Die attach system and method of attaching a die to a substrate

Abstract

A die attach system is provided. The die attach system includes: a support structure for supporting a substrate; a die supply source including a plurality of dies for attaching to the substrate; a soldering head for soldering the dies from the die supply source to the substrate, the soldering head including a soldering tool for contacting the dies during transfer from the die supply source to the substrate; a first motion system for moving the soldering head along a first axis; and a second motion system for moving the soldering tool along the first axis, independent of the first motion system.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application No. 62 / 726,387, filed September 3, 2018, the contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to systems and methods for attaching a die to a substrate, and more particularly, to improved systems and methods for attaching a die to a substrate without picking the die from a die supply. Background Art

[0004] With respect to placing dies on substrates (e.g., placing semiconductor dies on substrates), many conventional applications employ a "pick and place" operation. In such an operation, the dies are "picked" from a semiconductor wafer or other die supply source, and then the dies are moved to (and "placed" on) a target substrate. Such an operation may also employ one or more transfers between a "pick" tool and a "placement" tool.

[0005] Some die attach applications do not use pick and place operations. For example, a die supply source (e.g., a wafer including a plurality of dies) may be positioned between a welding tool and a substrate. The dies included in the die supply source may be attached to a film or the like. After alignment between the welding tool, the die to be attached, and the placement position of the substrate - the welding tool presses the die against the placement position of the substrate. The adhesive on the lower surface of the die (and / or on the placement position of the substrate) is arranged so that the die is fixed to the substrate at the bottom. Such a welding tool may include a plurality of pins (e.g., vertically actuatable pins) for contacting the die in association with the transfer from the die supply source to the substrate.

[0006] There are often complications associated with this type of application (one that does not use pick and place operations.) For example, the speed of the die attach operation and the associated UPH (i.e., units processed per hour) may suffer due to the varying alignment of multiple components (e.g., the bonding tool, the die to be attached, and the placement location of the substrate).

[0007] It would therefore be desirable to provide improved systems and methods for attaching a die to a substrate, particularly in connection with applications that do not use pick and place operations. Summary of the invention

[0008] According to an exemplary embodiment of the present invention, a die attachment system is provided. The die attachment system includes: a support structure for supporting a substrate; a die supply source including a plurality of dies for attaching to the substrate; a welding head for welding the dies from the die supply source to the substrate, the welding head including a welding tool for contacting the dies during transfer from the die supply source to the substrate; a first motion system for moving the welding head along a first axis; and a second motion system for moving the welding tool along the first axis, which is independent of the first motion system.

[0009] According to another exemplary embodiment of the present invention, a die attachment system is provided. The die attachment system includes: a support structure for supporting a substrate; a die supply source including a plurality of dies for attaching to the substrate; a welding head for welding the dies from the die supply source to the substrate, the welding head including a welding tool for contacting the dies during transfer from the die supply source to the substrate; a first motion system for moving the die supply source along a first axis; and a second motion system for moving the die supply source along the first axis, which is independent of the first motion system.

[0010] According to another exemplary embodiment of the present invention, a method for attaching a die to a substrate is provided. The method includes the following steps: (a) operating a first motion system for moving a welding head along a first axis, the welding head being used to weld the die from a die supply source to a substrate, the welding head including a welding tool for contacting the die during the transfer from the die supply source to the substrate; (b) operating a second motion system independent of the first motion system for moving the welding tool along the first axis; and (c) transferring the die from the die supply source to the substrate through the operation of the welding tool.

[0011] According to another exemplary embodiment of the present invention, another method for attaching a die to a substrate is provided. The method includes the following steps: (a) operating a first motion system for moving a die supply source along a first axis; (b) operating a second motion system for moving the die supply source along the first axis, which is independent of the first motion system; and (c) transferring the die from the die supply source to the substrate by operation of a bonding tool, the bonding tool being included as part of a bonding head, the bonding tool being used to contact the die during the transfer from the die supply source to the substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present invention can be best understood from the following detailed description when read in conjunction with the accompanying drawings. It is emphasized that, according to common practice, the various features of the drawings are not drawn to scale. On the contrary, the sizes of the various features are arbitrarily expanded or reduced for clarity.

