Low-pressure cleaning device and cleaning method for cleaning scaling powder

Abstract

The invention provides a low-pressure cleaning device and method for cleaning scaling powder, and the device comprises a cleaning chamber which can be opened and closed and is provided with an extraction opening, an air pressure release opening and a first cleaning liquid injection opening; the chuck assembly is rotatably arranged in the cleaning chamber and is used for adsorbing the wafer; and the rotary driving mechanism is connected with the chuck assembly. The swing arm assembly is rotatably arranged in the cleaning cavity, and the swing arm assembly is provided with a second cleaning liquid injection port and a plurality of nozzles; and the swing driving mechanism is connected with the swing arm assembly. The cleaning chamber is closed to form a closed environment, negative pressure is formed through air exhaust to exhaust air between the core particles and the wafer and damage the surface tension of the cleaning liquid, and the cleaning liquid flows into the gaps between the core particles and the wafer. After the interior of the cleaning cavity is restored to the normal pressure state through the air pressure release opening, the cleaning liquid is completely pressed into the gap under the action of the pressure difference, so that air holes in the tiny gap are eliminated, the cleaning liquid makes contact with the scaling powder in the gap, the scaling powder is dissolved, and technological defects are avoided.

Description

Technical Field

[0001] The present invention relates to the field of semiconductor manufacturing technology, and particularly to a low-pressure cleaning device and a cleaning method for cleaning flux. Background Art

[0002] In current 2.5D mass-produced products, the gap after the die and the wafer are bonded is 40 - 50 μm. On a single 12-inch interposer, 8 - 9 relatively large dies (about 80 mm in size) are bonded. Cleaning liquid, deionized water, etc. react with the flux successively, and after several cycles, the flux can be effectively cleaned. The cleaning time for a single piece is about 20 - 30 minutes. For advanced products in the layout, the gap after the die and the wafer are bonded is 10 - 20 μm. On a single 12-inch interposer, several small dies (about 20 mm in size) are bonded. Cleaning liquid, deionized water, etc. react with the flux successively, and the number of cycles is significantly more than that of existing mass-produced products. The cleaning time for a single piece is about 120 minutes or even longer. Since the die and the wafer achieve high-density interconnection through micro-bumps, the die pitch is reduced to 20 μm or even smaller, and the bump pitch is reduced to 10 μm or even smaller. Currently, the spraying method is used for cleaning, but under the action of surface tension, the liquid seals the gas in the gap between the die and the wafer, forming "cavities", resulting in the cleaning liquid being unable to contact the flux in the "cavities", thereby generating process defects and reducing the product yield.

[0003] In view of this, it is necessary to provide a low-pressure cleaning device and a cleaning method for cleaning flux to solve the above problems. Summary of the Invention

[0004] The purpose of the present invention is to provide a low-pressure cleaning device and a cleaning method for cleaning flux, so as to improve the problem that the existing cleaning method cannot effectively clean the residual flux in the gap between the die and the wafer.

[0005] The present invention provides a low-pressure cleaning device for cleaning flux, including: A cleaning chamber, which is hollow inside and can be opened and closed. An air extraction port, a pressure release port, and a first cleaning liquid injection port are respectively provided on the cleaning chamber. The air extraction port is used to connect to an air extraction device; A chuck assembly, which is rotatably arranged in the cleaning chamber and is used for adsorbing the wafer; A rotation driving mechanism, which is connected to the chuck assembly and is used to drive the chuck assembly to rotate; A swing arm assembly, which is rotatably arranged in the cleaning chamber. The swing arm assembly is hollow inside and is provided with a second cleaning liquid injection port. A plurality of nozzles are also spacedly arranged on the swing arm assembly, and the nozzles are arranged towards the placement position of the wafer; A swing drive mechanism, connected to the swing arm assembly and used to drive the swing arm assembly to swing.

[0006] The beneficial effects of the low-pressure cleaning device for cleaning flux provided by the present invention are as follows: When the cleaning chamber is closed, a sealed environment is formed inside the cleaning chamber. The gas inside the cleaning chamber is evacuated by the air extraction device. During the process of forming a negative pressure, the gas between the die on the wafer and the wafer is evacuated, and the surface tension of the cleaning liquid is broken, so that the cleaning liquid slowly flows into the gap between the die and the wafer. During the process of restoring the cleaning chamber to normal pressure through the air pressure release port, a pressure difference will be formed inside and outside the gap between the die and the wafer. Under the action of the pressure difference, the cleaning liquid is completely pressed into the gap, thereby eliminating the "cavitation" in the micro-gap, enabling the cleaning liquid to fully contact the flux in the gap and dissolve the flux, and avoiding process defects. The swing drive mechanism drives the swing arm assembly to perform a reciprocating swing motion. At the same time, with the cooperation of the wafer rotation mechanism driving the wafer to rotate, the high-pressure cleaning liquid sprayed by the nozzle can cover the entire surface of the wafer, thereby improving the cleaning efficiency of the flux at the gap between the die and the wafer.

[0007] In a possible embodiment, the cleaning chamber includes a lower sealing cavity with a hollow interior and an open top, and an upper sealing cavity with a hollow interior and an open bottom. The upper sealing cavity is connected with a lifting drive mechanism, and the lifting drive mechanism is used to drive the upper sealing cavity to lift and adjust, so that the upper sealing cavity is closed with the lower sealing cavity or the upper sealing cavity is separated from the lower sealing cavity.

[0008] The beneficial effects are as follows: The lifting drive mechanism drives the upper sealing cavity to lift and adjust, thereby realizing the opening and closing of the upper sealing cavity and the lower sealing cavity.

[0009] In a possible embodiment, a transfer shaft is provided at the bottom of the chuck assembly. The transfer shaft extends out of the lower sealing cavity and is connected to the rotation drive mechanism. A through hole is provided in the rotation drive mechanism. A vacuum transition seat is provided at one end of the transfer shaft away from the chuck assembly. The vacuum transition seat is located in the through hole. A rotary joint is provided at one end of the vacuum transition seat away from the transfer shaft, and the rotary joint is used to connect the air extraction component; An adsorption groove structure is provided on the top surface of the chuck assembly. An air passage communicating with the adsorption groove structure is provided inside the chuck assembly. A diversion channel communicating with the air passage is provided inside the transfer shaft. An air flow channel communicating with the diversion channel is provided inside the vacuum transition seat.

