A liquid alloy pressure leveling device for filling through-holes in silicon wafers

Abstract

This invention provides a liquid alloy pressurizing and leveling device for through-hole filling of silicon wafers, addressing the problems in existing technologies such as uneven filling due to coarse material feeding, void defects caused by lack of precise leveling, residual air bubbles due to static venting, and reliance on subsequent processes for waste material handling. The device comprises: a sealed chamber, a lifting and heating assembly, a hollow tubular solder, a filling and positioning assembly, a silicon wafer mounting assembly, and a silicon wafer leveling and liquid discharge assembly. The lifting and heating assembly drives a heating rod fitted with the hollow tubular solder to descend in an array, inserting it into the filling and positioning assembly and the through-hole of the silicon wafer, heating and melting it to achieve precise material feeding per hole. The silicon wafer leveling and liquid discharge assembly uses a two-stage coordinated leveling mechanism of threaded lifting and a wedge-shaped slider mechanism to ensure the silicon wafer is level. Vacuuming combined with a vent on the side of the heating rod enables dynamic venting, and nitrogen pressurization allows for dense filling of the molten liquid, improving the TSV filling yield.

Description

Technical Field

[0001] This invention relates to the field of semiconductor packaging technology, and in particular to a liquid alloy pressure leveling device for filling through-holes in silicon wafers. Background Technology

[0002] In the fields of semiconductor packaging, MEMS devices, and power module manufacturing, silicon wafer via filling is a core process that determines the electrical performance and structural reliability of devices. Currently, the industry mainly uses traditional processes such as electroplating deposition, solder paste screen printing, or overall molten flow for via filling. For example, the invention patent with publication number CN110791746B, "A method and apparatus for rapidly filling vertical silicon vias with liquid alloy," improves the filling efficiency to a certain extent through vacuum pretreatment and nitrogen pressurization forced filling. However, it still exposes the following significant technical bottlenecks in actual mass production applications: (1) The feeding method is crude and the filling uniformity is difficult to guarantee: relying on the natural flow of molten alloy or gravity flow, it is easily affected by the difference in surface tension and the micro-fluctuation of the hole diameter, making it difficult to achieve precise quantitative supply for a single hole, resulting in insufficient filling of some through holes and some overflow in the high-density micro-hole array; (2) Lack of leveling mechanism, which easily leads to void defects: The micro tilt caused by the warping of the silicon wafer itself, the cumulative tolerance of assembly and the high temperature thermal deformation is not considered. When there is an angular deviation between the through hole axis and the molten pool surface, it directly leads to poor wetting on one side and internal void defects. (3) Static exhaust path and high residual rate of air bubbles in the hole: relying solely on the overall vacuuming before filling to remove the gas in the chamber, it is impossible to dynamically remove the gas trapped inside the through hole during the flow of molten material, and the molten alloy is prone to encapsulating the air cavities and forming filling defects. (4) The blank handling of residual material affects the filling quality: the focus is on the filling process but no automatic discharge mechanism for the overflow at the port after filling is provided. It still needs to rely on subsequent mechanical grinding or chemical cleaning processes, which not only increases production costs and process cycle, but also easily scratches the smoothness of the inner wall of the hole.

[0003] Therefore, there is an urgent need in this field for a silicon wafer via filling equipment that can achieve precise quantitative feeding of single vias, multi-stage precision leveling, dynamic venting and pressurization coordination, and automatic discharge of excess material, so as to improve the microvia filling yield and process stability. Summary of the Invention

[0004] In view of the shortcomings of the prior art described above, the purpose of this invention is to provide a liquid alloy pressure leveling device for filling through-holes in silicon wafers, which solves the problems in the prior art such as uneven filling caused by rough material feeding for filling through-holes in silicon wafers, void defects caused by lack of precision leveling, easy retention of air bubbles due to static venting, and reliance on subsequent processes for handling leftover material.

[0005] To achieve the above and other related objectives, the present invention provides a liquid alloy pressure leveling device for filling through-holes in silicon wafers, comprising: A sealed chamber has upper and lower lifting slide rail grooves on the upper and lower parts of its four inner walls, respectively. A vacuum tube is connected to the side wall of the sealed chamber. A lifting heating assembly is slidably installed between the upper lifting slide rail grooves. A section of nitrogen pipe is fixed to the upper wall of the sealed chamber and the middle of the lifting heating assembly. A telescopic pipe is connected between the two sections of nitrogen pipe. A filling hole positioning assembly and a silicon wafer mounting assembly are slidably installed between the lower lifting slide rail grooves. The silicon wafer mounting assembly is located below the filling hole positioning assembly. The silicon wafer mounting assembly and the filling hole positioning assembly are intermittently slidably pressed together. A silicon wafer leveling and liquid discharge assembly is provided at the bottom of the silicon wafer mounting assembly. The lifting and heating assembly is used to precisely dispense material into each through hole by cooperating with the filling and positioning assembly through lifting, and to carry and precisely heat the hollow tubular welding material to a molten state. The filling and positioning assembly is used to cooperate with the silicon wafer mounting assembly to form a sealed pressure chamber and guide the molten solder to flow into the through holes of the silicon wafer. The silicon wafer mounting assembly is used to support the circular silicon wafer and achieve high-precision positioning and sealing. The silicon wafer leveling and liquid discharge assembly is used to perform multi-dimensional precision leveling of the circular silicon wafer and to control the discharge of excess molten liquid after the filling operation is completed.