[0013] Figure 1Ais a block diagram top view of elements of a die attach system according to an exemplary embodiment of the present invention;

[0014] Figure 1B yes Figure 1A Another block diagram top view of elements of a die attach system;

[0015] Figure 1C yes Figure 1A A block diagram side view of elements of a die attach system;

[0016] Figure 1D According to an exemplary embodiment of the present invention Figure 1A Detailed view of an example bonding tool of a die attach system of;

[0017] Figure 2A-2E is a block diagram side view showing an exemplary embodiment of the present invention Figure 1A a die attach operation of a die attach system; and

[0018] Figures 3A-3C is a block diagram side view showing another exemplary embodiment of the present invention Figure 1A A die attach operation of the die attach system. DETAILED DESCRIPTION

[0019] As used herein, the term "die" is intended to refer to any structure that includes (or is configured to include in a later step) a semiconductor chip or die. Exemplary "die" elements include: a bare semiconductor die including a bare LED semiconductor die, a semiconductor die on a substrate (e.g., a lead frame, a PCB, a carrier, a semiconductor chip, a semiconductor wafer, a BGA substrate, a semiconductor element, etc.), a packaged semiconductor device, a flip chip semiconductor device, a die embedded in a substrate, and the like.

[0020] According to certain exemplary embodiments of the present invention, a die attach system is provided, which includes an inventive device for supporting a welding head or a supply of die. Such a device includes: (i) a long stroke portion supporting a short stroke axis; and (ii) a short stroke portion supporting a welding head or a supply of die. For example, during a welding sequence, the long stroke axis can travel at a constant speed relative to a substrate (configured to receive a die in a die attach / welding sequence). During the welding action, the short stroke axis is stopped relative to the substrate. After the welding action, the short stroke axis catches up with the long stroke axis and moves to the next welding position.

[0021] Exemplary elements included in the apparatus of the present invention include the following combinations: (1) a short-long stroke welding head in combination with a relatively slow single axis die supply source, utilizing a method of skipping the die on the source to prevent the slower supply source axis from limiting the welding rate; (2) a short-long stroke welding head in combination with a short-long stroke die supply source; and (3) an alternative, fast welding device (e.g., laser, air pulse) in combination with a short-long stroke die supply source. Of course, other apparatuses (and associated methods of operation) are also contemplated.

[0022] Aspects of the invention relate to combining the advantages of a long-stroke axis and a short-stroke axis (associated with either or both of a welding head and a die supply). In certain examples applied to welding heads, the short-stroke portion of the motion axis enables a high welding rate, while the long-stroke portion enables the welding head to achieve a desired stroke. Exemplary ranges of motion for short stroke include: (i) less than 1 mm; (ii) less than 3 mm; or any desired range of motion.

[0023] Figure 1A The die attach system 100 is shown. The die attach system 100 includes a support structure 110 for supporting a substrate 112, a die supply source 108 including a plurality of dies 108a configured to be attached to the substrate 112, and a soldering head 104 including a soldering tool 104b for contacting the dies 108a during transfer of the dies 108a from the die supply source 108 to the substrate 112. The die attach system 100 also includes a soldering head support 102 and a supply support 106. The soldering head support 102 and the supply support 106 are each mounted on a machine structure 150 so that the soldering head support 102 and the supply support 106 can be independently moved relative to the machine structure 150. The soldering head support 102 supports a movable soldering head 104. The soldering head 104 includes a camera 104a (and other vision system components) for use in conjunction with alignment and / or inspection operations. The die supply source 108 is movably mounted on the supply support 106. Figure 1A in (and in Figure 1B-1C In the exemplary embodiment of the present invention shown in FIG. 1 , during a die attach operation, a die supply source 108 is positioned between a bonding tool 104 b and a substrate 112 supported by a support structure 110 .

