Semiconductor substrate wafer photoelectrochemical mechanical polishing apparatus and method based on multiple wavelength long-persistent luminescent particles

Abstract

The application relates to a kind of semiconductor substrate wafer photoelectrochemical mechanical polishing device and method based on multiple wavelength long afterglow luminescent particles, including frame, gantry, electrochemical workstation, polishing liquid recovery tank, control panel, jacking polishing disc and rotary vacuum light unit, electrically conductive rotating chuck is installed on gantry, workpiece to be processed is arranged at the end of electrically conductively rotating chuck, the jacking polishing disc is arranged below electrically conductively rotating chuck, the distance between polishing disc on it and workpiece to be processed is adjusted by height adjustment, long afterglow luminescent particles suitable for the material of semiconductor substrate wafer to be processed are arranged in rotary vacuum light unit, and the long afterglow luminescent particles excited are mixed into polishing liquid, and the photoelectrochemical mechanical polishing of the surface of semiconductor substrate wafer is completed.The application uses different long afterglow luminescent particles and different light sources, and is suitable for multiple semiconductor materials.The rotary vacuum light unit is rotated, and different wavelength light is replaced simply and quickly.

Description

Technical Field

[0001] This invention relates to the field of semiconductor substrate wafer polishing technology, and more particularly to a semiconductor substrate wafer photoelectrochemical mechanical polishing apparatus and method based on long-afterglow luminescent particles of various wavelengths. Background Technology

[0002] Semiconductor substrate wafers are the basic materials used in the manufacture of semiconductor devices, on which various semiconductor devices and circuits are manufactured. Substrate wafers play a crucial role in semiconductor manufacturing. As the foundation of devices and circuits, substrate wafers not only support the overall device structure but also provide necessary electrical, thermal, and mechanical support. Therefore, the quality of the substrate directly affects the performance and reliability of the final semiconductor device.

[0003] The superior properties of these materials present significant challenges to their processing. Due to their high hardness and stable chemical properties, both mechanical polishing and chemical mechanical polishing of semiconductor substrate wafers have extremely low material removal efficiency. Photoelectrochemical mechanical polishing is an effective solution, but currently, significant problems such as polishing pad blocking light, uneven material removal, strong selectivity of equipment for substrate wafer materials, high processing costs, and high equipment requirements severely restrict the development of semiconductor device manufacturing technology and its application in related fields.

[0004] Chinese patent application CN 116079580 A discloses a "method and apparatus for wireless photoelectrochemical mechanical polishing of semiconductor wafers," which solves the problem of light obstruction by creating holes in the polishing pad. However, the holes affect the uniformity of material removal and processing efficiency, and this apparatus structure is not suitable for mass production line processing.

[0005] Chinese patent CN 109465739 B discloses a “semiconductor wafer photoelectrochemical mechanical polishing device”. The device integrates only one wavelength of light source and can only be adapted to a very small number of semiconductor materials. If you want to use photoelectrochemical mechanical polishing to polish substrate wafers of other semiconductor materials, you can only disassemble and replace the light source or use other equipment. The processing efficiency is low and the cost is extremely high, making it unsuitable for industrial-scale mass polishing of semiconductor wafers.

[0006] Foreign researchers have used a special polishing device in the polishing process, in which components such as the polishing plate 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.). This increases the initial cost of the polishing device and makes it unsuitable for industrial-scale processing. Summary of the Invention

[0007] To address the aforementioned technical problems, this invention provides a method for photoelectrochemical mechanical polishing of semiconductor substrate wafers based on long-afterglow luminescent particles of multiple wavelengths, and designs a processing apparatus for this method. The photoelectrochemical mechanical polishing method for semiconductor substrate wafers based on long-afterglow luminescent particles of multiple wavelengths, as described in this invention, refers to a processing method that, based on existing photoelectrochemical mechanical polishing, introduces long-afterglow luminescent particles. These particles are first excited under a special environment and store the absorbed energy. Then, they are mixed into a polishing slurry to irradiate the semiconductor substrate wafer being polished. Under the action of an external electric field, they synergistically generate photoelectrochemical oxidation with ultraviolet light, thereby mechanically removing the oxide-modified layer of the semiconductor substrate wafer.