[0006] Optionally, the lifting and heating assembly includes an upper slider, a mounting plate, and a positioning plate. The upper slider is slidably installed in each of the four upper lifting slide rail grooves. The mounting plate is fixed between the four upper sliders. The positioning plate is fixedly embedded in the lower wall of the mounting plate. Several heating rods are arranged vertically downward on the lower wall of the positioning plate. The hollow tubular welding material is slidably sleeved on the outer wall of the heating rods.

[0007] Optionally, the bottom of the heating rod is inverted cone shape, and a vent is provided on the side of the heating rod.

[0008] Optionally, the filling positioning assembly includes a lower pressure plate slider, a filling pressure plate, and a sealing pressure plate. The lower pressure plate slider is slidably installed in each of the four lower lifting slide rail grooves. The filling pressure plate is fixed between the four lower pressure plate sliders. The sealing pressure plate is installed in the filling pressure plate. The bottom of the sealing pressure plate is provided with a frustum-shaped mating groove. Several solder transition holes are opened through the sealing pressure plate.

[0009] Optionally, the silicon wafer mounting assembly includes a lower substrate slider, a mounting substrate, and a hollow double-positioning frustum. The lower substrate slider is also slidably mounted in the four lower lifting slide rail grooves. The mounting substrate is fixed between the four lower substrate sliders. The upper wall of the mounting substrate is fixed with a hollow double-positioning frustum. The outer volume and bending angle of the hollow double-positioning frustum are the same as those of the frustum-shaped mating groove. The frustum-shaped mating groove and the hollow double-positioning frustum are intermittently sliding and sealingly fitted. The circular silicon wafer is slidably embedded in the hollow double-positioning frustum.

[0010] Optionally, the circular silicon wafer has a plurality of through holes that vertically penetrate the silicon wafer. The heating rod connects the solder transition hole and the silicon wafer through hole one by one on the vertical axis. The bottom of the heating rod is intermittently inserted into the top of the silicon wafer through hole. The outer diameter of the hollow tubular solder is smaller than the diameter of the solder transition hole.

[0011] Optionally, the silicon wafer leveling and liquid discharge assembly includes a leveling transmission groove, a supporting frustum, and a transition frustum. The mounting substrate has a leveling transmission groove inside. The supporting frustum and the transition frustum are slidably mounted within the leveling transmission groove. Three sets of wedge-shaped slider mechanisms are distributed at 120-degree intervals between the lower wall of the transition frustum and the inner side of the lower wall of the mounting substrate. Each set of wedge-shaped slider mechanisms includes a push-pull cylinder, a lower active wedge slider, a linkage block, a limit slot, an upper linkage block, and an upper driven wedge slider. The inner side of the outer wall of the mounting substrate... A push-pull cylinder is fixed, and a lower active wedge slider is fixed at the output end of the push-pull cylinder. A linkage block is fixed on the lower wall of the lower active wedge slider. Three limiting slots are provided at 120-degree intervals on the inner side of the lower wall of the mounting base, and the three linkage blocks are respectively slidably disposed in the three limiting slots. Three upper linkage blocks are fixed at 120-degree intervals on the lower wall of the transition truncated cone. An upper driven wedge slider is fixed on the lower wall of each of the three upper linkage blocks, and the upper driven wedge slider slides in cooperation with the lower active wedge slider.

[0012] Optionally, three sets of threaded lifting and leveling mechanisms are distributed at 120-degree intervals between the upper wall of the transition truncated cone and the lower wall of the supporting truncated cone. Each threaded lifting and leveling mechanism includes a lifting screw, a top block, and a servo motor. The servo motor is fixed to the upper wall of the transition truncated cone, and the lifting screw is installed at the output end of the servo motor. The top block is fixed to the top of the lifting screw and is fixed to the lower wall of the supporting truncated cone. The wedge-shaped slider mechanism and the threaded lifting and leveling mechanism are arranged alternately at 60-degree intervals when viewed from above.

[0013] Optionally, the supporting truncated cone has a liquid discharge lifting groove inside. Four lifting cylinders are fixedly installed at the bottom of the liquid discharge lifting groove. The output ends of the four lifting cylinders are jointly fixed with a linkage lifting block. A number of through-hole plugs are fixedly arrayed on the upper surface of the linkage lifting block. The number of through-hole plugs intermittently seal and abut against the bottom of the silicon wafer through holes, and the number of through-hole plugs are all slidably connected to the upper part of the liquid discharge lifting groove.

