JP2002231738A - Die bonder and method for detecting sucked article using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of such a die bonder as a light source is built in a collet in order to detect optically a semiconductor chip sucked to the collet that a wire connected with the collet is possibly broken when the collet moves at a high speed. SOLUTION: A light source is disposed fixedly on the outside of a collet having an optical through hole. Means for detecting the timing of the collet passing between the light source and a light receiving element is provided and a semiconductor chip sucked to the collet is detected by the light passed through the collet.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a die bonding apparatus for a semiconductor chip, and more particularly to a die bonding apparatus capable of confirming whether or not a semiconductor chip is correctly suctioned to a suction collet. The present invention relates to an adsorbate detection method.

[0002]

2. Description of the Related Art FIG. 7 is a diagram showing an entire configuration of a conventional semiconductor chip die bonding apparatus. The semiconductor chip 11 is attached to an adhesive sheet 12 attached to a ring 13 and is held on an XY table 14.

A camera 15 is provided above the die bonding apparatus, detects the position of the semiconductor chip 11 by image processing, and uses a computer (not shown) to execute X-ray detection based on the data.
The Y table 14 is controlled so that the semiconductor chip 11 comes to the pickup position below the collet 16. The collet 16 has a function of adsorbing the semiconductor chip 11 by, for example, reducing the pressure inside the collet 16.

The semiconductor chip 11 at the pickup position
Is sucked by the lowered collet 16, then the collet 16 is raised, and the semiconductor chip 11 is peeled off from the adhesive sheet 12 and held by the collet 16.

Next, the collet 16 moves in the horizontal direction as shown by the arrow A, and the semiconductor chip 1 placed at a predetermined position is moved.
1 reaches a position above the work 17 for die bonding. A conductive adhesive (not shown) such as an Ag paste is applied to the work 17, and the semiconductor chip 11 is die-bonded on the work 17 by lowering the collet 16 to the die bonding position and releasing the suction. The process is completed.

[0006]

When the semiconductor chip 11 is not well adsorbed from the adhesive sheet 12 and die-bonding is performed in a state where the semiconductor chip 11 is not adsorbed to the collet 16, a conductive adhesive is attached to the collet 16, The hole for adsorbing the semiconductor chip 11 is clogged,
Thereafter, a problem occurs in which the semiconductor chip suction ability of the collet is reduced.

For this reason, it has been determined whether or not the semiconductor chip 11 is sucked by a vacuum sensor (not shown) provided in a suction path (not shown) for reducing the pressure inside the collet 16. However, in this method, the pressure difference due to the presence / absence of the semiconductor chip 11 is small, so that it takes time to make a determination, which is an obstacle to increasing the tact time of the die bonding apparatus.

Also, there has been proposed an adsorbed object detecting device for determining the presence or absence of an adsorbed object by using an optical sensor as described in Japanese Patent Application Laid-Open No. 10-68759. FIG. 8 is an enlarged sectional view around the suction transfer arm. Suction transfer arm 12
For example, a light source 128 is disposed in the
Transfer arm 12 of stage 122 for mounting
The light receiving element 129 is arranged on the side facing 6. When there is no adsorbate 121 on the stage 122, the light (arrow C) emitted from the light source 128 passes through the transmissive material 131 and the light receiving element 1
Reach 29. On the other hand, the adsorbate 121 is
If there is, the light receiving element 12
In No. 9, no light is detected.

However, in this apparatus, since the light source 128 is incorporated in the suction / transport arm 126, the light source 128 inside the suction / transport arm 126 that moves frequently at high speed.
The wire 130 must be connected to the wire, and there is a risk of disconnection due to metal fatigue or the like. In particular, the electric wire 130 and the light source 12
The brazing portion connecting 8 is not flexible and is easily broken. Therefore, equipment stoppage due to disconnection frequently occurs,
This has led to an increase in the cost of semiconductor products due to a reduction in the equipment operation rate. Also, an example is shown in which the optical sensor unit is a sensor unit that is independent of the suction conveyance arm,
This is a device for detecting whether or not the adsorbate is present at a predetermined position on the stage, and cannot detect whether or not the adsorbate is actually adsorbed. Therefore, if it is used for a collet that adsorbs a semiconductor chip, if it is not adsorbed,
In the subsequent process, the above-described problem of clogging of the hole occurs. Furthermore, when the adsorbed material is small, such as an LED chip or a semiconductor laser chip, having a size of about several hundred μm square, the hole diameter of the collet naturally becomes small, so that it is difficult to detect the position of the chip through this hole.

