Wafer cleaning equipment

Abstract

A wafer cleaning device includes: a housing for holding cleaning liquid and wafers; a vibrating plate mounted within the housing; a drive assembly mounted within the housing for driving the wafers during cleaning; a piezoelectric assembly connected to the drive assembly for acquiring pressure signals from the drive assembly; and a float level monitoring assembly connected to the housing for monitoring the cleaning liquid level. By employing mechanical principles to form corresponding monitoring assemblies, the device effectively monitors the wafer position and liquid level, avoiding corrosion on the wafer surface after metal flattening, which can occur when using optical, magnetic, or electric field monitoring methods.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor manufacturing, and in particular to wafer cleaning equipment. Background Art

[0002] Chemical Mechanical Planarization (CMP) equipment is one of the seven key pieces of equipment in integrated circuit manufacturing. After CMP processing, residues and polishing fluid remain on the wafer surface. To promptly remove these contaminants, CMP equipment must be used in conjunction with wafer cleaning equipment.

[0003] However, existing wafer cleaning equipment after wafer planarization still has many problems. Summary of the Invention

[0004] The technical problem solved by the present invention is to provide a wafer cleaning device to avoid corrosion of the wafer surface after metal flattening when using optical, magnetic and electric field monitoring.

[0005] To solve the above problems, the technical solution of the present invention provides a wafer cleaning device, comprising: a box body for holding cleaning liquid and wafers; a vibration plate installed in the box body; a driving component installed in the box body, for driving the wafer to rotate during the wafer cleaning process; a piezoelectric component connected to the driving component, for obtaining a pressure signal from the driving component; and a float liquid level monitoring component connected to the box body, for monitoring the liquid level of the cleaning liquid.

[0006] Optionally, the driving assembly includes: a driving wheel and a driven wheel.

[0007] Optionally, it further includes: a card slot opened in the driving wheel and the driven wheel.

[0008] Optionally, the piezoelectric component includes: a box body fixed on the outer side wall of the box body; a transmission rod, including a first section and a second section that are relatively vertical, the first section passes through the side wall of the box body, and the end of the first section is rotatably connected to the driven wheel, and the end of the second section is rotatably connected to the box body; and a piezoelectric ceramic installed in the box body, the transition between the first section and the second section is in contact with the surface of the piezoelectric ceramic.

[0009] Optionally, the float liquid level monitoring assembly includes: a liquid level tube connected to the box body, a plurality of perforated baffles fixed in the liquid level tube, and the plurality of perforated baffles divide the inner cavity of the liquid level tube into a plurality of liquid level chambers; a liquid level ball placed in each of the liquid level chambers; and a plurality of capacitor plate groups fixed on the liquid level tube, each of the capacitor plate groups corresponding to one of the liquid level chambers.

[0010] Optionally, the plurality of liquid level chambers include: a low liquid level chamber, a middle liquid level chamber and a high liquid level chamber.

[0011] Optionally, the capacitor plate group is fixed to the outer wall of the liquid level tube.

[0012] Optionally, the capacitor plate group is located on the top of the liquid level chamber.

[0013] Optionally, it also includes: a pump body installed in the box body; a water supply pipe, including a first water supply end and a second water supply end relative to each other, the first water supply end is connected to the pump body, and the second water supply end is located at the top of the inner cavity of the liquid level pipe.

[0014] Optionally, it also includes: a sprinkler head connected to the second water supply end.

[0015] Optionally, the vibration plate is a megasonic vibration plate.

[0016] Compared with the prior art, the technical solution of the present invention has the following advantages:

[0017] The wafer cleaning equipment of the present invention includes a drive assembly mounted within the housing for rotating the wafer during cleaning; a piezoelectric assembly connected to the drive assembly for acquiring pressure signals from the drive assembly; and a float level monitoring assembly connected to the housing for monitoring the level of the cleaning liquid. By employing mechanical principles to form corresponding monitoring assemblies, the wafer position and liquid level can be effectively monitored, avoiding corrosion on the wafer surface after metal flattening, which can occur when using optical, magnetic, or electric field monitoring methods.