[0014] As described above, the liquid alloy pressure leveling device for filling through-holes in silicon wafers of the present invention has at least the following beneficial effects: 1. By coordinating the lifting heating component and the filling positioning component, independent quantitative feeding and in-situ melting of a single hole are achieved, solving the problem of uneven filling or cross-contamination caused by the overflow of molten material in the existing technology, and significantly improving the filling consistency of the high-density through-hole array. 2. Through the two-stage coordinated leveling of the threaded lifting and leveling mechanism and the wedge-shaped slider mechanism, the threaded mechanism first compensates for the height difference in the Z direction to achieve coarse leveling, and then the wedge-shaped slider mechanism performs fine adjustment of the micro-tilt angle to ensure that the silicon wafer through hole is horizontal when in contact with the molten alloy, thus eliminating poor wetting and void defects caused by tilting. 3. Through the dynamic coordination of the side vent of the heating rod and the nitrogen pressurization system, the vent actively removes the trapped air bubbles in the through hole during the solder melting and inflow stage. Then, nitrogen is injected to form a vertical downward pressure, which promotes the molten alloy to adhere tightly to the inner wall of the through hole, greatly improving the micropore filling rate and sidewall bonding quality. 4. Through the linkage discharge design of the through hole plug and the liquid discharge lifting tank, the bottom of the through hole is opened synchronously after filling is completed, so that the excess unformed solder automatically flows back and shrinks to the top of the liquid discharge lifting tank, eliminating the need for subsequent grinding and cleaning processes, and directly obtaining a high-quality through hole structure with smooth inner wall and no overflow. 5. The quick-change seal design using a square slider guide rail and a frustum-shaped mating groove utilizes geometric centering characteristics to achieve component sliding separation and rapid reset. This ensures assembly verticality and high-pressure sealing without the need for complex fixtures, greatly improving equipment maintenance efficiency and production cycle time. Attached Figure Description

[0015] Figure 1 The image shown is a perspective view of the overall structure of the present invention from a southwest angle.

[0016] Figure 2 The image shown is a bottom-view perspective view of the overall structure of the present invention.

[0017] Figure 3 The diagram shown is a cross-sectional view of the overall structure of the sealed chamber of the present invention.

[0018] Figure 4 The image shown is a southwest-view perspective perspective of the structure of the lifting heating component and the filling hole positioning component of the present invention.

[0019] Figure 5 The image shown is a bottom-view perspective view of the structure of the lifting heating component and the filling hole positioning component of the present invention.

[0020] Figure 6 The image shown is a bottom-view perspective view of the assembly structure of the heating rod and the hollow tubular solder of the present invention.

[0021] Figure 7 The image shown is a top-view perspective view of the assembly structure of the heating rod and the hollow tubular solder of the present invention.

[0022] Figure 8 The image shown is a southwest-view perspective perspective view of the inverted cone at the bottom of the heating rod and the vent structure of the present invention.

[0023] Figure 9 The image shown is a southwest-view perspective perspective of the mating structure of the filling positioning component and the silicon wafer mounting component of the present invention.

[0024] Figure 10 The image shown is a perspective view of the filling plate of the present invention from a southwest angle.

[0025] Figure 11 The image shown is a southwest perspective view of the sealed pressing cake of the present invention.

[0026] Figure 12 The image shown is a bottom-view perspective view of the frustum-shaped mating groove of the sealing pressing cake of the present invention.

[0027] Figure 13 The image shown is a southwest-view perspective view of the silicon wafer mounting assembly of the present invention.

[0028] Figure 14 The image shown is a southwest-view perspective view of the circular silicon wafer of this invention.

[0029] Figure 15 The image shown is a three-dimensional sectional view of the central part of the overall structure of the present invention.

[0030] Figure 16 The image shown is a front cross-sectional view of the central part of the overall structure of the present invention.

[0031] Figure 17 The diagram shown is a top view of the distribution positions of the threaded lifting and leveling mechanism and the wedge-shaped slider mechanism of the present invention.

[0032] Figure 18 The diagram shows the distribution of the threaded lifting and leveling mechanism and the wedge-shaped slider mechanism of the present invention from a southwest perspective.

[0033] Figure 19 This invention is shown as Figure 18 Enlarged view of the structure of region A in the image.

[0034] Figure 20 This invention is shown as Figure 18 Enlarged view of region B structure.

[0035] Figure 21 The image shown is a front perspective view of the overall structure of the sealed chamber of the present invention in cross-section.

