Pickup device

Abstract

The present invention provides a pickup device that easily picks up chip components to be picked up while preventing the chip components from falling off before pickup. [Solution] In a device 1 for picking up chip components attached to a sheet 2 via an adhesive layer, the adhesive layer has the characteristic that its ability to hold the chip components weakens when heated, and the device includes a laser heating unit 3 that irradiates a laser beam L to heat the adhesive layer toward the chip attachment area to which the chip components to be picked up are attached, and a collet 4 that peels the chip components to be picked up from the sheet and picks them up after being irradiated with the laser beam, and the laser heating unit has multiple heating areas set in the chip attachment area to heat the adhesive layer, with the intensity of the laser beam set to a different intensity for each heating area.

Description

[Technical Field]

[0001] The present invention relates to an apparatus for picking up chip components attached to an adhesive sheet. [Background Art]

[0002] A semiconductor device is formed by arranging a large number of chip components incorporated in the device in a matrix on a single semiconductor wafer (so-called pre-process), and is singulated, wired, and packaged in a process called dicing (so-called post-process).

[0003] In the post-process, a stretchable adhesive sheet (also called a dicing tape or an expand sheet) is attached to the wafer before cutting. After dicing to the size of the chip component, the chip components are picked up one by one using a suction head (also called a pickup or a collet), and are carried to a mounting target such as a lead frame or a substrate, and wiring and mounting are performed.

[0004] At this time, the diced chip components are held via an adhesive layer on a stretchable adhesive sheet (also called a dicing tape or an expand sheet), and are picked up in a state where the adhesive sheet is stretched (expanded state). And, when picking up the chip component from the adhesive sheet, a method of peeling (i.e., picking up) the chip component from the adhesive sheet with a pushing-up member called a needle is known.

[0005] Furthermore, in order to prevent the chip component from being damaged by the pushing-up of the needle, a method of heating the adhesive sheet to weaken the adhesive force with the chip component is known (for example, Patent Document 1). [Prior Art Documents] [Patent Documents]

[0006] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-281660 [Overview of the project] [Problems that the invention aims to solve]

[0007] In recent years, chip components have become increasingly miniaturized, with numerous chip components densely arranged on a single semiconductor wafer. In post-processing, it is necessary to pick up diced chip components with spacing between them of only a few tens to a hundred microns.

[0008] Figure 7 is a schematic diagram showing the positional relationship of the laser beam L and the distribution (i.e., profile) of the intensity B irradiated onto a chip component in an example of the conventional technology. Figure 7 shows an example of the positional relationship between the chip attachment area 23 of the chip component Dp to be picked up and the irradiated laser beam L, as well as the profile of the intensity B of the laser beam L.

[0009] Conventionally, when picking up a chip component Dp that is attached to a sheet 2 via an adhesive layer 22, the adhesive layer 22 was heated over the entire surface of the chip attachment area 23 to which the chip component Dp was attached in order to weaken the adhesive force between the chip component Dp and the adhesive layer 22. However, this caused a portion 29 of the area where adjacent chip components Dn that were not to be picked up were held to also be heated by the laser beam L, resulting in insufficient holding power for the chip components Dn, which could cause them to peel off or shift position before being picked up.

[0010] Furthermore, if the adhesive layer 22 was heated over the entire surface of the chip attachment area 23 to which the chip component Dp to be picked up was attached, the chip component Dp may warp, which could cause problems with the pickup, such as the collet not making proper contact.