[0018] Furthermore, the drive assembly includes: a driving wheel and a driven wheel connected to the driving wheel; the piezoelectric assembly includes: a box body fixed to the outer wall of the box body; a transmission rod including a first section and a second section that are relatively perpendicular, the first section passing through the side wall of the box body, and the end of the first section is rotatably connected to the driven wheel, and the end of the second section is rotatably connected to the box body; and a piezoelectric ceramic installed in the box body, the junction between the first section and the second section is in contact with the surface of the piezoelectric ceramic. When the wafer is placed on the driving wheel and the driven wheel, the weight of the wafer itself is used to apply pressure to the driven wheel, and the pressure applied to the driven wheel is transmitted to the piezoelectric ceramic through the transmission rod. When the piezoelectric ceramic is subjected to the force, it deforms and generates an electrical signal, thereby realizing the monitoring of the wafer position.

[0019] Furthermore, the float liquid level monitoring assembly includes: a liquid level tube connected to the housing, wherein a plurality of perforated baffles are fixed within the liquid level tube, wherein the plurality of perforated baffles divide the inner cavity of the liquid level tube into a plurality of liquid level chambers; a liquid level ball placed within each of the liquid level chambers; and a plurality of capacitor plate groups fixed to the liquid level tube, wherein each capacitor plate group corresponds to a liquid level chamber. Because the liquid level tube is connected to the housing to form a communicating vessel structure, when the liquid level of the cleaning liquid within the housing changes, the cleaning liquid within the liquid level tube will also change synchronously. When the liquid level rises, the liquid level ball will rise with the liquid level. When the liquid level ball rises between the capacitor plate groups, the dielectric between the capacitor plate groups changes from air to the liquid level ball. Because the dielectric constants of air and the liquid level ball are different, the corresponding circuit current will also change accordingly. By monitoring the changes in the circuit current, the changes in the liquid level within the housing can be inferred.

[0020] Furthermore, the device further comprises: a pump body mounted within the housing; and a water supply pipe comprising a first water supply end and a second water supply end, the first water supply end being connected to the pump body, and the second water supply end being located at the top of the inner cavity of the liquid level pipe. Due to the relatively small inner cavity of the liquid level pipe, impurities in the cleaning liquid easily accumulate within the liquid level pipe, making it difficult to clean out in time. The pump body circulates the cleaning liquid within the housing and the liquid level pipe, thereby reducing the accumulation of impurities within the liquid level pipe.

[0021] Furthermore, the apparatus further comprises a spray head connected to the second water supply end, through which cleaning liquid can be sprayed to wet and clean the inner wall of the liquid level tube, thereby reducing the degradation of cleaning effect caused by crystallization of impurities on the inner wall of the liquid level tube. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 1 is a schematic structural diagram of a wafer cleaning device according to an embodiment of the present invention;

[0023] Figure 2 Schematic diagram of the structure of the drive component and the piezoelectric component in the wafer cleaning device according to an embodiment of the present invention;

[0024] Figure 3 1 is a schematic diagram of wafer pressure decomposition in a wafer cleaning device according to an embodiment of the present invention;

[0025] Figure 4 1 is a schematic structural diagram of a float liquid level monitoring assembly in a wafer cleaning device according to an embodiment of the present invention;

[0026] Figure 5 This is a schematic structural diagram of a wafer cleaning device according to an embodiment of the present invention when the cleaning liquid is insufficient;

[0027] Figure 6This is a schematic structural diagram of a wafer cleaning device according to an embodiment of the present invention when the cleaning liquid is sufficient;

[0028] Figure 7 It is a structural schematic diagram of a wafer cleaning device according to an embodiment of the present invention when there is too much cleaning liquid. DETAILED DESCRIPTION

[0029] As described in the background art, existing wafer cleaning equipment after wafer planarization still has many problems, which will be described in detail below.

[0030] Existing wafer cleaning equipment uses optical sensors to monitor wafer position and the level of the cleaning liquid. These sensors are mounted centrally on either side of a cleaning chamber. The photoelectric sensor's light source emits a beam of light. When no wafers are present, the beam is received by the photoelectric sensor on the other side. However, when a wafer is present, the beam is blocked by the wafer and cannot be received by the photoelectric sensor on the other side, effectively detecting the presence of a wafer.

[0031] However, because optical sensors can cause photoinduced corrosion of metals, post-CMP wafer cleaning requires either removing the optical sensors or the megasonic plate during the cleaning process. Removing the optical sensors makes it impossible to monitor the level of the cleaning liquid and the position of the wafer; removing the megasonic plate significantly reduces cleaning effectiveness.