[0024] Figure 1B The figure shows the bonding head 104 (including the camera 104a and the bonding tool 104b) positioned over the die 108a, which in turn is positioned over the substrate 112. Figure 1C It is along line AA Figure 1B1 and illustrates a bonding head 104 with a camera 104a and a bonding tool 104b positioned over a substrate 112. Two "bonded" dies 108a' have been bonded to the substrate 112 at respective bonding locations, and the bonding tool 104b is shown engaged with another die 108a over a third respective bonding location on the substrate 112.

[0025] Figure 1D FIG. 1 is a block diagram of an example of a bonding tool 104 b. More specifically, the bonding tool 104 b may include at least one pin 104 b 1 for contacting a die 108 a associated with transfer from a die supply source 108 to a substrate 112. Figure 1D As shown in FIG. 1 , bonding tool 104 b may include a plurality of pins 104 b 1 for contacting die 108 a in connection with transfer from die supply 108 to substrate 112. Each of the plurality of pins 104 b 1 may be detachably or collectively movable (e.g., along a vertical axis) relative to the remainder of bonding tool 104 b to transfer die 108 a to substrate 112.

[0026] Of course, the welding tool 104b (such as Figure 1D ) is an example of the bonding tool 104b. In other embodiments of the present invention, the bonding tool 104b may not include the pins 104b1, but the die 108a can be transferred without the pins 104b1.

[0027] According to some exemplary embodiments of the present invention, at least one of (i) bonding tool 104b and (ii) die supply source 108 is moved along an axis (e.g., a horizontal axis or a substantially horizontal axis) using a first motion system and a second motion system. For example: Figure 2A-2E The figure shows a first motion system 102' and a second motion system 104' (hereinafter referred to as Figure 2A-2E Detailed description of the operation of the first motion system and the second motion system); and Figures 3A-3C The figure shows a first motion system 106' and a second motion system 108' (hereinafter referred to as Figures 3A-3C Detailed description of the operation of the first motion system and the second motion system). It will be appreciated that the die attach system 100 as shown and described herein may include: (i) a first motion system and a second motion system for moving the bonding tool 104b (eg, Figure 2A-2E (ii) a first motion system and a second motion system for moving the die supply source 108 (such as in Figures 3A-3C or both (i) and (ii).

[0028] Figure 2A FIG. 1 shows a die attach system 100 (previously incorporated with Figures 1A-1C 1 , but now the welding head 104 includes a first movable carrier 114 and a second movable carrier 116. The first movable carrier 114 is positioned between the welding head support 102 and the second movable carrier 116. The second movable carrier 116 is positioned between the first movable carrier 114 and the welding tool 104b. The first motion system 102' provides for the first movable carrier 114 to move relative to the welding head support 102 along the first axis ( Figure 2A The second motion system 104' provides for linear motion of the second movable carrier 116 relative to the first movable carrier 114 along the first axis. Figure 2A Also shown is a motion system 106' configured to move the die supply source 108 relative to the supply support 106. Each of the motion systems 102', 104', and 106' includes elements (not specifically shown for simplicity) between their adjacent components. For example, the motion system 102' includes motion system elements (e.g., motors, slides, ball screws, bearings, etc.) for providing movement between the first movable carrier 114 relative to the bonding head support 102.

[0029] The exemplary first motion system 102' is included in the gantry system of the die attach system 100 for carrying the bonding head 104. The die 108a is positioned above the bonding location 112a on the substrate 112 and will be bonded to the bonding location 112a on the substrate 112. Basically, the bonding head 104 will move in the vertical (e.g., z-axis) direction of the double-headed arrow while bonding the die 108a to the bonding location 112a.

[0030] Figure 2B The figure shows the movement of the welding head 104 along the welding head support 102 with the first motion system 102', while the welding tool 104b welds the leftmost tube core 108a and welds the leftmost tube core 108a to the leftmost welding position 112a. Figure 2B The bonding tool 104b is moved to the left relative to the first movable carrier 114 by the second motion system 104' and is held above the leftmost bonding position 112a, and bonds the leftmost die 108a to the leftmost bonding position 112a.

[0031] Figure 2CThe figure shows that the welding head 104 is moved further to the right along the welding head support 102 by using the first motion system 102', while the welding tool 104b is maintained above the leftmost welding position 112a by using the second motion system 104' to move further to the left relative to the first movable carrier 114, and the welding tool 104b is moved upward to its pre-welding position in the second movable carrier 116.