[0010]

In order to achieve the above object, a die bonding apparatus according to the present invention is a die bonding apparatus having a collet for sucking a semiconductor chip, picking up a semiconductor chip from a table, and moving the semiconductor chip to a work. A pair of through holes each having one end closed by a window through which light passes, and a pair of collets arranged at positions where the collet moves after adsorbing the semiconductor chip and the through holes of the collet pass therethrough. And a light transmitting unit and a light receiving unit.

[0011] Further, it is characterized in that it has a position detecting means comprising a member which moves with the movement of the collet and an optical coupling element for detecting the member.

Further, the window has a lens function.

[0013] Further, the invention is characterized in that the light transmitting section comprises a light emitting section and a component having a lens function, or the light receiving section comprises a light receiving element and a component having a lens function.

Further, the method for detecting an adsorbed object according to the present invention is characterized in that a semiconductor chip is picked up from a table by a collet provided with a through hole whose one end is closed by a window through which light passes, and is moved to a work. The semiconductor chip is determined by whether or not the light transmitted from the pair of light transmitting units and the light transmitting unit of the light receiving unit that are arranged to face each other passes through the through hole of the collet and is detected by the light receiving unit. In the adsorbate detection method of detecting whether or not is attracted to the collet, when the collet is not between the light transmitting unit and the light receiving unit, does not take out the output of the light receiving unit, the collet, It is characterized in that the output of the light receiving unit is taken out only when it is between the light emitting and transmitting unit and the light receiving unit.

[0015] Further, by detecting the position detecting means of the collet, which moves with the movement of the collet, by the optical coupling element, it is determined that the collet is between the optical transmission unit and the light receiving unit. It is characterized in that only light passing through the through hole is detected.

Further, the pulse width of the output signal from the light receiving portion due to the light passing through the through hole is extended by a delay circuit.

With the above configuration, the presence or absence of an adsorbed object can be detected by light without providing a light source or a light receiving element inside the collet, so that wiring to this portion is unnecessary, and the collet moves at high speed. Even if the wiring is not broken. Therefore, the operation rate of the apparatus is improved, and the moving speed of the collet can be further increased. Further, it is possible to increase the degree of freedom of the position where the optical transmitting unit and the light receiving unit are installed, and it is possible to allow a layout of the die bonding apparatus. Further, since it is sufficient to detect whether or not the semiconductor chip is being sucked, it is possible to cope with a small sucked object such as an LED chip or a semiconductor laser chip.

Further, since it is possible to detect the timing at which the collet passes through the optical signal detecting section having the optical transmitting section and the light receiving section as components, and to synchronize with this, it is possible to determine the presence / absence of chip suction. And erroneous detection can be reduced. By arranging components such as a condenser lens in the light transmitting unit and the light receiving unit, the detection sensitivity can be increased.

[0019]

Embodiments of the present invention will be described below in detail with reference to the drawings.

(First Embodiment) FIG. 1 is a schematic view of a die bonding apparatus according to a first embodiment of the present invention. The same parts as those of the conventional die bonding apparatus are denoted by the same reference numerals and description thereof will be omitted. The present device is different from the conventional example in that a light source 18 and a light receiving element 19 are arranged outside the collet 16. FIG. 2 is an enlarged cross-sectional view of the vicinity of the collet 16 as viewed from the moving direction of the collet 16 of the die bonding apparatus.
2 shows a state between the light receiving element 19 and the light receiving element 19.

The collet 16 of the die bonding apparatus according to the present invention comprises, for example, a collet holder 21 and a collet head 22 fitted therein. The collet holder 21 and the collet head 22 may be integrated, but they are separated so that they can be easily replaced when the size of the semiconductor chip is different. Each of the collet holder 21 and the collet head 22 has a through hole 26 through which the light source 18
The light (arrow B) emitted from the light reaches the light receiving element 19.
A suction port 20 is provided on a side surface of the collet holder 21,
The inside of the collet 16 is sucked by a vacuum pump or the like (not shown). The upper portion of the collet holder 21 is closed by a window 23 made of glass, resin, or the like so that the inside of the collet 16 can be kept at a low pressure and light can be transmitted. The window 23 may be a flat plate, but if it has a lens function, the light emitted from the light source 18 can be efficiently guided into the inside of the collet 16 and the S / N ratio can be increased. The light source 18 and the light receiving element 19 are arranged so as to face each other at a position where the collet head 22 moves after the semiconductor chip 11 is attracted and the through hole 26 of the collet 16 passes.

Next, the operation of the present apparatus will be described. When the collet head 22 is not holding the semiconductor chip 11, an output signal is generated in the light receiving element 19 by the light passing through the through hole 26. On the other hand, when the collet head 22 is sucking the semiconductor chip 11, no output signal is generated because the through hole 26 is closed. This makes it possible to determine whether or not the semiconductor chip 11 is attracted to the collet head 22.

