JP5953022B2 - Bonding method - Google Patents

Description

  The present invention relates to a die bonder.

  In general, in a die bonder, when a die (work) or the like is peeled from a wafer tape, a static eliminator ionizer is used to suppress the generation of static electricity and prevent electrostatic breakdown. An ionizer is one in which positive ions and negative ions are generated alternately to neutralize an object. The ion balance is a balance of positive ions and negative ions generated by the ionizer. The closer the ion balance is to OV, the better the charge removal.

Patent Documents 1 and 2 can be cited as conventional techniques of ionizers.
This Patent Document 1 describes that an ionization amount detection function is added to an ionizer in a stable measurement environment so that the ion balance can be adjusted based on the detection result. Further, Patent Document 2 provides means for measuring the absolute humidity of the controlled space, increases the relative generation amount of negative ions with respect to positive ions by increasing the absolute humidity, and increases positive ions with respect to negative ions by decreasing the absolute humidity. It is described that the relative generation amount of is increased.

JP-A-10-2899796 JP-A-5-94896

Now, inside the die bonder, the environment such as humidity is not constant but always changes.
Moreover, in the metal bond head, the die (work) is peeled off from the wafer tape and moved to be bonded to the substrate. With this operation, the work is bonded to a substrate or the like, which is called a die bonder. For this reason, environmental changes and operational changes always occur inside the die bonder.

However, using an ionizer in this changing environment and removing the static electricity caused new problems.
In other words, in the current ionizer, when the humidity of the measurement environment changes, the ion balance is lost, and appropriate neutralization cannot be performed on the object to be neutralized, increasing the possibility of reverse charging. In addition, the charged amount of a charged object cannot be accurately detected due to the approach of a metal or the like, so that an appropriate ion balance cannot be obtained, and the object to be neutralized may be reversely charged.

However, since the bonding temperature in the die bonder is high, the humidity around the bond head easily changes, and the charge amount of the die (work) also changes. For this reason, the ion balance around the bond head is lost, and there is a problem that the charge cannot be appropriately removed according to the charge amount of the die (workpiece).
Further, static electricity is generated when the die (work) is peeled off from the wafer tape by the bond head. In order to remove the generated static electricity, the ionizer needs to accurately detect the charge amount of the charged die (work). However, when the metal bond head is approached, the ionizer cannot accurately detect the charge amount of the die (work), and there is a problem that the charge of the die (work) cannot be removed.

  On the other hand, in the above-mentioned Patent Document 1, although it is described that the charge amount detection function is added to the ionizer in a stable measurement environment and the ion balance can be adjusted based on the detection result, the approach such as the metal product inside the die bonder is described. There is no description about the charge removal in accordance with the amount of charge of the charged object by the ionizer in the changing environment due to the above. Also, Cited Document 2 does not describe any control of humidity inside the die bonder.

  An object of the present invention is to provide a die bonder in which the quality of a product is improved by appropriately removing a charged material in accordance with an environmental change or an operation change inside the die bonder.

  In order to achieve the above object, the present invention includes a die (work) on a wafer tape and a bonding head, and is directed to the die (work) to be peeled from the wafer tape by the bond head. Is provided with an ionizer for removing static electricity generated when the film is peeled off.

  In order to achieve the above object, a potential detecting device for detecting the potential of the workpiece is preferably provided in the vicinity of the workpiece.

  In order to achieve the above object, preferably, the ionizer includes a control device that receives an output from the potential detection device.

  According to the present invention, a die bonder in which an appropriate ion balance is adjusted by a surface potential of a die (work) in an actual environment in accordance with environmental changes and operational changes inside the die bonder, and the product quality is improved by removing electricity. Can be provided.