[0011] Therefore, the present invention aims to provide a pickup device that can easily pick up chip components to be picked up while preventing the chip components from peeling off or becoming misaligned before pickup. [Means for solving the problem]

[0012] To solve the above problems, one aspect of the present invention is: In a device for picking up chip components attached to a sheet via an adhesive layer, The adhesive layer has the characteristic that its ability to hold chip components weakens when heated. A laser heating unit irradiates a laser beam to heat the adhesive layer towards the chip attachment area where the chip component to be picked up is attached, It comprises a collet that peels a chip component to be picked up from a sheet after being irradiated with a laser beam, The laser heating section is In the chip attachment area, multiple heating zones are set to heat the adhesive layer, and the intensity of the laser beam is set to a different intensity for each heating zone. [Effects of the Invention]

[0013] This system allows for easy pickup of chip components while preventing them from detaching or shifting position before pickup. [Brief explanation of the drawing]

[0014] [Figure 1] This is a schematic diagram showing the overall configuration of an example of an embodiment of the present invention. [Figure 2] This is a schematic diagram showing the main parts of an example embodiment of the present invention. [Figure 3] This is a schematic diagram showing the positional relationship and intensity B profile of the laser beam L irradiated onto the chip component Dp in an example of an embodiment of the present invention. [Figure 4] This is a flowchart of an example of an embodiment of the present invention. [Figure 5] This is a schematic diagram showing the main parts of an example embodiment of the present invention. [Figure 6] This is a schematic diagram showing specific examples and modified versions of the main parts of an example embodiment of the present invention. [Figure 7] The schematic diagram which shows the positional relationship and intensity B profile of the laser beam L irradiated to the chip component in an example of the prior art.

BEST MODE FOR CARRYING OUT THE INVENTION

[0015] FIG. 1 is a schematic diagram showing the overall configuration of an example of an embodiment embodying the present invention. FIG. 1 shows a schematic diagram of the pickup device 1 according to the present invention.

[0016] The pickup device 1 is a device for picking up the chip component D attached on the sheet 2. Specifically, the pickup device 1 irradiates the laser beam L toward the chip attachment area 23 where the chip component D is attached via the adhesive layer 22 on the sheet 2, and picks it up. More specifically, the pickup device 1 includes a laser heating unit 3, a collet 4, a sheet holding unit H, a moving unit M, an alignment camera C, a control unit CN, and the like.

[0017] The sheet 2 holds the chip component D in a predetermined posture and enables a large number of individual chip components D to be moved at once (that is, facilitates handling). Specifically, the sheet 2 has the diced chip component D attached and held on the holding surface (for example, the upper surface). Note that the large number of chip components D attached to the sheet 2 may be appropriately distinguished and referred to as the attached chip component Dp and the chip component Dn that is not the pickup target.

[0018] FIG. 2 is a schematic diagram showing a main part of an example of an embodiment embodying the present invention. FIG. 2 shows a cross-sectional view of the sheet 2 and the like to which the chip component D to be picked up is attached. More specifically, the sheet 2 includes a base material 21 and an adhesive layer 22, and the outer peripheral portion is attached to the ring-shaped frame Wf. The base material 21 is composed of a resin film or the like having elasticity while transmitting the laser beam L. The adhesive layer 22 has the characteristic that its ability to hold the attached chip component Dp weakens with heat. Specifically, the adhesive layer 22 is composed of a binding material called a binder, and the binding strength of this binder decreases when heated. More specifically, an example of an adhesive layer 22 is one in which the binder hardens or softens upon heating, resulting in a decrease in bonding strength. The area of ​​the adhesive layer 22 to which the chip component D is attached (i.e., the area inside the outer edge of the chip component D) is called the chip attachment area 23.

[0019] The frame Wf holds the sheet 2 in a predetermined position, allowing multiple chip components D to be moved at once (i.e., facilitating handling), and also secures the sheet 2 to prevent it from shifting position when picking up the chip components D. It is also called a carrier. Specifically, the frame Wf is made of a material such as resin or metal that is resistant to deformation.

[0020] The seat holder H holds the seat 2 in a predetermined position. Specifically, the sheet holding section H is configured to hold the ring-shaped frame Wf to which the sheet 2 is attached in a predetermined position. More specifically, the sheet holding section H can be configured to support the frame Wf from below and fix it by vacuum suction, or to sandwich and fix the frame Wf from above and below.

