Inclination mechanism for chip lamination

Abstract

The invention discloses an inclination mechanism for chip lamination, which comprises a base and a pick-up seat for picking up a chip, the pick-up seat is installed on the base through an adjusting mechanism, and the adjusting mechanism comprises a central shaft fixedly connected with the pick-up seat, a ball head arranged at the top end of the central shaft and a spherical seat; the spherical seat is provided with a concave spherical surface matched with the ball head; when external force is applied to the picking seat, the picking seat drives the center shaft to swing synchronously, and the inclination angle of the picking seat in the horizontal direction is changed. Compared with the prior art, the method has the advantage of keeping dynamic stability, and the rigidity in the vertical direction is strengthened. In the working process, in the deflection process of the picking seat, axial supporting force along the center shaft is provided through the center shaft, the ball head and the spherical seat, axial loads are mainly borne, the spherical seat is fixed to the base, and therefore the defect that in the prior art, the supporting force in the Z-axis direction is insufficient is overcome, and the Z-axis positioning precision is improved to the maximum extent.

Description

Technical Field

[0001] This invention relates to the field of chip bonding apparatus technology, and specifically to a tilting mechanism for chip bonding. Background Technology

[0002] A chip bonding machine is a device that picks up semiconductor chips from a semiconductor chip supply source (such as a wafer tray) and places them onto a semiconductor chip carrier (such as a lead frame). This process is called chip bonding. See [link to documentation]. Figure 1 As shown, the chip bonding machine consists of two important modules: 1. Bonding head 01, used to transfer and bond semiconductor chip 03 onto semiconductor chip carrier 04; 2. Lamination stage 02, used to place semiconductor chip carrier 04 during chip bonding process.

[0003] To ensure the quality and reliability of the chip bonding process, the bonding head and bonding stage must be precisely aligned. Therefore, before placing the semiconductor chip carrier on the bonding stage for chip bonding, the surfaces of the bonding head and bonding stage should be parallel to each other. During chip bonding, the bonding head presses the bonding surface of the semiconductor chip against the semiconductor chip carrier with a specified force and a specific temperature profile. Because the bonding surface of the semiconductor chip contains many solder or gold bumps no larger than a few hundred micrometers, alignment deviations of the bonding head relative to the bonding stage (e.g., 10 micrometers) can lead to lateral forces and bonding errors, thus affecting the quality and reliability of the chip bonding process. Therefore, maintaining precise alignment of the bonding head relative to the bonding stage is paramount in the chip bonding process to ensure the quality and reliability of chip bonding.

[0004] To achieve accurate alignment of the chip bonding surface, an adjustment mechanism is typically installed on the bonding head or bonding stage to precisely level the bonding surface. However, current adjustment devices suffer from the following problems: maintaining dynamic stability during chip bonding is difficult. The primary force during chip bonding is the bonding pressure along the Z-axis. However, existing adjustment mechanisms lack sufficient Z-axis support force. Therefore, even if the bonding surface is leveled through the adjustment mechanism, insufficient Z-axis support force during bonding causes the bonding surface to deflect again under the bonding force, resulting in uneven stress on the bonding surface and making defects such as poor soldering and bubbles on the chip bonding surface more likely.

[0005] Based on the above, the inventors propose the following technical solutions. Summary of the Invention

[0006] The technical problem to be solved by the present invention is to overcome the shortcomings of the prior art and to propose a tilting mechanism for chip bonding.

[0007] To solve the above-mentioned technical problems, the present invention adopts the following technical solution: a tilting mechanism for chip bonding, comprising: a base, a pick-up holder for picking up the chip, wherein the pick-up holder is mounted on the base via an adjustment mechanism, the adjustment mechanism comprising: a central shaft fixedly connected to the pick-up holder, a ball head disposed at the top of the central shaft, and a spherical seat; the spherical seat has a concave spherical surface that mates with the ball head; when an external force is applied to the pick-up holder, the pick-up holder drives the central shaft to swing synchronously, thereby realizing the change of the tilt angle of the pick-up holder in the horizontal direction.

[0008] Furthermore, in the above technical solution, the base is provided with a shaft hole for installing the central shaft, the central shaft is installed in the shaft hole through a bearing, the spherical seat is fixed above the shaft hole, and the ball head at the top of the central shaft contacts the concave spherical surface of the spherical seat.

