TWI702665B - Method and device for cleaning semiconductor substrate - Google Patents

Abstract

A method for cleaning a semiconductor substrate using an ultrasonic or megasonic device without damaging the patterned structure on the semiconductor substrate includes: spraying liquid into the gap between the semiconductor substrate and the ultrasonic or megasonic device; setting the ultrasonic or megasonic device The frequency of the sonic power supply is f ₁ , and the power is P ₁ to drive the ultrasonic or megasonic device; before the cavity oscillation in the liquid damages the patterned structure on the semiconductor substrate, the output of the ultrasonic or megasonic power supply is set to zero; After the temperature in the bubble drops to the set temperature, set the frequency of the ultrasonic or megasonic power supply to f ₁ and the power to P _{1 again} ; the detection frequency is f ₁ and the power-on time and power-off time when the power is P ₁ or ultrasonic detection or megabytes of the output waveform amplitude of each sound wave power; the detected conduction time and the predetermined time T ₁ are compared, or the detected power-off time and the predetermined time T ₂ by comparing each of the detected or and the preset value of the waveform amplitude comparing; shape if the amplitude of any wavelength of the detected conduction time longer than _a predetermined time T, the detected power-off time or shorter than the predetermined time T _2, or the ratio of the pre-detected If the value is large, the ultrasonic or megasonic power supply will be turned off and an alarm signal will be issued.

Description

Method and device for cleaning semiconductor substrate

The present invention relates to a method and device for cleaning a semiconductor substrate, in particular to controlling the cavitation oscillation generated by an ultrasonic or megasonic device during the cleaning process to obtain stable or controllable cavitation oscillation on the entire substrate, effectively removing particles, Without damaging the device structure on the substrate.

Semiconductor devices are made by forming transistors and interconnections on a semiconductor substrate through a series of different processing steps. Recently, the establishment of transistors has changed from two to three dimensions, such as fin-type field effect transistors. In order to electrically connect the transistor terminal and the semiconductor substrate, conductive (for example, metal) grooves, holes, and other similar structures must be made on the dielectric material of the semiconductor substrate as a part of the device. Slots and holes can transmit electrical signals and energy between transistors, internal circuits, and external circuits.

In order to form a fin-type field effect transistor and an interconnect structure on a semiconductor substrate, the semiconductor substrate needs to go through multiple steps, such as masking, etching and deposition, to form the required electronic circuits. In particular, the multi-layer mask and plasma etching steps can form fin-type field effect transistors and/or patterns of recessed areas in the dielectric layer of the semiconductor substrate as the fins of the transistors and/or the grooves and through holes of the interconnection structure . In order to remove the etching or photoresist ashing process Particles and contamination generated in the fin structure and/or grooves and through holes must be wet cleaned. In particular, when the device manufacturing node is constantly approaching or smaller than 14 or 16 nm, the sidewall loss of fins and/or grooves and vias is the key to maintaining critical dimensions. In order to reduce or eliminate sidewall loss, it is important to use mild, diluted chemicals, or sometimes only deionized water. However, diluted chemical reagents or deionized water generally cannot effectively remove particles in the fin structure and/or grooves and through holes. Therefore, mechanical force is required to effectively remove these particles, such as ultrasonic waves or megasonic waves. Ultrasonic waves or megasonic waves can generate cavitation oscillations to provide mechanical force to the substrate structure. These violent cavitation oscillations such as unstable cavitation oscillations or micro-jets will damage these patterned structures. Maintaining stable or controllable cavitation oscillation is a key parameter to control the limit of mechanical damage and effectively remove particles.

In US Patent No. 4,326,553, it is mentioned that megasonic energy can be combined with nozzles to clean semiconductor substrates. The fluid is pressurized, and megasonic energy is applied to the fluid through the megasonic sensor. A nozzle with a specific shape ejects a liquid like a ribbon, which vibrates at a megasonic frequency on the surface of the substrate.

In US Patent No. 6,039,059, it is mentioned that an energy source transmits sound wave energy into the fluid by vibrating an elongated probe. In one example, the fluid is sprayed on both sides of the substrate, and a probe is placed close to the upper surface of the substrate. In another example, the end of a short probe is placed close to the surface of the substrate. During the rotation of the substrate, the probe moves on the surface of the substrate.

In US Patent No. 6,843,257 B2, it is mentioned that an energy source causes a rod to vibrate about an axis parallel to the surface of the substrate. The surface of the rod is Etched into curvilinear dendrites, such as spiral grooves.

In order to effectively remove particles without damaging the device structure on the substrate, a good method is needed to control the cavitation oscillation generated by the ultrasonic or megasonic device during the cleaning process to obtain stable or controllable air on the entire substrate. Cavitation.

The present invention proposes a method to achieve no damage to the patterned structure on the substrate by maintaining stable air cavity oscillation when cleaning the substrate using ultrasonic or megasonic waves. Stable cavitation is provided an acoustic wave oscillation is controlled by the power supply time interval is less than the internal strength ratio T ₁ P _1, is provided at the acoustic power is greater than the time interval T ₂ internal strength ratio P _2, repeating the above steps until the substrate is cleaned, wherein The power P ₂ is equal to 0 or far less than the power P ₁ , T ₁ is the time interval for the temperature in the bubble to rise to the critical implosion temperature, and T ₂ is the time interval for the temperature in the bubble to drop far below the critical implosion temperature.

The present invention proposes another method of using ultrasonic or megasonic waves to clean the substrate by maintaining stable air cavity oscillation to achieve no damage to the patterned structure on the substrate. The stable cavitation oscillation is controlled by setting the frequency of the sonic power supply to f ₁ in the time interval less than T ₁ and setting the frequency of the sonic power supply to f ₂ in the time interval greater than T _2. Repeat the above steps until the substrate is cleaned, where, f _{2 is} much larger than f ₁ , preferably 2 or 4 times of f _1. T ₁ is the time interval for the temperature in the bubble to rise to the critical implosion temperature, and T ₂ is the temperature in the bubble to drop far below the critical temperature The time interval of explosion temperature.

The present invention also proposes a method of using ultrasonic or megasonic waves to clean the substrate by maintaining stable air cavity oscillation to achieve no damage to the patterned structure on the substrate, and the size of the bubbles is smaller than the spacing between the patterned structures. Stable bubble having a size smaller than the spacing between the patterned structure disposed cavitation oscillation controlled acoustic power in the time interval T ₁ is less than the internal strength ratio P _1, is provided at the acoustic power is greater than the time interval T ₂ internal strength ratio P _2, repeat The above steps until the substrate is cleaned, wherein the power P ₂ is equal to 0 or much less than the power P ₁ , T ₁ is the time interval for the bubble size to increase to the critical size, the critical size is equal to or greater than the patterned structure pitch, T ₂ is the size of the bubbles is reduced to much less than the value of the time spacing intervals between patterned structure.

The present invention also proposes a method of using ultrasonic or megasonic waves to clean the substrate by maintaining stable air cavity oscillation to achieve no damage to the patterned structure on the substrate, and the size of the bubbles is smaller than the spacing between the patterned structures. Stable bubble having a size smaller than the spacing between the patterned structure disposed cavitation oscillation controlled acoustic power in the time interval T ₁ is less than the frequency f _1, is provided at the acoustic power within the time interval T ₂ is greater than the frequency F ₂ is repeated The above steps until the substrate is cleaned, where f _{2 is} much greater than f ₁ , preferably 2 or 4 times of f _1. T ₁ is the time interval for the bubble size to increase to the critical size, and the critical size is equal to or Greater than the spacing between the patterned structures, T ₂ is the time interval for the size of the bubble to decrease to a value much smaller than the spacing between the patterned structures.

The present invention also proposes a method for maintaining stable cavity oscillation by detecting the working state of the ultrasonic or megasonic power when cleaning the substrate using ultrasonic or megasonic waves, so as to achieve no damage to the patterned structure on the substrate. The method includes the following steps: injecting liquid into the gap between the semiconductor substrate and the ultrasonic or megasonic device; setting the frequency of the ultrasonic or megasonic power source to f ₁ and the power to P ₁ to drive the ultrasonic or megasonic device; Before cavitation in the liquid damages the patterned structure on the semiconductor substrate, set the output of the ultrasonic or megasonic power supply to zero; after the temperature in the bubble drops to the set temperature, set the frequency of the ultrasonic or megasonic power supply to f again _1, power is P _1; detect frequency f _1, P is the power-on time and the power off time is _1; F ₁ is the frequency, the power P ₁ is the power-on time is detected and _a predetermined time T comparing, if the detected conduction time is longer than the predetermined time T _1, the ultrasonic or megasonic power off and an alarm signal; detected power-off time and the predetermined time T ₂ for comparison, if the detected broken power down time is shorter than the predetermined time T _2, is closed and ultrasonic or megasonic power alarm signal; repeating the above steps until the semiconductor substrate is cleaned.

