Chip bonder with rotary bonding arm actuator

Abstract

A semiconductor chip bonding apparatus includes: a bonding arm body; the clamping head is attached to the first end of the bonding arm main body and is used for clamping the semiconductor chip during picking and placing operations; and the voice coil actuator is positioned at the second end of the bonding arm main body and is used for driving the bonding arm main body to rotate around a pivot shaft positioned between the chuck and the voice coil actuator. The voice coil actuator includes: a pair of arcuate magnets having a concave arcuate surface facing the pivot, the concave arcuate surface forming an arcuate gap between the arcuate magnets; and an arcuate coil including a concave arcuate surface disposed within the arcuate gap, the arcuate coil configured to be movable relative to the arcuate magnet.

Description

Technical Field

[0001] The present invention relates to a chip bonding operation in which a semiconductor chip or a die is picked up by a bonding device mounted on a bonding head in a chip bonding device, and in particular to a bonding device having a rotary actuator for driving the pick-and-place operation of the bonding device. Background Art

[0002] The bonding head of the die bonding equipment is used to pick up semiconductor chips or dies from a semiconductor chip supply, such as a wafer mounted on a movable wafer table. After picking up the semiconductor chip with its bonding arm, the bonding arm places and bonds the semiconductor chip to a bonding pad on a substrate or carrier, which can be in the form of a lead frame or other substrate. Such a process is called die bonding.

[0003] Traditionally, the bond head is mounted on and driven by a positioning table. The positioning table can be a movable XY table, or a rotary table, and it cooperates with a workstation, which includes a semiconductor chip or substrate supply unit that is separately mounted on another movable XY table or a rotary table. The bond arm is usually mounted on the bond head, and it is linearly driven along the Z axis by a linear motor to move upward or downward (usually in practice toward or away from the direction of the semiconductor chip). Such a Z-axis linear motor can be a motor coupled between the bond head and the positioning table for moving the entire bond head, or it can be a motor coupled between the bond arm and the bond head to move the bond arm relative to the bond head.

[0004] An example of a prior art rotary table is described in the patent publication number CN115360127A, entitled "A double-head driving device for a DieBond process". After the rotary drive motor rotates the bond head assembly to position a pair of bond arms respectively above the target semiconductor chip and / or placement position, the linear vertical drive mechanism operates to drive the entire bond head assembly including the bond arms to linearly displace in the upward and downward directions.

[0005] One disadvantage of conventional bond heads carried by a positioning table and driven by a linear actuator to move along the Z axis is that the driving force and acceleration of the bond arm are limited in high-speed automatic chip bonders. This is due to the relatively heavy weight of the bond head carried by the positioning table as it moves along its respective axis of motion. Alternatively, where the bond arm is driven by a linear motor to move relative to the bond head to which the bond arm is mounted, the linear motor complicates the design of the bond head and significantly increases the weight of the bond head as it is moved by the positioning table.

[0006] Therefore, it would be beneficial to allow the bond arm's motion along the Z-axis to be driven independently of the bond head and reduce inertia to increase the bond arm's acceleration and velocity. This would help increase the throughput of pick and place operations performed by the bond head. Summary of the invention

[0007] Therefore, an object of the present invention is to seek to provide a chip bonder having a bonding device capable of faster acceleration and speed than the prior art.

[0008] Accordingly, the present invention provides a semiconductor chip bonding device, comprising: a bonding arm body; a chuck attached to a first end of the bonding arm body for clamping a semiconductor chip during a pick-and-place operation; and a voice coil actuator located at a second end of the bonding arm body for driving the bonding arm body to rotate around a pivot positioned between the chuck and the voice coil actuator, wherein the voice coil actuator further comprises: a pair of arc magnets having a concave arc surface facing the pivot, the concave arc surface forming an arc gap between the arc magnets; and an arc coil comprising a concave arc surface disposed within the arc gap, the arc coil being configured to be movable relative to the arc magnet.