[0032] On this basis, the present invention provides a wafer cleaning device, which forms a corresponding monitoring component through mechanical principles, and can effectively monitor the wafer position and liquid level height, avoiding corrosion of the wafer surface after metal flattening when using optical, magnetic field and electric field monitoring.

[0033] In order to make the above-mentioned objects, features and advantages of the present invention more obvious and easy to understand, specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0034] Figure 1 1 is a schematic structural diagram of a wafer cleaning device according to an embodiment of the present invention; Figure 2 Schematic diagram of the structure of the drive component and the piezoelectric component in the wafer cleaning device according to an embodiment of the present invention; Figure 3 1 is a schematic diagram of wafer pressure decomposition in a wafer cleaning device according to an embodiment of the present invention; Figure 4 1 is a schematic structural diagram of a float liquid level monitoring assembly in a wafer cleaning device according to an embodiment of the present invention; Figure 5 This is a schematic structural diagram of a wafer cleaning device according to an embodiment of the present invention when the cleaning liquid is insufficient; Figure 6 This is a schematic structural diagram of a wafer cleaning device according to an embodiment of the present invention when the cleaning liquid is sufficient; Figure 7 It is a structural schematic diagram of a wafer cleaning device according to an embodiment of the present invention when there is too much cleaning liquid.

[0035] Please refer to Figure 1 A wafer cleaning device includes: a box 10 for holding cleaning liquid 200 and wafers 100; a vibration plate 11 installed in the box 10; a driving component 12 installed in the box 10, for driving the wafer 100 to rotate during the cleaning process of the wafer 100; a piezoelectric component 13 connected to the driving component 12, for obtaining a pressure signal from the driving component 12; and a float liquid level monitoring component 14 connected to the box 10, for monitoring the liquid level of the cleaning liquid 200.

[0036] In this embodiment, a corresponding monitoring component is formed by mechanical principles, which can effectively monitor the position of the wafer 100 and the liquid level, avoiding corrosion of the wafer 100 surface after metal flattening when using optical, magnetic field and electric field monitoring.

[0037] Please refer to Figure 2 In this embodiment, the driving assembly 12 includes a driving wheel 121 and a driven wheel 122 .

[0038] In this embodiment, the wafer 100 is further secured in a secure position by providing a retaining groove 124 in the driving wheel 121 and the driven wheel 122.

[0039] Please continue to refer to Figure 2 In this embodiment, the piezoelectric component 13 includes: a box body 131 fixed to the outer wall of the box body 10; a transmission rod 132, including a relatively vertical first section 132b and a second section 132a, the first section 132b passes through the side wall of the box body 10, and the end of the first section 132b is rotatably connected to the driven wheel 122, and the end of the second section 132a is rotatably connected to the box body 131; and a piezoelectric ceramic 133 installed in the box body 131, and the transition between the first section 132b and the second section 132a is in contact with the surface of the piezoelectric ceramic 133.

[0040] Please refer to Figure 3 Since the end of the second section 132a of the transmission rod 132 is rotatably connected to the box body 131, and the junction between the first section 132b and the second section 132a contacts the surface of the piezoelectric ceramic 133, the transmission rod 132 and the piezoelectric ceramic 133 form a lever structure, with the piezoelectric ceramic 133 as the fulcrum. When the wafer 100 is placed on the driving wheel 121 and the driven wheel 122, the weight of the wafer 100 itself is used to apply pressure to the driven wheel 122. The direction and magnitude of the pressure at this time are F 压 ; F压 Decompose the forces in the horizontal and vertical directions. The vertical force F 竖 The transmission rod 132 is driven to rotate. At this time, the force acting on the piezoelectric ceramic 133 at the junction of the first section 132b and the second section 132a increases. The piezoelectric ceramic 133 is deformed after being subjected to the force and generates an electrical signal, thereby realizing the monitoring of the position of the wafer 100. Through the monitoring of the piezoelectric component 13, it is possible to monitor whether the wafer 100 has been installed in place.

[0041] In addition, if the wafer 100 is intact, the electrical signal detected by the piezoelectric component 13 will be basically stable after the wafer 100 is installed in place. If the wafer 100 is damaged, the pressure exerted by the wafer 100 on the driven wheel 122 will also change during the rotation of the wafer 100, and the electrical signal detected by the piezoelectric component 13 will also change, which can lead to the possibility that the wafer 100 is damaged. Therefore, the cooperation between the drive component 12 and the piezoelectric component 13 can prevent the wafer 100 from running idle during the cleaning process, causing unnecessary energy consumption and damage to the wafer 100.