The present invention also proposes a method for maintaining stable cavity oscillation by detecting the working state of the ultrasonic or megasonic power when cleaning the substrate using ultrasonic or megasonic waves, so as to achieve no damage to the patterned structure on the substrate. The method includes the following steps: injecting liquid into the gap between the semiconductor substrate and the ultrasonic or megasonic device; setting the frequency of the ultrasonic or megasonic power source to f1 and the power to P1 to drive the ultrasonic or megasonic device; in the liquid Before the cavitation oscillation damages the patterned structure on the semiconductor substrate, set the output of the ultrasonic or megasonic power supply to zero; after the temperature in the bubble drops to the set temperature, set the frequency of the ultrasonic or megasonic power supply to f1 and the power again P1; detect the amplitude of each waveform output by the ultrasonic or megasonic power supply; compare the amplitude of each detected waveform with the preset value, if the amplitude of any detected waveform is greater than the preset value, turn off the ultrasonic Or megasonic power supply and send out an alarm signal, where the preset value is greater than the waveform amplitude during normal operation; repeat the above steps until the semiconductor substrate is cleaned.

1003‧‧‧Ultrasonic device (megasonic device)

1004‧‧‧Sensor

1008‧‧‧Resonator

1010‧‧‧wafer

1012‧‧‧Nozzle

1014‧‧‧wafer chuck

1016‧‧‧Rotating drive device

1032‧‧‧Flowing liquid (deionized water)

2003‧‧‧Ultrasonic device (megasonic device, acoustic wave sensor)

2010‧‧‧wafer

2080‧‧‧Host

2082‧‧‧Sonic power supply

2086‧‧‧Detection System

2088‧‧‧Communication cable

2190‧‧‧Voltage attenuation circuit

2192‧‧‧Shaping Circuit

2194‧‧‧Main Controller

2196‧‧‧Communication circuit

2198‧‧‧Power circuit

2290‧‧‧Voltage attenuation circuit

2292‧‧‧Vibration detection circuit

2294‧‧‧Main Controller

2296‧‧‧Communication circuit

2298‧‧‧Power circuit

3052‧‧‧Bubble

4010‧‧‧Semiconductor wafer

4034‧‧‧Fine structure

6080‧‧‧Micro jet

6082‧‧‧Bubble

15010‧‧‧wafer

15034‧‧‧Pattern structure

15046‧‧‧Bubble

15048‧‧‧Bubble

16010‧‧‧wafer

16014‧‧‧wafer chuck

16016‧‧‧Rotating drive device

16060‧‧‧Deionized water

16062‧‧‧Ultrasonic device (megasonic device)

16064‧‧‧Nozzle

17010‧‧‧wafer

17017‧‧‧wafer

17070‧‧‧Cleaning liquid chemical reagent

17072‧‧‧Ultrasonic device (megasonic device)

17074‧‧‧Solution tank

17076‧‧‧wafer box

23102‧‧‧Operational amplifier

23104‧‧‧Operational amplifier

24102‧‧‧Window comparator

24104‧‧‧door

25102‧‧‧Pulse Conversion Module

25104‧‧‧Period measurement module

27114‧‧‧Window comparator

27116‧‧‧door

27118‧‧‧D/A converter

Figures 1A-1B are exemplary embodiments of a wafer cleaning device using ultrasonic or megasonic devices; Figures 2A-2G are various shapes of ultrasonic or megasonic sensors; Figure 3 is cavitation oscillation during wafer cleaning Figures 4A-4B show the patterned structure on the wafer damaged by the unstable cavitation oscillation during the cleaning process; Figures 5A-5C show the changes in the internal thermal energy of the bubbles during the cleaning process; Figure 6A-6C shows the wafer cleaning method 7A-7C is another exemplary embodiment of a wafer cleaning method; FIGS. 8A-8D are still another exemplary embodiment of a wafer cleaning method; FIGS. 9A-9D are another exemplary embodiment of a wafer cleaning method An exemplary embodiment; FIGS. 10A-10B are still another exemplary embodiment of the wafer cleaning method; FIGS. 11A-11B are still another exemplary embodiment of the wafer cleaning method; FIGS. 12A-12B are the wafer cleaning method Yet another exemplary embodiment; FIGS. 13A-13B are another exemplary embodiment of a wafer cleaning method; FIGS. 14A-14B are still another exemplary embodiment of a wafer cleaning method; FIGS. 15A-15C are in the cleaning process Stable air cavity oscillation damages the patterned structure on the wafer; FIG. 16 is another exemplary embodiment of a wafer cleaning device using an ultrasonic or megasonic device; FIG. 17 is an embodiment of a wafer cleaning device using an ultrasonic or megasonic device; FIG. 18A-18C is a wafer cleaning method Another exemplary embodiment; FIG. 19 is another exemplary embodiment of a wafer cleaning method; FIG. 20 is an exemplary embodiment of a control system for monitoring the working state of an acoustic wave power supply; FIG. 21 is a detection system for monitoring the working state of an acoustic wave power supply 22 is another exemplary embodiment of the detection system for monitoring the working state of the acoustic wave power supply; FIGS. 23A-23C are exemplary embodiments of the voltage attenuation circuit for monitoring the working state of the acoustic wave power supply; FIGS. 24A-24C are An exemplary embodiment of a shaping circuit for monitoring the working state of the acoustic wave power supply; FIGS. 25A-25C are exemplary embodiments of a main controller for monitoring the working state of the acoustic wave power supply; 27A-27C are exemplary embodiments of an amplitude detection circuit for monitoring the working state of the acoustic wave power supply.

Figures 1A-1B illustrate a wafer cleaning device using ultrasonic or megasonic devices. The wafer cleaning device includes a wafer 1010, a wafer chuck 1014 driven and rotated by a rotating drive device 1016, a nozzle 1012 spraying cleaning liquid chemicals or deionized water 1032, an ultrasonic or megasonic device 1003, and an ultrasonic or megasonic power supply . The ultrasonic or megasonic device 1003 further includes a piezoelectric sensor 1004 and an acoustic resonator 1008 paired therewith. The sensor 1004 vibrates after being energized, and the resonator 1008 transfers high-frequency acoustic energy into the liquid. The cavitation oscillation generated by ultrasonic or megasonic energy loosens the particles on the surface of the wafer 1010, so that the contaminants are detached from the surface of the wafer 1010 and then removed from the surface of the wafer through the flowing liquid 1032 provided by the shower head 1012.

Figures 2A-2G illustrate top views of the ultrasonic or megasonic device of the present invention. The ultrasonic or megasonic device 1003 shown in FIGS. 1A-1B can be replaced by an ultrasonic or megasonic device 2003 of different shapes, such as a triangle or pie shape as shown in FIG. 2A, a rectangle as shown in FIG. 2B, and as shown in FIG. 2C The octagon, the ellipse shown in Figure 2D, the semicircle shown in Figure 2E, the quarter circle shown in Figure 2F, and the circle shown in Figure 2G.

Figure 3 illustrates cavitation oscillations during compression. The shape of the bubble 3052 is gradually compressed from the spherical shape A to the apple shape G, and finally the bubble 3052 reaches the implosion state I and forms a microjet. As shown in FIGS. 4A and 4B, micro-jetting is very violent (can reach thousands of atmospheres and thousands of degrees Celsius), which can damage the fine structure 4034 on the semiconductor wafer 4010, especially when the feature size is reduced to 70 nm and less.

Figures 5A-5C illustrate simplified models of cavitation oscillations of the present invention. When the positive pressure of sound waves acts on the bubble, the bubble reduces its volume. In the volume reduction process, the acoustic pressure P _M is the bubble work, mechanical work converted to heat inside of the bubble, and therefore, the gas inside the bubble and / or increasing the temperature of the steam.

The ideal gas equation can be expressed as follows: p ₀ v ₀ /T ₀ =pv/T (1)

Among them, P ₀ is the pressure inside the bubble before compression, V ₀ is the initial volume of the bubble before compression, T ₀ is the gas temperature inside the bubble before compression, P is the pressure inside the bubble under pressure, and V is the pressure inside the bubble. Volume, T is the gas temperature inside the bubble under pressure.

In order to simplify the calculation, it is assumed that the temperature of the gas does not change when the compression or compression is very slow. Since the liquid surrounds the bubbles, the temperature increase can be ignored. Thus, a bubble process (unit amount N from the volume to a volume of 1 unit or a compression ratio of the amount of N), the sound pressure P _M doing mechanical work W _m can be expressed as follows Compression:

Among them, S is the area of the cylinder section, x ₀ is the length of the cylinder, and p ₀ is the pressure of the gas in the cylinder before compression. Equation (2) does not consider the temperature increase in the compression process. Therefore, due to the increase in temperature, the actual pressure in the bubble will be higher. In fact, the mechanical work done by the sound pressure is greater than the value calculated by Equation (2).