[0008] The technical means employed in this invention are as follows:

[0009] A photoelectrochemical mechanical polishing (CMP) device for semiconductor substrate wafers based on multi-wavelength long-afterglow luminescent particles includes a frame, a gantry, an electrochemical workstation, a polishing slurry recovery tank, a control panel, a lifting polishing disc, and a rotary vacuum illumination unit. The gantry, electrochemical workstation, polishing slurry recovery tank, control panel, lifting polishing disc, and rotary vacuum illumination unit are all mounted on the frame. A conductive rotating chuck is mounted on the gantry, and the workpiece to be processed is placed at the end of the conductive rotating chuck. The lifting polishing disc is positioned below the conductive rotating chuck, and the distance between the polishing disc and the workpiece to be processed can be adjusted by adjusting its height. The rotary vacuum illumination unit contains long-afterglow luminescent particles that are compatible with the semiconductor substrate wafer material to be processed. The excited long-afterglow luminescent particles are mixed into the polishing slurry, completing the photoelectrochemical mechanical polishing of the semiconductor substrate wafer surface.

[0010] Furthermore, the gantry frame includes fastening screws, columns, crossbeams, servo mounting bases, lead screws, and lifting beams. There are two columns, both of which are fixedly mounted on the frame by the fastening screws. The crossbeams are fixedly mounted on the tops of the two columns. The servo mounting bases are bolted to one end of the crossbeams. The lead screws are mounted on the crossbeams and connected to the motor at the servo mounting bases via flexible couplings. A transverse frame is slidably connected to the crossbeams and is connected to the lead screws. The lifting beams are fixedly mounted on the transverse frames, and the conductive rotary chucks are mounted on the lifting beams.

[0011] Furthermore, the conductive rotary suction cup clamps the workpiece to be processed through vacuum adsorption. Specifically, the spindle box and suction cup pump support are fixedly installed on the lifting beam of the gantry frame. 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 rotary suction cup. The spindle box is equipped with a suction cup rotary motor and a stepped shaft. The inner ring of the conductive slip ring is fastened to the stepped shaft with screws. The inner ring wire can rotate synchronously with the stepped shaft. The outer ring wire of the conductive slip ring connects to the inner ring wire, thereby connecting the workpiece to be processed. A pressure sensor is connected to the end of the stepped shaft.

[0012] Furthermore, the output end of the polishing head is provided with a stainless steel microporous core, which is arranged in an array within the micropores of the polishing head. The metal portion of the polishing head is connected to the inner ring wire of the conductive slip ring. One shoulder of the stepped shaft rests on the inner ring of the ball bearing, which serves to provide proper self-alignment, ensuring effective parallel contact between the semiconductor substrate wafer and the polishing pad. In actual operation, the polishing pad is bonded to a cast iron disc.

[0013] Furthermore, the lifting polishing disc includes a transition plate, a cast iron disc, a right-angle motor, and two lifting mechanisms. The transition plate is fixedly mounted on the frame with 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 transition plate, and the lifting cylinder is installed inside the cylinder seat. The output end of the lifting cylinder is provided with a cylinder push rod, which is connected to the flange. The end of the cylinder push rod is connected to the cast iron disc. The motor shaft of the right-angle motor is connected to the transition plate through a flexible coupling. The right-angle motor is used to drive the cast iron disc shaft, thereby causing the cast iron disc to rotate.

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

[0015] Furthermore, the rotary vacuum illumination unit includes a rotary spindle seat, a gas path diversion pressure ring, a negative pressure gauge, a light source water-cooling pipe, a vacuum illumination chamber mounting plate, a gas path plate gas pipe, a support column, a conveying pipe, a gas path plate, a slip ring, a slip ring clamping block, a long afterglow luminescent particle storage chamber, a storage chamber mounting plate, an intermediate gas path mounting plate, a light source, a rotary base plate gasket, an electrical control unit, a rotary spindle, and a vacuum illumination chamber. The rotary spindle seat is bolted to the frame, the rotary spindle is fixedly mounted on the rotary spindle seat and separated by the rotary base plate gasket, and the electrical control unit is fixedly mounted on the rotary spindle. The slip ring is mounted on the top of the rotary spindle and fixed by the slip ring clamping block. The gas path plate is fastened to the rotary spindle via the intermediate gas path mounting plate. The gas path diversion pressure ring is fixedly mounted on the bottom of the gas path plate, and the gas path plate is used to regulate the internal pressure of the vacuum illumination chamber during operation. The requirements are met; the vacuum illumination chamber mounting plate is fitted around the outer ring of the turntable spindle and secured, and can rotate with the spindle; multiple vacuum illumination chambers are fixedly installed around the outer circumference of the vacuum illumination chamber mounting plate at equal intervals; several light sources of different wavelengths are fixedly installed at the upper part 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 support column is located between two adjacent vacuum illumination chambers and is vertically fixedly installed on the vacuum illumination chamber mounting plate; the storage chamber mounting plate is fixedly installed on the top of the support column and is used to install the long-afterglow luminescent particle storage chamber; one end of the conveying pipe is connected to the bottom of the long-afterglow luminescent particle storage chamber, and the other end is connected to the vacuum illumination chamber; one end of the gas pipe of the gas path plate is connected to the vacuum illumination chamber, and the other end of the gas path plate is connected to the negative pressure pump inside the frame, and the negative pressure pump ensures the gas pressure conditions of the vacuum illumination chamber working chamber.

