JP2004241685A - Pellet carrying device, and method and device for pellet bonding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture a bonding product of high quality which can pick up and carry a pellet without damaging the pellet, and perform bonding operation without damaging the pellet. <P>SOLUTION: A pellet 1 located in a pick-up position is picked up by suction force of a suction nozzle 51, and it is carried to a bonding position of a lead frame 41 and bonded. It has a conduit 54 connecting the suction nozzle 51 and a vacuum source 55, a pressure adjusting device 57 which is provided to the conduit 54, a pressure sensor 56 which detects the pressure inside the conduit, and a control device 62 which controls suction force produced in the suction nozzle 51 by controlling the pressure adjusting device 57 based on a detection signal of the pressure sensor 56. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a pellet transporting apparatus for picking up and transporting a pellet such as a semiconductor chip from a predetermined position, and a pellet bonding method and a pellet bonding apparatus for picking up a pellet such as a semiconductor chip from a predetermined position and bonding the pellet to a substrate such as a lead frame. .
[0002]
[Prior art]
As one of semiconductor manufacturing processes, there is a process of bonding a pellet such as a semiconductor chip to a substrate such as a lead frame, and a pellet bonding apparatus is used in this process.
[0003]
In this pellet bonding apparatus, the pellets stuck on the sheet are lifted up one by one from the lower surface of the sheet by a lifting device, and the pellets are picked up by a suction force of a suction nozzle, conveyed to a bonding position and transferred to a bonding frame such as a lead frame. Bonding on the substrate. Note that an adhesive is applied on the substrate in advance, and the pellet is bonded to the substrate via the adhesive.
[0004]
FIGS. 4 and 5 show a suction nozzle normally used in a bonding apparatus. In each figure, (a) is a front sectional view, and (b) is a plan view. The suction nozzle includes a flat collet 2 for partially sucking the surface of the pellet 1 as shown in FIG. 4 and a taper collet 3 for pressing and sucking a side other than the surface of the pellet 1 as shown in FIG. . Normally, the flat collet 2 has an adsorbing surface slightly smaller than the pellet size at its tip, and a relief 4 for reducing an area in contact with the pellet surface is provided on the adsorbing surface. FIG. 5 shows a two-sided tapered collet in which a tapered inner surface 5 is formed on a pair of opposing surfaces among tapered collets.
[0005]
As the material of the suction nozzle, urethane rubber or resin is generally used for the flat collet 2, and cemented carbide or the like is generally used for the taper collet 3. However, in any of the suction nozzles of the flat collet 2 and the taper collet 3, A suction hole 6 connected to a vacuum source as needed is formed along the central axis, and the pellet 1 is suction-held by suction force generated in the suction hole 6.
[0006]
[Problems to be solved by the invention]
By the way, the thickness of a conventional pellet is about 100 to 250 μm, but in recent years, as electronic products have become lighter, thinner and shorter, for example, a pellet embedded in an IC card has a thickness of about 30 to 50 μm. Thin ones have been adopted. Then, when the extremely thin pellet 1 having a thickness of several tens of μm is sucked and held by the suction nozzle, if the suction force acting on the suction hole 6 is strong, the pellet 1 is bent as shown in FIG. As shown in FIG. 3B, warpage occurs, and depending on the degree of the warpage, damages such as changes in the characteristics of circuits and wirings inside the pellets held and held or breakage of the wirings are caused. Sometimes happened. This probability is more remarkable as the suction force acting on the suction hole 6 is larger and the thickness of the pellet is smaller.
[0007]
Therefore, it is conceivable that the suction force acting on the suction hole 6 is set to a pressure at which the pellet 1 does not bend or warp when the pellet 1 is sucked and held. However, in consideration of the difference in suction leakage between the suction surface of the suction nozzle and the upper surface of the pellet due to the upper surface of the pellet attached to the sheet being inclined or the unevenness of the pellet surface being slightly different for each pellet, Even if the pellets are in such a state, the suction force applied to the suction holes 6 is increased so that the picking up and transporting of the pellets can be reliably performed by the suction nozzle. It is the current state that it was kept. Therefore, the above-mentioned defects due to the curvature of the pellets and the like have not been removed.