[0009] Furthermore, in the above technical solution, the bearing is a self-aligning bearing or a hinged bearing.

[0010] Furthermore, in the above technical solution, the tilting mechanism also includes a driving unit for applying force to the pickup seat. The driving unit includes an X-axis actuator (Fx) that applies force to the pickup seat along the X-axis direction and a Y-axis actuator (Fy) that applies force to the pickup seat along the Y-axis direction. The driving unit drives the pickup seat to tilt along the X / Y axis direction with the bearing as the fulcrum.

[0011] Furthermore, in the above technical solution, the X-axis actuator Fx and the Y-axis actuator Fy adopt a lateral displacement mechanism that is linked to the pickup seat.

[0012] Furthermore, in the above technical solution, the X-axis actuator Fx and the Y-axis actuator Fy respectively adopt: a lateral displacement mechanism linked to the pickup seat, and a four-bar linkage mechanism, which is connected between the base and the pickup seat.

[0013] Furthermore, in the above technical solution, the linkage mechanism includes: two first linkages that are fixed relative to the base and symmetrically distributed, two second linkages that are fixed relative to the pickup seat and symmetrically distributed, and an intermediate linkage that is respectively connected between the two sets of first linkages and second linkages; at least one set of first linkages and intermediate linkages is provided with a rotating device, which drives the intermediate linkage, second linkages and pickup seat to swing about the first linkage as the axis of rotation.

[0014] Furthermore, in the above technical solution, the first connecting rod is a flexible connecting shaft, one end of which is fixedly connected to the base, and the other end is pivotally connected to the intermediate connecting rod through a rotating device; the rotating device is a frameless torque motor.

[0015] Furthermore, in the above technical solution, a flexible bending pivot is used between the second link and the intermediate link.

[0016] Compared with existing technologies, this invention has the advantage of maintaining dynamic stability, and it strengthens the vertical stiffness. During operation, when the pickup seat is oscillating, it provides an axial support force along the central axis through the central shaft, ball head, and spherical seat, primarily bearing the axial load. The spherical seat is fixed to the base, thus overcoming the shortcomings of insufficient Z-axis support force in existing technologies and maximizing Z-axis positioning accuracy. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of existing chip bonding equipment; Figure 2 This is a schematic diagram of the structure of the present invention used in a chip bonding device; Figure 3 This is a structural schematic diagram of Embodiment 1 of the present invention; Figure 4 This is a schematic diagram of the structure of Embodiment 2 of the present invention; Figure 5 This is a schematic diagram of the rotating device in Embodiment 2 of the present invention. Detailed Implementation

[0018] The present invention will be further described below with reference to specific embodiments and accompanying drawings.

[0019] See Figure 2 As shown, this is a schematic diagram of a chip bonding device according to the present invention. The chip bonding device includes: a pickup seat 2 for picking up chips 3 and a bonding stage 4 for placing a carrier board 6. The pickup seat 2 is mounted on a base 1 via an adjustment mechanism 50. The tilt angle of the pickup seat 2 can be adjusted by the adjustment mechanism 50, and the spatial state of the pickup seat 2 can be adjusted by the adjustment mechanism 50, ultimately ensuring that the chip 3 and the carrier board 6 remain parallel during the bonding process.

[0020] The adjustment mechanism 50 includes a central shaft 51, a ball head 52, a spherical seat 53, and a bearing 54. The lower end of the central shaft 51 is fixedly connected to the pickup seat 2, and the ball head 52 is installed at the upper end of the central shaft 51. The ball head 52 and the central shaft 51 are connected by a ball-and-socket mounting method, thereby enabling the ball head 52 to roll on its own.

[0021] The base 1 has a shaft hole 10 for mounting the central shaft 51, and the central shaft 51 is mounted in the shaft hole 10 via a bearing 54.

[0022] The spherical seat 53 is fixed above the shaft hole 10. For example, the spherical seat 53 can be directly fixed to the base 1 by bolts. The spherical seat 53 has a concave spherical surface 530 that mates with the ball head 52. The ball head 52 at the top of the central shaft 51 contacts the concave spherical surface 530 of the spherical seat 53.