Assuming that the mechanical work done by sound pressure is partly converted into heat energy and partly converted into the mechanical energy of the high-pressure gas and steam in the bubble. This heat energy completely promotes the increase in the temperature of the gas inside the bubble (no energy is transferred to the liquid molecules around the bubble). The gas quality in the bubble remains unchanged. After the bubble is compressed once, the temperature increase △T can be expressed by the following equation: △T=Q/(mc)=βw _m /(mc)=βSx ₀ p ₀ ln(x ₀ )/ (mc) (3)

Among them, Q is the thermal energy converted from mechanical work, β is the ratio of thermal energy to the total mechanical work done by sound pressure, m is the gas mass in the bubble, and c is the specific heat coefficient of the gas. Set β=0.65, S=1E-12 m ² , x ₀ =1000 麱m=1E-3 m (compression ratio N=1000), p ₀ =1 kg/cm ² =1E4 kg/m ² , the mass of hydrogen m=8.9E-17 kg, c=9.9E3 J/(kg ⁰ k) is substituted into equation (3), then △T=50.9 ⁰ C.

The gas temperature T ₁ in the bubble after one compression can be calculated: T ₁ =T ₀ +△T=20 ⁰ C+50.9 ⁰ C=70.9 ⁰ C (4)

When the bubble reaches a minimum of 1 micron, as shown in Figure 5B. At such a high temperature, the liquid around the bubbles evaporates, then the sound pressure becomes negative and the bubbles start to increase. In this reverse process, the hot gas and steam with pressure P _G will do work on the surrounding liquid surface. Meanwhile, the sound pressure P _M stretching bubble toward the direction of expansion, shown in Figure 5C. Therefore, the negative sound pressure _PM also does some work on the surrounding liquid. By the combined action of thermal energy inside the bubble can not release all or converted into mechanical energy, thus the temperature of the gas inside the bubble can not be reduced to the initial temperature T ₀ of the gas or liquid temperature. As shown in FIG. 6B, after the first period of cavitation oscillation is completed, the gas temperature T ₂ in the bubble will be between T ₀ and T ₁ . T ₂ can be expressed as follows: T ₂ =T1-δT=T ₀ +△T-δT (5)

Among them, δT is the temperature decrease after the bubble expands once, and δT is less than ΔT.

When the second period of cavitation oscillation reaches the minimum bubble size, the temperature T3 of the gas or vapor in the bubble is: T3=T2+△T=T ₀ +△T-δT+△T=T ₀ +2△T-δT ( 6)

When the second cycle of cavitation oscillation is completed, the temperature T4 of the gas or vapor in the bubble is: T4=T3-δT=T ₀ +2△T-δT-δT=T ₀ +2△T-2δT (7)

Similarly, when the nth cycle of cavitation oscillation reaches the minimum bubble size, the temperature T _2n-1 of the gas or steam in the bubble is: T _2n-1 =T ₀ +n△T-(n-1)δT (8)

When the nth cycle of cavitation oscillation is completed, the temperature T _2n of the gas or vapor in the bubble is: T _2n = T ₀ +n△T-nδT=T ₀ +n(△T-δT) (9)

As the number n of cavitation oscillation cycles increases, the temperature of the gas and steam will also increase, so more and more molecules on the surface of the bubble evaporate into the bubble 6082, and the bubble 6082 will also become larger, as shown in FIG. 6C. Finally, the temperature of the compressed gas bubbles within the implosion process will reach a temperature T _i (T _i temperature implosion typically up to several thousand degrees Celsius) to form a heavy microprojection 6080, shown in Figure 6C.

According to formula (8), the number of implosion cycles n _i can be expressed as follows: n _i =(T _i -T ₀ -△T)/(△T-δT)+1 (10)

According to formula (10), the implosion time T _i can be expressed as follows: T _i =n _i t ₁ =t ₁ ((T _i -T ₀ -△T)/(△T-δT)+1) =n _i / f ₁ =((T _i -T ₀ -△T)/(△T-δT)+1)/f ₁ (11)

Among them, t ₁ is the cycle period, and f ₁ is the frequency of ultrasonic or megasonic waves.

According to formulas (10) and (11), the number of implosion cycles n _i and the implosion time T _i can be calculated. Table 1 is an implosion period n _i, implosion time T _i and the (△ T-δT) relationship, assuming ^{Ti = 3000 0 C, △ T} = 50.9 0 C, T 0 = 20 0 C, f 1 = 500 KHz, f ₁ =1 MHz, and f ₁ = 2 MHz.

In order to avoid damage to the patterned structure on the wafer, it is necessary to maintain stable cavitation oscillation to avoid bubble implosion and micro-jetting. FIGS. 7A-7C show the patterned structure on the wafer without damaging the patterned structure by maintaining stable air cavity oscillation when cleaning the wafer with ultrasonic or megasonic waves according to the present invention. Fig. 7A is the output waveform of the power supply; Fig. 7B is the temperature curve corresponding to each cavitation oscillation period; Fig. 7C is the expansion size of the bubble corresponding to each cavitation oscillation period. The operation process steps of the present invention to avoid bubble implosion are as follows:

Step 1: Place the ultrasonic or megasonic device near the surface of the wafer or substrate set on the chuck or solution tank;

Step 2: Fill the space between the wafer and the ultrasonic or megasonic device with chemical liquid or water mixed with gas (hydrogen, nitrogen, oxygen or carbon dioxide);

Step 3: Spin the chuck or vibrate the wafer;

Step 4: Set the power supply frequency to f ₁ and power to P ₁ ;

Step 5: Before the gas or steam temperature in the bubble reaches the implosion temperature T _i (or the time reaches T _.1躿 T _i , T _i is calculated by formula (11)), set the output power of the power supply to 0 watts, so Since the temperature of the liquid or water is much lower than the temperature of the gas, the temperature of the gas inside the bubble begins to drop.

Step 6: After the gas temperature in the bubble is reduced to normal temperature T ₀ or the time (time of zero power) reaches T ₂ , set the power supply frequency to f ₁ and power to P _{1 again} ;

Step 7: Repeat step 1 to step 6 until the wafer is cleaned.

Step 5, in order to prevent the bubble burst, the time T ₁ must be less than T _i, T _i can be calculated by the formula (II).

In step 6, the temperature of the gas in the bubble does not have to be cooled to the normal temperature or the temperature of the liquid. It can be a specific temperature higher than the normal temperature or the temperature of the liquid, but it is better to be much lower than the implosion temperature T _i .

According to formulas 8 and 9, if (△T-δT) is known, T _i can be calculated. But generally speaking, (△T-δT) is not easy to be calculated or obtained directly. The following steps can be used to obtain the implosion time T _i through experiments.

Step 1: Based on Table 1, select five different times T ₁ as the experimental settings (DOE) conditions;

Step 2: Choose a time T ₂ that is at least ten times T ₁ , preferably 100 times T ₁ in the first test.

Step 3: Use the determined power P _{0 to} run the above five conditions to clean the wafers with the patterned structure respectively. Here, P ₀ is the power determined to cause damage to the patterned structure of the wafer in a continuous uninterrupted mode (non-pulse mode).

Step 4: Use the inspection instrument SEMS or the wafer pattern damage viewing tool to check the damage degree of the above five types of wafers, such as SEMVision or Hitachi IS3000 of applied materials, and then the implosion time T _i can be determined in a certain range.

Repeat steps 1 through 4 to narrow down the time T _i of implosion. Know implosion time T _i, T value of less than 0.5T _i may be set as the safety _factor. The following is an example to describe the experimental data: the patterned structure is a 55nm polysilicon grid line, the frequency of ultrasonic or megasonic wave is 1MHZ, the ultrasonic or megasonic device manufactured by Prosys is used, and the gap oscillation mode is adopted (disclosed in PCT/CN2008/073471) Operate to obtain more uniform energy distribution within and between wafers. Table 2 below summarizes other test parameters and the final pattern damage data:

It can be seen from the above table that under the feature size of 55nm, when T ₁ =2ms (or the number of cycles is 2000), the damage caused to the patterned structure is as high as 1216 points; but T ₁ =0.1ms (or the number of cycles is 100), the damage to the patterned structure is zero. Therefore, T ₁ is a value between 0.1 ms and 2 ms, and further experiments are needed to reduce this range. Obviously, the number of cycles is related to the power density and frequency of ultrasonic or megasonic waves. The greater the power density, the smaller the number of cycles; the lower the frequency, the smaller the number of cycles. From the above experimental results, it can be predicted that the number of cycles without damage should be less than 2000, assuming that the power density of ultrasonic or megasonic waves is greater than 0.1 watts/cm ² and the frequency is less than or equal to 1MHZ. If the frequency is increased to greater than 1MHZ or the power density is less than 0.1 watts/cm ² , then the number of cycles can be predicted to increase.