[0008]
Therefore, the present invention provides a pellet transporting apparatus and a pellet bonding method capable of picking up and transporting without damaging the pellet, performing bonding without damaging the pellet, and manufacturing a high quality bonding product. And a pellet bonding apparatus.
[0009]
[Means for Solving the Problems]
In order to solve the above problems, the pellet transport device of the present invention is a pellet transport device that picks up a pellet positioned at a predetermined position by a suction force of a suction nozzle and transports the pellet, and a pipe connecting the suction nozzle and a vacuum source. A pressure adjusting device provided in the conduit, a pressure detecting device for detecting a pressure in the conduit, and the pressure adjusting device based on a detection signal of the pressure detecting device, whereby the suction nozzle And a control device for controlling the suction force generated in the suction device.
[0010]
Further, in the pellet bonding method according to the present invention, in a pellet bonding method in which a pellet positioned at a predetermined position is picked up by a suction force of a suction nozzle and transported to a bonding position of a substrate for bonding, a tube for applying a suction force to the suction nozzle is provided. The pressure in the road is detected, and the suction force generated in the suction nozzle is controlled based on the detection result.
[0011]
Further, in a pellet bonding apparatus according to the present invention, in a pellet bonding apparatus in which a pellet positioned at a predetermined position is picked up by a suction force of a suction nozzle, transferred to a bonding position of a substrate, and bonded, the suction nozzle is connected to a vacuum source. A pipeline, a vacuum pressure adjusting device provided in the pipeline, a pressure detecting device for detecting pressure in the pipeline, and controlling the pressure adjusting device based on a detection signal of the pressure detecting device. And a control device for controlling a suction force generated in the suction nozzle.
[0012]
Further, in the pellet bonding method according to the present invention, in the pellet bonding method of picking up a pellet positioned at a predetermined position by a suction force of a suction nozzle and transporting the pellet to a bonding position of a substrate for bonding, the suction force of the suction nozzle is adjusted by the suction force. The nozzle is switched within an operation range from when the nozzle starts descending toward the pellet positioned at the predetermined position to when bonding is performed.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. The same components as those described with reference to FIGS. 4 to 6 are denoted by the same reference numerals, and description thereof will be omitted.
[0014]
FIG. 1 is a schematic front view of a pellet bonding apparatus to which the present invention is applied, FIG. 2 is a front sectional view of a pellet push-up apparatus used in FIG. 1, and FIG. FIG.
[0015]
First, the configuration of the pellet bonding apparatus will be described with reference to FIG. In FIG. 1, the pellet bonding apparatus 20 includes a wafer support unit 30, a lead frame transport unit 40, a bonding unit 50, and a control unit 60.
[0016]
The wafer support unit 30 has a wafer holder 32 for holding the pellets 1 stuck on the sheet 31 and an XY table 33 for mounting the wafer holders 32. The movement of the XY table 33 causes one pellet 1 to be moved. Are sequentially positioned at the pickup position, which is a predetermined position. Above the pickup position. A camera 34 is installed, and captures an image of the pellet 1 positioned at the pickup position. Below the sheet 31, a push-up device 35 is provided corresponding to the pickup position. The push-up device 35 pushes up the pellet 1 stuck on the sheet 31 from below, and FIG. 2 is a front sectional view of the push-up device 35. The push-up device 35 has a back-up holder 36 for appropriately sucking the sheet 31 on the upper surface thereof, and a pin holder 38 having a push-up pin 37 at the tip while moving up and down in the backup holder 36. By the movement, the push-up pins 37 push up the pellet 1 from the back surface of the sheet. The pellet 1 pushed up by the push-up pin 37 is taken up by a suction nozzle 51 described later.
[0017]
Returning to FIG. 1, the lead frame transport unit 40 intermittently transports a substrate 41 such as a lead frame along a transport rail 42 by a feed mechanism (not shown).