[0010] The beneficial effects are as follows: While ensuring that the rotation drive mechanism can drive the transfer shaft to rotate, it can also meet the adsorption and fixation of the wafer by the chuck assembly.

[0011] In a possible embodiment, the chuck assembly is mounted on the adapter shaft through a support disk. A plurality of eccentric swing blocks are spacedly arranged on the support disk corresponding to the placement position of the wafer. The eccentric swing blocks are rotatably arranged on the support disk through shaft rods. The weight of the lower part of the eccentric swing block is greater than that of the upper part of the eccentric swing block. When the chuck assembly rotates, under the action of centrifugal force, the eccentric swing blocks deflect to clamp the wafer.

[0012] The beneficial effect is that: the eccentric swing blocks deflect under the action of centrifugal force, and the plurality of eccentric swing blocks can tightly clamp the wafer, preventing the wafer from flying off under the action of centrifugal force and causing fragments, thereby enhancing safety.

[0013] In a possible embodiment, an elastic lip is provided on the top surface of the chuck assembly, and the adsorption groove structure is located within the lip.

[0014] The beneficial effect is that: by using the lip, a sealed space is formed among the chuck assembly, the lip and the wafer to better adsorb the wafer.

[0015] In a possible embodiment, the low-pressure cleaning device further includes a liquid receiving assembly disposed around the cleaning chamber, and the liquid receiving assembly is used to collect the liquid splashed out of the cleaning chamber.

[0016] In a possible embodiment, a drainage cover is provided on the top surface of the lower sealing cavity along the circumferential direction of the lower sealing cavity. The drainage cover extends outward into the liquid receiving assembly, and the drainage cover has a guiding surface inclined downward from the lower sealing cavity.

[0017] The beneficial effect is that: when the splashed cleaning liquid falls on the drainage cover, under the action of its own weight, it will flow smoothly into the liquid receiving assembly along the inclined direction of the guiding surface, realizing the diversion effect.

[0018] In a possible embodiment, the liquid receiving assembly includes a lower receiving container disposed around the lower sealing cavity and having an open top and an upper enclosure adapted to the lower receiving container. The upper enclosure is connected with a driving and adjusting assembly, and the driving and adjusting assembly is used to drive the upper enclosure to lift and adjust, so that the upper enclosure rises to the periphery of the chuck assembly, or the upper enclosure descends to be closed with the lower receiving container.

[0019] The beneficial effect is that: when the upper enclosure rises, it can block and receive the cleaning liquid injected during cleaning or the cleaning liquid splashed during rotational drying.

[0020] The present invention also provides a low-pressure cleaning method for cleaning flux, which uses the low-pressure cleaning device for cleaning flux in any of the above embodiments. The low-pressure cleaning method includes: S101: Open the cleaning chamber, place the wafer on the chuck assembly, the chuck assembly adsorbs the wafer, and inject the first cleaning liquid onto the surface of the wafer through the first cleaning liquid injection port; S102: Close the cleaning chamber, evacuate the cleaning chamber through the air extraction device to create a negative pressure environment in the cleaning chamber, so that the first cleaning liquid flows into the gap between the die on the wafer and the wafer. After reaching the preset negative pressure value, restore the cleaning chamber to the normal pressure state through the air pressure release port; S103: Open the cleaning chamber, drive the chuck assembly to rotate together with the wafer through the rotation drive mechanism, drive the swing arm assembly to reciprocate through the swing drive mechanism, and at the same time inject the second cleaning liquid into the swing arm assembly through the second cleaning liquid injection port and spray it onto the surface of the wafer to spray off the flux on the wafer. The injection pressure of the second cleaning liquid is greater than the injection pressure of the first cleaning liquid.

[0021] In a possible embodiment, after step S103, it further includes step S104: Continue to drive the chuck assembly to rotate together with the wafer through the rotation drive mechanism to spin-dry the wafer; or, Close the cleaning chamber, continue to drive the chuck assembly to rotate together with the wafer through the rotation drive mechanism, and at the same time evacuate the cleaning chamber through the air extraction device to spin-dry the wafer in a low-pressure environment.

[0022] The beneficial effect is that when the cleaning chamber is closed, the air extraction device is used to evacuate, so that the internal pressure at the gap between the die and the wafer is greater than the external pressure. Through the pressure difference, the cleaning liquid in the gap can be more easily ejected, enhancing the spin-drying effect. Description of the Drawings

[0023] Figure 1 It is a schematic diagram of the low-pressure cleaning device for cleaning flux of the present invention.

[0024] Figure 2 It is a sectional view of the low-pressure cleaning device for cleaning flux of the present invention in one embodiment.

[0025] Figure 3 It is a schematic diagram of the upper sealing cavity, cavity cover flange, lifting drive mechanism, and swing drive mechanism of the low-pressure cleaning device for cleaning flux of the present invention.

[0026] Figure 4 A sectional view of the upper sealing cavity, cavity cover flange, lifting drive mechanism, and swing arm assembly in the low-pressure cleaning device for cleaning flux according to the present invention.

[0027] Figure 5 A sectional view of the lower sealing cavity and tray in the low-pressure cleaning device for cleaning flux according to the present invention.

[0028] Figure 6 A schematic diagram of the chuck assembly, eccentric swing block, transfer shaft, and rotation drive mechanism in the low-pressure cleaning device for cleaning flux according to the present invention.

[0029] Figure 7 A sectional view of the chuck assembly, eccentric swing block, transfer shaft, and rotation drive mechanism in the low-pressure cleaning device for cleaning flux according to the present invention.

[0030] Figure 8 A schematic diagram of the swing arm assembly and swing drive mechanism in the low-pressure cleaning device for cleaning flux according to the present invention.