[0023] Furthermore, since the pickup seat 2 achieves tilt adjustment through the swing of the central shaft 51, the bearing 54 needs to be a self-aligning bearing or a hinged bearing to achieve the swing of the central shaft 51 along its axis. When a horizontal thrust or torque is applied to the pickup seat 2, the pickup seat 2 drives the central shaft 51 to swing synchronously, thereby changing the tilt angle of the pickup seat 2 in the horizontal direction. While the central shaft 51 swings, its upper ball head 52 forms an internal tangential contact with the concave spherical surface 530 of the spherical seat 53, providing an axial support force along the central shaft 51 to the pickup seat 2 through the spherical seat 53.

[0024] See Figure 3 As shown, in this first embodiment, a driving unit 70 can be provided on the chip bonding device to apply force or torque to the pickup holder 2. When a tilt angle of the pickup holder 2 is required, it is achieved through the driving unit 70. Figure 3 As shown, the drive unit 70 can be an X-axis actuator Fx that applies force to the pickup seat 2 along the X-axis and a Y-axis actuator Fy that applies force to the pickup seat 2 along the Y-axis. The drive unit 70 drives the pickup seat 2 to oscillate along the X / Y axes, using the bearing 54 as a fulcrum. The X-axis actuator Fx and the Y-axis actuator Fy employ a lateral displacement mechanism linked to the pickup seat 2; for example, the X-axis actuator Fx and the Y-axis actuator Fy can be a lead screw drive mechanism. Of course, in actual operation, since the tilt adjustment angle of the pickup seat 2 is usually small, a large lateral displacement mechanism is not required. Therefore, a high-precision cam drive mechanism can also be used. By controlling the offset of the cam, the pickup seat 2 is driven to oscillate along the X / Y axes, achieving tilt adjustment of the pickup seat 2 within a small angle range.

[0025] See Figure 4 As shown, this is Embodiment 2 of the present invention. The difference from Embodiment 1 is that in Embodiment 2, the X-axis actuator Fx and Y-axis actuator Fy respectively employ: a lateral displacement mechanism linked to the pickup seat 2, and a four-bar linkage 70, which connects the base 1 and the pickup seat 2. Specifically, the linkage 70 includes: two first links 71 fixed relative to the base 1 and symmetrically distributed; two second links 72 fixed relative to the pickup seat 2 and symmetrically distributed; and an intermediate link 73 connecting the two sets of first links 71 and second links 72. That is, the linkage 70 employs a four-bar linkage.

[0026] Since the linkage mechanism 70 adopts a four-bar linkage, a rotating device 74 can be set between only one set of the first link 71 and the intermediate link 73. The rotating device 74 drives the intermediate link 73, the second link 72 and the pickup seat 2 to swing around the first link 71 as the pivot.

[0027] Combination Figure 5 As shown, the rotating device 74 described in Embodiment 2 can be directly driven by a high-precision motor, such as a frameless torque motor. One end of the first connecting rod 71 is fixedly connected to the base 1 (or it can be fixed to the spherical base 53), and the other end of the first connecting rod 71 is connected to the rotating device 74 using a frameless torque motor. One end of the intermediate connecting rod 73 is fixed to the rotating end of the rotating device 74.

[0028] The working method of this embodiment two is as follows: Figure 3 The X / Y coordinate system is used as a reference: When it is necessary to tilt the pickup seat 2 along the X-axis: the lateral displacement mechanism in the X-axis actuator Fx is activated, pushing the pickup seat 2 along the bearing 54 as the fulcrum, causing the pickup seat 2 to swing around the Y-axis to achieve deflection in the X-axis.

[0029] When it is necessary to tilt the pickup seat 2 along the Y-axis: the rotating device 74 in the linkage mechanism 70 rotates, causing the intermediate link 73 to rotate around the axis of the first link 71 by a certain angle. The intermediate link 73 drives the second link 72 to rotate synchronously, and finally drives the pickup seat 2 to swing around the X-axis to achieve deflection along the Y-axis.

[0030] In actual operation, it is often necessary to adjust the tilt angles of the pickup seat 2 in both the X and Y axes simultaneously. When the X-axis actuator Fx uses a lateral displacement mechanism and the Y-axis actuator Fy uses the four-bar linkage 70, in order to constrain the degrees of freedom of the linkage 70 in the non-target directions and to accommodate the X-axis deflection of the lateral displacement mechanism, the first link 74 uses a flexible connecting shaft. When the pickup seat 2 deflects and slips along the X-axis, the first link 74 flexibly deforms to accommodate the deflection displacement. Simultaneously, a flexible bending pivot 75 is used between the second link 72 and the intermediate link 73 to constrain the deflection angle and direction.