[0036] Component designation explanation 1. Sealed chamber; 101. Upper lifting slide rail groove; 102. Lower lifting slide rail groove; 103. Vacuum tube; 104. Nitrogen tube; 105. Telescopic tube; 2. Lifting and heating assembly; 201. Upper slider; 202. Mounting plate; 203. Positioning plate; 204. Heating rod; 3. Hollow tubular solder; 4. Filling hole positioning assembly; 401. Lower pressure plate slider; 402. Filling hole pressure plate; 403. Sealing pressure plate; 404. Frustum-shaped mating groove; 405. Solder transition hole; 5. Silicon wafer mounting assembly; 501. Lower substrate slider; 502. Mounting substrate; 503. Hollow double positioning frustum; 6. Silicon wafer leveling and liquid discharge assembly; 601. Leveling transmission groove; 602. Supporting frustum; 603. Transition frustum; 604. Liquid discharge lifting groove; 605. Lifting cylinder; 606. Linkage lifting block; 607. Through hole plug; 608. Push-pull cylinder; 609. Lower active wedge slider; 610. Linkage block; 611. Limiting slot; 612. Upper linkage block; 613. Upper driven wedge slider; 614. Lifting screw; 615. Top block; 616. Servo motor; 7. Circular silicon wafer; 701. Through-hole silicon wafer. Detailed Implementation

[0037] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Example 1

[0038] Please see Figures 1-5 and Figure 13To achieve vertical positioning and high-pressure sealing during the silicon wafer via filling assembly process, this invention provides a liquid alloy pressure leveling device for silicon wafer via filling, comprising: a sealed chamber 1, with upper lifting slide rail grooves 101 and lower lifting slide rail grooves 102 respectively provided on the upper and lower parts of the four inner walls of the sealed chamber 1; a lifting heating component 2 is slidably installed between the upper lifting slide rail grooves 101; a filling positioning component 4 and a silicon wafer mounting component 5 are slidably installed between the lower lifting slide rail grooves 102, with the silicon wafer mounting component 5 located below the filling positioning component 4; the silicon wafer mounting component 5 and the filling positioning component 4 are intermittently slidably pressed together; and a silicon wafer leveling liquid discharge component 6 is provided inside the bottom of the silicon wafer mounting component 5. Among them, such as Figures 3-5 As shown, the lifting heating assembly 2 includes an upper slider 201, a mounting plate 202, and a positioning plate 203. The upper slider 201 is slidably installed in each of the four upper lifting slide rail grooves 101. The mounting plate 202 is fixed between the four upper sliders 201. The positioning plate 203 is fixedly embedded in the lower wall of the mounting plate 202. Several heating rods 204 are arranged vertically downward on the lower wall of the positioning plate 203. Among them, such as Figures 9-12 As shown, the filling positioning assembly 4 includes a lower pressure plate slider 401, a filling pressure plate 402, and a sealing pressure cake 403. The lower pressure plate slider 401 is slidably installed in each of the four lower lifting slide rail grooves 102. The filling pressure plate 402 is fixed between the four lower pressure plate sliders 401. The sealing pressure cake 403 is installed in the filling pressure plate 402. The bottom of the sealing pressure cake 403 is provided with a frustum-shaped mating groove 404. Among them, such as Figure 9 and Figure 13 As shown, the silicon wafer mounting assembly 5 includes a lower substrate slider 501, a mounting substrate 502, and a hollow double-positioning frustum 503. The lower substrate slider 501 is also slidably mounted within four lower lifting slide rail grooves 102. The cooperation between the slider and the slide rail grooves restricts the horizontal freedom of the assembly during lifting, preventing vertical deviation of the heating rod 204 when it descends, and preventing the heating rod 204 from scraping or getting stuck with the micro-hole due to lateral offset. The mounting substrate 502 is fixed between the four lower substrate sliders 501. The upper wall of the mounting substrate 502... A hollow double-positioning frustum 503 is fixed. The outer volume and bending angle of the hollow double-positioning frustum 503 are the same as those of the frustum-shaped mating groove 404. The frustum-shaped mating groove 404 and the hollow double-positioning frustum 503 are intermittently sliding and sealingly fitted. The circular silicon wafer 7 is slidably embedded in the hollow double-positioning frustum 503. The conical surface contact automatically corrects the lateral assembly error during the sliding process, which can realize the centering upon sliding in. The conical surface clamping force is evenly distributed radially to form a high-pressure airtight interface, eliminating the traditional bolt locking process and greatly improving the loading and unloading cycle time.

[0039] Working principle: The lifting heating component 2 normally resides in the sealed chamber 1. The upper sliders 201 at the four corners slide in conjunction with the upper lifting slide rail groove 101 to ensure that the overall lifting trajectory is vertical and without sway. The filling positioning component 4 and the silicon wafer mounting component 5 both adopt a modular quick-change design. They can slide out of the sealed chamber 1 through the lower pressure plate slider 401 and the lower substrate slider 501 along the lower lifting slide rail groove 102, which is convenient for manual loading and unloading. When loading, the operator places the circular silicon wafer 7 smoothly into the hollow double positioning frustum 503. Then, the filling positioning component 4 is slid into the chamber to reset, and then the silicon wafer mounting component 5 carrying the silicon wafer is slid in. Since the frustum-shaped mating groove 404 at the bottom of the filling pressure plate 402 and the outer contour of the hollow double positioning frustum 503 are mirror tapered, the two can achieve automatic centering and tight sealing when sliding and pressing together, without the need for additional bolts. Example 2

