring: FR=RFH×k1+a; In the formula, FR is the consumption of the focusing ring; RFH is the cumulative radio frequency time; k1 and a are parameter factors, which are obtained by fitting based on the collected historical production data; S12, the performance of wafer uniformity is numericalized and normalized to obtain the wafer uniformity value, and a mathematical model is constructed between the wafer uniformity value and the consumption of the focusing ring. NU = FR × k² + b; In the formula, NU is the uniformity value of the wafer; k2 and b are parameter factors, which are obtained by fitting based on the collected historical production data; S13, combining the two mathematical models, we get: RFH = [(NU-b) / k2-a] / k1; S14, according to the limit value NU of wafer uniformity * The radio frequency time threshold RFH is calculated * .

2. The wafer uniformity optimization method for an ICP chamber of claim 1, wherein, In step S2, for different etching process parameters, the power distribution of the source radio frequency is adjusted to change the power of the outer and inner coils of the inductive coupling coil, so that the edge and center regions of the wafer obtain different plasma density distributions. The process of compensating for the change in the plasma sheath layer in the wafer edge region caused by the consumption of the focusing ring includes the following steps: S21, set the power distribution of the source radio frequency to X and Y, where X and Y are both positive integers, X represents the capacitance value of the inner coil, Y represents the capacitance value of the outer coil, and the sum of X and Y is a fixed value; S22, Construct a mathematical model between cumulative RF time and wafer uniformity: NU1=(RFH×k1+a)×k2+b In the formula, NU1 is the uniformity of the wafer under the same power allocation setting, RFH is the cumulative radio frequency time, and k1, k2, a, and b are parameter factors that are fitted based on the collected historical production data. S23, Construct a mathematical model between the power allocation settings of the source RF and wafer uniformity: NU2 = X 2 ×c - Xxd + e In the formula, NU2 is the uniform value of the wafer within a similar radio frequency time; X is the source radio frequency power allocation setting value; c, d, and e are parameter factors, which are obtained by fitting based on the collected historical production data; S24, according to the preset period ΔRFH, calculate the change ΔNU1 of NU1: ΔNU1=(ΔRFH×k1+a)×k2+b Let the change amount of NU2 in the same period be ΔNU2, and a mathematical model between ΔNU1 and ΔNU2 is constructed: ΔNU2-(ΔNU1×k3+f)=0 After conversion, it is obtained as: ΔNU2=ΔNU1×k3+f In the formula, k3 and f are parameter factors, which are fitted according to the collected historical production data; S25, ΔNU2 obtained by conversion is substituted into the mathematical model between the power distribution setting value of the source radio frequency and the wafer uniformity, and the following is obtained: In the formula, is the value representing the uniformity of the wafer before compensation; Two solutions X1 and X2 are calculated, and the integer values of X1 and X2 are obtained: [X1] and [X2]; for different etching processes, [X1] or [X2] is automatically selected and used by the system.

3. The wafer uniformity optimization method for an ICP chamber of claim 2, wherein, The fixed value is 180.

4. The wafer uniformity optimization method for an ICP chamber of claim 1, wherein, The optimization method comprises the following steps: The uniformity of the wafer is monitored regularly, a curve of the uniformity changing with time is drawn, and the optimization effect is evaluated.