[0021] The laser heating unit 3 irradiates a laser beam L towards the chip attachment area 23 on which the chip component Dp to be picked up is attached, thereby heating the adhesive layer 22 on the sheet 2. Specifically, the laser heating unit 3 includes a laser oscillator 31, a modulator 32, a mirror 33, etc. The laser beam L is described in detail below, distinguishing between laser beams L1 to L3, but it is sometimes simply referred to as laser beam L.

[0022] The laser oscillator 31 emits the laser beam L1. Specifically, the laser oscillator 31 can be exemplified by a continuous-oscillation fiber laser that emits a laser beam L1 with a near-infrared wavelength, and is connected to the control unit CN.

[0023] The modulator 32 adjusts (i.e., modulates) the intensity B profile of the incident laser beam L1 before emitting it. Specifically, the modulator 32 modulates the intensity B profile of the emitted laser beam L2 by locally changing the phase of the incident laser beam L1. More specifically, the modulator 32 is connected to the control unit CN and performs a predetermined phase modulation, and an example of such a modulator is one equipped with a reflective spatial optical phase modulation module (SLM).

[0024] The mirror 33 changes the direction of the laser beam L2 emitted from the modulator 32. The laser beam L3 reflected by the mirror 33 is then irradiated onto the sheet 2. Specifically, the laser beam L3 heats the adhesive layer 22 on the sheet 2, making it easier to peel the chip component Dp to be picked up from the sheet 2. Furthermore, the laser heating unit 3 has multiple heating regions set in the chip attachment area 23 to heat the adhesive layer 22, and the intensity of the laser beam L3 is set to a different intensity for each heating region.

[0025] Figure 3 is a schematic diagram showing the positional relationship and intensity B profile of the laser beam L3 irradiated onto the chip component Dp in an example of an embodiment of the present invention. Figure 3 shows an example of the positional relationship between the chip attachment area 23 of the chip component Dp to be picked up and the multiple heating areas 25a, 25b, etc. irradiated by the laser beam L3, as well as the intensity B profile of the laser beam L3.

[0026] The moving part M moves the sheet 2 and the laser heating part 3 relative to each other. Specifically, the moving unit M moves the sheet holding unit H in the XY direction, stops it at a predetermined position, and changes the irradiation position of the laser beam L3 that irradiates the chip component D held on the sheet 2. More specifically, the moving unit M may be equipped with a mechanism combining a ball screw and a servo motor, or a linear motor, and may be configured to drive the seat holding unit H based on commands from the control unit CN.

[0027] Alignment camera C detects the position of chip component Dp. Specifically, the alignment camera C captures an image of the chip component Dp to be picked up, and based on the captured image, detects the position and angle of the outer edge of the chip component Dp, the position of the reference part and the center of gravity, etc., calculates where the chip component Dp is located within the field of view (and consequently, where the chip component Dp is located on sheet 2), and outputs this as position information for the chip component Dp. More specifically, the alignment camera C comprises an imaging camera C1 and an image processing unit (not shown).

[0028] The imaging camera C1 captures an image of the entire or a part of the chip component Dp to be picked up, and outputs the captured image to the image processing unit.

[0029] The image processing unit processes the acquired image, calculates the location of the outer edge, reference point, and center of gravity of the chip component Dp within the image, and outputs the positional information of the chip component Dp (coordinates of the center and outer edge, etc.) to the control unit CN.

[0030] Collet 4 is used to pick up the chip component Dp that is irradiated by the laser beam L3 by peeling it off the sheet 2. Specifically, the collet 4 is made of a rod-shaped member with a flat holding surface 41 (i.e., the side that contacts the upper surface of the chip component Dp; also called the lower end surface) that holds the chip component Dp, and pores and grooves are formed in this holding surface 41. These pores and grooves are connected to a negative pressure suction means (such as a vacuum pump or ejector) via a switching valve or the like, and when the negative pressure suction means is activated with the chip component Dp in contact with the holding surface 41, a suction force is generated in the space formed between these pores and grooves and the chip component Dp. As a result, the chip component Dp is attracted to the holding surface 41 of the collet 4 and held in place by suction. More specifically, the collet 4 is connected to the collet moving part 42, and by moving away from the sheet 2 while adsorbing and holding the chip component Dp, the chip component Dp can be separated from the sheet 2 (i.e., peeled off).

