Photoelectrochemical mechanical polishing device and method for semiconductor substrate wafer based on multi-wavelength long-afterglow light-emitting particles

Abstract

The invention relates to a semiconductor substrate wafer photoelectrochemical mechanical polishing device and method based on multi-wavelength long-afterglow light-emitting particles, and the device comprises a rack, a portal frame, an electrochemical workstation, a polishing solution recovery tank, a control panel, a jacking polishing disc and a rotating disc type vacuum illumination unit, a to-be-processed workpiece is arranged at the tail end of the conductive rotary suction cup, the jacking polishing disc is arranged below the conductive rotary suction cup, the distance between the polishing disc on the jacking polishing disc and the to-be-processed workpiece is adjusted by adjusting the height, and long-afterglow light-emitting particles matched with a to-be-processed semiconductor substrate wafer material are arranged in the rotary disc type vacuum illumination unit. And mixing the excited long-afterglow luminescent particles into the polishing solution to finish the photoelectrochemical mechanical polishing of the surface of the semiconductor substrate wafer. Different long-afterglow luminescent particles and different light sources are used, and the method is suitable for various semiconductor materials. Through rotation of the rotating disc type vacuum illumination unit, illumination of different wavelengths can be replaced simply and quickly.

Description

Technical Field

[0001] The present invention relates to the technical field of semiconductor substrate wafer polishing, and in particular to a semiconductor substrate wafer photoelectrochemical mechanical polishing device and method based on multi-wavelength long afterglow luminescent particles. Background Art

[0002] Semiconductor substrate wafers refer to the basic materials used in semiconductor device manufacturing, on which various semiconductor device and circuit manufacturing processes are carried out. Substrate wafers play a vital role in the semiconductor manufacturing process. As the basis of devices and circuits, substrate wafers not only support the structure of the entire device, but also provide necessary support in electrical, thermal and mechanical aspects. Therefore, the quality of the substrate directly affects the performance and reliability of the final semiconductor device.

[0003] The superior performance of these materials has brought great difficulties to processing. Due to their high hardness and stable chemical properties, the material removal efficiency of semiconductor substrate wafers using mechanical polishing and chemical mechanical polishing is extremely low; photoelectrochemical mechanical polishing is an effective solution, but currently there are significant problems such as polishing disks blocking light, uneven material removal, strong selectivity of equipment for substrate wafer materials, high processing costs and high equipment requirements, which seriously restrict the development of semiconductor device manufacturing technology and its application in related fields.

[0004] The Chinese patent application with the publication number CN 116079580 A discloses a "method and device for wireless photoelectrochemical mechanical polishing of semiconductor wafers", which solves the problem of light blocking by opening holes in the polishing disk. However, the holes affect the uniformity of material removal and processing efficiency, and the device structure is not suitable for large-scale production line processing.

[0005] The Chinese patent with authorization announcement number CN 109465739 B discloses "a semiconductor wafer photoelectrochemical mechanical polishing processing device". The device only integrates a light source of one wavelength and can only be adapted to a very small number of semiconductor materials. If you want to use photoelectrochemical mechanical polishing of substrate wafers of other semiconductor materials, you can only dismantle and replace the light source or use other equipment. The processing efficiency is low and the cost is extremely high. It is not suitable for industrial batch polishing of semiconductor wafers.

[0006] A foreign unit has studied the use of a special polishing device in the polishing process, in which the polishing plate and other components are made of transparent materials (Sadakuni, S., et al., Bias-Assisted Photochemical Planarization of GaN (0001) Substrate with Damage Layer. Japanese Journal of Applied Physics, 2013. 52 (3R): p. 036504.), which increases the initial cost of the polishing device and is not suitable for industrial processing. Summary of the invention

[0007] In response to the technical problems raised above, a photoelectrochemical mechanical polishing method for semiconductor substrate wafers based on multi-wavelength long afterglow luminescent particles is provided and a processing device is designed for the method. The photoelectrochemical mechanical polishing method for semiconductor substrate wafers based on multi-wavelength long afterglow luminescent particles described in the present invention refers to a processing method in which long afterglow luminescent particles are introduced on the basis of existing photoelectrochemical mechanical polishing. The long afterglow luminescent particles are first excited under a special environment and the absorbed energy is stored. Then, the particles are mixed into the polishing liquid to irradiate the semiconductor substrate wafer to be polished. Under the action of an external electric field, ultraviolet rays are used to produce photoelectrochemical oxidation, and then the oxidized modified layer of the semiconductor substrate wafer is removed by mechanical polishing.

[0008] The technical means adopted by the present invention are as follows:

[0009] A semiconductor substrate wafer photoelectrochemical mechanical polishing device based on multi-wavelength long afterglow luminescent particles comprises a frame, a gantry, an electrochemical workstation, a polishing liquid recovery tank, a control panel, a lifting polishing disk and a turntable vacuum illumination unit. The gantry, the electrochemical workstation, the polishing liquid recovery tank, the control panel, the lifting polishing disk and the turntable vacuum illumination unit are all mounted on the frame. A conductive rotating suction cup is mounted on the gantry, a workpiece to be processed is arranged at the end of the conductive rotating suction cup, the lifting polishing disk is arranged below the conductive rotating suction cup, and the distance between the polishing disk and the workpiece to be processed is adjusted by adjusting the height. The turntable vacuum illumination unit is provided with long afterglow luminescent particles matching the semiconductor substrate wafer material to be processed, and the excited long afterglow luminescent particles are mixed into the polishing liquid to complete the photoelectrochemical mechanical polishing of the surface of the semiconductor substrate wafer.