[0031] Figure 9 A sectional view of the swing arm assembly in the low-pressure cleaning device for cleaning flux according to the present invention.

[0032] Figure 10 A sectional view of the liquid storage assembly in the low-pressure cleaning device for cleaning flux according to the present invention.

[0033] Figure 11 A schematic diagram of the waste discharge collecting assembly in the low-pressure cleaning device for cleaning flux according to the present invention.

[0034] Figure 12 A flowchart of the low-pressure cleaning method for cleaning flux according to the present invention.

[0035] Description of reference numerals in the drawings: 100, cleaning chamber; 110, lower sealing cavity; 111, side wall section; 112, support section; 1121, second sealing ring; 113, bottom wall section; 114, tray; 1141, opening; 115, drainage cover; 116, pressing ring; 117, first waste discharge port; 120, upper sealing cavity; 121, air extraction port; 122, air pressure release port; 123, first cleaning liquid injection port; 125, detection interface; 126, dovetail groove; 127, first sealing ring; 130, chamber cover flange; 141, guide rod; 142, guide linear bearing; 150, lifting drive mechanism; 200, chuck assembly; 210, adsorption groove structure; 211, annular groove; 212, linear groove; 213, air duct; 220, lip; 230, eccentric swing block; 231, shaft rod; 240, swing block seat; 250, rotary drive mechanism; 251, perforation; 260, fixed seat; 310, adapter shaft; 311, fourth sealing ring; 312, diversion channel; 320, vacuum transition seat; 321, air flow channel; 322, fifth sealing ring; 330, rotary joint; 340, magnetic fluid seal; 400, support disk; 401, extension; 410, third sealing ring; 420, connection key; 430, protective cover; 500, swing arm assembly; 510, swing arm; 511, nozzle; 512, second joint; 513, second cleaning liquid injection port; 520, transmission shaft; 521, first liquid channel; 522, first joint; 530, vacuum sealing seat; 531, mounting hole; 532, sixth sealing ring; 533, seventh sealing ring; 534, bearing; 535, gland; 600, swing drive mechanism; 610, support; 620, swing drive motor; 630, second pulley; 640, synchronous belt; 700, liquid storage assembly; 710, lower storage container; 711, second waste discharge port; 720, upper enclosure; 721, support ring; 810, support seat; 820, support plate; 821, through hole; 900, waste discharge collection assembly; 910, waste liquid pipe; 911, waste liquid outlet; 920, mounting seat; 930, first liquid discharge joint; 940, second liquid discharge joint. Detailed implementation manners

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0037] Flip Chip packaging technology is an advanced integrated circuit packaging technology. It directly flips and mounts the chip on the packaging substrate or wafer, and then uses tiny solder joints or conductive adhesives for connection, reducing the packaging size. As a crucial process in the complex processes of 2.5D / 3D advanced packaging, the Flip Chip process relies on "soldering" to fixedly connect the diced chips with solder balls to the interposer, and this process requires a reflow soldering process. Flux and solder paste are commonly used in the reflow soldering process. They mainly consist of various components such as solvents, wetting agents, resins, corrosion inhibitors, and activators. There will inevitably be thermally modified products after soldering, and these substances dominate all pollutants. The post-soldering residues are the main factors affecting quality. Therefore, strict cleaning is required after reflow soldering.

[0038] In addition, in 2.5D / 3D advanced packaging, the requirements for the size of bumps in high-end / research and development processes are continuously reduced to 10 - 20 microns or even smaller. This has brought great difficulties to the flux cleaning process after reflow soldering, not only in terms of spending a large amount of cleaning time, but also in being difficult to effectively clean, seriously affecting the subsequent packaging process flow.

[0039] In view of the problems existing in the prior art, embodiments of the present invention provide a low-pressure cleaning device for cleaning flux, see Figure 1 、 Figure 2 and Figure 3 . The low-pressure cleaning device includes: a cleaning chamber 100, a chuck assembly 200, a rotation driving mechanism 250, a swing arm assembly 500, and a swing driving mechanism 600. The inside of the cleaning chamber 100 is hollow and can be opened and closed. The cleaning chamber 100 is respectively provided with an air extraction port 121, a pressure release port 122, a first cleaning liquid injection port 123, and a second cleaning liquid injection port 513. The air extraction port 121 is used to connect to an air extraction device. The chuck assembly 200 is rotatably arranged in the cleaning chamber 100 and is used to adsorb the wafer. The rotation driving mechanism 250 is connected to the chuck assembly 200 and is used to drive the chuck assembly 200 to rotate. See Figure 4 and Figure 8 . The swing arm assembly 500 is rotatably arranged in the cleaning chamber 100. The swing driving mechanism 600 is connected to the swing arm assembly 500. The inside of the swing arm assembly 500 is hollow and is provided with a second cleaning liquid injection port 513. The swing arm assembly 500 is also provided with a plurality of nozzles 511 at intervals. The nozzles 511 are arranged towards the placement position of the wafer.

[0040] When the cleaning chamber 100 is closed, a sealed environment is formed inside the cleaning chamber 100. Most of the gas inside the cleaning chamber 100 is evacuated by a pumping device, creating a negative pressure environment inside the cleaning chamber 100, which breaks the surface tension of the cleaning liquid, making it easier for the cleaning liquid to penetrate into the tiny gaps between the die and the wafer on the wafer. During the process of restoring the cleaning chamber 100 to atmospheric pressure through the air pressure release port 122, a pressure difference will be formed inside and outside the gaps between the die and the wafer. Under the action of the pressure difference, the cleaning liquid is completely pressed into the gaps, thereby eliminating the "cavities" inside the tiny gaps. After the cleaning liquid enters the gaps, it fully contacts the flux inside the gaps and dissolves the flux, avoiding process defects and improving the cleaning efficiency and quality. In addition, in the restored atmospheric environment, the swing arm assembly 500 performs high-pressure spraying on the surface of the rotating wafer, which can wash away the residual flux in the gaps between the die and the wafer, which is more conducive to the cleaning liquid flowing into the gaps between the die and the wafer when the negative pressure environment is formed again, improving the cleaning efficiency, enhancing the cleaning effect, and ensuring the stability of the process.