[0009] It will be convenient to describe the invention in more detail below by reference to the accompanying drawings which show specific preferred embodiments of the invention. The particularity of the drawings and the related description should not be understood as superseding the generality of the broad recognition of the invention as defined by the claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0010] An exemplary die bonding apparatus incorporating the present invention will now be described with reference to the accompanying drawings, in which:

[0011] Figure 1 is an isometric view of a bond arm according to a preferred embodiment of the present invention;

[0012] Figure 2 yes Figure 1 a side view of the bond arm shown;

[0013] Figure 3 is a side view of a bond arm mounted on a single-arm bond head movable in the X, Y and Z directions by a positioning stage; and

[0014] Figure 4 is a side view of a pair of bond arms mounted on opposite sides of a rotary dual-arm bond head according to a preferred embodiment of the present invention. DETAILED DESCRIPTION

[0015] Figure 11 is an isometric view of a semiconductor chip bonding apparatus or bonding arm 10 according to a preferred embodiment of the present invention. The bonding arm 10 generally includes an elongated bonding arm body 12, and a chuck 14 fixed or attached to a first end of the bonding arm body 12 for holding a semiconductor chip (not shown) during a pick and place process. To actuate the up and down movement of the chuck 14, a motor in the form of an arc-shaped voice coil actuator 16 is located at a second end of the bonding arm body 12, opposite to where the chuck 14 is attached.

[0016] The bond arm body 12 pivots at the pivot point 22 to make an arcuate motion about the pivot point 22, and the arcuate motion of the bond arm body 12 about the pivot point 22 is in turn actuated by the arcuate voice coil actuator 16. In the illustrated embodiment, the arcuate voice coil actuator 16 includes a coil that can move relative to a permanent magnet by means of electromagnetic interaction between the coil and the permanent magnet when current flows through the coil, which allows the arcuate voice coil actuator 16 to achieve an actuator arcuate motion path 28.

[0017] Therefore, the arc-shaped voice coil actuator 16 is unique in that it uses a pair of arc-shaped arc magnets 18 fixedly arranged along an arc, and a movable arc-shaped arc coil 20 positioned between the pair of arc magnets 18. The arc magnets 18 have a concave arc surface facing the pivot point 22. An arc gap 19 is formed between the arc magnets 18, and an arc coil 20 is arranged in the arc gap, which also has a concave arc surface facing the pivot point 22. Therefore, the arc coil 20 is configured to be movable relative to the arc magnet 18 in the arc gap 19.

[0018] The arc coil 20 is fixedly connected to the bond arm body 12 by a first connecting link 40, which couples the top edge of the arc coil 20 to the bond arm body 12, and a second connecting link 42, which couples the bottom edge of the arc coil 20 to the bond arm body 12. The angular motion range of the arc coil 20 relative to the arc magnet 18 is designed to be smaller than the angular distance between the first connecting link 40 and the second connecting link 42. When actuated by the arc voice coil actuator 16, the bond arm body 12 and the chuck 14 are driven to rotate along the bond arm arc motion path 26, which is opposite to the actuator arc motion path 28. The chuck 14 is configured to clamp the semiconductor chip during the pick and place process.

[0019] When the arc coil 20 is actuated by current flowing through the arc coil 20 to move relative to the arc magnet 18, such actuation causes the bond arm body 12 to rotate about the pivot point 22, and the chuck 14 is then driven to move in the opposite direction to the movement of the arc coil 20. Accordingly, the chuck 14 can move downward to pick up a semiconductor chip (not shown) at the tip of the chuck 14, then move upward to transport the semiconductor chip to a placement position, and finally move downward to bond the semiconductor chip at the placement position.

[0020] A position encoder 24 is coupled to the bond arm body 12 to determine the position and angular orientation of the bond arm body 12 during rotational movement of the bond arm body 12 about the pivot point 22 .