Knowing the time T ₁ , T ₂ can also be shortened based on the DOE method similar to the above. Determine the time T ₁ and gradually shorten the time T ₂ to run the DOE until it can be observed that the patterned structure is damaged. As the time T ₂ is shortened, the temperature of the gas or steam in the bubble cannot be sufficiently cooled, which will cause the average temperature of the gas or steam in the bubble to rise gradually, and eventually trigger the bubble implosion. The trigger time is called critical cooling time. After knowing the critical cooling time T _c , in order to increase the safety factor, the time T ₂ can be set to a value greater than 2T _c .

Figures 8A-8D illustrate the method of cleaning wafers using ultrasonic or megasonic devices of the present invention. This method is similar to the method illustrated in FIG. 7A, except that in step 4, the frequency of the ultrasonic or megasonic power supply is set to f ₁ , and the power is a waveform with amplitude variation. Fig. 8A illustrates another cleaning method. In step 4, the frequency of the ultrasonic or megasonic power source is set to f ₁ , and the power is a waveform with increasing amplitude. Fig. 8B illustrates another cleaning method. In step 4, the frequency of the ultrasonic or megasonic power supply is set to f ₁ , and the power is a waveform with a decreasing amplitude. FIG. 8C illustrates another cleaning method. In step 4, the frequency of the ultrasonic or megasonic power supply is set to f ₁ , and the power is a waveform whose amplitude first decreases and then increases. Fig. 8D illustrates another cleaning method. In step 4, the frequency of the ultrasonic or megasonic power supply is set to f ₁ , and the power is a waveform whose amplitude first increases and then decreases.

Figures 9A-9D illustrate the method of cleaning a wafer using an ultrasonic or megasonic device of the present invention. This method is similar to the method illustrated in FIG. 7A, except that step 4 sets the frequency of the ultrasonic or megasonic power source to continuously change. Figure 9A illustrates another cleaning method. In step 4, the frequency of the ultrasonic or megasonic power supply is set to f _{1 first} , and then f ₃ , and f _{1 is} higher than f ₃ . Fig. 9B illustrates another cleaning method. In step 4, the frequency of the ultrasonic or megasonic power supply is set to f ₃ first, then f ₁ , and f _{1 is} higher than f ₃ . Figure 9C illustrates another cleaning method. In step 4, the frequency of the ultrasonic or megasonic power supply is set to f ₃ first, then f ₁ , and finally f ₃ , and f _{1 is} higher than f ₃ . Figure 9D illustrates another cleaning method. In step 4, the frequency of the ultrasonic or megasonic power supply is set to f _{1 first} , then f ₃ , and finally f ₁ , and f _{1 is} higher than f ₃ .

Similar to the method illustrated in Fig. 9C, in step 4, the frequency of the ultrasonic or megasonic power supply is set to f _{1 first} , then f ₃ , and finally f ₄ , and f _{4 is} smaller than f ₃ , and f _{3 is} smaller than f ₁ .

Similar to the method illustrated in Fig. 9C, in step 4, the frequency of the ultrasonic or megasonic power supply is set to f ₄ first, then f ₃ , and finally f ₁ , and f _{4 is} smaller than f ₃ , and f _{3 is} smaller than f ₁ .

Similar to the method illustrated in FIG. 9C, in step 4, the frequency of the ultrasonic or megasonic power supply is set to f _{1 first} , then f ₄ , and finally f ₃ , and f _{4 is} smaller than f ₃ , and f _{3 is} smaller than f ₁ .

Similar to the method illustrated in Fig. 9C, in step 4, the frequency of the ultrasonic or megasonic power supply is set to f ₃ first, then f ₄ , and finally f ₁ , and f _{4 is} smaller than f ₃ , and f _{3 is} smaller than f ₁ .

Similar to the method illustrated in Fig. 9C, in step 4, the frequency of the ultrasonic or megasonic power supply is set to f ₃ first, then f ₁ , and finally f ₄ , and f _{4 is} smaller than f ₃ , and f _{3 is} smaller than f ₁ .

Similar to the method shown in Fig. 9C, in step 4, the frequency of the ultrasonic or megasonic power supply is set to f ₄ first, then f ₁ , and finally f ₃ , and f _{4 is} smaller than f ₃ , and f _{3 is} smaller than f ₁ .

10A-10B illustrate that the present invention uses ultrasonic or megasonic waves to clean the wafer by maintaining stable air cavity oscillation to achieve zero damage to the patterned structure on the wafer. Fig. 10A is a waveform of the power supply output, and Fig. 10B is a temperature curve corresponding to each cycle of cavitation oscillation. The operating process steps proposed by the present invention are as follows: Step 1: Place the ultrasonic or megasonic device near the surface of the wafer or substrate set on the chuck or solution tank; Step 2: Combine the wafer with the ultrasonic or megasonic device Is filled with chemical liquid or gas-enriched water; Step 3: Spin the chuck or vibrate the wafer; Step 4: Set the power frequency to f ₁ and the power to P ₁ ; Step 5: The temperature of the gas or steam in the bubble reaches Before the explosion temperature T _i (total time T ₁ elapses), set the power output frequency to f ₁ , power to P ₂ , and P _{2 to be} less than P _1. Therefore, because the temperature of liquid or water is much lower than the temperature of gas, the The gas temperature begins to drop; Step 6: The gas temperature in the bubble decreases to close to normal temperature T ₀ or the time (zero power time) reaches T ₂ , again set the power supply frequency to f ₁ and power to P ₁ ; Step 7: Repeat step 1 Go to step 6 until the wafer is cleaned.

In step 6, since the power is P ₂ , the temperature of the gas in the bubble cannot fall to room temperature, and a temperature difference ΔT _{2 needs to} exist in the time interval T ₂ , as shown in Fig. 10B.

11A-11B illustrate the wafer cleaning method using ultrasonic or megasonic devices of the present invention. It is similar to the method illustrated in FIG. 10A, except that step 5 sets the frequency of the ultrasonic or megasonic power supply to f ₂ and the power to P ₂ , where f _{2 is} smaller than f ₁ and P _{2 is} smaller than P ₁ . Since f _{2 is} smaller than f ₁ , the temperature of the gas or steam in the bubble rises rapidly, so P ₂ should be much smaller than P _1. In order to reduce the temperature of the gas or steam in the bubble, the difference between the two is preferably 5 or 10 times.

Figures 12A-12B illustrate a wafer cleaning method using an ultrasonic or megasonic device of the present invention. It is similar to the method illustrated in FIG. 10A, except that step 5 sets the frequency of the ultrasonic or megasonic power supply to f ₂ and the power to P ₂ , where f _{2 is} greater than f ₁ and P ₂ is equal to P ₁ .

Figures 13A-13B illustrate a wafer cleaning method using an ultrasonic or megasonic device of the present invention. It is similar to the method illustrated in FIG. 10A, except that step 5 sets the frequency of the ultrasonic or megasonic power supply to f ₂ and the power to P ₂ , where f _{2 is} greater than f ₁ and P _{2 is} less than P ₁ .

14A-14B illustrate the wafer cleaning method using ultrasonic or megasonic device of the present invention. It is similar to the method illustrated in FIG. 10A, except that step 5 sets the frequency of the ultrasonic or megasonic power supply to f ₂ and the power to P ₂ , where f _{2 is} greater than f ₁ , and P _{2 is} greater than P ₁ . Since f _{2 is} greater than f ₁ , the temperature of the gas or steam in the bubble rises slowly. Therefore, P ₂ can be slightly larger than P ₁ , but it must be ensured that the temperature of the gas or steam in the bubble in the time interval T ₂ is more than that of the time interval T ₁ Decrease, as shown in Figure 14B.

Figures 4A-4B illustrate that the patterned structure is damaged by violent micro-jetting. Figures 15A-15B illustrate that stable cavitation oscillation can also damage the patterned structure on the wafer. As the cavitation oscillation continues, the temperature of the gas or vapor in the bubble rises, so the size of the bubble 15046 is also increasing, as shown in FIG. 15A. When the size of the bubble 15048 becomes larger than the spacing W between the patterned structures on the wafer 15010 shown in FIG. 15B, the expansion of the air cavity oscillation will cause damage to the patterned structure 15034, as shown in FIG. 15C. The following is another cleaning method proposed by the present invention: Step 1: Place the ultrasonic or megasonic device near the surface of the wafer or substrate set on the chuck or solution tank; Step 2: Combine the wafer with the ultrasonic or megasonic The sound wave device is filled with chemical liquid or gas-enriched water; Step 3: Spin the chuck or vibrate the wafer; Step 4: Set the power frequency to f ₁ and the power to P ₁ ; Step 5: The size of the bubble reaches the patterned structure Before the interval W between (time T _{1 has} elapsed), set the output power of the power supply to 0 watts. Since the temperature of the liquid or water is much lower than the gas temperature, the gas temperature in the bubble begins to drop; Step 6: The gas temperature in the bubble cools After the normal temperature T ₀ or the time (zero power time) reaches T ₂ , the power frequency is set to f ₁ and the power is P _{1 again} ; Step 7: Repeat steps 1 to 6 until the wafer is cleaned.