[0031] The collet moving part 42 moves the collet 4 in the horizontal and vertical directions. Specifically, the collet movement unit 42 can be exemplified by a configuration that combines multiple articulated robots or multi-axis robots with a range of motion in the horizontal and vertical directions, or single-axis actuators, and is connected to the control unit CN.

[0032] The control unit CN controls each part of the pickup device 1. Specifically, the control unit CN has the following functions: • Variety information, such as the size, placement, and pickup order of the chip component Dp to be picked up, is acquired directly from upstream inspection equipment or via a host computer. • Control the sheet holder H to hold or release the sheet 2 frame Wf. Based on the placement information J of chip component D, the current position of the moving part M, and the position information of the chip component Dp to be picked up obtained from the alignment camera C, the irradiation position of the laser beam L3 is calculated. According to the size information of the chip component D included in the placement information J, a control signal is output to the modulator 32 of the laser heating unit 3, modulating the profile of the laser beam L intensity B. The movable unit M is controlled to adjust the irradiation position of the laser beam L3 onto the chip component D. A control signal is output to the laser oscillator 31 of the laser heating unit 3 to irradiate it with a laser beam L1, and the laser beam L1 is irradiated for a predetermined time and at a predetermined intensity B. The moving part M is driven to fine-tune (i.e., align) the position of the sheet holding part H (and consequently, the chip component Dp) so that the laser beam L3 is irradiated into the chip attachment area 23 on which the chip component Dp to be picked up is attached. The collet movement unit 41 is controlled to move the collet 4, thereby attracting and holding the chip component Dp to be picked up, or picking up the chip component Dp from the sheet 2. More specifically, the control unit CN consists of a computer and its executable program.

[0033] [Operation Flow] The following provides a detailed explanation of the procedure for picking up chip components D attached to sheet 2 using the pickup device 1 described above, illustrating it with an example of the operation flow.

[0034] Figure 4 is a flowchart of an example of an embodiment of the present invention.

[0035] Figure 5 is a schematic diagram showing the main parts of an example embodiment of the present invention. Figures 5(a) to (d) show, step by step, how a chip component D attached to a sheet 2 is picked up using the pickup device 1 according to the present invention.

[0036] First, variety information is obtained indicating the size, placement position, and pickup order of the chip component D held on the sheet 2 via the adhesive layer 22 (step s1).

[0037] Next, sheet 2 is placed on the sheet holder H and held in place (step s2: see Figure 5(a)).

[0038] Subsequently, the chip component Dp to be picked up is imaged by the alignment camera C, the position information of the chip component Dp is calculated and output to the control unit CN (step s3: see Figure 5(b)).

[0039] Subsequently, the moving unit 4 is controlled to move the sheet holding unit H so that the laser beam L3 is irradiated into the chip attachment area 23 of the chip component Dp (step s4). Then, the collet movement unit 42 is controlled to lower the collet 4, bringing the holding surface 41 into close contact with the chip component Dp to be picked up (step s5). Then, a laser beam L3 is irradiated onto the adhesive layer 22 within the chip attachment area 23 where the chip component Dp to be picked up is held, thereby weakening the holding force between the chip component Dp and the adhesive layer 22 (Step 6: See Figure 5(c)).

[0040] Next, the collet 4 is moved away from the sheet 2 to transfer the picked-up chip component Dp to another location (step s7: see Figure 5(d)).

[0041] Next, it is determined whether to process another chip component Dp (step s8), and if so, steps s3 to s8 described above are repeated. On the other hand, if another chip component Dp is not to be processed, sheet 2 is discharged (step s9), and the series of flows is terminated.

[0042] Because of this configuration, the pickup device 1 according to the present invention can easily pick up chip components D attached to the sheet 2 while preventing the chip components Dn from peeling off or shifting position before pickup.