[0041] In some specific embodiments, refer to Figure 3 , the cleaning chamber 100 further includes a detection interface 125 provided on the cleaning chamber 100. For example, the detection interface 125 is provided at the top of the upper sealing cavity 120. The detection interface 125 is connected to a pressure detection component, and the pressure detection component is used to detect the pressure condition inside the cleaning chamber 100. The specific structure and setting method of the pressure detection component are not limited here. For example, the pressure detection component is a vacuum gauge. The pumping device is a device capable of pumping air such as a vacuum pump. The pumping device is used to evacuate the air inside the cleaning chamber 100 to form a low pressure. The air pressure release port 122 is used to release gas into the cleaning chamber 100 to relieve its low pressure environment and restore the cleaning chamber 100 to the atmospheric environment. The first cleaning liquid injection port 123 is used to inject normal pressure cleaning liquid, and the second cleaning liquid injection port 513 is used to inject high pressure cleaning liquid.

[0042] In one embodiment, refer to Figure 2 、 Figure 4 and Figure 5, the cleaning chamber 100 includes a lower sealing cavity 110 with a hollow interior and an open top, and an upper sealing cavity 120 with a hollow interior and an open bottom. The upper sealing cavity 120 is connected to a lifting drive mechanism 150, which is used to drive the lifting and adjustment of the upper sealing cavity 120 so that the upper sealing cavity 120 is closed or separated from the lower sealing cavity 110. A dovetail groove 126 is provided along the circumferential direction of the bottom surface of the upper sealing cavity 120 and / or the top surface of the lower sealing cavity 110, and a first sealing ring 127 is provided in the dovetail groove 126. The first sealing ring 127 plays a sealing role when the upper sealing cavity 120 and the lower sealing cavity 110 are closed. Driven by the lifting drive assembly, the upper sealing cavity 120 can be conveniently lifted and adjusted, so as to realize the closing or separation of the upper sealing cavity 120 and the lower sealing cavity 110. A closed environment is formed after the upper sealing cavity 120 and the lower sealing cavity 110 are closed.

[0043] In a specific embodiment, refer to Figure 2 , Figure 3 and Figure 4 , a chamber cover flange 130 is provided at the top of the upper sealing cavity 120. Both ends of the chamber cover flange 130 extend outside the upper sealing cavity 120. The lifting drive mechanism 150 includes a pair of lifting adjustment components respectively provided at both ends of the chamber cover flange 130. The lifting adjustment components can be cylinders, hydraulic cylinders, electric telescopic rods or linear modules, etc. The specific structure and setting method of the lifting adjustment components are not limited here. The low-pressure cleaning device also includes a support base 810 in a frame structure and a support plate 820 provided on the support base 810. The lower sealing cavity 110 and a pair of lifting adjustment components are provided on the support plate 820. The pair of lifting adjustment components are symmetrically arranged. Vertical guide rods 141 are respectively provided at both ends of the chamber cover flange 130. The support plate 820 is respectively provided with guide holes at the positions corresponding to each guide rod 141. The guide rods 141 pass through the corresponding guide holes. In addition, a guide linear bearing 142 can also be provided at the guide holes on the support plate 820. The guide rods 141 pass through the corresponding guide linear bearings 142 and the corresponding guide holes to play a guiding role. The guiding role played by the cooperation of the guide rods 141, the guide linear bearings 142 and the guide holes ensures the smooth lifting of the upper sealing cavity 120. Of course, a pair of guide rods 141 can also be respectively provided on both sides of each lifting adjustment component to enhance the smoothness of lifting.

[0044] In an embodiment, refer to Figure 2 and Figure 5, a tray 114 is provided inside the lower sealing cavity 110. A chuck assembly 200 is disposed on the tray 114. An opening 1141 is provided on the tray 114. A transfer shaft 310 passes through the opening 1141 and is connected to the chuck assembly 200. A second sealing groove is provided at the position of the lower sealing cavity 110 corresponding to the tray 114, and a second sealing ring 1121 is provided in the second sealing groove to ensure the sealing performance of the cleaning chamber 100. The lower sealing cavity 110 includes a cylindrical side wall section 111, a cylindrical support section 112 located inside the side wall section 111, and an annular bottom wall section 113. The bottom wall section 113 is fixedly connected between the bottom of the side wall section 111 and the bottom of the support section 112. The side wall section 111, the support section 112, and the bottom wall section 113 are integrally formed structures. The tray 114 is disposed on the support section 112, and the tray 114 is adapted to the support section 112.

[0045] In one embodiment, referring to Figure 2 and Figure 7 , a transfer shaft 310 is provided at the bottom of the chuck assembly 200. The transfer shaft 310 extends outside the lower sealing cavity 110 and is connected to a rotary drive mechanism 250. A through hole 251 is provided in the rotary drive mechanism 250. A vacuum transition seat 320 is provided at one end of the transfer shaft 310 away from the chuck assembly 200. The vacuum transition seat 320 is located in the through hole 251. A rotary joint 330 is provided at one end of the vacuum transition seat 320 away from the transfer shaft 310. The rotary joint 330 is used to connect an air extraction component. An adsorption groove structure 210 is provided on the top surface of the chuck assembly 200. An air passage 213 communicating with the adsorption groove structure 210 is provided inside the chuck assembly 200. A diversion channel 312 communicating with the air passage 213 is provided inside the transfer shaft 310. An air flow channel 321 communicating with the diversion channel 312 is provided inside the vacuum transition seat 320.

[0046] The air flow channel 321 of the vacuum transition seat 320, the diversion channel 312 of the transfer shaft 310, the air passage 213 of the chuck assembly 200, and the adsorption groove structure 210 form a continuous air flow path. By extracting air through the air extraction component, a negative pressure is formed between the chuck assembly 200 and the wafer to adsorb the wafer. A through hole 251 is provided in the rotary drive mechanism 250 to accommodate the vacuum transition seat 320. With such a structural arrangement, while ensuring that the rotary drive mechanism 250 can drive the transfer shaft 310 to rotate, it can also meet the adsorption and fixation of the wafer by the chuck assembly 200.