[0040] Please see Figures 15-20 This invention provides a liquid alloy pressure leveling device for filling through-holes in silicon wafers, further comprising: a silicon wafer leveling and liquid discharge assembly 6. The silicon wafer leveling and liquid discharge assembly 6 includes a leveling transmission groove 601, a supporting frustum 602, and a transition frustum 603. The leveling transmission groove 601 is provided inside the mounting substrate 502. The supporting frustum 602 and the transition frustum 603 are slidably mounted within the leveling transmission groove 601. The leveling transmission groove 601 provides radial constraint and axial sliding freedom, allowing the platform to undergo minor thermal expansion and contraction displacement during leveling and heating, releasing structural internal stress, and preventing rigid connections from causing silicon wafer warping or sealing failure. Three sets of wedge-shaped slider mechanisms are distributed at 120-degree intervals between the lower wall of the transition frustum 603 and the inner side of the lower wall of the mounting substrate 502. Each set of wedge-shaped slider mechanisms includes a push-pull cylinder 608, a lower active wedge slider 609, a linkage block 610, a limit slot 611, and an upper linkage block 61. 2. The upper driven wedge slider 613 and the upper driven wedge slider 609 are fixed to the inner side of the outer wall of the mounting substrate 502. The lower active wedge slider 609 is fixed to the output end of the push-pull cylinder 608. The lower wall of the lower active wedge slider 609 is fixed to the linkage block 610. Three limiting slots 611 are opened at 120-degree intervals on the inner side of the lower wall of the mounting substrate 502. The three linkage blocks 610 are respectively slidably arranged in the three limiting slots 611. The horizontal thrust of the push-pull cylinder 608 can be converted into vertical differential displacement, blocking the transmission of lateral friction force to the silicon wafer platform, and preventing the generation of horizontal shear force during the leveling process, which may cause microcracks or misalignment of the silicon wafer or through holes. The lower wall of the transition frustum 603 is fixed with three upper linkage blocks 612 at 120-degree intervals. The lower wall of each of the three upper linkage blocks 612 is fixed with an upper driven wedge slider 613. The upper driven wedge slider 613 and the lower active wedge slider 609 slide in cooperation. Three sets of threaded lifting and leveling mechanisms are distributed at 120-degree intervals between the upper wall of the transition frustum 603 and the lower wall of the supporting frustum 602. The threaded lifting and leveling mechanism includes a lifting screw 614, a top block 615, and a servo motor 616. The servo motor 616 is fixed to the upper wall of the transition frustum 603, and the lifting screw 614 is installed at the output end of the servo motor 616. The top block 615 is fixed to the top of the lifting screw 614, and the top block 615 is fixed to the lower wall of the supporting frustum 602. The wedge-shaped slider mechanism and the threaded lifting and leveling mechanism are arranged alternately at 60-degree intervals when viewed from above. The coarse adjustment and fine adjustment are spatially staggered to avoid interference between the two sets of mechanisms. The 120° symmetrically distributed coarse adjustment points and fine adjustment points cross-support to form a stable triangular couple to resist the platform torsional deformation caused by heating and thermal expansion.

[0041] Working principle: After the component is reset, the silicon wafer leveling and liquid discharge assembly 6 is activated for high-precision leveling. First, three sets of threaded lifting and leveling mechanisms work together: the servo motor 616 drives the lifting screw 614 to rotate, pushing the top block 615 to vertically lift the lower wall of the supporting frustum 602, compensating for the vertical height difference of the circular silicon wafer 7 caused by thickness tolerance or placement tilt, and completing the initial coarse leveling; after the coarse leveling is completed, three sets of wedge slider mechanisms intervene for micro-tilt fine adjustment: the push-pull cylinder 608 pushes the lower active wedge slider 60 9. Horizontal movement is achieved by the guiding constraint of the linkage block 610 within the limiting slot 611, converting the horizontal displacement into vertical differential movement. This drives the upper linkage block 612 and the upper driven wedge slider 613, causing the transition frustum 603 and the upper supporting frustum 602 to generate micron-level tilt compensation. In a top-down view, the threaded leveling mechanism and the wedge slider mechanism are alternately distributed at 60°, forming a stable triangular couple support. Ultimately, this ensures that the surface of the circular silicon wafer 7 is level, preventing deviation and laying the geometric foundation for subsequent precise filling. Example 3