[0010] Furthermore, the gantry includes fastening screws, columns, beams, servo mounting seats, screw rods and lifting beams. There are two columns and both columns are fixedly mounted on the frame by the fastening screws. The beam is fixedly mounted on the tops of the two columns. The servo mounting seat is mounted on one end of the beam by bolts. The screw rod is mounted on the beam and connected to the motor at the servo mounting seat by an elastic coupling. A transverse frame is slidably connected to the beam, and the transverse frame is connected to the screw rod. The lifting beam is fixedly mounted on the transverse frame, and the conductive rotating suction cup is mounted on the lifting beam.

[0011] Furthermore, the conductive rotating suction cup completes the clamping of the workpiece to be processed by vacuum adsorption. Specifically, the spindle box and the suction cup pump support are fixedly installed on the lifting beam of the gantry, the suction cup pump is fixed on the suction cup pump support, one end of the suction cup air pipe is connected to the suction cup pump, and the other end is connected to the conductive rotating suction cup; the spindle box is provided with a suction cup rotating motor and a step shaft, the inner ring of the conductive slip ring is fastened to the step shaft by screws, the inner ring wire can rotate synchronously with the step shaft, the outer ring wire of the conductive slip ring is connected to the inner ring wire and then connects the workpiece to be processed, and the end of the step shaft is connected to a pressure sensor.

[0012] Furthermore, the output end of the polishing head is provided with a stainless steel microporous core, the stainless steel microporous core array is arranged in the micropores of the polishing head, the metal part of the polishing head is connected to the inner ring wire of the conductive slip ring, a shoulder of the step shaft is pressed against the inner ring of the ball bearing, and the ball bearing is used for proper centering so that the semiconductor substrate wafer and the polishing pad can effectively parallel fit contact. In actual work, the polishing pad is bonded to the cast iron disk.

[0013] Furthermore, the lifting polishing plate includes an adapter plate, a cast iron plate, a right-angle motor and two sets of lifting mechanisms. The adapter plate is fixedly mounted on the frame by bolts. The lifting mechanism includes a cylinder seat, a lifting cylinder, a cylinder push rod and a flange. The cylinder seat is fixedly mounted on the bottom of the adapter plate, and the lifting cylinder is installed inside the cylinder seat. A cylinder push rod is provided at the output end of the lifting cylinder, and the cylinder push rod is connected to the flange. The end of the cylinder push rod is connected to the cast iron plate. The motor shaft of the right-angle motor is connected to the adapter plate through an elastic coupling. The right-angle motor is used to drive the rotating shaft of the cast iron plate, thereby driving the cast iron plate to rotate.

[0014] Furthermore, the polishing liquid output mechanism is connected to the lifting polishing plate, and includes a polishing liquid tank and a nozzle. The polishing liquid tank is located at the lower end of the adapter plate, and the output end of the polishing liquid tank is connected to the nozzle. The nozzle protrudes from a preset height of the cast iron plate, and the polishing liquid nozzle is connected to the cast iron plate through a flange.

[0015] Furthermore, the turntable type vacuum illumination unit comprises a turntable spindle seat, an air path shunt pressure ring, a negative pressure gauge, a light source water cooling pipe, a vacuum illumination chamber mounting plate, an air path plate air pipe, a supporting column, a feed pipe, an air path plate, a slip ring, a slip ring clamping block, a long afterglow luminescent particle storage bin, a storage bin mounting plate, an intermediate air path mounting plate, a light source, a turntable bottom plate gasket, an electrical control unit, a turntable spindle and a vacuum illumination chamber, wherein the turntable spindle seat is fixedly mounted on the frame by bolts, the turntable spindle is fixedly mounted on the turntable spindle seat and separated by the turntable bottom plate gasket, and the electrical control unit is fixedly mounted on the turntable spindle; the slip ring is mounted on the top of the turntable spindle and fixed by the slip ring clamping block; the air path plate is fastened to the turntable spindle through the intermediate air path mounting plate; the air path shunt pressure ring is fixedly mounted on the bottom of the air path plate, and the air path plate is used to adjust the internal pressure of the working vacuum illumination chamber. The requirements are met; the vacuum illumination chamber mounting disk is sleeved on the outer ring of the turntable main shaft and fastened, and can rotate with the main shaft; the vacuum illumination chamber is multiple and fixedly installed at equal intervals around the outer side of the vacuum illumination chamber mounting disk; several light sources of different wavelengths are respectively fixedly installed at the upper position of the corresponding vacuum illumination chamber to excite different long afterglow luminescent particles; the negative pressure gauge is fixedly installed on the top of the vacuum illumination chamber; the supporting column is located between two adjacent vacuum illumination chambers and is vertically fixedly installed on the vacuum illumination chamber mounting disk; the storage bin mounting disk is fixedly installed on the top of the supporting column for installing the long afterglow luminescent particle storage bin; one end of the feed pipe is connected to the bottom of the long afterglow luminescent particle storage bin, and the other end is connected to the vacuum illumination chamber; one end of the air pipe of the air circuit disk is connected to the vacuum illumination chamber, and the other end of the air circuit disk is connected to the negative pressure pump inside the frame, and the negative pressure pump ensures the air pressure conditions of the vacuum illumination chamber working room.

