CN116169046A - A wafer cleaning method - Google Patents

Abstract

The invention discloses a wafer cleaning method, which includes: checking the horizontal position of the driving wheel and the driven wheel, and adjusting the driving wheel and/or the driven wheel as needed, so that the driving wheel and the driven wheel are located in the same plane; The circle is placed on the support device formed by the driving wheel and the driven wheel; the cleaning brushes located on both sides of the wafer move to the cleaning position to clean the front and back sides of the wafer with a rolling brush.

Description

A wafer cleaning method

technical field

The invention belongs to the technical field of wafer post-processing, and in particular relates to a wafer cleaning method.

Background technique

The integrated circuit industry is the core of the information technology industry and plays a key role in promoting the transformation and upgrading of the manufacturing industry to digital and intelligent. A chip is the carrier of an integrated circuit, and chip manufacturing involves technological processes such as chip design, wafer manufacturing, wafer processing, electrical measurement, cutting, packaging, and testing. Among them, chemical mechanical polishing (Chemical Mechanical Planarization, CMP) belongs to the wafer manufacturing process, which is an ultra-precision surface processing technology for global planarization.

After chemical mechanical polishing, the wafer needs to be cleaned, dried and other post-treatments to avoid contamination of semiconductor devices by trace ions and metal particles, and to ensure the performance and pass rate of semiconductor devices. Wafer cleaning methods include: roller brush cleaning, megasonic cleaning, etc. Among them, roller brush cleaning is widely used, but there are also some problems.

During the cleaning process of the wafer with a rolling brush, a pair of driving wheels and a driven wheel are used to form a supporting device to vertically support and drive the wafer to rotate, wherein the driven wheel is arranged between a pair of driving wheels, and the driving wheel and the driven wheel The moving wheel is arranged on the installation seat of the cleaning shell.

Due to processing and assembly errors, the grooves on the driving wheel and the driven wheel may not be in the same plane, so that the wafers placed on the support device are tilted or displaced, that is, it is impossible to ensure that the brushed wafers are in a vertical state. There are at least the following problems in the wafer cleaning process: the clamping state of the tilted wafer is inconsistent, which causes the torque of the driving motor of the cleaning brush to fluctuate and affects the uniformity of wafer cleaning; the tilted wafer cannot be placed on the driven wheel In the washer, the wafer slips and a false alarm of speed drop is issued; the tilted wafer is also not conducive to the pick-up of the manipulator, and it is easy to fail to take the slice or fragments and interrupt production; if the lower part of the cleaning shell is equipped with a megasonic cleaning module , the ultrasonic waves emitted by the megasonic cleaning module cannot completely cover the wafer surface and affect the cleaning effect of the wafer.

Contents of the invention

An embodiment of the present invention provides a wafer cleaning method, aiming to solve at least one of the technical problems existing in the prior art.

The first aspect of the embodiments of the present invention provides a wafer cleaning method, including:

S1, check the horizontal position of the driving wheel and the driven wheel, and adjust the driving wheel and/or the driven wheel if necessary, so that the driving wheel and the driven wheel are in the same plane;

S2, placing the wafer on the supporting device formed by the driving wheel and the driven wheel;

S3, the cleaning brushes located on both sides of the wafer are moved to the cleaning position to clean the front and back sides of the wafer with rolling brushes.

Further, in step S1, the checking step includes:

S11, using a position detection component to measure the horizontal position of the driving wheel and the driven wheel;

S12, compare the horizontal position of driving wheel and driven wheel;

S13, according to the comparison result, adjust the horizontal position of the driving wheel and/or the driven wheel by using the position adjusting component.

In one embodiment, after the wafer is placed on the supporting device, a position detection component is used to measure and verify the horizontal positions of the driving wheel and the driven wheel.

Further, in step S1, the horizontal position of the driving wheel is adjusted based on the driven wheel.

In one embodiment, the driving wheel is configured with an independently operating position adjustment component to adjust the horizontal position of the driving wheel according to the comparison result.