In step 6, the temperature of the gas in the bubble does not have to drop to room temperature, it can be any temperature, but it is better to be much lower than the implosion temperature T _i . In step 5, the size of the bubble may be slightly larger than the size of the spacing between the patterned structures, as long as the expansion force of the bubble does not damage the patterned structure. Time T ₁ may be determined through the following method: Step 1: Similar to Table 1, select five different time T condition ₁ as the experimental set (DOE); a step 2: selecting at least a T ₁ 10 times the time T _2, the first The test is best to choose 1 times; Step 3: Use the determined power P _{0 to} run the above five conditions to clean the wafers with patterned structure respectively. Here, P ₀ is determined in the continuous uninterrupted mode (non-pulse mode) The power that will cause damage to the patterned structure of the wafer; Step 4: Use the inspection instrument SEMS or the wafer pattern damage viewing tool to check the damage of the above five types of wafers, such as SEMVision or Hitachi IS3000, and then the damage time T _i can be determined in a certain range; repeat steps 1 to 4 to narrow the range of damage time T _d . Knowing the damage time T _d , T ₁ can be set to a value less than 0.5T _d under the safety factor.

All the methods described in FIGS. 7 to 14 are suitable for this or combined with the method described in FIG. 15.

Fig. 16 shows an embodiment of a device for cleaning wafers using ultrasonic or megasonic devices. The wafer cleaning device includes a wafer 16010, a wafer chuck 16014 driven and rotated by a rotating drive device 16016, a nozzle 16064 spraying cleaning liquid chemicals or deionized water 16060, an ultrasonic or megasonic device 16062 combined with the nozzle 16064, and Ultrasonic or megasonic power supply. The ultrasonic or megasonic energy generated by the ultrasonic or megasonic device 16062 is transmitted to the wafer through the chemical reagent or deionized water column 16060 ejected from the nozzle 16064. All the cleaning methods described in FIGS. 7 to 15 are applicable to the cleaning device shown in FIG. 16.

Fig. 17 is an embodiment of a wafer cleaning device using an ultrasonic or megasonic device. The wafer cleaning device includes a wafer 17010, a solution tank 17074, a wafer cassette 17076 placed in the solution tank 17074 to support the wafer 17010, a cleaning solution chemical reagent 17070, and an ultrasonic or megasonic device set on the outer wall of the solution tank 17074 17072 and ultrasonic or megasonic power supply. At least one inlet is used to supply the cleaning solution chemical reagent 17070 into the solution tank 17074 to immerse the wafer 17010. All the cleaning methods described in FIGS. 7 to 15 are applicable to the cleaning device shown in FIG. 17.

18A-18C illustrate an embodiment of a method for cleaning a wafer using an ultrasonic or megasonic device of the present invention. This method is similar to the method shown in FIG. 7A, except that step 5, the temperature in the gas or vapor bubbles implode reaches temperature T _i (or quench time reaches T ₁ T _i, T _i is calculated by the equation (11)) before , Set the power output value to a positive or negative DC value to maintain or stop the vibration of the ultrasonic or megasonic device. Therefore, since the temperature of the liquid or water is much lower than the temperature of the gas, the temperature of the gas inside the bubble begins to drop. The positive or negative value here can be greater than, equal to or less than the power P ₁ .

FIG. 19 illustrates an embodiment of a method for cleaning a wafer using an ultrasonic or megasonic device of the present invention. Similar to the method shown in Figure 7A, except for step 5, before the gas or vapor temperature in the bubble reaches the implosion temperature T _i (or the time reaches T _{1 and} T _i , T _i is calculated by formula (11)), set The output frequency of the power supply is the same as f ₁ , and the phase is opposite to the phase of f ₁ to quickly stop the cavitation oscillation of the bubbles. Therefore, since the temperature of the liquid or water is much lower than the temperature of the gas, the temperature of the gas inside the bubble starts to drop. The positive or negative value here can be greater than, equal to or less than the power P ₁ . During the above operation, the output frequency of the power supply can be different from the frequency f ₁ but the phase is opposite to the phase of f ₁ to quickly stop the cavitation oscillation of the bubbles.

Generally speaking, ultrasonic or megasonic waves with a frequency range of 0.1MHZ-10MHZ can be applied to the method proposed in the present invention.

In all the above embodiments, all the key process parameters of the sonic power supply are set in the power controller in advance, such as power, frequency, power-on time (T ₁ ), power-off time (T ₂ ), but not in the wafer cleaning process Provide immediate monitoring. During the wafer cleaning process, if the sonic power supply does not work normally, it will inevitably cause damage to the patterned structure. Therefore, a device and method are needed to monitor the working status of the acoustic wave power supply in real time. If the parameters are not within the normal range, the sonic power supply should be turned off and an alarm signal will be issued.

FIG. 20 illustrates an embodiment of the control system with a detection system for monitoring the operating parameters of the acoustic wave power supply during the wafer cleaning process using the ultrasonic or megasonic device of the present invention. The control system of this embodiment includes a host 2080, an acoustic wave power supply 2082, an acoustic wave sensor 2003, a detection system 2086, and a communication cable 2088. The host 2080 sends the acoustic wave parameter setting values to the acoustic wave power supply 2082, such as power setting value P ₁ , power-on time setting value T ₁ , power setting value P ₂ , power-off time setting value T ₂ , frequency setting value and control commands, such as power supply Turn on the command. The acoustic wave power supply 2082 generates an acoustic wave waveform after receiving the above instruction, and sends the acoustic wave waveform to the acoustic wave sensor 2003 to clean the wafer 2010. At the same time, the parameter setting value sent by the host 2080 and the actual output value of the acoustic wave power supply 2082 are read by the detection system 2086. The detection system 2086 compares the actual output value of the acoustic wave power source 2082 with the parameter setting value sent by the host 2080, and sends the comparison result to the host 2080 through the communication cable 2088. If the actual output value of the sonic power supply 2082 is different from the parameter setting value sent by the host 2080, the detection system 2086 will send an alarm signal to the host 2080. After receiving the alarm signal, the host 2080 turns off the sonic power supply 2082 to prevent further damage to the patterned structure on the wafer 2010.

FIG. 21 illustrates an embodiment of the detection system of the present invention for monitoring the operating parameters of the acoustic wave power supply during the wafer cleaning process using the ultrasonic or megasonic device. The detection system includes a voltage attenuation circuit 2190, a shaping circuit 2192, a main controller (FPGA) 2194, a communication circuit (RS 232 or 485) 2196, and a power supply circuit 2198.

Figures 23A-23C illustrate an embodiment of the voltage attenuation circuit of the present invention. When the acoustic wave signal output by the acoustic wave power supply 2082 is read for the first time, the acoustic wave signal has a relatively high amplitude value, as shown in FIG. 23B. The voltage attenuation circuit 2190 uses two operational amplifiers 23102 and 23104 to reduce the wave The amplitude value of the shape is shown in Figure 23C. The setting range of the attenuation rate of the voltage attenuation circuit 2190 is between 5-100, preferably 20. Voltage attenuation can be expressed by the following formula: Vout=(R2/R1)*Vin

Suppose R1=200k, R2=R3=R4=10K, Vout=(R2/R1)*Vin=Vin/20

Vout is the amplitude value output by the voltage attenuation circuit 2190, Vin is the amplitude value input by the voltage attenuation circuit 2190, and R1, R2, R3, and R4 are the resistances of the two operational amplifiers 23102 and 23104.

The output terminal of the voltage attenuation circuit 2190 is connected to the shaping circuit 2192. The waveform output by the voltage attenuation circuit 2190 is input to the shaping circuit 2192, and the shaping circuit 2192 converts the sine wave into a square wave for processing by the main controller (FPGA). Figures 24A-24C illustrate an embodiment of the shaping circuit of the present invention. As shown in FIG. 24A, the shaping circuit 2192 includes a window comparator 24102 and an OR gate 24104. When Vcal-<Vin<Vcal+, Vout=0; otherwise, Vout=1. Among them, Vcal- and Vcal+ are two thresholds, Vin is the input value of the shaping circuit 2192, and Vout is the output value of the shaping circuit. After the waveform passes through the voltage attenuation circuit 2190, the waveform (sine wave) is input to the shaping circuit 2192, and the shaping circuit 2192 converts the sine wave into a square wave, as shown in FIG. 24C.