[0018]
The bonding section 50 has a bonding head 52 having a suction nozzle 51 at the tip. The suction nozzle 51 is provided with a suction hole 53 along the central axis, and the suction hole 53 is appropriately connected to a vacuum source 55 such as a vacuum pump via a pipe 54. A pressure sensor 56 and a pressure adjusting device 57 are provided in the middle of the pipe 54. The pressure sensor 56 is disposed as close as possible to the suction nozzle 51, detects the pressure in the pipe 54, and outputs a detection signal to a control device 62 described later. A regulator or the like is used as the pressure adjusting device 57 to increase or decrease or maintain the pressure in the pipe 54 based on a command from the control device 62. The bonding head 52 is placed on an XY table (not shown), and the suction nozzle 51 is moved up and down with respect to the bonding head 52 by a lifting device (not shown).
[0019]
The control unit 60 includes an image processing device 61 and a control device 62. The image processing device 61 processes the pellet image captured by the camera 34, detects a positional displacement state of the pellet 1 positioned at the pickup position, and transmits the state to the control device 62. The control device 62 drives and controls the XY table 33 to move the wafer holder 32 in consideration of the position shift state of the pellets 1 detected by the image processing device 61, and accurately positions the pellets 1 one by one at the pickup position. . The storage device in the control device 62 stores a reference suction force value at the suction nozzle 51 to such an extent that the pellet 1 does not bend or warp (see FIG. 6) when the pellet 1 is suction-held by the suction nozzle 51. That is, the reference pressure value in the pipeline 54 is stored. The reference pressure value is determined by finding a value that does not cause a curve or a warp or the like in the pellet 1 normally sucked and held by the suction nozzle 51 and obtains a necessary pellet holding force by an experiment or the like. It is.
[0020]
The control device 62 obtains the detection value from the pressure sensor 56, and adjusts the suction force of the suction nozzle 51 by using the pressure adjustment device 57 by feedback control so that the difference between the detection value and the reference pressure value is eliminated. I do. This control is continued from the time when the suction nozzle 51 descends from above the pickup position to contact the pellet 1 until bonding, and is controlled so that the suction force on the pellet 1 is maintained at the reference pressure value. become.
[0021]
Next, the operation of the above-described pellet bonding apparatus 20 will be described with reference to the operation of peeling the pellet 1 from the sheet 31 shown in FIG.
[0022]
First, by moving the XY table 33, one of the pellets 1 on the sheet 31 is positioned at the pickup position. Next, the image of the pellet 1 is captured by the camera 34, and the captured image is processed by the image processing device 61 to detect the position shift state of the pellet 1. The control device 62 controls the driving of the XY table 33 so as to eliminate the position shift state.
[0023]
The pellet 1 in which the misalignment has been corrected in this manner is suction-held on the upper surface of the backup holder 36 of the push-up device 35 via the sheet 31 (FIG. 3A). Next, the suction nozzle 51 descends from above the pickup position, contacts the pellet 1, and holds the pellet 1 by suction (FIG. 3B). The push-up pin 37 rises to push up the pellet 1 from below via the sheet 31 (FIG. 3C). At this time, the suction nozzle 51 rises together with the push-up pin 37 while sandwiching the pellet 1 between the pellet 1 and the push-up pin 37. The push-up pin 37 stops when it rises to a predetermined position (FIG. 3D). Thereafter, the pellet 1 is taken out by the suction nozzle 51 (FIG. 3E).
[0024]
By the way, in this embodiment, the pressure in the pipe 54 is detected by the pressure sensor 56 from the time when the suction nozzle 51 starts to descend from above the pickup position. When the suction nozzle 51 comes into contact with the pellet, the suction hole 53 of the suction nozzle 51 is closed by the pellet 1 at this point, so that the pressure in the pipe 54 drops rapidly. Detected. That is, the point in time when this pressure change is detected can be said to be the point in time when the suction nozzle contacts the pellet 1. Then, after detecting this pressure change, the control device 62 compares the pressure value in the pipe line 54 detected by the pressure sensor 56 with a reference pressure value stored in advance, and detects the value detected by the pressure sensor 56 as the reference pressure value. The pressure adjusting device 57 is controlled so that This control is continued until the pellet 1 sucked and held by the suction nozzle 51 is bonded to the lead frame 41.