[0021] Figure 2 yes Figure 1 A side view of the bond arm 10 is shown. In the figure, the first end of the bond arm body 12 including the collet 14 is drivable to move along the bond arm arcuate motion path 26, and the arcuate coil 20 is drivable to move along the actuator arcuate motion path 28. During the rotational movement of the bond arm body 12 about the pivot point 22, the directions of the bond arm arcuate motion path 26 and the actuator arcuate motion path 28 are generally always opposite.

[0022] Figure 3 1 is a side view of a bond arm 10 mounted on a single-arm bond head 30, which can be moved in orthogonal X, Y and Z directions in a three-dimensional space according to a Cartesian coordinate system by a positioning table (not shown). The bond arm 10 is carried by the single-arm bond head 30, which generally positions the collet 14 of the bond arm body 12 between multiple pick-up and placement positions. The positioning of the single-arm bond head 30 can be driven by a conventional XYZ table. For example, the single-arm bond head 30 can move the collet 14 to a position above a semiconductor chip to be picked up, thereby leaving a gap between the collet 14 and the semiconductor chip.

[0023] Then, the arc voice coil actuator 16 is operated to provide current in the arc coil 20 for driving the arc coil 20 to move in the counterclockwise direction along the actuator arc motion path 28. Therefore, the chuck 14 is also moved counterclockwise along the bond arm arc motion path 26 so as to be driven downward to gently touch the semiconductor chip. Once the chuck 14 contacts the semiconductor chip, a vacuum suction force is generated at the opening of the chuck 14 so as to clamp the semiconductor chip.

[0024] The arcuate voice coil actuator 16 is then operated to provide a current in the opposite direction in the arcuate coil 20 to drive the arcuate coil 20 to move in the clockwise direction along the actuator arcuate motion path 28. The chuck 14 is caused to move clockwise along the bond arm arcuate motion path 26 while holding the semiconductor chip, thereby picking up the semiconductor chip. Thereafter, the single-arm bond head 30 transports the bond arm body 12 in the X, Y and Z directions while the single-arm bond head 30 is driven to a placement position by a conventional XY worktable.

[0025] At the placement position where the semiconductor chip is to be bonded, the bonding arm body 12 positions the chuck 14 so that a gap is left between the semiconductor chip and the bonding position. Here, the arc-shaped voice coil actuator 16 similarly provides current in the arc-shaped coil 20 to drive the arc-shaped coil 20 to move in the counterclockwise direction, thereby moving the chuck 14 counterclockwise to place the semiconductor chip to the placement position, where the semiconductor chip is placed on a chip carrier or substrate. After the semiconductor chip is placed in place, the vacuum suction at the opening of the chuck 14 is closed, and when the arc-shaped voice coil actuator 16 drives the chuck 14 to move upward, the chuck 14 releases the semiconductor chip and is separated from the semiconductor chip.

[0026] The die bonding equipment will repeat the above die bonding process for other semiconductor chips from the semiconductor chip supply. The position encoder 24 is used to provide accurate position feedback to the processor 25 during the die bonding process. By comparing the position feedback from the position encoder 24 with the current intensity in the arc coil 20, the processor 25 can detect and control the impact force applied by the chuck 14 to the semiconductor chip during the pick-up and placement process to minimize the bonding force and avoid damaging the semiconductor chip during the entire die bonding process.

[0027] Figure 4 1 is a side view of a first bond arm 10 and a second bond arm 10' according to a preferred embodiment of the present invention, wherein the first and second bond arms are mounted on opposite sides of a rotary dual-arm bond head 32. The rotary dual-arm bond head 32 is coupled to a rotary drive (not shown) that rotates the corresponding bond arms 10, 10' between a pick-up position 44 and a placement position 46, wherein a semiconductor chip supply is located at the pick-up position 44, and the placement position 46 includes various bonding pads at which semiconductor chips should be bonded. The corresponding bond arm bodies 12 of the two bond arms 10, 10' are separated by an angle of 180 degrees. Since the second bond arm 10' can have the same structure as the first bond arm 10 described in detail above, the composition of each bond arm 10, 10' will not be described in further detail in this embodiment.