5. An ICP chamber, comprising: The ICP chamber comprises a vacuum reaction chamber, an electrostatic chuck, a protection ring, a focusing ring, a coupling window, an inductive coupling coil, a power distribution box, a source radio frequency matching device, a source radio frequency power supply and a processor; The electrostatic chuck is placed on the middle base of the vacuum reaction chamber, the protection ring is arranged on the side of the electrostatic chuck, and the focusing ring is placed on the edge of the electrostatic chuck; The top of the vacuum reaction chamber is provided with the coupling window, the inductive coupling coil is placed on the upper part of the coupling window, the inductive coupling coil is divided into an outer coil and an inner coil, and the outer coil and the inner coil are connected with the source radio frequency matching device through the power distribution box and are provided with energy by the source radio frequency power supply; The processor continuously monitors the cumulative radio frequency time, and judges the consumption amount of the focusing ring through the cumulative radio frequency time; When the cumulative radio frequency time exceeds the pre-set radio frequency time threshold value, the processor adjusts the power distribution of the source radio frequency, changes the power of the outer coil and the inner coil of the inductive coupling coil, so that the edge region and the center region of the wafer obtain different plasma density distributions, and the change of the plasma sheath layer of the edge region of the wafer caused by the consumption of the focusing ring is compensated; The calculation process of the radio frequency time threshold value comprises the following steps: S11, a mathematical model between the cumulative radio frequency time and the consumption amount of the focusing ring is constructed: FR=RFH×k1+a; In the formula, FR is the consumption amount of the focusing ring; RFH is the cumulative radio frequency time; k1 and a are parameter factors, which are fitted according to the collected historical production data; S12, the performance of the wafer uniformity is numerically processed and normalized to obtain the uniformity value of the wafer, and a mathematical model between the uniformity value of the wafer and the consumption amount of the focusing ring is constructed; NU=FR×k2+b; In the formula, NU is the uniformity value of the wafer; k2 and b are parameter factors, which are fitted according to the collected historical production data; S13, two mathematical models are integrated to obtain: RFH= [(NU-b) / k2-a] / k1; S14, according to the limit value NU of wafer uniformity * The radio frequency time threshold RFH is calculated * .

6. The ICP chamber of claim 5, wherein, For different etching process parameters, by adjusting the power distribution of the source radio frequency, changing the power of the outer coil and the inner coil of the inductive coupling coil, the edge region and the center region of the wafer obtain different plasma density distribution, the process of compensating the change of the plasma sheath of the edge region of the wafer caused by the consumption of the focusing ring includes the following steps: S21, set the power distribution of the source radio frequency to X and Y, X and Y are positive integers, X represents the capacitance value of the inner coil, Y represents the capacitance value of the outer coil, and the sum of X and Y is a certain value; S22, construct a mathematical model between the cumulative radio frequency time and the wafer uniformity: NU1=(RFH×k1+a)×k2+b In the formula, NU1 is the uniformity of the wafer under the same power distribution setting value, RFH is the cumulative radio frequency time; k1, k2, a and b are parameter factors, which are obtained by fitting the collected historical production data; S23, construct a mathematical model between the power distribution setting value of the source radio frequency and the wafer uniformity: NU2 = X 2 x c - x d + e In the formula, NU2 is the uniformity of the wafer in the similar radio frequency time; X is the power distribution setting value of the source radio frequency; c, d and e are parameter factors, which are obtained by fitting the collected historical production data; S24, according to the preset period ΔRFH, the change amount ΔNU1 of NU1 is calculated: ΔNU1=(ΔRFH×k1+a)×k2+b Let the change amount of NU2 in the same period be ΔNU2, and construct a mathematical model between ΔNU1 and ΔNU2: ΔNU2-(ΔNU1×k3+f)=0 After transformation, it is obtained that: ΔNU2=ΔNU1×k3+f In the formula, k3 and f are parameter factors, which are obtained by fitting the collected historical production data; S25, substitute the converted ΔNU2 into the mathematical model between the power distribution setting value of the source radio frequency and the wafer uniformity, to obtain: In the formula, is the value representing the uniformity of the wafer before compensation; Two solutions X1 and X2 are calculated, and the integer part of X1 and X2 is obtained: [X1] and [X2]; for different etching processes, the system automatically selects to use [X1] or [X2].

7. The ICP chamber of claim 6, wherein, The fixed value is 180.

8. An ICP apparatus, characterized by, The ICP equipment includes the ICP chamber of claim 5. The ICP equipment includes the ICP chamber of claim 5.

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