[0016] Furthermore, it also includes a chamber swing arm, a chamber cover and a swing arm driving motor, the chamber cover is connected to the chamber swing arm, and the chamber cover is installed on the top of the vacuum illumination chamber; the swing arm driving motor is installed on the back of the vacuum illumination chamber, driving the swing arm to drive the chamber cover to complete the opening and closing cover action. When the light source excites the luminescent particles, the chamber cover remains closed to ensure darkness in the vacuum illumination chamber. During polishing, the chamber cover is opened to allow the excited luminescent particles to fall and mix with the polishing liquid.

[0017] Furthermore, it also includes a light source water cooling pipe, one end of which is connected to a cold water pump located inside the rack, and the other end of which is connected to a corresponding light source.

[0018] The present invention also discloses a polishing method of a semiconductor substrate wafer photoelectrochemical mechanical polishing device based on the above-mentioned multi-wavelength long afterglow luminescent particles, comprising the following steps:

[0019] Step 1, semiconductor substrate wafer cleaning: Use anhydrous ethanol to ultrasonically clean the semiconductor substrate wafer, and rinse it repeatedly with deionized water. Then soak the substrate wafer in a 40%-60%wt% concentrated hydrofluoric acid solution, and then rinse it repeatedly with deionized water for 10 minutes, and finally blow it dry with pure nitrogen. Place it on the stainless steel microporous core of the conductive rotating chuck, and connect the gas path of the conductive rotating chuck to achieve adsorption and fixation of the semiconductor substrate wafer;

[0020] When performing step 1, the equipment will simultaneously complete the following tasks: according to the bandgap width of the semiconductor substrate wafer material and the following formula, a long afterglow luminescent particle with a corresponding emission wavelength is selected, and the luminescent particle enters the vacuum illumination chamber with a light source of a corresponding excitation wavelength through the feed pipe; the air pipe of the gas path plate extracts the air in the chamber to make the vacuum illumination chamber reach a vacuum; the light source water cooling pipe circulates cold water to prevent the light source from overheating and burning during operation; the light source irradiates the luminescent particle, and the luminescent particle is excited and stores the absorbed energy;

[0021]

[0022] Step 2: Move and adjust the position of the polishing disk and make it contact with the semiconductor substrate wafer. The polishing pressure signal is collected and processed by the pressure sensor. The processed signal can be fed back to the cylinder to adjust the polishing pressure; it can also be fed back to the electrochemical workstation to adjust the anodic oxidation potential of the electrochemical workstation and adjust the oxidation rate. The loading of the polishing pressure depends on the cylinder in the jacking polishing disk. During this process, the pressure is monitored by the pressure sensor.

[0023] Step 3: The vacuum main turntable mechanism rotates so that the vacuum illumination chamber containing the irradiated long afterglow luminescent particles is located above the lifting polishing plate; the chamber swing arm drives the chamber cover to lift up, and the excited long afterglow luminescent particles are mixed into the polishing liquid.

[0024] Step 4: The polishing liquid is used to form a closed loop between the semiconductor substrate wafer surface as the anode and the polishing disk as the cathode; the electrochemical workstation applies an anode bias to separate the electron-hole pairs generated by the luminescent particles irradiating the semiconductor substrate wafer surface, and the semiconductor substrate wafer surface is modified to generate a soft oxide layer.

[0025] Step 5: The conductive rotating chuck spindle drives the semiconductor substrate wafer to rotate, and the polishing pad presses abrasive particles and luminescent particles (with a hardness between the oxide layer and the matrix) to remove the oxide layer on the surface of the semiconductor substrate wafer. The polishing pressure is adjustable, and the surface oxidation-mechanical removal reciprocating cycle is performed to achieve high-quality and efficient polishing of the semiconductor substrate wafer.

[0026] Compared with the prior art, the present invention has the following advantages: the present invention uses different long afterglow luminescent particles and different light sources, and is suitable for a variety of semiconductor materials. By rotating the turntable vacuum illumination unit, it is simple and fast to change the illumination of different wavelengths. The problem of the polishing disc blocking the illumination is solved under the premise of using an ordinary cast iron disc and not destroying the structure of the polishing disc, ensuring that the polishing disc structure is simple and low-cost, and ensuring the uniformity of material removal. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0028] Figure 1 A schematic diagram of the structure of a semiconductor substrate wafer photoelectrochemical mechanical polishing device based on multiple wavelength long afterglow luminescent particles, in which some consumables and accessories are hidden for the present invention;

[0029] Figure 2 It is a schematic diagram of the gantry in the present invention;

[0030] Figure 3 It is a schematic diagram of the bottom of the conductive rotating chuck in the present invention;

[0031] Figure 4 It is a schematic diagram of the lifting polishing plate in the present invention;

[0032] Figure 5 It is a schematic diagram of a rotary disk type vacuum illumination unit in the present invention;

[0033] Figure 6 The process flow chart of the photoelectrochemical mechanical polishing method of semiconductor substrate wafer based on multi-wavelength long afterglow luminescent particles;