The square wave output by the shaping circuit 2192 is input to the main controller (FPGA) 2194. Figures 25A-25C illustrate an embodiment of the main controller (FPGA) of the present invention. As shown in FIG. 25A, the main controller (FPGA) includes a pulse conversion module 25102 and a period measurement module 25104. The pulse conversion module 25102 is used to convert the pulse signal of time T ₁ into a high level signal, and the low level signal of time T ₂ remains unchanged, as shown in Figure 25B-25C. FIG. 25A illustrates the circuit symbol of the pulse conversion module 25102, where Clk_Sys is a 50MHz clock signal, Pulse_In is an input signal, and Pulse_Out is an output signal. The period measurement module 25104 uses a counter to measure the time of high level and low level. FIG. 25A illustrates the circuit symbol of the period measurement module 25104, where Clk_Sys is a 50MHz clock signal, Pulse_In is an input signal, and Pulse_Out is an output signal.

T ₁ =Counter_H*20ns, T ₂ =Counter_L*20ns

Among them, Counter_H is the number of high levels, and Counter_L is the number of low levels.

The main controller (FPGA) 2194 compares the calculated power-on time with the preset time T _1. If the calculated power-on time is longer than the preset time T ₁ , the main controller (FPGA) 2194 sends an alarm signal to the host 2080 and the host 2080 When the alarm signal is received, the sound wave power supply 2082 is turned off. The main controller (FPGA) 2194 compares the calculated power-off time with the preset time T _2. If the calculated power-off time is shorter than the preset time T ₂ , the main controller (FPGA) 2194 sends an alarm signal to the host 2080, When the host 2080 receives the alarm signal, the sound wave power supply 2082 is turned off. The model of the main controller (FPGA) 2194 can be Altera Cyclone IV EP4CE22F17C6N.

As shown in FIG. 26, due to the characteristics of the device itself, after the host 2080 turns off the acoustic wave power source 2082, the acoustic wave power source 2082 still continues to oscillate for multiple cycles. The main controller (FPGA) 2194 also measures the time T ₃ of the multiple cycles, and the time T ₃ can be obtained through experiments. Therefore, the actual power-on time is equal to TT ₃ , where T is the time calculated by the period measurement module 25104, and T ₃ is the time for the sonic power source 2082 to continue to oscillate for multiple cycles after the host 2080 turns off the sonic power source 2082. The main controller (FPGA) 2194 compares the actual power-on time with the preset time T ₁ , and if the actual power-on time is longer than the preset time T ₁ , the main controller (FPGA) 2194 sends an alarm signal to the host 2080.

As shown in FIG. 21, the communication circuit 2196 is set as the interface of the host 2080, and the communication circuit 2196 and the host 2080 have achieved RS232 or RS485 serial communication to read the parameter setting values sent by the host 2080 and send the comparison result to the host 2080.

As shown in FIG. 21, in order to provide DC voltages of 1.2V, 3.3V, and 5V to the entire system, the power supply circuit 2198 converts the 15V DC voltage into a target voltage.

FIG. 22 illustrates another embodiment of the detection system of the present invention for monitoring the operating parameters of the acoustic wave power supply during the wafer cleaning process using the ultrasonic or megasonic device. The detection system includes a voltage attenuation circuit 2290, an amplitude detection circuit 2292, a main controller (FPGA) 2294, a communication circuit (RS 232 or 485) 2296, and a power supply circuit 2298.

Figures 23A-23C illustrate an embodiment of the voltage attenuation circuit of the present invention. When the acoustic wave signal output by the acoustic wave power supply 2082 is read for the first time, the acoustic wave signal has a relatively high amplitude value, as shown in FIG. 23B. The voltage attenuation circuit 2290 uses two operational amplifiers 23102 and 23104 to reduce the amplitude value of the waveform, as shown in FIG. 23C. The setting range of the attenuation rate of the voltage attenuation circuit 2290 is between 5-100, preferably 20.

27A-27C illustrate an embodiment of the amplitude detection circuit of the present invention. Amplitude detection circuit 2292 includes reference voltage generation circuit and comparison Circuit. As shown in FIG. 27B, the reference voltage generating circuit uses the D/A converter 27118 to convert the digital input signal of the main controller (FPGA) 2294 into analog DC reference voltages Vref+ and Vref-, as shown in FIG. 27C. The comparison circuit uses the window comparator 27114 and the gate 27116 to compare the amplitude Vin output by the voltage attenuation circuit 2190 with the reference voltages Vref+ and Vref-. If the attenuated amplitude Vin exceeds the reference voltages Vref+ and Vref-, the amplitude detection circuit 2292 sends an alarm signal to the host 2080, and the host 2080 receives the alarm signal and turns off the sonic power supply 2082 to avoid damage to the patterned structure on the wafer 2010 .

The present invention provides a method for cleaning a substrate using ultrasonic or megasonic waves without causing damage to the patterned structure on the substrate. The method includes the following steps: Step 1: Spraying liquid between the substrate and the ultrasonic or megasonic device Step 2: Set the frequency of the ultrasonic or megasonic power supply to f ₁ and the power to P ₁ to drive the ultrasonic or megasonic device; Step 3: Before cavitation in the liquid damages the patterned structure on the substrate , Set the output of the ultrasonic or megasonic power supply to zero; Step 4: After the temperature in the bubble drops to the set temperature, set the frequency of the ultrasonic or megasonic power supply to f ₁ and the power to P _{1 again} ; Step 5: detect the frequencies separately Is f ₁ and the power-on time and power-off time when the power is P ₁ ; Step 6: Compare the power-on time detected when the frequency is f ₁ and the power is P ₁ with the preset time T ₁ , if the power-on time is detected If it is longer than the preset time T ₁ , turn off the ultrasonic or megasonic power and send an alarm signal; Step 7: Compare the detected power-off time with the preset time T ₂ , if the detected power-off time is longer than the preset time T ₂ Short, turn off the ultrasonic or megasonic power supply and send out an alarm signal; Step 8: Repeat steps 1 to 7 until the substrate is cleaned.

In one embodiment, step 5 further includes: attenuating the amplitude of the output waveform of the ultrasonic or megasonic power; converting the attenuated sine wave into a square wave; converting the pulse signal of the power-on time into a high-level signal, and the power-off time The low-level signal of remains unchanged; the high-level and low-level times are measured and compared with the preset time T ₁ and the preset time T _{2 respectively} .

The range of the attenuation rate is set between 5-100, preferably 20.

In one embodiment, the actual power-on time is equal to TT ₃ , where T is the measured high-level time, and T ₃ is the time for the ultrasonic or megasonic power supply to continue to oscillate for multiple cycles after the ultrasonic or megasonic power supply is turned off. Actual energization time and the predetermined time T ₁ are compared, if the actual energization time is longer than the predetermined time T _1, the ultrasonic or megasonic power off and an alarm signal.

The present invention provides another method for cleaning a substrate using ultrasonic or megasonic waves without causing damage to the patterned structure on the substrate. The method includes the following steps: Step 1: Spray liquid onto the substrate and the ultrasonic or megasonic device Step 2: Set the frequency of the ultrasonic or megasonic power source to f ₁ and the power to P ₁ to drive the ultrasonic or megasonic device; Step 3: Cavitation oscillation in the liquid damages the patterned structure on the substrate Before, set the output of the ultrasonic or megasonic power supply to zero; Step 4: After the temperature in the bubble drops to the set temperature, set the frequency of the ultrasonic or megasonic power supply to f ₁ and the power to P _{1 again} ; Step 5: Detect ultrasonic Or the amplitude of each waveform output by the megasonic power supply; Step 6: Compare the amplitude of each detected waveform with the preset value. If the amplitude of any detected waveform is greater than the preset value, turn off the ultrasonic or Megasonic power supply and send out an alarm signal, where the preset value is greater than the waveform amplitude during normal operation; Step 7: Repeat steps 1 to 6 until the substrate is cleaned.

In one embodiment, the method further includes: attenuating the amplitude of the output waveform of the ultrasonic or megasonic power supply; obtaining analog DC reference voltages Vref+ and Vref-; comparing the attenuated amplitude Vin with the reference voltages Vref+ and Vref-, if attenuated After the amplitude Vin exceeds Vref+ and Vref-, the ultrasonic or megasonic power supply is turned off and an alarm signal is issued.

The invention provides a device for cleaning semiconductor substrates using ultrasonic or megasonic waves, which includes a chuck, an ultrasonic or megasonic device, at least one nozzle, an ultrasonic or megasonic power supply, a host and a detection system. The chuck supports the semiconductor substrate. Ultrasonic or megasonic devices are placed near the semiconductor substrate. At least one nozzle sprays a chemical liquid into the semiconductor substrate and the gap between the semiconductor substrate and the ultrasonic or megasonic device. The host sets the ultrasonic or megasonic power supply to drive the ultrasonic or megasonic device with frequency f1 and power P1. Before the cavity oscillation in the liquid damages the patterned structure on the semiconductor substrate, the output of the ultrasonic or megasonic power is set to zero. After the temperature in the bubble drops to the set temperature, set the frequency of the ultrasonic or megasonic power supply to f ₁ and the power to P _{1 again} . Detection systems detect frequencies f _1, P is the power-on time and the power off time is _1:00, the frequency is f _1, the power P ₁ is the power-on time of the detected predetermined time T ₁ and are compared, if the detection The power-on time is longer than the preset time T ₁ , the detection system sends an alarm signal to the host, and the host turns off the ultrasonic or megasonic power when receiving the alarm signal; compare the detected power-off time with the preset time T ₂ , if it is detected the power-off time is shorter than the predetermined time T _2, the detection system transmits an alarm signal to the host, then the alarm signal is received ultrasonic or megasonic power off.