In one embodiment, the position detection component includes a distance measuring sensor, which emits laser light toward the sides of the driving wheel and the driven wheel, so as to obtain the horizontal positions of the driving wheel and the driven wheel.

In one embodiment, the ranging sensor emits laser light toward the center of the driving wheel and the driven wheel, and the wavelength of the laser light is greater than 1000 nm.

Further, during the wafer brushing process, when the rotation speed of the driven wheel is lower than the wafer rotation speed, or when the torque of the cleaning brush fluctuates, use the combination of the position detection component and the position adjustment component to check the rotation speed of the driving wheel and the driven wheel. horizontal position.

The second aspect of the embodiments of the present invention provides a control module, which includes a memory, a processor, and a computer program stored in the memory and operable on the processor, and the processor executes the The computer program implements the steps of the wafer cleaning method described above.

A third aspect of the embodiments of the present invention provides a computer-readable storage medium, the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the wafer cleaning method described above is implemented. step.

The beneficial effects of the present invention include:

a. Before the wafer is placed on the support device, measure and adjust the horizontal position of the driving wheel and the driven wheel of the support device to effectively ensure that the wafer to be cleaned is in a vertical state and prevent false alarms due to the speed drop of the driven wheel;

b. During the wafer cleaning process, the state of the supporting device is indirectly judged by monitoring the rotation speed of the driven wheel and/or the torque fluctuation of the driving motor configured by the cleaning brush, so as to determine whether to perform position calibration before cleaning the next wafer Nuclear to ensure cleaning effect and improve cleaning efficiency.

Description of drawings

The advantages of the present invention will become clearer and easier to understand through the detailed description in conjunction with the following drawings, which are only schematic and do not limit the protection scope of the present invention, wherein:

Fig. 1 is a schematic diagram of a cleaning device provided by an embodiment of the present invention;

Fig. 2 is a sectional view of a driven wheel provided by an embodiment of the present invention;

Fig. 3 is a schematic diagram showing that the driven wheel and the driving wheel are not on the same plane;

Fig. 4 is a flow chart of a wafer cleaning method provided by an embodiment of the present invention;

Fig. 5 is a flow chart of the verification steps provided by an embodiment of the present invention;

Fig. 6 is a schematic diagram of a position detection component and a position adjustment component provided in a cleaning device according to an embodiment of the present invention;

Fig. 7 is a schematic diagram of measuring a horizontal position by a ranging sensor according to an embodiment of the present invention;

FIG. 8 is a flowchart of a wafer cleaning method provided in another embodiment of the present invention;

FIG. 9 is a flowchart of a wafer cleaning method provided in another embodiment of the present invention;

Fig. 10 is a schematic diagram of a control device provided by an embodiment of the present invention.

Detailed ways

The technical solutions of the present invention will be described in detail below in conjunction with specific embodiments and accompanying drawings. The examples described here are specific implementations of the present invention and are used to illustrate the concept of the present invention; these descriptions are all explanatory and exemplary, and should not be construed as limiting the implementation of the present invention and the protection scope of the present invention . In addition to the embodiments described here, those skilled in the art can also adopt other obvious technical solutions based on the claims of the application and the contents disclosed in the specification, and these technical solutions include adopting any modifications made to the embodiments described here. Obvious alternatives and modified technical solutions.

The accompanying drawings in this specification are schematic diagrams, which assist in explaining the concept of the present invention, and schematically represent the shapes of various parts and their interrelationships. It should be understood that, in order to clearly show the structures of the components in the embodiments of the present invention, the drawings are not drawn in the same scale, and the same reference signs are used to represent the same parts in the drawings.

In the present invention, a wafer (Wafer, W) is also called a substrate (Substrate), and its meaning and actual function are equivalent.