[0034] In the figure: 1. gantry; 2. electrochemical workstation; 3. conductive rotating suction cup; 4. polishing liquid recovery tank; 5. control panel; 6. lifting polishing disc; 7. turntable vacuum illumination unit; 8. rack; 101. fastening screws; 102. column; 103. beam; 104. servo mounting seat; 105. screw rod; 106. lifting beam; 107. suction cup pump; 108. suction cup pump support; 109. suction cup air pipe; 110. spindle box; 301. suction cup rotating motor; 302. conductive slip ring; 303. step shaft; 304. pressure sensor; 305. ball bearing; 306. polishing head; 307. stainless steel microporous core; 601. cylinder seat; 602. lifting cylinder; 603. cylinder push rod; 604. cast iron plate; 605. flange plate; 606. polishing Liquid nozzle; 607, cast iron disc shaft; 608, right-angle motor; 609, polishing liquid tank; 610, adapter plate; 611, flange; 701, turntable spindle seat; 702, gas path diversion pressure ring; 703, negative pressure gauge; 704, light source water cooling pipe; 705, vacuum illumination chamber installation plate; 706, gas path disc air pipe; 707, supporting column; 708, feed pipe; 709, gas path disc; 710, slip ring; 711, slip ring clamping block; 712, long afterglow luminous particle storage bin; 713, storage bin installation disk; 714, chamber swing arm; 715, chamber cover; 716, intermediate gas path installation disk; 717, light source; 718, turntable bottom plate gasket; 719, swing arm drive motor; 720, electrical control unit; 721, turntable spindle; 722, vacuum illumination chamber. DETAILED DESCRIPTION

[0035] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other. The present invention will be described in detail below with reference to the accompanying drawings and in combination with the embodiments.

[0036] In order to make the purpose, 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 in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. The following description of at least one exemplary embodiment is actually only illustrative and is by no means intended to limit the present invention and its application or use. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0037] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit exemplary embodiments according to the present invention. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprising" and / or "including" are used in this specification, it indicates the presence of features, steps, operations, devices, components and / or combinations thereof.

[0038] Unless otherwise specifically stated, the relative arrangement of the parts and steps described in these embodiments, the numerical expressions and numerical values ​​do not limit the scope of the present invention. At the same time, it should be clear that, for ease of description, the sizes of the various parts shown in the drawings are not drawn according to the actual proportional relationship. The technology, methods and equipment known to ordinary technicians in the relevant field may not be discussed in detail, but in appropriate cases, the technology, methods and equipment should be regarded as part of the authorization specification. In all examples shown and discussed here, any specific value should be interpreted as merely exemplary, rather than as a limitation. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar numbers and letters represent similar items in the following drawings, so once an item is defined in one drawing, it does not need to be further discussed in subsequent drawings.

[0039] In the description of the present invention, it is necessary to understand that the directions or positional relationships indicated by directional words such as "front, back, up, down, left, right", "lateral, vertical, perpendicular, horizontal" and "top, bottom" are usually based on the directions or positional relationships shown in the drawings. They are only for the convenience of describing the present invention and simplifying the description. Unless otherwise specified, these directional words do not indicate or imply that the device or element referred to must have a specific direction or be constructed and operated in a specific direction. Therefore, they cannot be understood as limiting the scope of protection of the present invention: the directional words "inside and outside" refer to the inside and outside relative to the contours of each component itself.

[0040] For ease of description, spatially relative terms such as "above", "above", "on the upper surface of", "above", etc. may be used here to describe the spatial positional relationship between a device or feature and other devices or features as shown in the figure. It should be understood that spatially relative terms are intended to include different orientations of the device in use or operation in addition to the orientation described in the figure. For example, if the device in the accompanying drawings is inverted, the device described as "above other devices or structures" or "above other devices or structures" will be positioned as "below other devices or structures" or "below their position devices or structures". Thus, the exemplary term "above" can include both "above" and "below". The device can also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatially relative descriptions used here are interpreted accordingly.

[0041] In addition, it should be noted that the use of terms such as "first" and "second" to limit components is only for the convenience of distinguishing the corresponding components. If not otherwise stated, the above terms have no special meaning and therefore cannot be understood as limiting the scope of protection of the present invention.

[0042] The present invention provides a photoelectrochemical mechanical polishing method for semiconductor substrate wafers based on multi-wavelength long afterglow luminescent particles. During the polishing process, the long afterglow luminescent particles are excited under specific conditions and store the absorbed energy; during the polishing process, the excited long afterglow luminescent particles are mixed into the polishing liquid to irradiate the polished semiconductor substrate wafer; during the polishing process, the substrate wafer acts as an anode and undergoes photoelectrochemical oxidation modification under an external electric field; during the polishing process, the abrasive particles in the polishing liquid interact with the surface of the oxidized and modified substrate wafer. The semiconductor substrate wafer is connected to the positive pole of an external power supply, and the polishing disc is connected to the negative pole of the external power supply; the external power supply, the semiconductor substrate wafer, the polishing liquid, and the polishing disc form a closed loop.

[0043] Specifically, Figures 1 to 5As shown, the embodiment of the present invention discloses a semiconductor substrate wafer photoelectrochemical mechanical polishing device based on multi-wavelength long afterglow luminescent particles, comprising a frame 8, a gantry 1, an electrochemical workstation 2, a polishing liquid recovery tank 4, a control panel 5, a lifting polishing disk 6 and a turntable vacuum illumination unit 7, wherein the gantry 1, the electrochemical workstation 2, the polishing liquid recovery tank 4, the control panel 5, the lifting polishing disk 6 and the turntable vacuum illumination unit 7 are all fixedly mounted on the frame 8; the conductive rotating suction cup 3 is mounted on the gantry 1; the gantry 1 is mounted with a conductive rotating suction cup, a workpiece to be processed is arranged at the end of the conductive rotating suction cup, the lifting polishing disk 6 is arranged below the conductive rotating suction cup, and the distance between the polishing disk and the workpiece to be processed is adjusted by adjusting the height, and the turntable vacuum illumination unit 7 is provided with long afterglow luminescent particles matching the semiconductor substrate wafer material to be processed, and the excited long afterglow luminescent particles are mixed into the polishing liquid to complete the photoelectrochemical mechanical polishing of the surface of the semiconductor substrate wafer.