[0043] [Specific examples / variations] Figure 6 is a schematic diagram showing specific examples and modified variations of the main parts of an example embodiment of the present invention. Figures 6(a) to (d) show a plan view illustrating the positional relationship between the chip attachment area 23 and the beam heating area 25, as well as specific examples and modified examples of the positional relationship of the laser beam L3 and the profile of intensity B. In a specific example shown in Figure 6(a), the first heating region 25a is set slightly inward from the outer edge of the chip attachment region 23, and the second heating region 25b is set further inward from there. The beam intensity B is set higher in the second heating region 25b than in the first heating region 25a. In the modified example shown in Figure 6(b), the first heating region 25a is set slightly inward from the outer edge of the chip attachment region 23, the second heating region 25b is set further inward from that, and the third heating region 25c is set further inward from that. The beam intensity B is highest in the second heating region 25b, and lower in the first heating region 25a and the third heating region 25c than in the second heating region 25b. In the modified example shown in Figure 6(c), a heating region 25 is set up slightly inward from the outer edge of the chip attachment region 23, and is divided into three large blocks. Within each heating region 25, a first heating region 25a and a second heating region 25b are set up. In this case, the second heating region 25b is set inside the first heating region 25a, and the beam intensity B is set higher in the second heating region 25b than in the first heating region 25a. In the modified example shown in Figure 6(d), a heating region 25 is set up slightly inward from the outer edge of the chip attachment region 23, divided into nine 3x3 matrix blocks. Within each heating region 25, a first heating region 25a and a second heating region 25b are set up. In this case, the second heating region 25b is set inside the first heating region 25a, and the beam intensity B is set higher in the second heating region 25b than in the first heating region 25a.

[0044] As mentioned above, Figures 6(a) to 6(d) illustrate an example in which the heating region 25 is set to be inside the outermost periphery of the chip attachment region 23. With this configuration, the area outside the outermost periphery of the chip attachment region 23 is not heated, so when picking up the chip component Dp to be picked up, the outer periphery of the adjacent chip component Dn that is not to be picked up is not heated, and the holding force of the adhesive layer 22 does not decrease, which is preferable. However, when applying the present invention, the outer edge of the chip heating region 25 may be set to overlap with the dicing line around the chip attachment region 23 (i.e., the gap between chip component Dp and chip component Dn). Even in this case, the outer periphery of chip component Dp and the adjacent chip component Dn is not heated, and the holding force of the adhesive layer 22 does not decrease, which is preferable.

[0045] As mentioned above, Figure 6(b) illustrates an example where the intensity B of the laser beam L3 irradiating the heating region 25 is set to be strongest in the region inside the outermost periphery of the chip attachment region 23 and outside the center. With this configuration, the holding force of the adhesive layer 22 acting on the outer edge of the chip component Dp to be picked up is eliminated, preventing stress concentration during pickup and thus preventing cracks or chips from occurring in the chip component Dp. On the other hand, since some holding force of the adhesive layer 22 near the center of the chip component Dp remains, misalignment does not occur, and pickup can be performed without stress, which is preferable.

[0046] [Other variations] In the above description, a fiber laser emitting a laser beam L1 with a near-infrared wavelength was used as an example of the laser oscillator 31. However, it may also be a laser that emits a laser beam L1 with a visible light wavelength, a semiconductor laser, or a CO2 laser that emits a laser beam L1 with a far-infrared wavelength. In this case, the laser beam L should be appropriately selected to have a wavelength that penetrates the substrate 21, is absorbed by the adhesive layer 22, and heats the binder contained in the adhesive layer 22.

[0047] Alternatively, the laser beam L may be selected to have a wavelength that penetrates the substrate 21 and the adhesive layer 22 while absorbing heat at the surface of the chip component Dp to be picked up. In this case, examples of adhesive layers 22 include those in which the binder at the interface in contact with the chip component Dp is heated by the heat propagated from the surface of the chip component Dp, causing it to harden or soften and reducing the bonding strength, or those in which air bubbles contained in the binder become larger due to heating, reducing the bonding strength.