[0016] Furthermore, it also includes a chamber swing arm, a chamber cover, and a swing arm drive motor. The chamber cover is connected to the chamber swing arm and is installed on the top of the vacuum illumination chamber. The swing arm drive motor is installed on the back of the vacuum illumination chamber and drives the swing arm to move the chamber cover to complete the opening and closing action. When the light source excites the luminescent particles, the chamber cover remains closed to ensure that the vacuum illumination chamber is dark. During polishing, the chamber cover opens 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 frame, and the other end is connected to the corresponding light source.

[0018] This invention also discloses a polishing method for a semiconductor substrate wafer photoelectrochemical mechanical polishing apparatus based on the above-mentioned long-afterglow luminescent particles of various wavelengths, comprising the following steps:

[0019] Step 1: Semiconductor substrate wafer cleaning: The semiconductor substrate wafer is ultrasonically cleaned in anhydrous ethanol and rinsed repeatedly with deionized water. Then, the substrate wafer is immersed in a 40%-60% wt% concentrated hydrofluoric acid solution, rinsed repeatedly with deionized water for 10 minutes, and finally dried with pure nitrogen. It is then placed on the stainless steel microporous core of the conductive rotating chuck, with the air path of the conductive rotating chuck connected to achieve adsorption and fixation of the semiconductor substrate wafer.

[0020] During step 1, the equipment will simultaneously perform the following tasks: based on the bandgap of the semiconductor substrate wafer material and the following formula, select long-afterglow luminescent particles corresponding to the emission wavelength; these luminescent particles enter the vacuum illumination chamber with a light source of the corresponding excitation wavelength through the feed tube; the gas path plate evacuates the air in the chamber to achieve a vacuum in the vacuum illumination chamber; the light source water cooling pipe circulates cold water to prevent the light source from overheating and burning out during operation; the light source irradiates the luminescent particles, which are excited and store the absorbed energy.

[0021]

[0022] Step 2: Move and adjust the position of the polishing pad to contact the semiconductor substrate wafer. A pressure sensor collects and processes the polishing pressure signal. The processed signal can be fed back to the cylinder to adjust the polishing pressure, or it can be fed back to the electrochemical workstation to adjust the anodic oxidation potential and regulate the oxidation rate. The polishing pressure is applied by the cylinder that lifts the polishing pad; 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 positioned above the lifting polishing disk; the chamber swing arm drives the chamber cover to lift, and the excited long afterglow luminescent particles are mixed into the polishing liquid.

[0024] Step 4: The polishing solution forms a closed circuit between the semiconductor substrate wafer surface (anode) and the polishing disk (cathode); the electrochemical workstation applies an anode bias voltage to separate the electron-hole pairs generated by the light-emitting particles irradiating the semiconductor substrate wafer surface, thereby modifying the semiconductor substrate wafer surface to form a soft oxide layer.

[0025] Step 5: The conductive rotary chuck spindle drives the semiconductor substrate wafer to rotate. The polishing pad presses abrasive particles and light-emitting particles (with hardness between the oxide layer and the substrate) to remove the oxide layer on the surface of the semiconductor substrate wafer. The polishing pressure is adjustable. The surface oxidation-mechanical removal cycle repeats to achieve high-quality and high-efficiency polishing of the semiconductor substrate wafer.

[0026] Compared with existing technologies, this invention has the following advantages: It uses different long-afterglow luminescent particles and different light sources, making it suitable for a variety of semiconductor materials. By rotating a rotary vacuum illumination unit, different wavelengths of light can be easily and quickly changed. The problem of light obstruction by the polishing disc is solved without damaging the polishing disc structure, ensuring a simple and low-cost polishing disc structure and guaranteeing the uniformity of material removal. Attached Figure Description

[0027] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0028] Figure 1 This is a schematic diagram of the structure of a semiconductor substrate wafer photoelectrochemical mechanical polishing device based on long-afterglow luminescent particles of multiple wavelengths, which conceals some consumable components in this invention.