[0042] Please see Figure 1 , Figures 3-9 , Figures 11-12 , Figures 14-16 and Figure 21This invention provides a liquid alloy pressure leveling device for filling through-holes in silicon wafers, further comprising: a vacuum tube 103, the side wall of a sealed chamber 1 being connected to the vacuum tube 103, a hollow tubular solder 3 slidably sleeved on the outer wall of a heating rod 204, the bottom of the heating rod 204 being inverted conical, the inverted conical surface of the heating rod 204 generating a radial self-centering force at the contact point with the inlet of the through-hole 701 of the silicon wafer, compensating for the small eccentricity accumulated in the early assembly, achieving soft landing insertion, protecting the edge of the brittle silicon wafer opening from hard impact and chipping, and the side of the heating rod 204 being provided with a vent, which constitutes an active exhaust path through the through-hole during the insertion of the heating rod 204 and the solder melting stage, real-time extraction of residual gas and flux volatiles at the bottom of the hole displaced by the molten alloy, preventing filling voids formed by gas encapsulation, and several solder passages being opened through the sealed pressure plate 403. The circular silicon wafer 7 has several through-holes 701 vertically penetrating it. The heating rod 204 connects the solder transition holes 405 and the through-holes 701 one by one on the vertical axis. This one-to-one correspondence structure cuts off the flow path of the molten material between the holes, enabling precise volume control of one material per hole. When pressurized, the nitrogen pressure is transmitted to the bottom of each micro-hole without attenuation along the vertical channel, ensuring the uniformity of the high-density array filling. The bottom of the heating rod 204 is intermittently inserted into the top of the through-hole 701. The outer diameter of the hollow tubular solder 3 is smaller than the diameter of the solder transition hole 405. The hollow structure allows heat to be conducted from both the inner and outer walls of the solder, increasing the hot melt area and eliminating the false melt defect of solid columnar solder where the outside melts and the inside is solid. The gap in the outer diameter provides a gas escape channel during the vacuuming stage, preventing a sudden increase in gas pressure inside the hole from hindering the flow of molten material.

[0043] Working principle: After leveling and locking, the drive vacuum tube 103 evacuates the sealed chamber 1, expelling ambient gas and residual air at the edge of the through hole. Subsequently, the lifting heating assembly 2 descends along the upper lifting slide rail 101, allowing the heating rod 204, which is fitted with hollow tubular solder 3, to be precisely inserted into the solder transition hole 405 of the filling plate 402. It continues to descend, intermittently inserting the bottom conical end of the heating rod 204 into the top of the silicon wafer through hole 701 of the circular silicon wafer 7. At this time, the heating rod 204 is powered on and heated. The heat is efficiently conducted through the rod body to the hollow tubular solder 3, causing it to melt rapidly. Under the guidance of gravity and the conical heating rod 204, the molten alloy flows precisely and vertically into the corresponding silicon wafer through hole 701. During this process, the vent on the side of the heating rod 204 continuously discharges the residual gas displaced by the molten material in the through hole 701 to the vacuum system, completely eliminating the defect of bubble encapsulation. Example 4

[0044] Please see Figures 15-16 and Figure 21The present invention provides a liquid alloy pressure leveling device for filling through holes in silicon wafers, which further includes: a nitrogen pipe 104, a section of nitrogen pipe 104 is fixed on the upper wall of the sealed chamber 1 and the middle of the lifting heating assembly 2, and a telescopic pipe 105 is connected between the two sections of nitrogen pipe 104. The telescopic pipe 105 can extend and retract with the lifting heating assembly 2 to ensure that the gas path of the upper and lower sections of nitrogen pipe 104 is always connected. Among them, such as Figures 15-16 As shown, a liquid discharge lifting tank 604 is provided inside the supporting truncated cone 602. Four lifting cylinders 605 are fixedly installed at the bottom of the liquid discharge lifting tank 604. The output ends of the four lifting cylinders 605 are all fixedly connected to a linkage lifting block 606. Several through-hole plugs 607 are fixedly arrayed on the upper end face of the linkage lifting block 606. The several through-hole plugs 607 intermittently seal and abut against the bottom of several silicon wafer through holes 701. The several through-hole plugs 607 are all slidably connected to the upper part of the liquid discharge lifting tank 604. The linkage lifting block 606 is rigidly connected to the output ends of the four sets of lifting cylinders 605, forcing all through-hole plugs 607 to descend or rise synchronously with the same stroke and the same speed. This can prevent local backflow of molten material caused by premature pressure release of a single hole, or microcracks caused by uneven stress on the silicon wafer.

[0045] Working principle: After the molten alloy completely wets the silicon wafer through-hole 701, the nitrogen pipe 104 is activated, and nitrogen can be injected into the upper part of the sealed chamber 1 through the telescopic pipe 105, forming a uniform vertical downward pressure on the surface of the molten pool. This causes the molten alloy to adhere tightly to the inner wall of the silicon wafer through-hole 701, expelling tiny gaps and ensuring a dense, void-free filling. After the filling and pressure holding are completed, the lifting heating component 2 rises and resets, disengaging from the solder transition hole 405. Subsequently, the four sets of lifting cylinders 605 retract synchronously, driving the linkage lifting block 606 to smoothly descend along the liquid discharge lifting groove 604. As the lifting block 606 descends, several through-hole plugs 607 at the upper end of the linkage lifting block 606 move down synchronously, releasing the blockage on the bottom of the silicon wafer through-hole 701. At this time, the excess solder that is not fully shaped or overflows in the through-hole is automatically discharged downward into the upper temporary storage area of ​​the liquid discharge lifting tank 604 under the action of gravity and the slight positive pressure of the chamber. After the molten material cools and solidifies, the circular silicon wafer 7 is taken out, and a high-quality through-hole structure silicon wafer with smooth inner wall and no overflow at the end can be obtained. Then, several through-hole plugs 607 are activated to rise synchronously, which can directly push out the solidified overflow, making cleaning convenient.