[0028] The rotary dual-arm bond head 32 can be driven by a rotary drive to rotate along the θ motion path 34 about a central rotation axis 36, which is centered between the dual bond arms 10, 10'. Therefore, the pick-up position 44 and the placement position 46 will be located on opposite sides of the central rotation axis 36. Unlike the single-arm bond head 30, the rotary dual-arm bond head 32 does not need to carry the dual bond arms 10, 10' for vertical (or in the Z axis) movement at all. This is because the pick-up position 44 and the placement position 46 can already be set at one or more heights h, that is, within the range of motion of the chuck 14 along the bond arm arcuate motion path 26.

[0029] Therefore, when the first bond arm 10 is rotated to be positioned above the pick-up position 44, there is a gap equal to the height h between the tip of the collet 14 and the pick-up or placement position 44, 46. The arc-shaped voice coil actuator 16 can drive the collet 14 to move downward to close the gap, thereby contacting the semiconductor chip to be picked up. After the semiconductor chip has been picked up by the collet 14, the arc-shaped coil 20 can move in the opposite direction to lift the semiconductor chip from the pick-up position 44.

[0030] Then, by rotating the rotary dual-arm bond head 32 by 180 degrees, the first bond arm 10' is transported to a position above the placement position 46. At this position, there is a gap between the semiconductor chip and the placement position 46 again. At the same time, the rotation of the rotary dual-arm bond head 32 also causes the second bond arm 10' to be located above the pick-up position 44. Therefore, when the chuck 14 of the first bond arm 10 is moved downward by the arc voice coil actuator 16 to bond the semiconductor chip at the placement position 46, the second bond arm 10' can simultaneously pick up another semiconductor chip for bonding at the placement position.

[0031] Once a semiconductor chip has been bonded by the first bond arm 10 and another semiconductor chip has been picked up by the second bond arm 10', the rotary dual-arm bond head 32 is rotated again by 180 degrees, so that the first bond arm 10 is positioned above the pick-up position 44 and the second bond arm 10' is positioned above the placement position 46. At this time, the first bond arm 10 can pick up another semiconductor chip, while the second bond arm 10' bonds the semiconductor chip it has picked up at the same time.

[0032] The above process can be repeated until all semiconductor chips have been picked up from the pick-up position 44 and bonded at the placement position 46. With the rotary dual-arm bond head 32 configuration, each bond arm body 10, 10' can perform the above chip bonding process sequentially or in parallel without causing any performance loss. Figure 4 The throughput of the dual-arm embodiment shown can be much higher than Figure 3 The throughput of the single-arm embodiment is shown.

[0033] The rotary dual-arm bond head 32 is capable of high-speed rotational motion along the θ motion path 34 around the rotation axis 36. The arc voice coil actuator 16 helps provide a compact structure with lower inertia. By comparing the position feedback from the position encoder 24 with the current intensity in the arc coil 20, the processor 25 can detect and control the impact force applied by the chuck 14 during chip pick-up and placement to minimize the bonding force and avoid damaging the semiconductor chip. The travel path of the rotary dual-arm bond head 32 around the center line of the rotation axis 36 can be further configured to match different chip bonding platforms with each bond arm body 10, 10' so as to perform the above chip bonding process sequentially or in parallel.

[0034] It should be understood that the bond arm and bond head according to the preferred embodiment of the present invention incorporate a low inertia high speed arcuate voice coil driven chip bond arm for use with an automatic chip bonder. An arcuate motion (rather than conventional linear motion) is provided in the Z-axis for the semiconductor chip pick and place process. The arcuate motion employs a rotary pivot and lever structure. The conventional vertical linear pick and place motion is replaced by the arcuate voice coil actuator 16. Using the apparatus according to the preferred embodiment of the present invention, a greater actuator torque output can be achieved to increase the motion speed, thereby maintaining higher accelerations, and the bonding impact force is actually reduced without affecting the effectiveness of the chip bonding operation.