[0025]
Now, the pellet 1 taken out of the sheet 31 is transported to the bonding position of the lead frame 41 transported along the transport rail 42 by the movement of the suction nozzle 51, and the suction nozzle 51 is lowered to bond the lead frame. Bonded in position. After the bonding, the suction force to the suction nozzle 51 is cut off to release the held pellet 1. Note that the air may flow into the suction holes 53 to promote the separation of the pellets.
[0026]
Thereafter, by moving the XY table 33, a new pellet 1 is positioned at the pickup position, and the above-described operation is repeated.
[0027]
According to the embodiment described above, the pressure in the conduit 54 between the suction nozzle 51 and the vacuum source 55 is detected by the pressure sensor 56 so that the detected pressure matches a preset reference pressure value. The pressure regulator 57 is controlled. The reference pressure value is set to a value that does not cause bending, warping, or the like when the pellet 1 is suction-held by the suction nozzle 51, and that a necessary pellet holding force is obtained. Therefore, even if the upper surface of the pellet 1 affixed to the sheet 31 is inclined or the unevenness of the pellet surface is slightly different for each pellet, the state of the suction leak between the suction surface of the suction nozzle 51 and the upper surface of the pellet is reduced. Even when the suction nozzles 51 are different from each other, it is possible to prevent the occurrence of a curve or a warp when being suction-held by the suction nozzle 51 and to prevent the suction nozzle 51 from being dropped during conveyance, and to be suction-held with an appropriate suction force. Thus, the pellet 1 can be picked up, transported, and bonded without damaging the pellet 1, and a high-quality bonded product can be manufactured.
[0028]
Further, even if the appropriate suction force is different depending on the material and thickness of the pellet, it is only necessary to change the reference pressure value in the storage device of the control device 62. Can respond. In order to make the setting change easier, for example, a condition input device may be attached to the control device 62.
[0029]
Further, in the practice of the present invention, the conventional suction nozzle can be used as it is, so that new equipment costs can be reduced.
[0030]
In the above-described embodiment, a constant suction force is applied to the suction nozzle 51 (in the embodiment, the “reference pressure”) from the time when the suction nozzle contacts the pellet 1 until the time when the pellet 1 is bonded to the lead frame 41. Value)) has been described. However, it can be modified as follows. That is, the pressure is changed immediately after the suction nozzle comes into contact with the pellet positioned at the predetermined position. This is because, for example, the pressure after the suction nozzle comes into contact with the pellet is the same as in the above-described embodiment, and when the pellet is suction-held by the suction nozzle, the pellet is prevented from being bent or warped. Although the pressure is set to about the same level, the suction force until the suction nozzle comes into contact with the pellets is set to a stronger suction force. It has been confirmed that when the suction nozzle comes into contact with the pellet, the suction nozzle jumps up due to the reaction, and this phenomenon is repeated several times for the same pellet. Therefore, in order to prevent this rebound, the suction force of the suction nozzle is set to a strong suction force that is sufficient to resist the rebound. By setting the conditions in this way, the suction collet that is about to bounce will surely stick to the pellet without bounce. Then, the pellets are attached to a sheet that is suction-held by the backup holder 36. Therefore, this can reliably prevent the rebound and further obtain the effect that the adverse effect of the rebound can be removed. At the time of implementation, the reference pressure values before and after the suction nozzle 51 contacts the pellet 1 are set in the storage device of the control device 62, and the feedback control based on the output value of the pressure sensor 56 is performed as described above. But it's fine.
[0031]
Further, the switching of the suction force is not limited to one time. For example, the relation between the height position of the suction nozzle or the elapsed time after the start of descent of the suction nozzle and the suction force is set and stored in advance as a table, and the actually measured suction nozzle is referred to while referring to this table. May be adjusted to the suction force corresponding to the height position or the elapsed time.
[0032]
Further, in the above-described embodiment, the example in which the pellet 1 stuck on the sheet 31 is picked up by the suction nozzle and bonding is described, but the pellets stored in the case such as the chip tray are sequentially positioned at the predetermined position and picked up. You may apply to what is bonded.