[0044] The gantry 1 includes a fastening screw 101, a column 102, a beam 103, a servo mounting seat 104, a screw 105 and a lifting beam 106. There are two columns 102, and both columns 102 are fixedly mounted on the frame 8 by the fastening screws 101. The beam 103 is fixedly mounted on the top of the two columns 102; the servo mounting seat 104 is mounted on one end of the beam 103 by bolts; the screw 105 is installed on the beam 103 and is connected to the motor at the servo mounting seat 104 through an elastic coupling; a transverse frame is slidably connected to the beam 103, and the transverse frame is connected to the screw 105; the lifting beam 106 is fixedly mounted on the transverse frame; the spindle box 110 and the suction cup pump support 108 are fixedly mounted on the lifting beam 106.

[0045] The conductive rotating suction cup completes the clamping of the workpiece to be processed by vacuum adsorption. Specifically, the spindle box 110 and the suction cup pump support 108 are fixedly installed on the lifting beam 106 of the gantry 1, and the suction cup pump 107 is fixed on the suction cup pump support 108; one end of the suction cup air pipe 109 is connected to the suction cup pump 107, and the other end is connected to the conductive rotating suction cup 3; the suction cup rotating motor 301 and the stepped shaft 303 are fixedly installed on the spindle box 110; the inner ring of the conductive slip ring 302 is fastened to the stepped shaft 303 by screws, and the inner ring wire can rotate synchronously with the stepped shaft 303, and the outer ring wire of the conductive slip ring 302 is connected to the inner ring wire and then connects the semiconductor substrate wafer; the end of the stepped shaft 303 is connected to the pressure sensor 304;

[0046] The output end of the polishing head 306 is provided with a stainless steel microporous core 307, and the stainless steel microporous core 307 is arrayed in the micropores of the polishing head 306; the metal part on the polishing head 306 is connected to the inner ring wire of the conductive slip ring 302, and a shoulder of the step shaft 303 is pressed against the inner ring of the ball bearing 305. The ball bearing 305 can bear a certain amount of axial load and has a proper self-aligning effect. When the semiconductor substrate wafer contacts the polishing pad due to installation error or the surface error between the semiconductor substrate wafer and the polishing head 306 is small, the semiconductor substrate wafer and the polishing pad can be properly parallel and fit in contact through the proper self-aligning effect of the ball bearing 305.

[0047] The lifting polishing disc 6 includes an adapter plate 610, a cast iron disc 604, a right-angle motor 608 and two sets of lifting mechanisms. The adapter plate 610 is fixedly installed on the frame 8 by bolts and is responsible for connecting the lifting polishing disc 6, the polishing liquid recovery tank 4 and the frame 8; the cylinder seat 601 is fixedly installed at the bottom of the adapter plate 610; the lifting cylinder 602 is installed inside the cylinder seat 601, and the cylinder push rod 603 is connected to the flange 611 to give the cast iron disc 604 an upward force when polishing the semiconductor substrate wafer; the cylinder seat 601, the lifting cylinder 602, the cylinder push rod 603, and the flange 611 are all left There is one on each side, symmetrically placed; the motor shaft of the right-angle motor 608 is connected to the adapter plate 610 through an elastic coupling, located between the left and right lifting cylinders 602, responsible for driving the cast iron disk shaft 607, and then driving the cast iron disk 604 to rotate; the polishing liquid tank 609 is located at the lower end of the adapter plate 610, between the two lifting cylinders 602; the cast iron disk 604 is connected to the polishing liquid nozzle 606 through a flange 605 and fixed on the flange 605, and its lower end is connected to the polishing liquid tank 609; when polishing the semiconductor substrate wafer, the polishing liquid is sprayed from the nozzle onto the polishing pad to act on the semiconductor substrate wafer.

[0048] The turntable spindle seat 701 is fixedly mounted on the frame 8 by bolts; the turntable spindle 721 is fixedly mounted on the turntable spindle seat 701 and separated by the turntable bottom plate gasket 718 to prevent the polishing liquid from flowing into the frame 8 and to achieve a vibration isolation effect; the electrical control unit 720 is fixedly mounted on the turntable spindle 721; the slip ring 710 is mounted on the top of the turntable spindle 721 and fixed by the slip ring clamping block 711; the air circuit plate 709 is fastened to the turntable spindle 721 through the intermediate air circuit mounting plate 716; the air circuit diversion pressure ring 702 is fixedly mounted on the bottom of the air circuit plate 709, and the air circuit plate 709 is reasonably distributed and controlled to make the internal pressure of the working vacuum illumination chamber 722 meet the requirements; the vacuum illumination chamber mounting plate 705 is sleeved on the outer ring of the turntable spindle 721 and fastened, and can rotate with the spindle.