[0032] Figure 2D The figure shows that the welding head 104 continues to move to the right along the welding head support 102 using the first motion system 102', while the welding tool 104b is now moved to the right relative to the first movable carrier 114 using the second motion system 104' so that the welding tool 104b is now positioned above the next welding position 112a where the next welding is expected to be performed. The tube die supply source 108 (e.g., a wafer, such as an LED wafer or other LED tube die source) is moved to the left relative to the supply support 106 using the third motion system 106'.

[0033] Figure 2E The die supply 108 is shown moved to the right relative to the substrate 112 using the motion system 106' so that the remaining leftmost die 108a is now above the next bonding position 112a and below the bonding tool 104b. Figure 2A-2E The process is repeated to solder the leftmost die 108a to the next soldering location 112a, and then reset to solder the next remaining leftmost die 108a (or other dies 108a, as needed) to the next next soldering location 112a.

[0034] Figure 3A The figure shows a further embodiment of the invention, in which a single motion system 102' for the welding head 104 (including a movable carrier) is provided. Figure 3A (as well as Figure 3B-3C ), a supply support 106 (for supporting a supply of dies 108) includes a support 118, a first motion system 106', a movable carrier 120 (for carrying the supply of dies 108, which may be a wafer, such as an LED wafer or other source of LED dies), and at least a portion of a second motion system 108'. A bonding tool 104b (shown as a vertical dashed line below the bonding head 104) is located above the leftmost bonding die 108a and the leftmost bonding location 112a.

[0035] The first motion system 106' provides for the movable carrier 120 to move relative to the support 118 along a first axis ( Figure 3AThe second motion system 108' provides linear motion for the die supply source 118 relative to the movable carrier 120 along the first axis. Each of the motion systems 102', 106' and 108' includes elements (not specifically shown for simplicity) between their adjacent components. For example, the motion system 106' includes motion system elements (e.g., motors, slides, ball screws, bearings, etc.) for providing motion between the movable carrier 120 and the support 118.

[0036] Figure 3B The figure shows the welding of the leftmost welding tube core 108a to the leftmost welding position 112a when the movable carrier 120 moves to the right and the tube core supply source 108 moves to the left relative to the movable carrier 120 and remains stationary relative to the welding tool when forming a weld between the leftmost welding tube core 108a and the leftmost welding position 112a.

[0037] Figure 3C The figure shows that after the first welding, the welding head 104 moves to the right to position the welding tool above the next welding position 112a, and the fourth movable carrier 120 moves to the right, and the tube die supply source 108 also moves to the right to align the welding tool above the leftmost welding tube die 108a on the tube die supply source 108 above the next welding position 112a. For the next welding, continue similar to Figures 3A-3C process.

[0038] As shown in the various figures, double-headed arrows are intended to indicate motion (or potential motion through a motion system) of an associated element.

[0039] Exemplary embodiments of the present invention tend to result in significantly higher welding rates without loss of precision.

[0040] Although not explicitly shown in the drawings, the present invention contemplates embodiments in which each of the bonding head and the die supply includes multiple motion systems. For example, a die attach system within the scope of the present invention may include a first motion system and a second motion system for moving the bonding tool (e.g., Figure 2A-2E ), and a first motion system and a second motion system for moving a die supply source (such as in Figures 3A-3C middle).

[0041] Although the present invention is primarily described with respect to a die attach operation without a "pick-up" operation, the present invention is not limited thereto. The present invention has broad applicability in the semiconductor bonding industry including die attach machines (sometimes referred to as die bonding machines) or other packaging machines (e.g., flip chip machines / operations, advanced packaging operations, etc.).

[0042] Although the present invention has been described and illustrated with respect to exemplary embodiments of the present invention, it will be appreciated by those skilled in the art that the above and various other changes, omissions and additions may be made therein and thereon without departing from the spirit and scope of the present invention. More specifically, various modifications may be made to the details within the scope of the claims and equivalents without departing from the present invention.