The IC process is implemented in a clean room using some organic and inorganic chemical materials. Due to the influence of personnel, environment and other factors, pollutants such as particles, organic matter, metal pollutants and/or oxides will be produced during wafer processing, and the particle size of these pollutants varies from a few nanometers to hundreds of nanometers. Wafer cleaning is mainly to remove the pollutants attached to the wafer surface, and to control the size and quantity of the pollutant particles within the range of process requirements.

1 is a schematic diagram of a wafer cleaning device. The wafer cleaning device includes a housing 10, and a supporting device 20 is provided inside the housing 10 to vertically support and position a wafer W to be cleaned. Cleaning brushes 30 are provided on both sides of the wafer W, and driving motors (not shown) are connected to ends of the cleaning brushes 30 to drive the cleaning brushes 30 to rotate around their axes. The upper part of the casing 10 is provided with a spraying pipeline to spray DIW and/or cleaning liquid onto the wafer W.

The supporting device 20 includes a pair of driving wheels 21 and driven wheels 22. The driven wheels 22 are located in the middle of the driving wheels 21 and distributed along the edge of the wafer W to vertically support and drive the wafer to rotate.

When the wafer is cleaned, the motor arranged on the side of the driving wheel 21 drives it to rotate in the same direction, and under the action of friction, the wafer W vertically arranged on the supporting device 20 rotates around the axis of the wafer. Since the wafer is inserted into the driven wheel 22 , specifically, the wafer is inserted into the groove (shown in FIG. 2 ) on the washer in the driven wheel 22 , and then drives the driven wheel 22 to rotate. Usually, an unshown speed measurement module is provided on one side of the driven wheel 22 to monitor the rotation speed of the wafer.

In the embodiment shown in FIG. 1 , the cleaning brush 30 can be made of a porous material, such as polyvinyl alcohol, and the cleaning brush 30 can absorb a large amount of cleaning liquid for cleaning the surface of the wafer W. The rolling cleaning brush 30 is in contact with the rotating wafer W to remove contaminants on the surface of the wafer W. The cleaning brushes 30 located on both sides of the wafer W can move horizontally to move away from or approach the wafer W. Referring to FIG. When the cleaning brush 30 is far away from the wafer W, a certain gap is reserved between the cleaning brush 30 and the wafer W, and the wafer handling manipulator can hold the wafer W to take away the cleaned wafer; the cleaning brush 30 moves close to the wafer W, cleaning The brush 30 comes into contact with the wafer W and cleans the surface of the wafer in contact.

In the wafer cleaning device shown in FIG. 1 , due to processing and assembly errors, after the driving wheel 21 and the driven wheel 22 are installed, the situation that the driving wheel 21 and the driven wheel 22 are not coplanar is likely to occur, as shown in FIG. 3 , The wafer placed on the supporting device 20 is tilted, and even the wafer cannot be accurately inserted into the washer of the driven wheel 22 .

In order to solve the above problems, the present invention provides a wafer cleaning method, its flow chart, as shown in Figure 4, a wafer cleaning method comprising:

S1, check the horizontal position of the driving wheel 21 and the driven wheel 22, and adjust the driving wheel 21 and/or the driven wheel 22 as required, so that the driving wheel 21 and the driven wheel 22 are located in the same plane;

Specifically, in order to ensure that the wafers disposed in the casing 10 are in a vertical state, the washers in the driving wheel 21 and the driven wheel 22 need to be consistent in horizontal position.

S2, placing the wafer on the supporting device 20 formed by the driving wheel 21 and the driven wheel 22;

Specifically, the wafer handling manipulator places the wafer to be cleaned on the support device 20 through the opening above the housing 10;

S3, the cleaning brushes 30 located on both sides of the wafer are moved to the cleaning position to clean the front and back sides of the wafer with rolling brushes.

After the wafer is placed on the supporting device 20, the cleaning brush 30 arranged in parallel moves to the cleaning position toward the wafer; then, the cleaning brush 30 rolls around the central axis to brush off the particles on the surface of the wafer by rolling; the driving wheel 21 The configured motor drives it to rotate, so as to drive the wafer to rotate, so that the cleaning brush 30 can fully cover the surface of the wafer, ensuring a good cleaning effect.