[0048] In the above description, the modulator 32 of the laser heating unit 3 was exemplified as being equipped with a reflective spatial optical phase modulation module (SLM). With this configuration, the profile of the laser beam L3 intensity B is modulated based on the control signal output from the control unit CN, which facilitates handling of multiple product types and is therefore preferable. However, if single-product handling or product changeover through setup changes is permitted, a homogenizer or diffractive optical element (DOE) with minute irregularities formed on the mirror surface may be used as the modulator 32. Furthermore, while the homogenizer or diffractive optical element (DOE) may be of the reflective type as described above, it may also be of the transmissive type with minute irregularities formed on the incident or exit surface of the transparent material.

[0049] As described above, the configuration involves bringing the collet 4 into close contact with the chip component Dp to be picked up, and then irradiating the heating region 25 with the laser beam L3. This configuration is preferable because, even when the holding force of the chip attachment area 23 is almost completely lost due to heating by the laser beam L3, the chip component Dp can be picked up while preventing misalignment. However, if heating is performed as illustrated in Figures 6(b) to (d), and the holding force of the chip component Dp remains partially within the chip attachment area 23, and there is no concern about misalignment, the collet 4 may be brought into close contact with the chip component Dp after heating with the laser beam L3 and then picked up. Alternatively, the configuration may involve using the needle to push up the chip component Dp and then picking it up with the collet 4. By applying the present invention, the holding force of the chip attachment area 23 is reduced, so that even if the needle pushes up the chip component Dp, cracks or chips will not occur.

[0050] In the above example, a method was described in which the laser beam L that heats the adhesive layer 22 of sheet 2 is irradiated toward the substrate 21 of sheet 2, but a method in which the laser beam L is irradiated from the chip component Dp side is also acceptable. In this case, one example is a method in which the chip component Dp is directly heated by a laser beam L of a wavelength that absorbs heat at the chip component Dp, and the adhesive layer 22 is heated by the heat that propagates. Alternatively, a method may be used in which the adhesive layer 22 is heated by irradiating it with a laser beam L of a wavelength that penetrates the chip component Dp and absorbs heat at the adhesive layer 22.

[0051] Although the above example uses a stretchable resin film as the base material 21 of sheet 2, the present invention can be applied regardless of whether or not the material is stretchable. [Explanation of Symbols]

[0052] 1. Pickup device 2 sheets 3. Laser heating section 4 Colettes D-chip component Dp pickup target chip component Dn chip components not targeted by pickup 21 Base material 22 Adhesive layer 23 Chip application area 25 heating area 25a 1st heating area 25b 2nd heating area 25c 3rd heating area 31. Laser Oscillator 32 Converters 33 Mirror 41 Collet moving part L laser beam B. Intensity of the laser beam H Sheet holding section M Moving part C Alignment Camera CN Control Unit

Claims

1. In a device for picking up chip components attached to a sheet via an adhesive layer, The adhesive layer has the characteristic that its ability to hold the chip component weakens when heated. A laser heating unit that irradiates a laser beam to heat the adhesive layer toward the chip attachment area to which the chip component to be picked up is attached, The system includes a collet that peels the chip component to be picked up, which has been irradiated with the laser beam, from the sheet and picks it up, The laser heating unit is In the chip attachment area, multiple heating regions are set for heating the adhesive layer, and the intensity of the laser beam is set to a different intensity for each heating region. A pickup device characterized by the following features.

2. The heating region is set to be inward from the outermost periphery of the chip attachment region. The pickup device according to claim 1, characterized in that

3. The outer edge of the heating region is set to overlap with the dicing line around the chip attachment region. The pickup device according to claim 1, characterized in that

4. It includes an alignment camera that detects the position of the chip component to be picked up, Based on the positional information of the chip component captured by the alignment camera, the laser beam is irradiated toward the chip attachment area to which the chip component is attached. The pickup device according to claim 1, characterized in that

5. The intensity of the laser beam irradiating the heating region is set to be strongest in the region inside the outermost periphery of the chip attachment area and outside the center. A pickup device according to any one of claims 1 to 4, characterized in that

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