[0029] Figure 2 This is a schematic diagram of the gantry frame in this invention;

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

[0031] Figure 4 This is a schematic diagram of the lifting polishing disc in this invention;

[0032] Figure 5 This is a schematic diagram of the rotary vacuum illumination unit in this invention;

[0033] Figure 6 This is a process flow diagram of a semiconductor substrate wafer photoelectrochemical mechanical polishing method based on long-afterglow luminescent particles of various wavelengths;

[0034] In the diagram: 1. Gantry frame; 2. Electrochemical workstation; 3. Conductive rotary chuck; 4. Polishing slurry recovery tank; 5. Control panel; 6. Lifting polishing disc; 7. Rotary vacuum illumination unit; 8. Frame; 101. Fastening screw; 102. Column; 103. Crossbeam; 104. Servo mounting base; 105. Lead screw; 106. Lifting beam; 107. Chuck pump; 108. Chuck pump support; 109. Chuck air pipe; 110. Spindle box; 301. Chuck rotary motor; 302. Conductive slip ring; 303. Stepped 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 disc; 605. Flange; 606. Polishing head. 607. Liquid nozzle; 608. Cast iron disc shaft; 609. Right-angle motor; 610. Polishing liquid tank; 611. Adapter plate; 612. Flange; 703. Turntable spindle seat; 704. Gas path diversion pressure ring; 705. Negative pressure gauge; 706. Light source water cooling pipe; 707. Vacuum illumination chamber mounting plate; 708. Gas path plate and gas pipe; 709. Support column; 700. Material conveying pipe; 710. Gas path plate; 711. Slip ring; 712. Slip ring clamping block; 713. Long afterglow luminescent particle storage chamber; 714. Storage chamber mounting plate; 715. Chamber swing arm; 716. Chamber cover; 717. Intermediate gas path mounting plate; 718. Light source; 719. Turntable base plate gasket; 720. Swing arm drive motor; 721. Electrical control unit; 722. Turntable spindle; 723. Vacuum illumination chamber. Detailed Implementation

[0035] It should be noted that, unless otherwise specified, the embodiments and features described in the present invention can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0036] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

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

[0038] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0039] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention. The directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

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

[0041] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0042] This invention provides a photoelectrochemical mechanical polishing method for semiconductor substrate wafers based on long-afterglow luminescent particles of various wavelengths. During the polishing process, the long-afterglow luminescent particles are excited under specific conditions and store the absorbed energy. The excited long-afterglow luminescent particles are mixed into a polishing slurry to irradiate the semiconductor substrate wafer being polished. During polishing, the substrate wafer acts as the anode, undergoing photoelectrochemical oxidation modification under an applied electric field. The polishing process is completed through the interaction between the abrasive particles in the polishing slurry and the oxidized substrate wafer surface. The semiconductor substrate wafer is connected to the positive terminal of an external power supply, and the polishing disk is connected to the negative terminal of the external power supply. The external power supply, semiconductor substrate wafer, polishing slurry, and polishing disk form a closed circuit.

[0043] Specifically, such as Figures 1-5As shown in the figure, this invention discloses an opto-chemical mechanical polishing device for semiconductor substrate wafers based on long-afterglow luminescent particles of various wavelengths. The device includes a frame 8, a gantry 1, an electrochemical workstation 2, a polishing slurry recovery tank 4, a control panel 5, a lifting polishing disc 6, and a rotary vacuum illumination unit 7. The gantry 1, electrochemical workstation 2, polishing slurry recovery tank 4, control panel 5, lifting polishing disc 6, and rotary vacuum illumination unit 7 are all fixedly mounted on the frame 8. A conductive rotating suction cup 3 is mounted on the gantry 1. The conductive rotating suction cup is mounted on the gantry 1, and the workpiece to be processed is placed at the end of the conductive rotating suction cup. The lifting polishing disc 6 is located below the conductive rotating suction cup, and the distance between the polishing disc and the workpiece to be processed is adjusted by adjusting its height. The rotary vacuum illumination unit 7 contains long-afterglow luminescent particles that are compatible with the semiconductor substrate wafer material to be processed. The excited long-afterglow luminescent particles are mixed into the polishing slurry, completing the opto-chemical mechanical polishing of the semiconductor substrate wafer surface.