It is the conceptual diagram which looked at the die bonder which concerns on Example 1 of this invention from the top. It is the conceptual diagram which looked at the die bonder which concerns on Example 1 of this invention from the top. It is a schematic sectional drawing of the bond head, the pushing-up unit, and ionizer which concern on Example 1 of this invention. It is a conceptual diagram of a pick-up jig and a push-up unit according to an embodiment of the present invention. It is a flowchart which shows operation | movement of the Example which concerns on this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

1 is a conceptual view of a die bonder according to a first embodiment of the present invention as viewed from above.
In FIG. 1, the die bonder roughly includes a wafer supply unit 1, a substrate supply / conveyance unit 2, and a die bonding unit 3. The substrate supply / conveyance unit 2 includes a stack loader 21, a feeder 22, and an unloader 23. The substrate (supplied to the feeder 22 by the stack loader 21) is transferred to the unloader 23 through two processing positions on the feeder 22.

  The die bonding unit 3 includes a preform unit 31 and a bonding head unit 32. The preform part 31 which is a pre-process of the die bonding part 3 is a part for applying an adhesive to the substrate conveyed by the feeder 22. The bonding head unit 32 picks up a die (work) from the die (work) supply unit 12 and moves up to a bonding point on the feeder 22. Therefore, the bonding head unit 32 lowers the die (work) and bonds it to the substrate conveyed by the feeder 22.

  The wafer supply unit 1 includes a wafer cassette lifter 11 and a die (work) supply unit 12. The wafer cassette lifter 11 has a wafer cassette (not shown) filled with a ring in which a diced wafer is fixed to a wafer tape, and a ring in which the diced wafer is fixed to the wafer tape is supplied as a die (work). Supply to unit 12. Then, the workpiece to be peeled off from the push-up unit 26 is pushed up, and the bonding head portion 32 picks up the pushed-up die (work).

FIG. 2 is a top view of the die bonder according to the present invention. Note that the same reference numerals as those in FIG.
In FIG. 2, a wafer tape 24 on which a diced wafer is fixed is mounted on a wafer table 13. The bonding head unit 32 picks up 24 target dies (workpieces) 28 (details will be described later) and bonds the picked up die (workpiece) onto a substrate (not shown). A pick-up jig 25 is used when the die (work) 28 is peeled from the wafer tape 24.

  The die is reliably peeled off by a push-up unit 26 (details will be described in FIG. 3). This peeling operation is illuminated by the lighting unit 29 so that safe and accurate work can be performed.

FIG. 3 is a sectional view of the pickup jig and the push-up unit.
In FIG. 3, the pickup jig 25 attached to the bonding head 33 is provided with a plurality of suction holes 25a. One end of each suction hole 25a is connected to a vacuum supply source (not shown) via a bond head or the like. Because of the communication, the die 34 is attracted to the suction hole 25a by the vacuum supply source. When the die 34 is sucked into the suction hole 25a of the pickup jig 25, the die 34 is peeled off from the wafer tape 24a. In order to perform this peeling operation more reliably, a push-up unit 26 is provided below the wafer tape 24a.

  The push-up unit 26 includes a push-up portion 26 a that pushes up the outer periphery of the die 34 and a center push-up portion 26 b that pushes up the central portion of the die (work) 34.

Incidentally, the pick-up jig shown in FIG. 3 generates static electricity when the die (work) is peeled off from the wafer tape. In order to prevent electrostatic damage to the die (work) or the substrate, an ionizer installed in the vicinity is used to neutralize the die (work) and the pickup jig.
This ionizer is affected by the humidity of the environment and breaks down. In particular, since the humidity inside the die bonder device and around the bond head is likely to change, the static electricity generated when the die (workpiece) is peeled off cannot be removed well, and static electricity accumulates.
Also, due to the approach of the metal bond head, the ionizer breaks the ion balance and the die (work) cannot be neutralized.

  As one means for solving such a problem, it is known that the ion balance can be controlled by measuring the humidity of the environment around the charged object as in the cited document 2. In addition, it has been found that the use of an ionizer such as that of Cited Document 1 is effective in removing static electricity from charged objects. Since it is known that static electricity consists of negative ions and positive ions, the ambient air around the static object is ionized with an ionizer and neutralizes the static electricity generated by the generated ion balance. It is.

  In the first place, the ion balance is lost due to environmental changes or operational changes. Accordingly, the inventors of the present invention have always measured the charge amount of the die (work), and variously studied to feed back the measurement result to the adjustment of the ionizer. As a result, the following examples were obtained.