[0049] In the present embodiment, there are five vacuum illumination chambers 722, which are fixedly installed at equal intervals around the outer side of the vacuum illumination chamber mounting plate 705. Correspondingly, there are five other supporting equipment. In other optional implementations, they can be adjusted according to actual conditions; the chamber cover 715 is connected to the chamber swing arm 714 and installed on the top of the vacuum illumination chamber 722; the swing arm drive motor 719 is installed on the back of the vacuum illumination chamber 722, driving the swing arm to drive the chamber cover 715 to complete the opening and closing cover action. When the light source excites the luminescent particles, the chamber cover 715 remains closed to ensure that the vacuum illumination chamber 722 is dark. During polishing, the chamber cover 715 is opened to allow the excited luminescent particles to fall and mix with the polishing liquid; the five light sources of different wavelengths are respectively fixedly installed on the upper side of the five vacuum illumination chambers 722. position, to excite different long afterglow luminescent particles; the negative pressure gauge 703 is fixedly mounted on the top of the vacuum illumination chamber 722; there are 5 supporting columns 707, which are respectively located in the middle of the two vacuum illumination chambers 722 and are vertically fixedly mounted on the vacuum illumination chamber mounting plate 705; the storage bin mounting plate 713 is fixedly mounted on the top of the 5 supporting columns 102, and is used to install the 5 long afterglow luminescent particle storage bins 712; there are 5 feeding pipes 708, one end of which is connected to the bottom of the long afterglow luminescent particle storage bin 712, and the other end is connected to the vacuum illumination chamber 722; there are 5 air pipes 706 of the gas circuit disk, one end of which is connected to the gas circuit disk 709, and the other end is connected to the vacuum illumination chamber 722; there are 5 light source water cooling pipes 704, one end of which is connected to the cold water pump located inside the frame 8, and the other end is connected to the light source 717;

[0050] like Figure 6 As shown, the polishing method of the present invention comprises the following steps:

[0051] Step 1, semiconductor substrate wafer cleaning: Use anhydrous ethanol to ultrasonically clean the semiconductor substrate wafer for 5 minutes, and rinse it repeatedly with deionized water for 3 minutes. Then soak the substrate wafer in a 50wt% concentrated hydrofluoric acid solution for 10 minutes, and rinse it repeatedly with deionized water for 10 minutes. Finally, blow it dry with pure nitrogen. Place it on the stainless steel microporous core of the conductive rotating chuck, connect the gas path of the conductive rotating chuck, and realize the adsorption and fixation of the semiconductor substrate wafer;

[0052] When performing step 1, the equipment will simultaneously complete the following tasks: according to the bandgap width of the semiconductor substrate wafer material and the following formula, a long afterglow luminescent particle with a corresponding emission wavelength is selected, and the luminescent particle enters the vacuum illumination chamber with a light source of a corresponding excitation wavelength through the feed pipe; the air pipe of the gas path plate extracts the air in the chamber to make the vacuum illumination chamber reach a vacuum; the light source water cooling pipe circulates cold water to prevent the light source from overheating and burning during operation; the light source irradiates the luminescent particle, and the luminescent particle is excited and stores the absorbed energy;

[0053]

[0054] Step 2: Move and adjust the position of the polishing disk to contact the semiconductor substrate wafer, collect the polishing pressure signal through the pressure sensor, and process the signal. The processed signal can be fed back to the cylinder to adjust the polishing pressure; it can also be fed back to the electrochemical workstation to adjust the anodic oxidation potential of the electrochemical workstation and adjust the oxidation rate.

[0055] Step 3: The vacuum main turntable mechanism rotates so that the vacuum illumination chamber containing the irradiated long afterglow luminescent particles is located above the lifting polishing plate; the chamber swing arm drives the chamber cover to lift up, and the excited long afterglow luminescent particles are mixed into the polishing liquid.

[0056] Step 4: The polishing liquid is used to form a closed loop between the semiconductor substrate wafer surface as the anode and the polishing disk as the cathode; the electrochemical workstation applies an anode bias to separate the electron-hole pairs generated by the luminescent particles irradiating the semiconductor substrate wafer surface, and the semiconductor substrate wafer surface is modified to generate a soft oxide layer.

[0057] Step 5: The conductive rotating chuck spindle drives the semiconductor substrate wafer to rotate, and the polishing pad presses abrasive particles and luminescent particles (with a hardness between the oxide layer and the matrix) to remove the oxide layer on the surface of the semiconductor substrate wafer. The polishing pressure is adjustable, and the surface oxidation-mechanical removal reciprocating cycle is performed to achieve high-quality and efficient polishing of the semiconductor substrate wafer.

[0058] Using this method in combination with a processing device can achieve a processing effect with a faster removal rate.