[0044] The gantry frame 1 includes fastening screws 101, columns 102, crossbeams 103, servo mounting bases 104, lead screws 105, and lifting beams 106. There are two columns 102, both of which are fixedly mounted on the frame 8 using the fastening screws 101. The crossbeams 103 are fixedly mounted on the tops of the two columns 102. The servo mounting base 104 is bolted to one end of the crossbeam 103. The lead screw 105 is mounted on the crossbeam 103 and connected to a motor at the servo mounting base 104 via a flexible coupling. A transverse frame is slidably connected to the crossbeam 103, and the transverse frame is connected to the lead screw 105. The lifting beam 106 is fixedly mounted on the transverse frame. The spindle box 110 and the suction pump support 108 are fixedly mounted on the lifting beam 106.

[0045] The conductive rotary chuck clamps the workpiece to be processed by vacuum adsorption. Specifically, the spindle box 110 and the chuck pump support 108 are fixedly installed on the lifting beam 106 of the gantry frame 1, and the chuck pump 107 is fixed on the chuck pump support 108. One end of the chuck air pipe 109 is connected to the chuck pump 107, and the other end is connected to the conductive rotary chuck 3. The chuck rotary 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 with screws. The inner ring wire can rotate synchronously with the stepped shaft 303. The outer ring wire of the conductive slip ring 302 connects to the inner ring wire, thereby connecting the semiconductor substrate wafer. A pressure sensor 304 is connected to the end of the stepped shaft 303.

[0046] The output end of the polishing head 306 is provided with a stainless steel microporous core 307, which is arranged in an array in the micropores of the polishing head 306. The metal part of the polishing head 306 is connected to the inner ring wire of the conductive slip ring 302. One shoulder of the stepped shaft 303 rests on the inner ring of the ball bearing 305. The ball bearing 305 can bear a certain amount of axial load and has an appropriate self-aligning function. When the semiconductor substrate wafer contacts the polishing pad, if the installation error or the surface error between the semiconductor substrate wafer and the polishing head 306 is small, the appropriate self-aligning function of the ball bearing 305 can make the semiconductor substrate wafer and the polishing pad better parallel and in contact.

[0047] The lifting polishing disc 6 includes a transition plate 610, a cast iron disc 604, a right-angle motor 608, and two lifting mechanisms. The transition plate 610 is bolted to the frame 8 and connects the lifting polishing disc 6, the polishing fluid recovery tank 4, and the frame 8. The cylinder seat 601 is fixedly installed at the bottom of the transition 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, providing an upward force to the cast iron disc 604 during the polishing of the semiconductor substrate wafer. The cylinder seat 601, the lifting cylinder 602, the cylinder push rod 603, and the flange 611 are all left-handed. There is one on each side, placed symmetrically; the motor shaft of the right-angle motor 608 is connected to the adapter plate 610 through a flexible coupling, located between the two lifting cylinders 602, responsible for driving the cast iron disc rotating shaft 607, thereby driving the cast iron disc 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 disc 604 is connected to the polishing liquid nozzle 606 through a flange 605 and fixed on the flange 605, with its lower end connected to the polishing liquid tank 609; when polishing the semiconductor substrate wafer, 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 base plate gasket 718 to prevent polishing liquid from flowing into the frame 8 and to provide vibration isolation; 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 passage plate 709 is fastened to the turntable spindle 721 by the intermediate air passage mounting plate 716; the air passage diverting pressure ring 702 is fixedly mounted on the bottom of the air passage plate 709, and the air passage plate 709 reasonably distributes and controls the pressure inside the working vacuum illumination chamber 722 to 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 this embodiment, there are five vacuum illumination chambers 722, which are fixedly installed at equal intervals around the outer perimeter of the vacuum illumination chamber mounting plate 705. Correspondingly, there are also five other supporting devices. In other optional embodiments, adjustments can be made according to actual conditions. The chamber cover 715 is connected to the chamber swing arm 714 and is 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 move the chamber cover 715 to complete the opening and closing action. When the light source excites the luminescent particles, the chamber cover 715 remains closed to ensure darkness inside the vacuum illumination chamber 722. During polishing, the chamber cover 715 opens 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 inside the five vacuum illumination chambers 722, slightly above the center. Position, exciting different long-afterglow luminescent particles; the negative pressure gauge 703 is fixedly installed on the top of the vacuum illumination chamber 722; there are 5 support columns 707, located in the middle of two vacuum illumination chambers 722, and vertically fixedly installed on the vacuum illumination chamber mounting plate 705; the storage chamber mounting plate 713 is fixedly installed on the top of the 5 support columns 102, and is used to install 5 long-afterglow luminescent particle storage chambers 712; there are 5 conveying pipes 708, one end of which is connected to the bottom of the long-afterglow luminescent particle storage chamber 712, and the other end is connected to the vacuum illumination chamber 722; there are 5 gas pipes 706, one end of which is connected to the gas pipe 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 includes the following steps:

[0051] Step 1: Semiconductor substrate wafer cleaning: The semiconductor substrate wafer is ultrasonically cleaned in anhydrous ethanol for 5 minutes, then rinsed repeatedly with deionized water for 3 minutes. Next, the substrate wafer is immersed in a 50wt% concentrated hydrofluoric acid solution for 10 minutes, followed by rinsing repeatedly with deionized water for 10 minutes. Finally, it is dried with pure nitrogen. The wafer is then placed on the stainless steel microporous core of the conductive rotating chuck, with the air path of the chuck connected to achieve adsorption and fixation of the semiconductor substrate wafer.

[0052] During step 1, the equipment will simultaneously perform the following tasks: based on the bandgap of the semiconductor substrate wafer material and the following formula, select long-afterglow luminescent particles corresponding to the emission wavelength; these luminescent particles enter the vacuum illumination chamber with a light source of the corresponding excitation wavelength through the feed tube; the gas path plate evacuates the air in the chamber to achieve a vacuum in the vacuum illumination chamber; the light source water cooling pipe circulates cold water to prevent the light source from overheating and burning out during operation; the light source irradiates the luminescent particles, exciting them and storing the absorbed energy.

[0053]

[0054] Step 2: Move and adjust the position of the polishing pad to contact the semiconductor substrate wafer. Acquire the polishing pressure signal using a pressure sensor and process the signal. The processed signal can be fed back to the cylinder to adjust the polishing pressure; or it can be fed back to the electrochemical workstation to adjust the anodic oxidation potential and regulate 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 positioned above the lifting polishing disk; the chamber swing arm drives the chamber cover to lift, and the excited long afterglow luminescent particles are mixed into the polishing liquid.

[0056] Step 4: The polishing solution forms a closed circuit between the semiconductor substrate wafer surface (anode) and the polishing disk (cathode); the electrochemical workstation applies an anode bias voltage to separate the electron-hole pairs generated by the light-emitting particles irradiating the semiconductor substrate wafer surface, thereby modifying the semiconductor substrate wafer surface to form a soft oxide layer.

[0057] Step 5: The conductive rotary chuck spindle drives the semiconductor substrate wafer to rotate. The polishing pad presses abrasive particles and light-emitting particles (with hardness between the oxide layer and the substrate) to remove the oxide layer on the surface of the semiconductor substrate wafer. The polishing pressure is adjustable. The surface oxidation-mechanical removal cycle repeats to achieve high-quality and high-efficiency polishing of the semiconductor substrate wafer.

[0058] Using this method in conjunction with a processing device can achieve faster removal rates.