  An embodiment of the present invention will be described below with reference to FIGS.

FIG. 4 is a conceptual diagram of a pickup jig and a push-up unit according to an embodiment of the present invention.
FIG. 5 is a flowchart of this embodiment.

  In FIG. 4, a die (work) 34 was picked up by the bond head 32, and static electricity was generated when the raised die (work) 34 was picked up. The generated static electricity is going to be removed by an ionizer 36 installed in the vicinity.

  In this figure, this ionizer 36 injects ion balance and is always inclined at an angle at which ion balance is injected toward the pickup jig 25.

  After reaching the set number of times of bonding, the potential of the die (work) 34 is detected by the potential detector 36. The ionizing effect of the ionizer is judged based on the detected potential. If the detected potential is abnormal, the next bonding is performed after the ion balance adjustment.

In FIG.
(1) The die (workpiece) affixed on the wafer tape is sucked by the suction force of the pickup jig so that the die is peeled off and bonded to the substrate. Repeat operation (101)
(2) Reach the set number of times (102)
(3) Measure die (workpiece) surface potential (103)
(4) Judging the appropriateness of ion balance from the measured potential value (104)
(5) If normal, return to (101) because there is no problem. (105)
(6) If on-balance adjustment is performed in the case of abnormality, the process returns to (103). (106)
Thus, in this embodiment, since the ionizer 36 is controlled in accordance with the potential state of the die 34, more accurate charge removal can be performed.

  In the first embodiment, it has been described that the potential is detected by the die (work) corresponding to the environmental change and reflected on the ionizer, but in this embodiment, the potential change according to the operating environment of the metal bonding head as the movable portion. Will always be detected. That is, the ion balance changes to the position of the bonding head that becomes the metal movable part.

Accordingly, the inventors of the present invention detect the potential of the die (work) in accordance with the movement of the bonding head and apply feedback to the control of the ionizer.
In FIG. 4, the charge amount of the die (work) 34 is detected and controlled by the ionizer 36 to obtain an appropriate ion balance. Excluding the influence of the bonding head 33, the static electricity is removed from the die (work).

  As described above, according to this embodiment, since the potential can be accurately detected and reflected in the control of the ionizer 36 due to the change in the operation of the bond head 33 or the surrounding environment, accurate discharge can be performed.

  As described above, the present invention can eliminate the environmental change or the operation change of the bonding head and provide the ion balance in accordance with the charged state of the die (work) to eliminate the charge.

  DESCRIPTION OF SYMBOLS 1 ... Wafer supply part, 2 ... Substrate supply and conveyance part, 3 ... Die bonding part, 11 ... Wafer cassette lifter, 12 ... Wafer table, 21 ... Stack dodder, 22 ... Loader, 23 ... Unloader, 24 ... Wafer, 24a ... Wafer tape, 24b ... Workpiece, 25 ... Pickup jig, 25a ... Through hole, 26 ... Push-up unit, 26a ... Push-up portion, 26b ... Center push-up portion, 30 ... Transfer chute, 31 ... Preform portion, 32 ... Boarding head 32a ... bonding head, 36 ... ionizer, 36a ... potential detection device, 36b ... control device.

Claims (2)

A metal bonding head that bonds the die to the substrate;
A pickup jig attached to the bonding head and sucking the die;
And ionizer before Symbol bond head to remove static electricity generated when peeling the die from the wafer tape,
A die bonder bonding method comprising:
(A) While ejecting positive ions and negative ions to the pickup jig, the die attached to the wafer tape is sucked by the suction force of the pickup jig to peel the die, Bonding to the substrate;
(B) measuring the surface potential of the die after repeating step (a) a predetermined number of times;
(C) judging the appropriateness of the ion balance between positive ions and negative ions released from the ionizer from the measured potential, and adjusting the ion balance if not appropriate;
Bonding wherein the comprises a. The bonding method according to claim 1,
In the bonding method , the step (b) measures the surface potential of the die according to the movement of the bonding head.

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