[0046] In summary: I. This invention utilizes a vertically penetrating structure with one-to-one corresponding heating rods 204 to transition holes and then to through holes, which realizes independent quantitative feeding and in-situ melting of single holes, improves the filling consistency of high-density through-hole arrays, and solves the problem of uneven filling caused by molten material overflow in the prior art. Second, the present invention utilizes a two-stage differential leveling mechanism of thread coarse adjustment and wedge fine adjustment. First, the thread mechanism compensates for the height difference in the Z direction to achieve coarse leveling, and then the wedge slider mechanism performs micro-tilt fine adjustment to ensure that the silicon wafer through hole 701 is horizontal when in contact with the molten alloy, thus solving the problem of poor wetting and high void ratio caused by silicon wafer tilt in the prior art. Third, the present invention utilizes a combined process of dynamic exhaust from the vent of the heating rod 204 and vertical pressurization of nitrogen. During the solder melting and inflow stage, the vent actively removes the trapped air bubbles in the through hole. Subsequently, nitrogen is injected to form vertical downward pressure, which promotes the molten alloy to adhere tightly to the inner wall of the through hole, greatly improving the micropore filling rate and sidewall bonding quality, and solving the problem of micropore bubble residue and poor sidewall bonding in the prior art. Fourth, the present invention utilizes the linkage and automatic discharge of excess material design of the through hole plug 607. After filling is completed, the plug 607 is lowered synchronously to open the bottom of the through hole, so that the excess unformed solder automatically flows back and shrinks to the top of the discharge lifting tank 604. This eliminates the need for subsequent grinding and cleaning processes, and directly obtains a high-quality through hole structure with smooth inner wall and no overflow. This solves the problem that the subsequent cleaning process in the prior art is cumbersome and easily damages the hole wall.

[0047] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. A liquid alloy pressure leveling device for filling through-holes in silicon wafers, characterized in that, include: A sealed chamber (1) has an upper lifting slide rail groove (101) and a lower lifting slide rail groove (102) respectively on the upper and lower parts of its four inner walls. A vacuum tube (103) is connected to the side wall of the sealed chamber (1). A lifting heating assembly (2) is slidably installed between the upper lifting slide rail grooves (101). A section of nitrogen pipe (104) is fixed to the upper wall of the sealed chamber (1) and the middle of the lifting heating assembly (2). A telescopic pipe (105) is connected between the two sections of nitrogen pipe (104). A filling hole positioning assembly (4) and a silicon wafer mounting assembly (5) are slidably installed between the lower lifting slide rail grooves (102). The silicon wafer mounting assembly (5) is located below the filling hole positioning assembly (4). The silicon wafer mounting assembly (5) and the filling hole positioning assembly (4) are intermittently slid and pressed together. A silicon wafer leveling and liquid discharge assembly (6) is provided in the bottom of the silicon wafer mounting assembly (5). The lifting and heating assembly (2) is used to accurately dispense materials for each through hole by cooperating with the filling and positioning assembly (4) through lifting and heating, and to carry and accurately heat the hollow tubular welding material (3) to a molten state; The filling positioning component (4) is used to cooperate with the silicon wafer mounting component (5) to form a closed pressurized cavity and guide the molten solder to flow into the through hole of the silicon wafer. The silicon wafer mounting assembly (5) is used to support the circular silicon wafer (7) and achieve high-precision positioning and sealing. The silicon wafer leveling and liquid discharge assembly (6) is used to perform multi-dimensional precision leveling of the circular silicon wafer (7) and to control the discharge of excess molten liquid after the filling operation is completed. The silicon wafer mounting assembly (5) includes a lower substrate slider (501), a mounting substrate (502), and a hollow double positioning frustum (503). The lower substrate slider (501) is also slidably mounted in the four lower lifting slide rail grooves (102). The mounting substrate (502) is fixed between the four lower substrate sliders (501). The hollow double positioning frustum (503) is fixed on the upper wall of the mounting substrate (502). The circular silicon wafer (7) has several through holes (701) arranged vertically through the silicon wafer. The silicon wafer leveling and liquid discharge assembly (6) includes a leveling transmission groove (601), a supporting frustum (602), and a transition frustum (603). The mounting substrate (502) has a leveling transmission groove (601) inside. The supporting frustum (602) and the transition frustum (603) are slidably installed in the leveling transmission groove (601). Three sets of wedge-shaped slider mechanisms are distributed at 120-degree intervals between the lower wall of the transition frustum (603) and the inner side of the lower wall of the mounting substrate (502).