[0059] The polishing slurry of this invention comprises a 5 wt% silica sol polishing slurry with a particle size of 50–100 nm and a potassium sulfate aqueous solution with a concentration of 0.1 mol / L. In this invention, the use of 50–100 nm silica abrasive particles ensures the surface quality of the substrate wafer after polishing. The 5 wt% silica sol and the 0.1 mol / L potassium sulfate aqueous solution ensure good conductivity of the polishing slurry and prevent silica particles from agglomerating and settling, thereby ensuring good light transmittance of the polishing slurry and reducing the obstruction of 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, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions 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 apparatus based on a plurality of wavelength long afterglow luminescent particles, characterized by, The system includes a frame, a gantry, an electrochemical workstation, a polishing slurry recovery tank, a control panel, a lifting polishing disc, and a rotary vacuum illumination unit. All components are mounted on the frame. A conductive rotating chuck is mounted on the gantry, with the workpiece to be processed placed at its end. The lifting polishing disc is positioned below the conductive rotating chuck, and its height is adjusted to regulate the distance between the polishing disc and the workpiece. The rotary vacuum illumination unit contains long-afterglow luminescent particles that interact with the semiconductor substrate wafer material to be processed. These excited particles are incorporated into the polishing slurry, completing the photoelectrochemical mechanical polishing of the semiconductor substrate wafer surface. The conductive rotary chuck clamps the workpiece to be processed by vacuum adsorption. Specifically, the spindle box and the chuck pump support are fixedly installed on the lifting beam of the gantry frame. The chuck pump is fixed on the chuck pump support. One end of the chuck air pipe is connected to the chuck pump, and the other end is connected to the conductive rotary chuck. The spindle box is equipped with a chuck rotary motor and a stepped shaft. The inner ring of the conductive slip ring is fastened to the stepped shaft with screws. The inner ring wire can rotate synchronously with the stepped shaft. The outer ring wire of the conductive slip ring is connected to the inner ring wire, thereby connecting the workpiece to be processed. A pressure sensor is connected to the end of the stepped shaft. The rotary vacuum illumination unit includes a rotary spindle seat, a gas path diversion pressure ring, a negative pressure gauge, a light source water-cooling pipe, a vacuum illumination chamber mounting plate, a gas path plate gas pipe, a support column, a feed pipe, a gas path plate, a slip ring, a slip ring clamping block, a long afterglow luminescent particle storage chamber, a storage chamber mounting plate, an intermediate gas path mounting plate, a light source, a rotary base plate gasket, an electrical control unit, a rotary spindle, and a vacuum illumination chamber. The rotary spindle seat is bolted to the frame, and the rotary spindle is fixedly mounted on the rotary spindle seat and separated by the rotary base plate gasket. The electrical control unit is fixedly mounted on the rotary spindle. The slip ring is mounted on the top of the rotary spindle and fixed by the slip ring clamping block. The gas path plate is fastened to the rotary spindle via the intermediate gas path mounting plate. The gas path diversion pressure ring is fixedly mounted on the bottom of the gas path plate. The gas path plate is used to regulate the internal pressure of the vacuum illumination chamber to achieve the required pressure. The vacuum illumination chamber mounting plate is fitted around the outer ring of the turntable spindle and secured, allowing it to rotate with the spindle. Multiple vacuum illumination chambers are fixedly installed around the outer circumference of the mounting plate at equal intervals. Several light sources of different wavelengths are fixedly installed in the upper part of their respective vacuum illumination chambers to excite different long-afterglow luminescent particles. A negative pressure gauge is fixedly installed on the top of the vacuum illumination chamber. A support column, located between two adjacent vacuum illumination chambers, is vertically fixed on the mounting plate. A storage chamber mounting plate is fixedly installed on the top of the support column for installing the long-afterglow luminescent particle storage chamber. One end of the feed pipe is connected to the bottom of the long-afterglow luminescent particle storage chamber, and the other end is connected to the vacuum illumination chamber. One end of the gas pipe on the gas path plate is connected to the vacuum illumination chamber, and the other end is connected to a negative pressure pump inside the frame via the gas path plate. The negative pressure pump ensures the air pressure conditions in the working chamber of the vacuum illumination chamber.

2. The semiconductor substrate wafer photoelectrochemical mechanical polishing apparatus based on multiple wavelength long afterglow luminescent particles according to claim 1, characterized in that, The gantry frame includes fastening screws, columns, crossbeams, servo mounting bases, lead screws, and lifting beams. There are two columns, both of which are fixedly mounted on the frame by the fastening screws. The crossbeams are fixedly mounted on the tops of the two columns. The servo mounting bases are bolted to one end of the crossbeams. The lead screws are mounted on the crossbeams and connected to the motor at the servo mounting bases via flexible couplings. A transverse frame is slidably connected to the crossbeams and is connected to the lead screws. The lifting beams are fixedly mounted on the transverse frames, and the conductive rotary chucks are mounted on the lifting beams.

3. The semiconductor substrate wafer photoelectrochemical mechanical polishing apparatus based on multiple wavelength long afterglow luminescent particles according to claim 2, characterized in that, One shoulder of the stepped shaft rests on the inner ring of the ball bearing. A polishing head is located below the ball bearing. The output end of the polishing head is provided with a stainless steel micro-hole core. The stainless steel micro-hole core is arranged in an array in the micro-holes of the polishing head. The metal part of the polishing head is connected to the inner ring wire of the conductive slip ring. The ball bearing is used for proper self-aligning so that the semiconductor substrate wafer and the polishing pad can be effectively parallel and in contact.