[0042] In this embodiment, the length of the first section 132b is greater than that of the second section 132a. The longer the length of the first section 132b is, the better the force amplification effect on the piezoelectric ceramic 133 at the junction of the first section 132b and the second section 132a is, thereby improving the detection sensitivity.

[0043] In this embodiment, the first section 132 b passes through the side wall of the box body 10 and is sealed by a sealing ring 134 to prevent the cleaning liquid 200 from leaking.

[0044] Please refer to Figure 4 In this embodiment, the float liquid level monitoring assembly 14 includes: a liquid level tube 141 connected to the box body 10, a plurality of perforated baffles 142 fixed in the liquid level tube 141, and the plurality of perforated baffles 142 divide the inner cavity of the liquid level tube 141 into a plurality of liquid level chambers 143; a liquid level ball 144 placed in each of the liquid level chambers 143; and a plurality of capacitor plate groups 145 fixed on the liquid level tube 141, each of the capacitor plate groups 145 corresponding to one of the liquid level chambers 143.

[0045] In this embodiment, since the liquid level tube 141 is connected to the housing 10 to form a communicating vessel structure, when the liquid level of the cleaning liquid 200 in the housing 10 changes, the cleaning liquid 200 in the liquid level tube 141 will also change synchronously. When the liquid level rises, the liquid level ball 144 will rise along with the liquid level. When the liquid level ball 144 rises between the capacitor plate group 145, the dielectric between the capacitor plate group 145 changes from air to the liquid level ball 144. Since the dielectric constants of air and the liquid level ball 144 are different, the corresponding circuit current will also change accordingly. By monitoring the change in the circuit current, the change in the liquid level in the housing 10 can be obtained.

[0046] Please continue to refer to Figure 4 In this embodiment, the liquid level chambers 143 include: a low liquid level chamber 143a, a middle liquid level chamber 143b and a high liquid level chamber 143c; the capacitor plate group 145 is fixed to the outer wall of the liquid level tube 141; the capacitor plate group 145 is located at the top of the liquid level chamber 143.

[0047] Please refer to Figure 5 In this embodiment, when the cleaning liquid 200 in the box body 10 is insufficient, the liquid level balls 144 in the low liquid level chamber 143a, the middle liquid level chamber 143b and the high liquid level chamber 143c are all at the lowest position, and the dielectric between the capacitor plate group 145 installed on the side wall of the low liquid level chamber 143a is air. By setting the capacitance of the capacitor plate group 145 to an abnormal state at this time, it is reminded that the cleaning liquid 200 in the box body 10 is insufficient and it is added in time.

[0048] Please refer to Figure 6 In this embodiment, when the cleaning liquid 200 in the box body 10 is sufficient, the liquid level ball 144 in the low liquid level chamber 143a floats at the highest position, and the dielectric between the capacitor plate group 145 installed on the side wall of the low liquid level chamber 143a is the liquid level ball 144. By setting the capacitance of the capacitor plate group 145 to a normal state at this time, it is reminded that the cleaning liquid 200 in the box body 10 is sufficient and does not need to be increased.

[0049] Please refer to Figure 7 In this embodiment, when there is too much cleaning liquid 200 in the box body 10, the liquid level ball 144 in the high liquid level chamber 143c floats at the highest position, and the dielectric between the capacitor plate group 145 installed on the side wall of the high liquid level chamber 143c is the liquid level ball 144. By setting the capacitance of the capacitor plate group 145 to an abnormal state at this time, it is reminded that there is too much cleaning liquid 200 in the box body 10 and it is removed in time.

[0050] In other embodiments, the inner cavity of the liquid level tube may be divided into more liquid level chambers so as to obtain a more accurate position height of the cleaning liquid 200 .

[0051] Please continue to refer to Figure 1 In this embodiment, it also includes: a pump body 15 installed in the box body 10; a water supply pipe 16, including a first water supply end 16a and a second water supply end 16b opposite to each other, the first water supply end 16a is connected to the pump body 15, and the second water supply end 16b is located at the top of the inner cavity of the liquid level tube 141.