[0059] The polishing liquid of the present invention has a silica sol polishing liquid with a mass fraction of 5wt% and an abrasive particle size of 50-100nm and is mixed with a potassium sulfate aqueous solution with a molar concentration of 0.1mol / L. In the present invention, the selection of 50-100nm silicon dioxide abrasive particles can ensure the surface quality of the substrate wafer after polishing, and the silica sol with a mass fraction of 5wt% and the potassium sulfate aqueous solution with a molar concentration of 0.1mol / L can ensure that the polishing liquid has good conductivity and can also ensure that the silicon dioxide particles do not aggregate and settle, thereby ensuring that the polishing liquid has good light transmittance and reducing the shielding of the particle luminescence during the polishing process.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein with equivalents. However, these modifications or replacements do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A semiconductor substrate wafer photoelectrochemical mechanical polishing device based on multi-wavelength long afterglow luminescent particles, characterized in that: The invention comprises a frame, a gantry, an electrochemical workstation, a polishing liquid recovery tank, a control panel, a lifting polishing disk and a turntable type vacuum illumination unit, wherein the gantry, the electrochemical workstation, the polishing liquid recovery tank, the control panel, the lifting polishing disk and the turntable type vacuum illumination unit are all installed on the frame, the gantry is installed with a conductive rotating suction cup, a workpiece to be processed is arranged at the end of the conductive rotating suction cup, the lifting polishing disk is arranged below the conductive rotating suction cup, and the distance between the polishing disk and the workpiece to be processed is adjusted by adjusting the height, and the turntable type vacuum illumination unit is provided with long afterglow luminescent particles matching the semiconductor substrate wafer material to be processed, and the excited long afterglow luminescent particles are mixed into the polishing liquid to complete the photoelectrochemical mechanical polishing of the surface of the semiconductor substrate wafer.

2. The semiconductor substrate wafer photoelectrochemical mechanical polishing device based on multiple wavelength long afterglow luminescent particles according to claim 1 is characterized in that: The gantry includes fastening screws, columns, beams, servo mounting seats, screw rods and lifting beams. There are two columns and both of them are fixedly mounted on the frame by the fastening screws. The beam is fixedly mounted on the tops of the two columns. The servo mounting seat is mounted on one end of the beam by bolts. The screw rod is mounted on the beam and is connected to the motor at the servo mounting seat by an elastic coupling. A transverse frame is slidably connected to the beam, and the transverse frame is connected to the screw rod. The lifting beam is fixedly mounted on the transverse frame, and the conductive rotating suction cup is mounted on the lifting beam.

3. The semiconductor substrate wafer photoelectrochemical mechanical polishing device based on multiple wavelength long afterglow luminescent particles according to claim 1 is characterized in that: The conductive rotating suction cup completes the clamping of the workpiece to be processed by vacuum adsorption. Specifically, the spindle box and the suction cup pump support are fixedly installed on the lifting beam of the gantry, the suction cup pump is fixed on the suction cup pump support, one end of the suction cup air pipe is connected to the suction cup pump, and the other end is connected to the conductive rotating suction cup; the spindle box is provided with a suction cup rotating motor and a step shaft, the inner ring of the conductive slip ring is fastened to the step shaft by screws, the inner ring wire can rotate synchronously with the step shaft, the outer ring wire of the conductive slip ring is connected to the inner ring wire and then connects the workpiece to be processed, and the end of the step shaft is connected to a pressure sensor.

4. The device for photoelectrochemical mechanical polishing of semiconductor substrate wafers based on multi-wavelength long afterglow luminescent particles according to claim 1, characterized in that: The output end of the polishing head is provided with a stainless steel microporous core, and the stainless steel microporous core array is arranged in the micropores of the polishing head. The metal part on the polishing head is connected to the inner ring wire of the conductive slip ring, and a shoulder of the step shaft is pressed against the inner ring of the ball bearing. The ball bearing is used for proper centering so that the semiconductor substrate wafer and the polishing pad can be effectively parallel and in contact.

5. The semiconductor substrate wafer photoelectrochemical mechanical polishing device based on multiple wavelength long afterglow luminescent particles according to claim 1 is characterized in that: The lifting polishing plate includes an adapter plate, a cast iron plate, a right-angle motor and two sets of lifting mechanisms. The adapter plate is fixedly mounted on the frame by bolts. The lifting mechanism includes a cylinder seat, a lifting cylinder, a cylinder push rod and a flange. The cylinder seat is fixedly mounted on the bottom of the adapter plate, and the lifting cylinder is mounted inside the cylinder seat. A cylinder push rod is provided at the output end of the lifting cylinder, and the cylinder push rod is connected to the flange. The end of the cylinder push rod is connected to the cast iron plate. The motor shaft of the right-angle motor is connected to the adapter plate through an elastic coupling. The right-angle motor is used to drive the rotating shaft of the cast iron plate, thereby driving the cast iron plate to rotate.

6. The semiconductor substrate wafer photoelectrochemical mechanical polishing device based on multiple wavelength long afterglow luminescent particles according to claim 5 is characterized in that: The polishing liquid output mechanism is connected to the lifting polishing plate, and includes a polishing liquid tank and a nozzle. The polishing liquid tank is located at the lower end of the adapter plate, and the output end of the polishing liquid tank is connected to the nozzle. The nozzle protrudes from a preset height of the cast iron plate, and the polishing liquid nozzle is connected to the cast iron plate through a flange.