[0047] In a specific embodiment, referring to Figure 6 , the adsorption groove structure 210 includes a plurality of annular grooves 211 centered on the center of the chuck assembly 200 and at least one linear groove 212 arranged in the radial direction of the chuck assembly 200. The linear groove 212 passes through the plurality of annular grooves 211 and communicates with the plurality of annular grooves 211, which can enhance the adsorption effect on the wafer.

[0048] In a specific embodiment, refer to Figure 2 , a cylindrical magneto-rheological fluid seal 340 is provided at the connection between the transfer shaft 310 and the lower sealing cavity 110. The magneto-rheological fluid seal 340 is provided on the bottom surface of the tray 114 and is located within the support section 112, and the transfer shaft 310 passes through the magneto-rheological fluid seal 340. After the cleaning chamber 100 is sealed, rotational power is transmitted through the magneto-rheological fluid seal 340, enabling the high-speed rotation of the chuck assembly 200. Through the magneto-rheological fluid sealing effect, it can be ensured that the chuck assembly 200 can rotate whether under normal pressure or low pressure without affecting the sealing performance within the cleaning chamber 100.

[0049] In a specific embodiment, refer to Figure 2 , a through hole 821 corresponding to the support section 112 is provided on the support plate 820, the transfer shaft 310 passes through the through hole 821, and the rotational drive mechanism 250 is mounted on the bottom surface of the support plate 820 through the fixed seat 260. The rotational drive mechanism 250 is a drive member such as a motor that can provide rotational power. For example, the rotational drive mechanism 250 is a hollow shaft motor.

[0050] In an embodiment, refer to Figure 6 , an elastic lip 220 is provided on the top surface of the chuck assembly 200, and the adsorption groove structure 210 is located within the lip 220. When the wafer is placed on the chuck assembly 200, the lip 220 is higher than the top surface of the chuck assembly 200. Even for warped wafers, the elastic lip 220 can contact the wafer surface. When evacuating and adsorbing the wafer, a sealed negative pressure space is formed among the chuck assembly 200, the lip 220, and the wafer to effectively and firmly adsorb the wafer.

[0051] In an embodiment, refer to Figure 6 and Figure 7 , the chuck assembly 200 is mounted on the transfer shaft 310 through the support plate 400. A plurality of eccentric swing blocks 230 are evenly spaced at positions corresponding to the placement position of the wafer on the support plate 400. The eccentric swing blocks 230 are rotatably provided on the support plate 400 through the shaft rods 231. When the chuck assembly 200 rotates, under the action of centrifugal force, the eccentric swing blocks 230 swing to clamp the wafer, which can not only accommodate the adsorption of warped wafers but also adapt to the situation of reduced adsorption force under vacuum to better protect the wafer from being thrown off by centrifugal force and causing fragments.

[0052] In a specific embodiment, refer to Figure 6 and Figure 7The weight of the lower part of the eccentric pendulum block 230 is greater than the weight of the upper part of the eccentric pendulum block 230. During the rotation, the lower part of the eccentric pendulum block 230 deflects outward from the wafer under the action of centrifugal force, and the upper part of the eccentric pendulum block 230 deflects toward the side of the wafer, thereby clamping the wafer through the deflection of several eccentric pendulum blocks 230. The eccentric pendulum block 230 is mounted on the support plate 400 through the pendulum block seat 240, and the eccentric pendulum block 230 is rotatably arranged on the corresponding pendulum block seat 240 through the shaft 231.

[0053] In a specific embodiment, see Figure 7 The top surface of the support plate 400 is provided with a third sealing groove corresponding to the location of the chuck assembly 200, and a third sealing ring 410 is provided in the third sealing groove to achieve sealing between the support plate 400 and the chuck assembly 200. The bottom surface of the support plate 400 extends downward to form a tubular extension portion 401, and the extension portion 401 extends into the opening 1141 of the tray 114. The adapter shaft 310 is located in the extension portion 401, and the adapter shaft 310 and the extension portion 401 are fixedly connected by symmetrically arranged connecting keys 420. The bottom surface of the support plate 400 is provided with a protective cover 430, and the protective cover 430 is arranged around the extension portion 401.

[0054] In a specific embodiment, see Figure 7 The top surface of the transfer shaft 310 is provided with a fourth sealing groove, and a fourth sealing ring 311 is provided in the fourth sealing groove to achieve sealing between the transfer shaft 310 and the support plate 400. The top surface of the vacuum transition seat 320 is provided with a fifth sealing groove, and a fifth sealing ring 322 is provided in the fifth sealing groove to achieve sealing between the vacuum transition seat 320 and the transfer shaft 310.

[0055] In one embodiment, see Figure 3 , Figure 8 as well as Figure 9, the swing arm assembly 500 includes a swing arm 510 in an arc shape, a transmission shaft 520 provided on the swing arm 510, and a vacuum seal seat 530 sleeved on the transmission shaft 520. The arc design of the swing arm 510 can better adapt to the circular space of the cavity. The transmission shaft 520 is rotatably provided at the top of the upper seal cavity 120 through the vacuum seal seat 530. The vacuum seal seat 530 is sleeved on the transmission shaft 520 through a bearing 534. The outer ring of the bearing 534 is fixed to the vacuum seal seat 530, and the inner ring of the bearing 534 is fixed to the transmission shaft 520. The transmission shaft 520 can rotate relative to the vacuum seal seat 530. The top of the bearing 534 is covered with a gland 535 to prevent the bearing 534 from axially moving. The top of the transmission shaft 520 extends out of the top of the upper seal cavity 120 and is connected to the swing drive mechanism 600. The specific structure and setting method of the swing drive mechanism 600 are not limited here. The swing drive mechanism 600 includes a swing drive motor 620 and a belt drive mechanism or a gear drive mechanism, etc. The belt drive mechanism or the gear drive mechanism is connected to the transmission shaft 520 to transmit the rotational driving force of the motor to the transmission shaft 520, so that the transmission shaft 520 can rotate, and then drive the swing arm 510 to swing. The vacuum seal seat 530 provides a stable dynamic seal between the transmission shaft 520 and the upper seal cavity 120, with a rotary seal design. While the swing arm 510 swings, it can also ensure the low-pressure process requirements in the cleaning chamber 100 without affecting the sealing environment of the entire cleaning chamber 100.