[0052] In this embodiment, due to the small inner volume of the liquid level tube 141, impurities in the cleaning liquid 200 are easily accumulated in the liquid level tube 141 and cannot be cleaned in time. The pump body 15 circulates the cleaning liquid 200 in the tank 10 and the liquid level tube 141, thereby reducing the accumulation of impurities in the liquid level tube 141.

[0053] Please continue to refer to Figure 1 In this embodiment, the apparatus further includes a spray head 17 connected to the second water supply end 16b. The spray head 17 can spray cleaning liquid 200 to wet and clean the inner wall of the liquid level tube 141, thereby reducing the degradation of the cleaning effect caused by crystallization of impurities on the inner wall of the liquid level tube 141.

[0054] In this embodiment, the vibration plate 11 adopts a megasonic vibration plate. The megasonic vibration plate is used to generate megasonic waves. Megasonic cleaning uses a transducer to emit megahertz-level high-energy sound waves. The solution molecules are accelerated under the impetus of such sound waves, and the maximum instantaneous speed can reach 30 cm / s. Due to the high frequency, cavitation bubbles cannot be formed like ultrasonic cleaning, but only the high-speed fluid dynamic layer generated by the strong sound pressure gradient and acoustic flow can continuously impact the substrate surface, so that the particles attached to the substrate surface are forcibly removed and enter the medium liquid. Megasonic cleaning not only retains the advantages of ultrasonic cleaning, but also overcomes its shortcomings. Megasonic cleaning can remove particles smaller than 0.1llxm on the substrate surface, playing a role that ultrasonic waves cannot play. This method can simultaneously play the role of mechanical wiping (torsion) and chemical cleaning. In addition, the frequency of megasonic cleaning is higher. Unlike ultrasonic cleaning that generates standing waves, it will not damage the cleaning object. In addition, megasonic cleaning has different requirements in terms of viscous layer thickness, power density, and resonance effect. 、 It has more advantages than ultrasound in terms of diffraction effect.

[0055] Although the present invention is disclosed as above, the present invention is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention should be based on the scope defined by the claims.

Claims

1. A wafer cleaning device, characterized in that: include: A box body, used for containing cleaning liquid and wafers; a vibration plate installed in the box; A driving assembly installed in the box, used to drive the wafer to rotate during the wafer cleaning process; a piezoelectric component connected to the driving component, for acquiring a pressure signal from the driving component; as well as The float liquid level monitoring assembly communicated with the box is used to monitor the liquid level of the cleaning liquid; wherein, The driving assembly includes: a driving wheel and a driven wheel; The piezoelectric assembly includes: a box body fixed to the outer side wall of the box body; a transmission rod, including a first section and a second section that are relatively perpendicular, the first section passing through the side wall of the box body, and the end of the first section is rotatably connected to the driven wheel, and the end of the second section is rotatably connected to the box body; and a piezoelectric ceramic installed in the box body, the transition between the first section and the second section is in contact with the surface of the piezoelectric ceramic.

2. The wafer cleaning equipment according to claim 1, wherein: Also includes: A card slot is provided in the driving wheel and the driven wheel.

3. The wafer cleaning equipment according to claim 1, wherein: The float liquid level monitoring assembly includes: a liquid level tube connected to the box body, a plurality of perforated baffles fixed in the liquid level tube, and the plurality of perforated baffles divide the inner cavity of the liquid level tube into a plurality of liquid level chambers; a liquid level ball placed in each of the liquid level chambers; and a plurality of capacitor plate groups fixed on the liquid level tube, each of the capacitor plate groups corresponding to one of the liquid level chambers.

4. The wafer cleaning equipment according to claim 3, wherein: The liquid level chambers include a low liquid level chamber, a middle liquid level chamber and a high liquid level chamber.

5. The wafer cleaning equipment according to claim 3, wherein: The capacitor plate group is fixed to the outer side wall of the liquid level tube.

6. The wafer cleaning equipment according to claim 3, wherein: The capacitor plate set is located on top of the liquid level chamber.

7. The wafer cleaning equipment according to claim 3, wherein: Also includes: A pump body is installed in the box body; a water delivery pipe includes a first water delivery end and a second water delivery end opposite to each other, the first water delivery end is connected to the pump body, and the second water delivery end is located at the top of the inner cavity of the liquid level pipe.

8. The wafer cleaning equipment according to claim 7, wherein: Also includes: A sprinkler head is connected to the second water delivery end.

9. The wafer cleaning equipment according to claim 1, wherein: The vibration plate adopts a megasonic vibration plate.

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