Fig. 5 is a flow chart of the checking steps provided by an embodiment of the present invention. In step S1, the checking steps include:

S11, use the position detection assembly 40 (shown in Figure 6) to measure the horizontal position of the driving wheel 21 and the driven wheel 22;

S12, compare the horizontal position of driving wheel 21 and driven wheel 22;

S13, adjust the horizontal position of the driving wheel 21 and/or the driven wheel 22 using the position adjusting assembly 50 (shown in FIG. 6 ) according to the comparison result.

In the present invention, when checking the driving wheel 21 and the driven wheel 22, a position detection assembly 40 and a position adjustment assembly 50 need to be used, as shown in FIG. 6 . The position detection assembly 40 includes a distance measuring sensor 41 (shown in FIG. 7 ), which is arranged on the outside of the housing 10, and the front end of the distance measuring sensor 41 is configured with a transparent window to face the driving wheel 21 and the driven wheel 22 in the housing 10 The light signal is emitted to realize the measurement of the horizontal position of the driving wheel 21 and the driven wheel 22 .

In Fig. 6, the position adjustment assembly 50 includes a servo motor 51, a lead screw 52 and a slide block 53, the slide block 53 is arranged on the lead screw 52, and the slide block 53 is connected with the mounting seat of the driving wheel 21 or the driven wheel 22 to drive the driving The wheel 21 or the driven wheel 22 moves in the horizontal direction to adjust the position of the driving wheel 21 or the driven wheel 22 .

As an embodiment of the present invention, the position of the driven wheel 22 is relatively fixed, and the position adjustment assembly 50 is specially configured for the driving wheel 21; the position detection assembly 40 measures the horizontal position of the driving wheel 21 and the driven wheel 22 to obtain measurement results; position adjustment The component 50 adjusts the horizontal position of the driving wheel 21 as needed according to the measurement results, so that the driving wheel 21 and the driven wheel 22 are in the same plane. Specifically, the grooves of the washer in the driving wheel 21 and the driven wheel 22 are in the same plane, so that the wafer inserted into the groove of the washer is in a vertical state.

That is, each driving wheel 21 is configured with an independently operating position adjustment assembly 50 to adjust the horizontal position of the driving wheel 21 according to the measurement result of the horizontal position, so that a pair of driving wheels 21 and driven wheels 22 are in the same plane.

It should be noted that the horizontal position of the driving wheel 21 and the driven wheel 22 is based on the distance measuring sensor 41 (shown in FIG. 7 ) as the reference plane, and the distance D between the outer end surfaces of the driving wheel 21 and the driven wheel 22 and the reference plane.

As an aspect of this embodiment, the ranging sensor 41 is a laser ranging sensor, which emits laser light toward the sides of the driving wheel 21 and the driven wheel 22 to obtain the horizontal positions of the driving wheel 21 and the driven wheel 22 .

In the embodiment shown in FIG. 7 , the horizontal distance of the driven wheel 22 measured by the ranging sensor 41 is D _i , and the horizontal distance of the driving wheel 21 measured by the ranging sensor 41 is D _d .

If D _d <D _i , the driving wheel 21 needs to move away from the distance measuring sensor 41 so that D _d =D _i ; or the difference between the two is within the allowable tolerance range.

If D _d >D _i , the driving wheel 21 needs to move towards the distance measuring sensor 41 so that D _d =D _i ; or the difference between the two is within the allowable tolerance range.

In FIG. 7 , the ranging sensor 41 emits laser light toward the center positions of the driving wheel 21 and the driven wheel 22 to measure the horizontal positions of the driving wheel 21 and the driven wheel 22 .