2. The liquid alloy pressure leveling device for filling through-holes in silicon wafers according to claim 1, characterized in that: The lifting and heating assembly (2) includes an upper slider (201), a mounting plate (202), and a positioning plate (203). The upper slider (201) is slidably installed in each of the four upper lifting slide rail grooves (101). The mounting plate (202) is fixed between the four upper sliders (201). The positioning plate (203) is fixedly embedded in the lower wall of the mounting plate (202). Several heating rods (204) are arranged vertically downward on the lower wall of the positioning plate (203). The hollow tubular solder (3) is slidably sleeved on the outer wall of the heating rods (204).

3. The liquid alloy pressure leveling device for filling through-holes in silicon wafers according to claim 2, characterized in that: The bottom of the heating rod (204) is inverted cone-shaped, and the side of the heating rod (204) is provided with a vent.

4. The liquid alloy pressure leveling device for filling through-holes in silicon wafers according to claim 3, characterized in that: The filling positioning assembly (4) includes a lower pressure plate slider (401), a filling pressure plate (402), and a sealing pressure plate (403). The lower pressure plate slider (401) is slidably installed in each of the four lower lifting slide rail grooves (102). The filling pressure plate (402) is fixed between the four lower pressure plate sliders (401). The sealing pressure plate (403) is installed in the filling pressure plate (402). The bottom of the sealing pressure plate (403) is provided with a frustum-shaped mating groove (404). Several solder transition holes (405) are opened through the sealing pressure plate (403).

5. The liquid alloy pressure leveling device for filling through-holes in silicon wafers according to claim 4, characterized in that: The outer volume and bending angle of the hollow double positioning frustum (503) are the same as those of the frustum-shaped mating groove (404). The frustum-shaped mating groove (404) and the hollow double positioning frustum (503) are intermittently sliding and sealingly fitted. The circular silicon wafer (7) is slidably embedded in the hollow double positioning frustum (503).

6. The liquid alloy pressure leveling device for filling through-holes in silicon wafers according to claim 4, characterized in that: The heating rod (204) connects the solder transition hole (405) and the silicon wafer through hole (701) one by one on the vertical axis, and the bottom of the heating rod (204) is intermittently inserted into the top of the silicon wafer through hole (701). The outer diameter of the hollow tubular solder (3) is smaller than the diameter of the solder transition hole (405).

7. The liquid alloy pressure leveling device for filling through-holes in silicon wafers according to claim 1, characterized in that: Each set of wedge-shaped slider mechanisms includes a push-pull cylinder (608), a lower active wedge slider (609), a linkage block (610), a limiting slot (611), an upper linkage block (612), and an upper driven wedge slider (613). A push-pull cylinder (608) is fixed to the inner side of the outer wall of the mounting base plate (502). A lower active wedge slider (609) is fixed to the output end of the push-pull cylinder (608). A linkage block (610) is fixed to the lower wall of the lower active wedge slider (609). The lower wall of the mounting base (502) is provided with three limiting slots (611) spaced 120 degrees apart, and three linkage blocks (610) are respectively slidably disposed in the three limiting slots (611). The lower wall of the transition truncated cone (603) is fixed with three upper linkage blocks (612) spaced 120 degrees apart. The lower wall of each of the three upper linkage blocks (612) is fixed with an upper driven wedge slider (613), and the upper driven wedge slider (613) slides in cooperation with the lower active wedge slider (609).

8. The liquid alloy pressure leveling device for filling through-holes in silicon wafers according to claim 7, characterized in that: Three sets of threaded lifting and leveling mechanisms are distributed at 120-degree intervals between the upper wall of the transition truncated cone (603) and the lower wall of the supporting truncated cone (602). The threaded lifting and leveling mechanism includes a lifting screw (614), a top block (615) and a servo motor (616). The servo motor (616) is fixed on the upper wall of the transition truncated cone (603). The lifting screw (614) is installed on the output end of the servo motor (616). The top block (615) is fixed on the top of the lifting screw (614), and the top block (615) is fixed to the lower wall of the supporting truncated cone (602). The wedge-shaped slider mechanism and the threaded lifting and leveling mechanism are arranged alternately at 60-degree intervals when viewed from above.

9. The liquid alloy pressure leveling device for filling through-holes in silicon wafers according to claim 8, characterized in that: The supporting truncated cone (602) has a liquid discharge lifting groove (604) inside. Four lifting cylinders (605) are fixedly installed at the bottom of the liquid discharge lifting groove (604). The output ends of the four lifting cylinders (605) are fixedly connected to a linkage lifting block (606). A number of through hole plugs (607) are fixedly arrayed on the upper surface of the linkage lifting block (606). The number of through hole plugs (607) intermittently seal and abut against the bottom of the number of silicon wafer through holes (701), and the number of through hole plugs (607) are all slidably connected to the upper part of the liquid discharge lifting groove (604).

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