[0033]
Further, in the embodiment of the present invention, when the pellet stuck on the sheet 31 is peeled off, the pellet is pushed up from below the sheet by the push-up pin 38, but this pushing-up device is not necessarily required.
[0034]
Further, in the above-described embodiment, the present invention has been described as an example in which the present invention is applied to a pellet bonding apparatus. However, in a flip chip bonding apparatus or the like, the present invention may be applied to a pellet transport apparatus that picks up a flip chip and transfers it to a collet. .
[0035]
【The invention's effect】
According to the present invention, a pellet can be picked up and transported without damaging it, and when applied to a pellet bonding apparatus, a bonding operation can be performed without damaging the pellet and a high-quality bonded product can be manufactured. Can be.
[Brief description of the drawings]
FIG. 1 is a schematic front view of a pellet bonding apparatus to which the present invention is applied.
FIG. 2 is a front sectional view of the pellet push-up device used in FIG.
FIG. 3 is a front sectional view illustrating a step of peeling a pellet from a sheet and picking up the sheet.
4A and 4B show a suction nozzle, wherein FIG. 4A is a front sectional view and FIG. 4B is a plan view.
5A and 5B show a suction nozzle, wherein FIG. 5A is a front sectional view and FIG. 5B is a plan view.
FIG. 6 is a front sectional view showing a drawback of the prior art.
[Explanation of symbols]
REFERENCE SIGNS LIST 1 pellet 2 flat collet 3 taper collet 4 ridge 5 taper inner surface 6 suction hole 20 pellet bonding device 30 wafer support unit 31 sheet 32 wafer holder 33 XY table 34 camera 35 push-up device 36 backup holder 37 push-up pin 38 pin holder 40 lead frame transport unit 41 Lead frame 42 Transfer rail 50 Bonding unit 51 Suction nozzle 52 Bonding head 53 Suction hole 54 Pipe line 55 Vacuum source 56 Pressure sensor 57 Pressure adjusting device 60 Control unit 61 Image processing device 62 Control device

Claims (6)

In the pellet transport device that picks up the pellet positioned at the predetermined position by the suction force of the suction nozzle and transports the pellet,
A pipe connecting the suction nozzle and a vacuum source,
A pressure adjusting device provided in the conduit;
A pressure detector for detecting the pressure in the pipeline,
A control device for controlling a suction force generated in the suction nozzle by controlling the pressure adjustment device based on a detection signal of the pressure detection device. In a pellet bonding method in which a pellet positioned at a predetermined position is picked up by a suction force of a suction nozzle and transported to a bonding position of a substrate and bonded,
A pellet bonding method, comprising: detecting a pressure in a pipeline for applying a suction force to the suction nozzle, and controlling a suction force generated in the suction nozzle based on a result of the detection. In a pellet bonding apparatus that picks up a pellet positioned at a predetermined position by a suction force of a suction nozzle, transports the pellet to a bonding position of a substrate, and performs bonding,
A pipe connecting the suction nozzle and a vacuum source,
A pressure adjusting device provided in the conduit;
A pressure detector for detecting the pressure in the pipeline,
A pellet bonding apparatus, comprising: a control device that controls a suction force generated in the suction nozzle by controlling the pressure adjustment device based on a detection signal of the pressure detection device. In a pellet bonding method in which a pellet positioned at a predetermined position is picked up by a suction force of a suction nozzle and transported to a bonding position of a substrate and bonded,
Wherein the suction force of the suction nozzle is switched within a working range from when the suction nozzle starts descending toward the pellet positioned at the predetermined position to when bonding is performed, pellet bonding. Method. 5. The pellet bonding method according to claim 4, wherein the suction force of the suction nozzle is switched immediately after the suction nozzle comes into contact with the pellet positioned at the predetermined position. 6. The pellet bonding method according to claim 5, wherein the suction force of the suction nozzle is switched to a suction force that is weaker than the suction force before the contact immediately after the suction nozzle comes into contact with the pellet.

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