As an embodiment of the present invention, after the wafer is placed on the supporting device 20 , it is usually not necessary to use the ranging sensor 41 to measure the horizontal position of the driving wheel 21 or the driven wheel 22 . However, in some special processes, it is necessary to monitor whether the verticality of the wafer changes in real time, or whether the horizontal position of the driving wheel 21 or the driven wheel 22 changes after the wafer is placed on the supporting device 20 . Therefore, when the wafer is placed on the supporting device 20 , the ranging sensor 41 also needs to emit laser light toward the driving wheel 21 or the driven wheel 22 to measure the horizontal position.

As an aspect of this embodiment, the wavelength of the laser light emitted by the ranging sensor 41 is greater than 1000 nm. Since the laser wavelength is greater than 1000nm, photocorrosion will hardly be caused in the wafer cleaning device. Therefore, setting the ranging sensor 41 in this way can ensure the effect of wafer cleaning and avoid affecting the yield of wafer cleaning due to photocorrosion.

As another embodiment of the present invention, in order to avoid the impact of the ranging sensor 41 on the cleaning effect during the wafer cleaning process, the driving wheel 21 or the driven wheel 22 during the brushing process can be indirectly obtained by monitoring the rotation speed V _i of the driven wheel 21. Whether the position of the wafer has changed to determine the verticality of the brushed wafer.

The flowchart of the wafer cleaning method described above is shown in FIG. 8 . The rotational speed V _i of the driven wheel 21 is compared with the rotational speed V _w of the wafer W brushed:

If V _i <V _w , it indicates that there is a problem of speed drop of the scrubbed wafer, which indirectly reflects that the driving wheel 21 and the driven wheel 22 may be in different planes. Therefore, before cleaning the next wafer, the calibration step shown in FIG. 5 needs to be adopted to check the horizontal positions of the driving wheel 21 and the driven wheel 22 .

If V _i =V _w , it means that the speed measurement module configured on the driven wheel 22 can accurately measure the rotation speed of the wafer W, and there is no need to check the horizontal positions of the driving wheel 21 and the driven wheel 22 before cleaning the next wafer.

As a variation of the embodiment in FIG. 8 , it is also possible to detect the fluctuation of the torque T of the driving motor configured with the cleaning brush 30 to determine whether the brush cleaning wafer is in a vertical state. FIG. 9 is a flowchart of a corresponding wafer cleaning method.

During the wafer cleaning process, the torque of the drive motor configured by the cleaning brush 30 is monitored in real time, and the real-time measured torque _Tc is compared with the set torque _Tr of the drive motor to determine the state of the wafer being brushed.

If | _c - _Tr |> _Tr *15%, it means that during the wafer cleaning process, the torque of the driving motor configured by the cleaning brush 30 fluctuates greatly. Therefore, before cleaning the next wafer, it is necessary to use the The verification step shown is to verify the horizontal position of the driving wheel 21 and the driven wheel 22 .

If | _c - _Tr | _≤Tr *15%, it means that during the wafer cleaning process, the torque of the driving motor configured by the cleaning brush 30 fluctuates within the set range, and there is no need to check before cleaning the next wafer The horizontal position of driving wheel 21 and driven wheel 22.

Fig. 10 is a schematic diagram of a control device provided by an embodiment of the present invention. In this embodiment, the control device includes: a processor, a memory, and a computer program stored in the memory and operable on the processor. When the processor executes the computer program, the steps in the embodiments of the above-mentioned wafer cleaning method embodiments are realized. Alternatively, when the processor executes the computer program, the functions of the modules/units in the above-mentioned system embodiments are realized.

Control devices refer to terminals with data processing capabilities, including but not limited to computers, workstations, servers, and even smart phones with excellent performance, handheld computers, tablet computers, personal digital assistants (PDAs), smart TVs (Smart TVs), etc. .

A control device may include, but is not limited to, a processor, memory. Those skilled in the art can understand that FIG. 10 is only an example of the control device, and does not constitute a limitation to the control device. It may include more or less components than shown in the figure, or combine some components, or different components, such as Control devices may also include input and output devices, network access devices, buses, and so on.