[0056] In a specific embodiment, refer to Figure 3 and Figure 8 , the swing drive mechanism 600 includes a support 610 provided above the upper seal cavity 120, a swing drive motor 620 provided on the support 610, a first pulley fixedly sleeved on the output shaft of the swing drive motor 620, a second pulley 630 fixedly sleeved on the top of the transmission shaft 520, and a synchronous belt 640 wound around the first pulley and the second pulley 630. By driving the first pulley to rotate through the swing drive motor 620, and through the transmission of the synchronous belt 640, the second pulley 630 is driven to rotate. The second pulley 630 drives the transmission shaft 520 to rotate, and the transmission shaft 520 drives the swing arm 510 to perform a reciprocating swing motion.

[0057] In a specific embodiment, refer to Figure 8 and Figure 9, a first liquid passage 521 is provided inside the transmission shaft 520. The top of the transmission shaft 520 is provided with the above-mentioned second cleaning liquid injection port 513. A first joint 522 communicating with the first liquid passage 521 is provided on the transmission shaft 520. A second liquid passage is provided inside the swing arm 510. A second joint 512 communicating with the second liquid passage is provided on the swing arm 510. An infusion tube is connected between the second joint 512 and the first joint 522. The infusion tube can be a flexible tube, etc. A plurality of nozzles 511 are arranged at intervals along the extending direction of the swing arm 510 at the bottom of the swing arm 510. There are various models of nozzles 511, which can spray liquids in different states.

[0058] In a specific embodiment, refer to Figure 9 , an installation hole 531 is provided inside the vacuum sealing seat 530. The transmission shaft 520 is rotatably inserted into the installation hole 531. A sixth sealing groove is provided on the inner wall of the installation hole 531. A sixth sealing ring 532 is provided in the sixth sealing groove. The sixth sealing ring 532 is a star-shaped sealing ring, which can ensure the sealing performance when the transmission shaft 520 swings back and forth. The vacuum sealing seat 530 is provided with a seventh sealing groove corresponding to the upper sealing cavity 120. A seventh sealing ring 533 is provided in the seventh sealing groove.

[0059] In an embodiment, refer to Figure 1 , Figure 2 and Figure 10 , the low-pressure cleaning device further includes a liquid collection assembly 700 arranged around the cleaning chamber 100. The liquid collection assembly 700 is used to collect the liquid splashed out of the cleaning chamber 100.

[0060] In an embodiment, refer to Figure 2 , a drainage cover 115 is provided on the top surface of the lower sealing cavity 110 along the circumferential direction of the lower sealing cavity 110. The drainage cover 115 extends outward into the liquid collection assembly 700. The drainage cover 115 has a guiding surface inclined downward from the lower sealing cavity 110. A fixing groove is provided along the peripheral edge of the top of the lower sealing cavity 110. The drainage cover 115 is sleeved at the fixing groove, and the drainage cover 115 is tightly fixed in the fixing groove by a pressing ring 116. The top surface of the pressing ring 116 is flush with the top surface of the lower sealing cavity 110.

[0061] In an embodiment, refer to Figure 2 and Figure 10, the liquid storage component 700 includes a lower storage container 710 that is arranged around the lower sealing cavity 110 and has an open top, and an upper enclosure 720 that is adapted to the lower storage container 710. The upper enclosure 720 is connected with a driving and adjusting component (not shown in the figure), and the driving and adjusting component is used to drive the upper enclosure 720 to lift and adjust, so that the upper enclosure 720 rises to the periphery of the chuck assembly 200, or the upper enclosure 720 descends to be closed with the lower storage container 710. The specific structure and setting mode of the driving and adjusting component are not limited here. The driving and adjusting component is a cylinder, a hydraulic cylinder, an electric telescopic rod, etc. Under the driving action of the driving and adjusting component, the upper enclosure 720 can move up and down relative to the lower storage container 710. When the chuck assembly 200 rotates for spin-drying and when cleaning liquid is injected to clean the wafer, the upper enclosure 720 is raised to the height of the chuck assembly 200, which can block and collect the splashing cleaning liquid.

[0062] Further, referring to Figure 2 and Figure 10 , the upper enclosure 720 is cylindrical, the caliber of the top of the upper enclosure 720 gradually decreases from bottom to top to form a necked shape, and a support ring 721 is sleeved on the top of the upper enclosure 720. The support ring 721 is connected with the driving and adjusting component.

[0063] In a specific embodiment, referring to Figure 1 , Figure 2 , Figure 5 and Figure 11, a first waste discharge port 117 is provided at the bottom of the lower sealing cavity 110, and there are two first waste discharge ports 117 which are symmetrically arranged. A on-off valve is provided at the first waste discharge port 117, and the on-off valve is used to control the sealing of the cleaning chamber 100 and the discharge of waste liquid. When the on-off valve is opened, the waste liquid can be discharged, and when the on-off valve is closed, the cleaning chamber 100 can be sealed. A second waste discharge port 711 is provided at the bottom of the lower storage container 710, and there are two second waste discharge ports 711 which are symmetrically arranged. The low-pressure cleaning device further includes a waste discharge collecting assembly 900 connected to the first waste discharge port 117 and the second waste discharge port 711. The waste discharge collecting assembly 900 is located in the mounting seat 920 of the frame structure and is used to collect waste liquid and discharge the waste liquid. The waste discharge collecting assembly 900 includes a waste liquid pipe 910, a mounting seat 920, a first liquid discharge joint 930 and a second liquid discharge joint 940 which are spaced apart and mounted on the waste liquid pipe 910. The waste liquid pipe 910 is installed and fixed in the mounting seat 920 through the mounting seat 920. The first liquid discharge joint 930 is arranged in one-to-one correspondence with the first waste discharge port 117. The first liquid discharge joint 930 is connected to the first waste discharge port 117 through a first pipeline. The second liquid discharge joint 940 is connected to the second waste discharge port 711 through a second pipeline. The model specifications of the first liquid discharge joint 930 and the second liquid discharge joint 940 can be flexibly set according to needs. One end of the waste liquid pipe 910 is closed and the other end is a waste liquid outlet 911. The waste liquid in the lower sealing cavity 110 enters the waste liquid pipe 910 through the first waste discharge port 117, the first pipeline and the first liquid discharge joint 930. The waste liquid in the lower storage container 710 enters the waste liquid pipe 910 through the second waste discharge port 711, the second pipeline and the second liquid discharge joint 940. The waste liquid in the waste liquid pipe 910 is discharged through the waste liquid outlet 911.