[0031] Of course, the present invention can also employ a four-bar linkage 70 for the X-axis actuator Fx and a lateral displacement mechanism for the Y-axis actuator Fy. Alternatively, both the X-axis actuator Fx and the Y-axis actuator Fy can employ a four-bar linkage 70. Regardless of the mechanism used, the present invention has the advantage of maintaining dynamic stability and enhances the vertical stiffness. During the yaw process, the pickup seat 2 provides an axial support force along the central axis 51 through the concave spherical surface 530 of the central axis 51, ball head 52, and spherical seat 53, bearing the main axial load. The spherical seat 53 is fixed on the base 1, overcoming the shortcomings of insufficient support force in the Z-axis direction in the prior art and maximizing the Z-axis positioning accuracy.

[0032] Of course, the above description is only a specific embodiment of the present invention and is not intended to limit the scope of the present invention. All equivalent changes or modifications made to the structure, features and principles described in the claims of the present invention should be included in the scope of the claims of the present invention.

Claims

1. A tilting mechanism for chip bonding, comprising: A base (1) and a pickup holder (2) for picking up the chip (3), wherein the pickup holder (2) is mounted on the base (1) via an adjustment mechanism (50), characterized in that: The adjustment mechanism (50) includes: a central shaft (51) fixedly connected to the pickup seat (2), a ball head (52) disposed at the top of the central shaft (51), and a spherical seat (53); the spherical seat (53) has a concave spherical surface (530) that mates with the ball head (52). When an external force is applied to the pickup seat (2), the pickup seat (2) drives the central shaft (51) to swing synchronously, thereby changing the tilt angle of the pickup seat (2) in the horizontal direction.

2. The tilting mechanism for chip bonding according to claim 1, characterized in that: The base (1) has a shaft hole (10) for mounting the central shaft (51). The central shaft (51) is mounted in the shaft hole (10) by a bearing (54). The spherical seat (53) is fixed above the shaft hole (10), and the ball head (52) at the top of the central shaft (51) contacts the concave spherical surface (530) of the spherical seat (53).

3. The tilting mechanism for chip bonding according to claim 2, characterized in that: The bearing (54) mentioned above is a self-aligning bearing or a hinged bearing.

4. The tilting mechanism for chip bonding according to claim 2, characterized in that: The tilting mechanism also includes a drive unit (7) for applying force to the pickup seat (2), the drive unit (7) including: an X-axis actuator (Fx) for applying force to the pickup seat (2) along the X-axis direction and a Y-axis actuator (Fy) for applying force to the pickup seat (2) along the Y-axis direction; the drive unit (7) drives the pickup seat (2) to tilt along the bearing (54) as the fulcrum to achieve the tilting along the X / Y axis direction.

5. The tilting mechanism for chip bonding according to claim 4, characterized in that: The X-axis actuator (Fx) and Y-axis actuator (Fy) are lateral displacement mechanisms that are linked to the pickup seat (2).

6. The tilting mechanism for chip bonding according to claim 4, characterized in that: The X-axis actuator (Fx) and Y-axis actuator (Fy) respectively adopt: a lateral displacement mechanism linked to the pickup seat (2) and a four-bar linkage (70), which is connected between the base (1) and the pickup seat (2).

7. A tilting mechanism for chip bonding according to claim 6, characterized in that: The linkage mechanism (70) includes: two first links (71) that are fixed relative to the base (1) and symmetrically distributed; two second links (72) that are fixed relative to the pickup seat (2) and symmetrically distributed; and an intermediate link (73) that is connected between the two sets of first links (71) and second links (72). At least one rotating device (74) is provided between the first link (71) and the intermediate link (73). The rotating device (74) drives the intermediate link (73), the second link (72) and the pickup seat (2) to swing around the first link (71) as the pivot.

8. The tilting mechanism for chip bonding according to claim 7, characterized in that: The first connecting rod (71) adopts a flexible connecting shaft, one end of which is fixedly connected to the base (1), and the other end is pivotally connected to the intermediate connecting rod (73) through a rotating device (74); The rotating device (74) is a frameless torque motor.

9. A tilting mechanism for chip bonding according to claim 7, characterized in that: The second link (72) and the intermediate link (73) are connected by a flexible bending pivot (75).

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