In one embodiment, the ultrasonic or megasonic device is combined with the nozzle and placed near the semiconductor substrate, and the energy of the ultrasonic or megasonic device is transferred to the semiconductor substrate through the liquid column ejected from the nozzle.

The present invention provides another device for cleaning semiconductor substrates using ultrasonic or megasonic waves, including a chuck, an ultrasonic or megasonic device, at least one nozzle, an ultrasonic or megasonic power supply, a host, and a detection system. The chuck supports the semiconductor substrate. Ultrasonic or megasonic devices are placed near the semiconductor substrate. At least one nozzle sprays a chemical liquid into the semiconductor substrate and the gap between the semiconductor substrate and the ultrasonic or megasonic device. The host sets the ultrasonic or megasonic power supply to drive the ultrasonic or megasonic device with frequency f1 and power P1. Before the cavity oscillation in the liquid damages the patterned structure on the semiconductor substrate, the output of the ultrasonic or megasonic power is set to zero. After the temperature in the bubble drops to the set temperature, set the frequency of the ultrasonic or megasonic power supply to f ₁ and the power to P _{1 again} . The detection system detects the amplitude of each waveform output by the ultrasonic or megasonic power supply, and compares the amplitude of each detected waveform with the preset value. If the amplitude of any waveform is detected to be greater than the preset value, the detection system sends an alarm When the signal reaches the host, the host will turn off the ultrasonic or megasonic power when it receives the alarm signal, and the preset value is greater than the waveform amplitude during normal operation.

In one embodiment, the ultrasonic or megasonic device is combined with the nozzle and placed near the semiconductor substrate, and the energy of the ultrasonic or megasonic device is transferred to the semiconductor substrate through the liquid column ejected from the nozzle.

The invention also provides a device for cleaning semiconductor substrates using ultrasonic or megasonic waves, which includes a wafer box, a solution tank, an ultrasonic or megasonic device, at least one inlet, an ultrasonic or megasonic power source, a host, and a detection system. The wafer cassette contains at least one semiconductor substrate. The solution tank contains the wafer cassette. The ultrasonic or megasonic device is arranged on the outer wall of the solution tank. At least one inlet is used to fill the solution tank with chemical liquid, which immerses the semiconductor substrate. The host sets the ultrasonic or megasonic power supply to drive the ultrasonic or megasonic device with frequency f1 and power P1. Before the cavity oscillation in the liquid damages the patterned structure on the semiconductor substrate, the output of the ultrasonic or megasonic power is set to zero. After the temperature in the bubble drops to the set temperature, set the frequency of the ultrasonic or megasonic power supply to f ₁ and the power to P _{1 again} . Detection systems detect frequencies f _1, when power is P ₁ and the power-off time period, the comparison frequency f _1, the power P ₁ is the power-on time and the detected predetermined time T _1, if the detected The power-on time is longer than the preset time T ₁ , the detection system sends an alarm signal to the host, and the host turns off the ultrasonic or megasonic power when receiving the alarm signal; compare the detected power-off time with the preset time T ₂ , if the detected power-off power down time is shorter than the predetermined time T _2, the detection system transmits an alarm signal to the host, then the alarm signal is received ultrasonic or megasonic power off.

The invention also provides a device for cleaning semiconductor substrates using ultrasonic or megasonic waves, which includes a wafer box, a solution tank, an ultrasonic or megasonic device, at least one inlet, an ultrasonic or megasonic power source, a host, and a detection system. The wafer cassette contains at least one semiconductor substrate. The solution tank contains the wafer cassette. The ultrasonic or megasonic device is arranged on the outer wall of the solution tank. At least one inlet is used to fill the solution tank with chemical liquid, which immerses the semiconductor substrate. The host sets the ultrasonic or megasonic power supply to drive the ultrasonic or megasonic device with frequency f1 and power P1. Before the cavity oscillation in the liquid damages the patterned structure on the semiconductor substrate, the output of the ultrasonic or megasonic power is set to zero. After the temperature in the bubble drops to the set temperature, set the frequency of the ultrasonic or megasonic power supply to f ₁ and the power to P _{1 again} . The detection system detects the amplitude of each waveform output by the ultrasonic or megasonic power supply, and compares the amplitude of each detected waveform with the preset value. If the amplitude of any waveform is detected to be greater than the preset value, the detection system sends an alarm When the signal reaches the host, the host will turn off the ultrasonic or megasonic power when it receives the alarm signal, and the preset value is greater than the waveform amplitude during normal operation.

Although the present invention is illustrated by specific embodiments, examples, and applications, obvious modifications and replacements in the art will still fall within the protection scope of the present invention.

1003‧‧‧Ultrasonic device (megasonic device)

1004‧‧‧Sensor

1008‧‧‧Resonator

1010‧‧‧wafer

1012‧‧‧Nozzle

Claims (27)