[0064] The present invention also provides a low-pressure cleaning method for cleaning flux, which adopts the low-pressure cleaning device for cleaning flux in any of the above embodiments. Refer to Figure 12 , the low-pressure cleaning method includes: S101: Open the cleaning chamber 100, place the wafer on the chuck assembly 200, the chuck assembly 200 adsorbs the wafer, and inject the first cleaning liquid onto the surface of the wafer through the first cleaning liquid injection port 123; S102: Close the cleaning chamber 100, evacuate the inside of the cleaning chamber 100 through the air extraction device to form a negative pressure environment inside the cleaning chamber 100, extract the gas between the die on the wafer and the wafer, and then make the first cleaning liquid flow into the gap between the die on the wafer and the wafer. After reaching the preset negative pressure value, restore the inside of the cleaning chamber 100 to the atmospheric pressure state through the air pressure release port 122; S103: Open the cleaning chamber 100, drive the chuck assembly 200 to rotate together with the wafer through the rotation driving mechanism 250, drive the swing arm assembly 500 to reciprocate through the swing driving mechanism 600. At the same time, inject the second cleaning liquid into the swing arm assembly 500 through the second cleaning liquid injection port 513, and spray it onto the wafer surface through the nozzle 511 to spray off the impurities on the wafer. The injection pressure of the second cleaning liquid is greater than that of the first cleaning liquid. The types of the first cleaning liquid and the second cleaning liquid can be the same or different, and can be flexibly selected according to process requirements.

[0065] In one embodiment, after step S103, step S104 is further included: Continue to drive the chuck assembly 200 to rotate together with the wafer through the rotation driving mechanism 250 to dry the wafer by centrifugal force; or, Close the cleaning chamber 100, continue to drive the chuck assembly 200 to rotate together with the wafer through the rotation driving mechanism 250, and at the same time evacuate the cleaning chamber 100 through the air extraction device to dry the wafer under a low-pressure environment.

[0066] This low-pressure cleaning device can realize the high-speed rotation of the chuck assembly 200 with the wafer loaded in a negative-pressure environment. When the process returns to normal pressure after forming a negative pressure, the cleaning liquid can penetrate into the gap between the die and the wafer. To better eject the cleaning liquid that has penetrated into the gap, the cleaning chamber 100 can be closed during rotation, and the gas can be evacuated to form a negative pressure. The process of forming a negative pressure can suck out and throw away the cleaning liquid in the gap, so as to ensure that the cleaning liquid that has penetrated into the gap is ejected and taken away, together with the flux dissolved in the cleaning liquid.

[0067] In one embodiment, steps S101 to S104 are repeatedly executed until the cleaning is completed.

[0068] The following combines specific examples to explain in detail the low-pressure cleaning method for cleaning flux of the present invention.

[0069] In the initial state, the upper sealing cavity 120 rises to the highest position, and the upper enclosure 720 is at the lowest position. First, the robot finger transfers the wafer to be cleaned and places it on the chuck assembly 200. The air extraction component is turned on to adsorb the wafer on the chuck assembly 200. A certain amount of normal-pressure cleaning liquid is injected from the first cleaning liquid injection port 123. After the cleaning liquid injection is completed, the lifting drive mechanism 150 drives the upper sealing cavity 120 to descend and close with the lower sealing cavity 110 to form a sealed space. The air extraction device extracts air through the air extraction port 121 to create a negative pressure in the cleaning chamber 100. In the negative pressure environment, the surface tension of the cleaning liquid is broken, making it easier for the cleaning liquid to penetrate into the tiny gaps between the die and the wafer. After the cleaning chamber 100 reaches the predetermined negative pressure value, the negative pressure is released through the air pressure release port 122 to restore the cleaning chamber 100 to atmospheric pressure. The lifting drive mechanism 150 drives the upper sealing cavity 120 to rise to the highest position, and the upper enclosure 720 rises to the highest position; the rotation drive mechanism 250 drives the chuck assembly 200 to rotate together with the wafer thereon. While the chuck assembly 200 is rotating, the second cleaning liquid injection port 513 injects high-pressure cleaning liquid, and the swing drive mechanism 600 drives the swing arm 510 to swing reciprocally to increase the area of the high-pressure cleaning liquid covering the wafer. The flux between the die and the wafer can be cleaned off by the high-pressure cleaning liquid; after the cleaning is completed, the swing arm 510 stops swinging and the second cleaning liquid injection port 513 stops injecting high-pressure cleaning liquid; the chuck assembly 200 continues to rotate to drive the wafer to perform a drying process; after the drying is completed, the chuck assembly 200 stops rotating, and the upper enclosure 720 drops to the lowest position; cleaning liquid is re-injected, vacuum is pumped, high-pressure spraying, and drying are performed in several cycles; the chuck assembly 200 is closed, and the robot takes away the wafer, and the cleaning is completed.

[0070] In addition, the following process can be added during the rotation and drying process: when the wafer is in a state to be dried, the upper sealing cavity 120 descends to fit with the lower sealing cavity 110 to form a sealed space. The chuck assembly 200 drives the wafer to rotate at a high speed. At the same time, the air extraction device extracts air through the air extraction port 121 to make the internal pressure at the gap between the die and the wafer on the wafer greater than the external pressure. Through the pressure difference, the cleaning liquid in the gap is more easily thrown out, enhancing the drying effect.