The so-called processor can be a central processing unit (Central Processing Unit, CPU), and can also be other general-purpose processors, digital signal processors (Digital Signal Processor, DSP), application specific integrated circuits (Application Specific Integrated Circuit, ASIC), off-the-shelf Programmable gate array (Field-Programmable Gate Array, FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, etc.

The storage may be an internal storage unit of the control device, such as a hard disk or memory of the control device. The memory can also be an external storage device of the control device, such as a plug-in hard disk equipped on the control device, a smart memory card (SmartMedia Card, SMC), a secure digital (Secure Digital, SD) card, a flash memory card (Flash Card) and the like.

Further, the memory may also include both an internal storage unit of the control device and an external storage device. Memory is used to store computer programs and other programs and data needed to control equipment. The memory can also be used to temporarily store data that has been output or will be output.

In the description of this specification, references to the terms "one embodiment," "some embodiments," "exemplary embodiments," "example," "specific examples," or "some examples" are intended to mean that the implementation A specific feature, structure, material, or characteristic described by an embodiment or example is included in at least one embodiment or example of the present invention. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

Although the embodiments of the present invention have been shown and described, those skilled in the art can understand that various changes, modifications, substitutions and modifications can be made to these embodiments without departing from the principle and spirit of the present invention. The scope of the invention is defined by the claims and their equivalents.

Claims (10)

1. A wafer cleaning method, characterized in that, comprising: S1, check the horizontal position of the driving wheel and the driven wheel, and adjust the driving wheel and/or the driven wheel if necessary, so that the driving wheel and the driven wheel are in the same plane; S2, placing the wafer on the supporting device formed by the driving wheel and the driven wheel; S3, the cleaning brushes located on both sides of the wafer are moved to the cleaning position to clean the front and back sides of the wafer with rolling brushes. 2. wafer cleaning method as claimed in claim 1, is characterized in that, in step S1, checking step comprises: S11, using a position detection component to measure the horizontal position of the driving wheel and the driven wheel; S12, compare the horizontal position of driving wheel and driven wheel; S13, according to the comparison result, adjust the horizontal position of the driving wheel and/or the driven wheel by using the position adjusting component. 3. The wafer cleaning method according to claim 2, wherein after the wafer is placed on the supporting device, the horizontal position of the driving wheel and the driven wheel is measured and verified using a position detection component. 4. The wafer cleaning method according to claim 1, wherein in step S1, the horizontal position of the driving wheel is adjusted with the driven wheel as a reference. 5. The wafer cleaning method according to claim 2, wherein the driving wheel is equipped with an independently operating position adjustment component to adjust the horizontal position of the driving wheel according to the comparison result. 6. The wafer cleaning method according to claim 2, wherein the position detection assembly includes a distance measuring sensor, which emits laser light towards the sides of the driving wheel and the driven wheel to obtain the horizontal position of the driving wheel and the driven wheel . 7. The wafer cleaning method according to claim 6, wherein the ranging sensor emits laser light toward the center of the driving wheel and the driven wheel, and the wavelength of the laser light is greater than 1000nm. 8. The wafer cleaning method according to claim 2, wherein during the wafer scrubbing process, when the rotational speed of the driven wheel is lower than the wafer rotational speed, or when the torque of the cleaning brush fluctuates, position detection is used. The assembly and the position adjustment assembly are combined to check the horizontal position of the driving wheel and the driven wheel. 9. A control module, characterized in that it comprises a memory, a processor, and a computer program stored in the memory and operable on the processor, when the processor executes the computer program, the computer program according to claim 1 is realized. The steps of the wafer cleaning method described in any one of 1 to 8. 10. A computer-readable storage medium, characterized in that the computer-readable storage medium stores a computer program, and when the computer program is executed by a processor, the wafer according to any one of claims 1 to 8 is realized. Steps in the cleaning method.

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