7. The device for photoelectrochemical mechanical polishing of semiconductor substrate wafers based on multi-wavelength long afterglow luminescent particles according to claim 1 is characterized in that: The turntable type vacuum illumination unit comprises a turntable spindle seat, an air path shunt pressure ring, a negative pressure gauge, a light source water cooling pipe, a vacuum illumination chamber mounting plate, an air path plate air pipe, a supporting column, a feed pipe, an air path plate, a slip ring, a slip ring clamping block, a long afterglow luminous particle storage bin, a storage bin mounting plate, an intermediate air path mounting plate, a light source, a turntable bottom plate gasket, an electrical control unit, a turntable spindle and a vacuum illumination chamber. The turntable spindle seat is fixedly mounted on the frame by bolts, the turntable spindle is fixedly mounted on the turntable spindle seat and separated by the turntable bottom plate gasket, and the electrical control unit is fixedly mounted on the turntable spindle; the slip ring is mounted on the top of the turntable spindle and fixed by the slip ring clamping block; the air path plate is fastened to the turntable spindle through the intermediate air path mounting plate; the air path shunt pressure ring is fixedly mounted on the bottom of the air path plate, and the air path plate is used to adjust the internal pressure of the working vacuum illumination chamber to reach the required pressure. Requirement: the vacuum illumination chamber mounting disk is sleeved on the outer ring of the turntable main shaft and fastened, and can rotate with the main shaft; the vacuum illumination chamber is multiple and fixedly mounted on the outer side of the vacuum illumination chamber mounting disk at equal intervals; several light sources of different wavelengths are respectively fixedly mounted on the upper position of the corresponding vacuum illumination chamber to excite different long afterglow luminescent particles; the negative pressure gauge is fixedly mounted on the top of the vacuum illumination chamber; the supporting column is located between two adjacent vacuum illumination chambers and is vertically fixedly mounted on the vacuum illumination chamber mounting disk; the storage bin mounting disk is fixedly mounted on the top of the supporting column for installing the long afterglow luminescent particle storage bin; one end of the feed pipe is connected to the bottom of the long afterglow luminescent particle storage bin, and the other end is connected to the vacuum illumination chamber; one end of the air pipe of the air path disk is connected to the vacuum illumination chamber, and the other end is connected to the negative pressure pump inside the frame through the air path disk, and the negative pressure pump ensures the air pressure conditions of the vacuum illumination chamber working room.

8. The semiconductor substrate wafer photoelectrochemical mechanical polishing device based on multiple wavelength long afterglow luminescent particles according to claim 7 is characterized in that: It also includes a chamber swing arm, a chamber cover and a swing arm driving motor, wherein the chamber cover is connected to the chamber swing arm, and the chamber cover is installed on the top of the vacuum illumination chamber; the swing arm driving motor is installed on the back of the vacuum illumination chamber, driving the swing arm to drive the chamber cover to complete the opening and closing cover action. When the light source excites the luminescent particles, the chamber cover remains closed to ensure darkness in the vacuum illumination chamber. During polishing, the chamber cover is opened to allow the excited luminescent particles to fall and mix with the polishing liquid.

9. The device for photoelectrochemical mechanical polishing of semiconductor substrate wafers based on multi-wavelength long afterglow luminescent particles according to claim 7, characterized in that: It also includes a light source water cooling pipe, one end of which is connected to a cold water pump located inside the rack, and the other end of which is connected to a corresponding light source.

10. A method for photoelectrochemical mechanical polishing of a semiconductor substrate wafer based on the photoelectrochemical mechanical polishing device according to any one of claims 1 to 9 and based on multi-wavelength long afterglow luminescent particles, characterized in that: The steps include: Step 1, semiconductor substrate wafer cleaning: use anhydrous ethanol to ultrasonically clean the semiconductor substrate wafer, and rinse it repeatedly with deionized water; then use concentrated hydrofluoric acid solution to soak the substrate wafer, and rinse it repeatedly with deionized water; then blow it dry with pure nitrogen; the cleaned semiconductor substrate wafer is placed on the stainless steel microporous core of the conductive rotating chuck, and the gas path of the conductive rotating chuck is connected to achieve adsorption and fixation of the semiconductor substrate wafer; According to the bandgap width of the semiconductor substrate wafer material and the following formula, a long afterglow luminescent particle with a corresponding emission wavelength is selected, and the luminescent particle enters a vacuum illumination chamber with a light source with a corresponding excitation wavelength through a feed pipe; Step 2, moving and adjusting the position of the polishing plate to contact the semiconductor substrate wafer, collecting polishing pressure signals through a pressure sensor, and processing the signals; The processed signal is fed back to the cylinder to adjust the polishing pressure; at the same time, it is fed back to the electrochemical workstation to adjust the anodic oxidation potential of the electrochemical workstation and regulate the oxidation rate; Step 3, the air pipe of the gas circuit plate extracts the air in the chamber to make the vacuum illumination chamber reach vacuum; the light source water cooling pipe circulates cold water to prevent the light source from overheating and burning during operation; the light source irradiates the luminescent particles, the luminescent particles are excited and store the absorbed energy; the vacuum main turntable mechanism rotates so that the vacuum illumination chamber containing the irradiated long afterglow luminescent particles is located above the lifting polishing plate; the chamber swing arm drives the chamber cover to lift up, and the excited long afterglow luminescent particles are mixed into the polishing liquid; Step 4: The semiconductor substrate wafer surface as an anode and the polishing disk as a cathode form a closed loop through the polishing liquid; the electrochemical workstation applies an anode bias to separate the electron-hole pairs generated by the luminescent particles irradiating the semiconductor substrate wafer surface, and the semiconductor substrate wafer surface is modified to form a soft oxide layer; Step 5. The conductive rotating suction cup spindle drives the semiconductor substrate wafer to rotate, and the polishing pad presses the abrasive particles and the luminescent particles to remove the oxide layer on the surface of the semiconductor substrate wafer. In this process, the polishing pressure is adjusted based on the value transmitted by the pressure sensor, and the surface oxidation-mechanical removal reciprocating cycle is performed to achieve the polishing of the semiconductor substrate wafer.

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