[0071] It should be noted that when the cleaning chamber 100 returns to atmospheric pressure, the on-off valve at the second waste outlet 711 is in a conducting state.

[0072] Although the embodiments of the present invention have been described in detail above, it is obvious to those skilled in the art that various modifications and changes can be made to these embodiments. However, it should be understood that such modifications and changes are all within the scope and spirit of the present invention described in the claims. Moreover, the present invention described herein may have other embodiments and can be implemented or realized in various ways. Unless otherwise defined, the technical terms or scientific terms used herein should have the ordinary meaning understood by those of ordinary skill in the art to which the present invention pertains.

Claims

1. A low-pressure cleaning device for cleaning flux, characterized in that Comprising: A cleaning chamber, which is hollow inside and can be opened and closed. An air extraction port, a pressure release port, and a first cleaning liquid injection port are respectively provided on the cleaning chamber. The air extraction port is used to connect to an air extraction device; A chuck assembly, rotatably arranged inside the cleaning chamber and used for adsorbing wafers; A rotation driving mechanism, connected to the chuck assembly and used for driving the chuck assembly to rotate; A swing arm assembly, rotatably arranged inside the cleaning chamber. The swing arm assembly is hollow inside and is provided with a second cleaning liquid injection port. A plurality of nozzles are also spacedly provided on the swing arm assembly. The nozzles are arranged towards the placement position of the wafer; A swing driving mechanism, connected to the swing arm assembly and used for driving the swing arm assembly to swing.

2. The low-pressure cleaning device for cleaning flux according to claim 1, characterized in that, The cleaning chamber includes a lower sealed cavity that is hollow inside and has an open top and an upper sealed cavity that is hollow inside and has an open bottom. The upper sealed cavity is connected with a lifting driving mechanism. The lifting driving mechanism is used to drive the upper sealed cavity to lift and adjust, so that the upper sealed cavity is closed with the lower sealed cavity or the upper sealed cavity is separated from the lower sealed cavity.

3. The low-pressure cleaning device for cleaning flux according to claim 2, characterized in that, A transfer shaft is provided at the bottom of the chuck assembly. The transfer shaft extends outside the lower sealed cavity and is connected to the rotation driving mechanism. A perforation is provided inside the rotation driving mechanism. A vacuum transition seat is provided at one end of the transfer shaft away from the chuck assembly. The vacuum transition seat is located inside the perforation. A rotary joint is provided at one end of the vacuum transition seat away from the transfer shaft. The rotary joint is used to connect to an air extraction part; An adsorption groove structure is provided on the top surface of the chuck assembly. An air duct communicating with the adsorption groove structure is provided inside the chuck assembly. A diversion channel communicating with the air duct is provided inside the transfer shaft. An air flow channel communicating with the diversion channel is provided inside the vacuum transition seat.

4. The low-pressure cleaning device for cleaning flux according to claim 3, characterized in that, The chuck assembly is installed on the transfer shaft through a support plate. A plurality of eccentric swing blocks are spacedly provided on the support plate corresponding to the placement position of the wafer. The eccentric swing blocks are rotatably arranged on the support plate through shaft rods. When the chuck assembly rotates, under the action of centrifugal force, the eccentric swing blocks swing to clamp the wafer.

5. The low-pressure cleaning device for cleaning flux according to claim 3, characterized in that, An elastic lip is provided on the top surface of the chuck assembly. The adsorption groove structure is located inside the lip.

6. The low-pressure cleaning device for cleaning flux according to claim 3, wherein, A magnetic fluid seal is provided at the connection between the transfer shaft and the lower sealed cavity.

7. The low-pressure cleaning device for cleaning flux according to any one of claims 2-6, characterized in that, It further includes a liquid collection assembly arranged around the cleaning chamber. The liquid collection assembly is used to collect the liquid splashed outside the cleaning chamber.

8. The low-pressure cleaning device for cleaning flux according to claim 7, characterized in that, The liquid collection assembly includes a lower collection container arranged around the lower sealed cavity and having an open top and an upper enclosure adapted to the lower collection container. The upper enclosure is connected with a driving and adjusting assembly. The driving and adjusting assembly is used to drive the upper enclosure to lift and adjust, so that the upper enclosure rises to the periphery of the chuck assembly, or the upper enclosure descends to be closed with the lower collection container.

9. A low-pressure cleaning method for cleaning flux, characterized in that, Using the low-pressure cleaning device for cleaning flux as described in any one of claims 1-8, the low-pressure cleaning method includes: S101: Open the cleaning chamber, place the wafer on the chuck assembly, which adsorbs the wafer, and inject a first cleaning liquid onto the surface of the wafer through the first cleaning liquid injection port; S102: Close the cleaning chamber, evacuate the cleaning chamber through the evacuation device to create a negative pressure environment in the cleaning chamber, so that the first cleaning liquid flows into the gap between the die on the wafer and the wafer. After reaching the preset negative pressure value, restore the cleaning chamber to the atmospheric pressure state through the air pressure release port; S103: Open the cleaning chamber, drive the chuck assembly to rotate together with the wafer through the rotation driving mechanism, drive the swing arm assembly to reciprocate through the swing driving mechanism, and at the same time inject a second cleaning liquid into the swing arm assembly through the second cleaning liquid injection port and spray it onto the surface of the wafer through the nozzle to spray off the flux on the wafer. The injection pressure of the second cleaning liquid is greater than the injection pressure of the first cleaning liquid.

10. The low-pressure cleaning method for cleaning flux according to claim 9, characterized in that, After step S103, there is also step S104: Continue to drive the chuck assembly to rotate together with the wafer through the rotation driving mechanism to spin-dry the wafer; or, Close the cleaning chamber, continue to drive the chuck assembly to rotate together with the wafer through the rotation driving mechanism, and at the same time evacuate the cleaning chamber through the evacuation device to spin-dry the wafer in a low-pressure environment.

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