4. The semiconductor substrate wafer photoelectrochemical mechanical polishing apparatus based on multiple wavelength long afterglow luminescent particles according to claim 3, characterized in that, The lifting polishing disc includes a transition plate, a cast iron disc, a right-angle motor, and two lifting mechanisms. The transition plate is fixedly mounted on the frame with 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 transition plate. The lifting cylinder is installed inside the cylinder seat. The output end of the lifting cylinder is provided with a cylinder push rod, which is connected to the flange. The end of the cylinder push rod is connected to the cast iron disc. The motor shaft of the right-angle motor is connected to the cast iron disc through a flexible coupling. The right-angle motor is used to drive the cast iron disc shaft, thereby causing the cast iron disc to rotate.

5. The semiconductor substrate wafer photoelectrochemical mechanical polishing apparatus based on multiple wavelength long afterglow luminescent particles according to claim 4, characterized in that, The polishing fluid output mechanism is connected to the lifting polishing disc. It includes a polishing fluid tank and a nozzle. The polishing fluid tank is located at the lower end of the adapter plate. The output end of the polishing fluid tank is connected to the nozzle. The nozzle protrudes from the cast iron disc at a preset height and is connected to the cast iron disc through a flange.

6. The photoelectrochemical mechanical polishing apparatus for semiconductor substrate wafers based on long-afterglow luminescent particles of multiple wavelengths according to claim 5, characterized in that, It also includes a chamber swing arm, a chamber cover, and a swing arm drive motor. The chamber cover is connected to the chamber swing arm and is installed on the top of the vacuum illumination chamber. The swing arm drive motor is installed on the back of the vacuum illumination chamber and drives the swing arm to move the chamber cover to complete the opening and closing action. When the light source excites the luminescent particles, the chamber cover remains closed to ensure that the vacuum illumination chamber is dark. During polishing, the chamber cover opens to allow the excited luminescent particles to fall and mix with the polishing liquid.

7. The photoelectrochemical mechanical polishing apparatus for semiconductor substrate wafers based on long-afterglow luminescent particles of multiple wavelengths according to claim 6, 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 frame, and the other end is connected to the corresponding light source.

8. A method for photoelectrochemical mechanical polishing of semiconductor substrate wafers based on long-afterglow luminescent particles of multiple wavelengths using the photoelectrochemical mechanical polishing apparatus of claim 7, characterized in that, Includes the following steps: Step 1: Cleaning the semiconductor substrate wafer: Ultrasonically clean the semiconductor substrate wafer in anhydrous ethanol and rinse it repeatedly with deionized water; then immerse the substrate wafer in concentrated hydrofluoric acid solution and rinse it repeatedly with deionized water; finally, dry it with pure nitrogen gas; place the cleaned semiconductor substrate wafer on the stainless steel microporous core of the conductive rotating chuck, and connect the air path of the conductive rotating chuck to achieve adsorption and fixation of the semiconductor substrate wafer. Based on the bandgap of the semiconductor substrate wafer material and the following formula, long-afterglow luminescent particles corresponding to the emission wavelength are selected, and these luminescent particles are fed into a vacuum illumination chamber with a light source of the corresponding excitation wavelength through a feed tube. ； Step 2: Move and adjust the position of the polishing pad to contact the semiconductor substrate wafer, collect the polishing pressure signal through the pressure sensor, and process the signal; 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 air circuit plate draws air from the chamber to make the vacuum illumination chamber a vacuum; the water cooling pipe of the light source circulates cold water to prevent the light source from overheating and burning out during operation; the light source irradiates the luminescent particles, which are excited and store the absorbed energy; the vacuum main turntable mechanism rotates to position the vacuum illumination chamber containing the irradiated long-afterglow luminescent particles above the lifting polishing disc; the chamber swing arm drives the chamber cover to lift, and the excited long-afterglow luminescent particles mix into the polishing liquid. Step 4: The polishing solution forms a closed circuit between the semiconductor substrate wafer surface (anode) and the polishing disk (cathode); the electrochemical workstation applies an anodic bias voltage to separate the electron-hole pairs generated by the luminescent particles irradiating the semiconductor substrate wafer surface, thereby modifying the semiconductor substrate wafer surface to form a soft oxide layer. Step 5: The conductive rotary chuck spindle drives the semiconductor substrate wafer to rotate. The polishing pad presses abrasive particles and light-emitting particles to remove the oxide layer on the surface of the semiconductor substrate wafer. During this process, the polishing pressure is adjusted based on the value transmitted by the pressure sensor. The surface oxidation-mechanical removal cycle repeats to achieve the polishing of the semiconductor substrate wafer.

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