[0035] like Figure 3 and Figure 4 As shown, the chip bond head can be configured with one bond arm or two bond arms based on different application requirements without losing its performance.

[0036] Using arc motion instead of conventional linear motion to drive the bond arm body 12 up and down helps to generate greater torque in a limited space. The rotation pivot point 22 can be appropriately lowered to reduce the height difference h between the bonding point (i.e., the bottom surface of the chuck 14) and the pick-up and / or placement position 44, 46, thereby maintaining a high level of parallelism between the lower surface of the semiconductor chip and the surface of the semiconductor chip to be picked up or bonded.

[0037] The bonding force can be controlled within a wide range.Such a compact structure enables low inertia of the vertical movement of the bond arm body 12, both for a single bond arm configuration and even more advantageously for a double bond arm configuration.

[0038] Variations, modifications and / or additions may be made to the invention described herein in addition to those specifically described, and it is to be understood that the invention includes all such variations, modifications and / or additions that fall within the spirit and scope of the foregoing description.

Claims

1. A semiconductor chip bonding device, comprising: a bonding arm body; a chuck attached to the first end of the bond arm body for holding a semiconductor chip during a pick and place operation; as well as a voice coil actuator located at the second end of the bond arm body, for driving the bond arm body to rotate about a pivot located between the chuck and the voice coil actuator; Wherein, the voice coil actuator also includes: a pair of arc-shaped magnets, which have a concave arc surface facing the pivot, and the concave arc surface forms an arc gap between the arc-shaped magnets; and an arc coil, which includes a concave arc surface arranged in the arc gap, and the arc coil is configured to be able to move relative to the arc magnet.

2. The semiconductor chip bonding device according to claim 1, further comprising a first connecting rod and a second connecting rod, wherein the first connecting rod and the second connecting rod respectively connect the top edge and the bottom edge of the arc coil to the bonding arm body, wherein The angular motion range of the arc-shaped coil relative to the arc-shaped magnet is smaller than the angular distance between the first connecting rod and the second connecting rod.

3. The semiconductor die bonding apparatus of claim 1, further comprising a position encoder coupled to the bond arm body for determining an angular orientation of the bond arm body during rotational movement of the bond arm body about the pivot axis.

4. The semiconductor die bonding apparatus according to claim 3, further comprising a processor operative to compare position feedback from the position encoder with the current intensity in the arc coil for controlling the impact force applied by the chuck.

5. The semiconductor chip bonding device according to claim 1, wherein: The bond arm body is mounted on a single bond arm bond head that is movable along three orthogonal axes for positioning the collet at a plurality of pick and place positions.

6. The semiconductor chip bonding device according to claim 1, wherein: The bond arm body is mounted on a rotary double-arm bond head, and the rotary double-arm bond head includes a pair of bond arm bodies separated by an angle of 180 degrees.

7. The semiconductor chip bonding device according to claim 6, wherein: The rotary dual-arm bond head is operated to rotate the corresponding bond arms along a θ motion path about a central rotation axis, and the pair of bond arm bodies are positionable at the pick-up position and the placement position located on opposite sides of the central rotation axis.

8. The semiconductor chip bonding device according to claim 7, wherein: The arcuate coil can be driven to move along an actuator arcuate motion path, and the collet can be driven to move along a bond arm arcuate motion path, the bond arm arcuate motion path being opposite in direction to the actuator arcuate motion path.

9. The semiconductor chip bonding device according to claim 8, wherein: The pick-up position and the placement position are disposed at one or more heights that are within a range of motion of the collet along the arcuate motion path of the bond arm.

10. The semiconductor chip bonding device according to claim 9, wherein: The one or more heights are set so that when the chuck is rotated to the corresponding position, there is a gap between the chuck and the pick-up position or the placement position, and the voice coil actuator is operated to drive the chuck to close the gap.

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