A method for cleaning a semiconductor substrate without damaging the patterned structure on the semiconductor substrate using an ultrasonic or megasonic device, which is characterized in that it comprises: spraying liquid into the gap between the semiconductor substrate and the ultrasonic or megasonic device; Set the frequency of the ultrasonic or megasonic power supply to f ₁ and the power to P ₁ to drive the ultrasonic or megasonic device; before the cavity oscillation in the liquid damages the patterned structure on the semiconductor substrate, set the output of the ultrasonic or megasonic power supply When the temperature in the bubble drops to the set temperature, set the frequency of the ultrasonic or megasonic power supply to f ₁ and the power to P _{1 again} ; respectively detect the power-on time and power-off when the frequency is f ₁ and the power is P ₁ Time; compare the power-on time detected when the frequency is f ₁ and the power is P ₁ with the preset time T _1. If the detected power-on time is longer than the preset time T ₁ , turn off the ultrasonic or megasonic power supply and alarm signal; the detected power-off time and the predetermined time T ₂ for comparison, if the detected power-off time is shorter than the predetermined time T _2, is closed and ultrasonic or megasonic power alarm signal; repeating the above steps Until the semiconductor substrate is cleaned. The method according to claim 1, wherein the detecting the power-on time and the power-off time when the frequency is f ₁ and the power is P ₁ respectively includes: attenuating the amplitude of the output waveform of the ultrasonic or megasonic power supply; The attenuated sine wave is converted into a square wave; the pulse signal of the power-on time is converted into a high-level signal, and the low-level signal of the power-off time remains unchanged; the time of high level and low level is measured and the measured high level signal The time to level the low level is compared with the preset time T1 and the preset time T2. The method according to claim 2, characterized in that the setting range of the attenuation rate is 5-100. The method according to claim 1, characterized in that the actual power-on time is equal to T-T3, where T is the measured high level time, and T3 is the ultrasonic or megasonic power supply after the ultrasonic or megasonic power is turned off. The time to oscillate for multiple cycles. The method according to the requested item, wherein said energization time is detected and the predetermined time T ₁ for comparison, if the detected conduction time is longer than the predetermined time T _1, the closed ultrasonic or megasonic power source and an alarm signal, comprising: a power-on time and the actual predetermined time T ₁ are compared, if the actual energization time is longer than the predetermined time T _1, the ultrasonic or megasonic power off and an alarm signal. A method for cleaning a semiconductor substrate without damaging the patterned structure on the semiconductor substrate using an ultrasonic or megasonic device, which is characterized in that it comprises: spraying liquid into the gap between the semiconductor substrate and the ultrasonic or megasonic device; Set the frequency of the ultrasonic or megasonic power supply to f ₁ and the power to P ₁ to drive the ultrasonic or megasonic device; before the cavity oscillation in the liquid damages the patterned structure on the semiconductor substrate, the output of the ultrasonic or megasonic power supply is set to Zero; After the temperature in the bubble drops to the set temperature, set the frequency of the ultrasonic or megasonic power supply to f ₁ and the power to P _{1 again} ; detect the amplitude of each waveform output by the ultrasonic or megasonic power supply; each will be detected Compare the amplitude of each waveform with the preset value. If the amplitude of any detected waveform is greater than the preset value, turn off the ultrasonic or megasonic power supply and send an alarm signal, where the preset value is greater than the waveform amplitude during normal operation; Repeat the above steps until the semiconductor substrate is cleaned. The method according to claim 6, further comprising: attenuating the amplitude of the output waveform of the ultrasonic or megasonic power supply; obtaining analog DC reference voltages Vref+ and Vref-; and combining the attenuated amplitude Vin and the reference voltages Vref+ and Vref- For comparison, if the attenuated amplitude Vin exceeds the reference voltages Vref+ and Vref-, the ultrasonic or megasonic power supply is turned off and an alarm signal is issued. A device for cleaning a semiconductor substrate using an ultrasonic or megasonic device, which is characterized by comprising: a chuck supporting the semiconductor substrate; an ultrasonic or megasonic device placed near the semiconductor substrate; at least one spray head spraying chemical liquid to the semiconductor In the gap between the substrate and the semiconductor substrate and the ultrasonic or megasonic device; ultrasonic or megasonic power; host, set the frequency of the ultrasonic or megasonic power to f ₁ and power to P ₁ to drive the ultrasonic or megasonic device, Before cavitation in the liquid damages the patterned structure on the semiconductor substrate, set the output of the ultrasonic or megasonic power supply to zero. After the temperature in the bubble drops to the set temperature, set the frequency of the ultrasonic or megasonic power supply again to f ₁ , the power is P ₁ ; the detection system separately detects the power-on time and power-off time when the frequency is f ₁ and the power is P ₁ , and the power-on time and the power-off time detected when the frequency is f ₁ and the power is P ₁ Set time T ₁ for comparison. If the detected power-on time is longer than the preset time T ₁ , the detection system sends an alarm signal to the host, and the host receives the alarm signal and turns off the ultrasonic or megasonic power supply, and the detected power-off time is compared with The preset time T ₂ is compared. If the detected power failure time is shorter than the preset time T ₂ , the detection system sends an alarm signal to the host, and the host receives the alarm signal and turns off the ultrasonic or megasonic power supply. The device according to claim 8, wherein the detection system includes a voltage attenuation circuit, a shaping circuit, a main controller, a communication circuit, and a power supply circuit. The device according to claim 9, characterized in that the voltage attenuation circuit reduces the amplitude value of the output waveform of the ultrasonic or megasonic power supply. The device according to claim 10, wherein the attenuation rate setting range of the voltage attenuation circuit is 5-100. The device according to claim 9, wherein the waveform (sine wave) is input to the shaping circuit after the waveform passes through the voltage attenuation circuit, and the shaping circuit converts the sine wave into a square wave. The device according to claim 9, wherein the main controller includes a pulse conversion module and a period measurement module, the pulse conversion module converts the pulse signal at time T ₁ into a high-level signal, and the time T ₂ The low-level signal remains unchanged, and the period measurement module measures the high-level and low-level time through a counter. Request entries apparatus of claim 9, characterized in that the master controller of the measured energization time and the predetermined time T ₁ are compared, if the measured energization time is longer than the predetermined time T _1, master controller send alarm signals to the host, the host controller and the measured power-off time of the predetermined time T ₂ for comparison, if the measured power-off time is shorter than the predetermined time T _2, the main controller to send alarm signals to the host. The device according to claim 13, characterized in that the actual power-on time is equal to TT ₃ , where T is the time measured by the period measurement module, and T ₃ is the ultrasonic or megasonic power supply after the host turns off the ultrasonic or megasonic power supply continues to oscillate a plurality of time periods, the main controller actual energization time and the predetermined time T ₁ are compared, if the actual energization time is longer than the predetermined time T _1, the master controller sends a warning signal to the host. The device according to claim 9, characterized in that the communication circuit is set as an interface of the host, and the communication circuit achieves RS232 or RS485 serial communication with the host. The device according to claim 9, wherein the power supply circuit converts a direct current 15V into a target voltage. The device according to claim 8, wherein the ultrasonic or megasonic device is combined with a nozzle and placed near the semiconductor substrate, and the energy of the ultrasonic or megasonic device is transmitted to the semiconductor substrate through the liquid column ejected from the nozzle. A device for cleaning a semiconductor substrate using an ultrasonic or megasonic device, which is characterized by comprising: a chuck supporting the semiconductor substrate; an ultrasonic or megasonic device placed near the semiconductor substrate; at least one spray head spraying chemical liquid to the semiconductor In the gap between the substrate and the semiconductor substrate and the ultrasonic or megasonic device; ultrasonic or megasonic power; host, set the frequency of the ultrasonic or megasonic power to f ₁ and power to P ₁ to drive the ultrasonic or megasonic device, Before cavitation in the liquid damages the patterned structure on the semiconductor substrate, set the output of the ultrasonic or megasonic power supply to zero. After the temperature in the bubble drops to the set temperature, set the frequency of the ultrasonic or megasonic power supply again to f ₁ , the power is P ₁ ; the detection system detects the amplitude of each waveform output by the ultrasonic or megasonic power supply, and compares the amplitude of each detected waveform with the preset value. If the amplitude ratio of any waveform is detected The preset value is large, the detection system sends an alarm signal to the host, and the host turns off the ultrasonic or megasonic power when receiving the alarm signal. The preset value is greater than the waveform amplitude during normal operation. The device according to claim 19, wherein the detection system includes a voltage attenuation circuit, an amplitude detection circuit, a main controller, a communication circuit, and a power supply circuit. The device according to claim 20, wherein the voltage attenuation circuit reduces the amplitude value of the output waveform of the ultrasonic or megasonic power supply. The device according to claim 20, wherein the amplitude detection circuit includes a reference voltage generation circuit and a comparison circuit, the reference voltage generation circuit converts the digital input of the main controller into analog DC reference voltages Vref+ and Vref-, and compares The circuit compares the amplitude Vin output by the voltage attenuation circuit with reference voltages Vref+ and Vref-. If the attenuated amplitude Vin exceeds the reference voltages Vref+ and Vref-, the amplitude detection circuit sends an alarm signal to the host. The device according to claim 19, wherein the ultrasonic or megasonic device is combined with a nozzle and placed near the semiconductor substrate, and the energy of the ultrasonic or megasonic device is transmitted to the semiconductor substrate through the liquid column ejected from the nozzle. A device for cleaning a semiconductor substrate using an ultrasonic or megasonic device, which is characterized in that it comprises: a wafer cassette containing at least one semiconductor substrate; a solution tank containing the wafer cassette; an ultrasonic or megasonic wave arranged on the outer wall of the solution tank Device; at least one inlet to fill the solution tank with chemical liquid to immerse the semiconductor substrate; ultrasonic or megasonic power supply; host, set the frequency of the ultrasonic or megasonic power supply to f ₁ and power to P ₁ to drive the ultrasonic or megasonic device, Before cavitation in the liquid damages the patterned structure on the semiconductor substrate, set the output of the ultrasonic or megasonic power supply to zero. After the temperature in the bubble drops to the set temperature, set the frequency of the ultrasonic or megasonic power supply again to f ₁ , the power is P ₁ ; the detection system separately detects the power-on time and power-off time when the frequency is f ₁ and the power is P ₁ , and the power-on time and the power-off time detected when the frequency is f ₁ and the power is P ₁ Set time T ₁ for comparison. If the detected power-on time is longer than the preset time T ₁ , the detection system sends an alarm signal to the host, and the host receives the alarm signal and turns off the ultrasonic or megasonic power supply, and the detected power-off time is compared with The preset time T ₂ is compared. If the detected power failure time is shorter than the preset time T ₂ , the detection system sends an alarm signal to the host, and the host receives the alarm signal and turns off the ultrasonic or megasonic power supply. The device according to claim 24, wherein the detection system includes a voltage attenuation circuit, a shaping circuit, a main controller, a communication circuit, and a power supply circuit. A device for cleaning a semiconductor substrate using an ultrasonic or megasonic device, which is characterized in that it comprises: a wafer cassette containing at least one semiconductor substrate; a solution tank containing the wafer cassette; an ultrasonic or megasonic wave arranged on the outer wall of the solution tank Device; at least one inlet to fill the solution tank with chemical liquid to immerse the semiconductor substrate; ultrasonic or megasonic power supply; host, set the frequency of the ultrasonic or megasonic power supply to f ₁ and power to P ₁ to drive the ultrasonic or megasonic device, Before cavitation in the liquid damages the patterned structure on the semiconductor substrate, set the output of the ultrasonic or megasonic power supply to zero. After the temperature in the bubble drops to the set temperature, set the frequency of the ultrasonic or megasonic power supply again to f ₁ , the power is P ₁ ; the detection system detects the amplitude of each waveform output by the ultrasonic or megasonic power supply, and compares the amplitude of each detected waveform with the preset value. If the amplitude ratio of any waveform is detected The preset value is large, the detection system sends an alarm signal to the host, and the host turns off the ultrasonic or megasonic power when receiving the alarm signal. The preset value is greater than the waveform amplitude during normal operation. The device according to claim 26, wherein the detection system includes a voltage attenuation circuit, an amplitude detection circuit, a main controller, a communication circuit, and a power supply circuit.

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