Claims

1. A die attach system, comprising: a support structure for supporting a substrate; A die supply including a plurality of dies for attachment to a substrate; a bonding head for bonding dies from a die supply to a substrate, the bonding head comprising a bonding tool for contacting the die supply during transfer of the die from the die supply to the substrate; a first motion system for moving a welding head including the welding tool along a first axis; as well as A second motion system for moving the welding tool along the first axis, independent of the first motion system.

2. The die attach system of claim 1, wherein: The bonding tool includes at least one pin for contacting a die supply in connection with transfer of the die from the die supply to the substrate.

3. The die attach system of claim 1, wherein: The bonding tool includes a plurality of pins for contacting a die supply in connection with transfer of the die from the die supply to the substrate.

4. The die attach system of claim 1, wherein: The supply of die includes an LED wafer, and the plurality of dies is a plurality of LED dies.

5. The die attach system of claim 1, wherein: At least one of (i) the die and (ii) the substrate's bonding location configured to receive the die includes an adhesive for securing the die to the bonding location after transfer from the die supply to the substrate.

6. The die attach system of claim 1, wherein: The first motion system is included in a gantry system of the die attach system for carrying a bonding head.

7. The die attach system of claim 1, wherein: The first axis is the x-axis or the y-axis of the die attach system.

8. The die attach system of claim 1, wherein: The second motion system selectively moves the welding tool in a second direction along the first axis while the welding head moves in a first direction along the first axis, the second direction being opposite to the first direction.

9. The die attach system of claim 1, wherein: The die supply is configured to be positioned between the substrate and the bonding tool during a bonding operation.

10. A method of attaching a die to a substrate, the method comprising the steps of: (a) a first motion system operative to move a bonding head including a bonding tool along a first axis, the bonding head being used to bond dies from a die supply to a substrate, the bonding tool being used to contact the die supply during transfer of the dies from the die supply to the substrate; (b) a second motion system operable to move the welding tool along the first axis, independent of the first motion system; as well as (c) transferring the die from the die supply source to the substrate by contacting the bonding tool with the die supply source.

11. The method of claim 10, wherein: The bonding tool includes at least one pin for contacting the die supply in connection with the transfer of the die from the die supply to the substrate in step (c).

12. A die attach system comprising: a support structure for supporting a substrate; A die supply including a plurality of dies for attachment to a substrate; a bonding head for bonding a die from a die supply to a substrate, the bonding head including a bonding tool for contacting the die during transfer from the die supply to the substrate; a first motion system for moving the die supply along a first axis; as well as A second motion system for moving the die supply along the first axis, independent of the first motion system.

13. The die attach system of claim 12, wherein: The bonding tool includes at least one pin for contacting a die in connection with transfer from a die supply to a substrate.

14. The die attach system of claim 12, wherein: The bonding tool includes a plurality of pins for contacting the die in connection with transfer from a die supply to a substrate.

15. The die attach system of claim 12, wherein: The supply of die includes an LED wafer, and the plurality of dies is a plurality of LED dies.

16. The die attach system of claim 12, wherein: At least one of (i) the die and (ii) the substrate's bonding location configured to receive the die includes an adhesive for securing the die to the bonding location after transfer from the die supply to the substrate.

17. The die attach system of claim 12, wherein: The first axis is the x-axis or the y-axis of the die attach system.

18. The die attach system of claim 12, wherein: The second motion system selectively moves the die supply in a second direction along the first axis while the die supply moves in a first direction along the first axis, the second direction being opposite to the first direction.

19. The die attach system of claim 12, wherein: The die supply is configured to be positioned between the substrate and the bonding tool during a bonding operation.

20. A method of attaching a die to a substrate, the method comprising the steps of: (a) operating a first motion system for moving a die supply along a first axis; (b) a second motion system operable to move the die supply along the first axis, independent of the first motion system; as well as (c) transferring the die from the die supply to the substrate by operation of a bonding tool, the bonding tool being included as part of the bonding head, the bonding tool being used to contact the die during transfer from the die supply to the substrate.

21. The method of claim 20, wherein: The bonding tool includes at least one pin for contacting the die in connection with the transfer from the die supply to the substrate in step (c).

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