FIG. 3 is a block diagram showing a circuit configuration for detecting and processing the output signal of the light receiving element 19. FIG. 4 shows a case where the collet head 22 does not adsorb the semiconductor chip 11, and FIG.
This shows an example of an output signal obtained by each circuit when 1 is adsorbed. The horizontal axis represents time, and the vertical axis represents output voltage. 4 (a) to 5 (e) correspond to FIGS. 3 (a) to 3 (e).

The output signal of the light receiving element 19 is
After performing amplification, impedance conversion, and the like in 6, a Schmitt trigger circuit 37 shapes the waveform.

When the semiconductor chip 11 is not attracted to the collet head 22, when the collet 16 passes between the light source 18 and the light receiving element 19, the output signal output from the light receiving element circuit 36 changes as shown in FIG. Become like Until the collet 16 reaches between the light source 18 and the light receiving element 19, a large output voltage is output because light is directly incident on the light receiving element 19 from the light source 18.
When the voltage reaches between 8 and the light receiving element 19, the output voltage decreases from the point X and temporarily becomes 0. Next, since the light passing through the through hole 26 enters the light receiving element 19, the output voltage increases, passes through the point P, becomes 0 again, and then, when the collet 16 passes, the output voltage returns to a large state.

In the present embodiment, the outer diameter of the collet holder 21 is 1.5 mm, and the diameter of the narrowest part of the through hole 26 is 0.13 mm, which is used when the collet 16 moves from above the pickup position to above the die bonding position. Speed is 1m
/ Sec. When this output signal is passed through a Schmitt trigger circuit 37 whose threshold voltage is Vth, an output signal that sharply falls from a point Y corresponding to the point X as shown in FIG. 4B is obtained. The width of the output signal of the light that has passed through the through-hole 26 is 0.
8 msec, which is wider than the output signal width of 0.13 msec expected from the calculation. This is because the light spreads after passing through the through hole 26.

In this embodiment, the light receiving element 1
If a condenser lens (not shown) is provided before 9, the light-receiving field of view is widened, so that the input to the light-receiving element 19 increases and the width of the output signal passing through the Schmitt trigger circuit 37 increases to 2.9 msec. That is, the semiconductor chip 11
It is easy to detect whether or not is absorbed by the collet 16.

On the other hand, when the semiconductor chip 11 is attracted, no light passes through the collet 16, so that an output signal without a point P as shown in FIG. The output of 37 is as shown in FIG. That is, it is detected that the collet 16 has reached between the light source 18 and the light receiving element 19 at the fall of the signal output of the Schmitt trigger circuit 37 (point Y), and thereafter, the peak of the output signal (point P) within a certain period of time. If this does not occur, it can be determined that the semiconductor chip 11 is normally attracted to the collet head 22. An output signal from the Schmitt trigger circuit 37 is taken into the CPU of the control computer, and if this determination is made, it is possible to determine whether or not the semiconductor chip 11 is attracted. If it is determined that the collet 16 is not sucking the semiconductor chip 11, the collet head 22 is prevented from descending to the die bonding position, so that the conductive adhesive adheres to the inside of the collet 16 and the through hole 26 is not clogged. There is no.

In practice, since the control computer controls many other tasks in parallel, it is necessary to read output signals that change at high speed more reliably. The method will be described below. As shown in FIG. 2, in order to detect the position of the collet 16, a reflective optical coupling element (photo interrupter) 24 having a light emitting unit and a light receiving unit is connected to the collet 1.
In order not to hinder the movement of the collet 6, for example, in FIG.
It is set to be shifted. The reflection plate 25 is a member that moves in conjunction with the collet 16 and is arranged to reflect the light of the optical coupling element 24. As shown in FIG. 4C, the setting is made so that an output signal rising at the point Z is obtained from the optical coupling element output detection circuit 38 when the reflection plate 25 passes through the optical coupling element 24.

The output signal of the Schmitt trigger circuit 37 and the output signal of the optical coupling element output detection circuit 38 are
9 and the AND circuit 39 takes the logical product of these two signals, and outputs the output to the OFF delay circuit 40 as necessary. Output signal of AND circuit 39 or OF
By determining the output signal of the F delay circuit 40, it can be determined whether the semiconductor chip 11 is attracted to the collet 16.

The Schmitt trigger circuit 37 is ANDed.
A method is also conceivable in which the output signal of the light receiving element circuit 36 and the output signal of the optical coupling element output detection circuit 38 are logically arranged after the circuit 39 is provided, and the waveform is shaped.

Here, if the position of the reflector 25 is adjusted so that the timings of the points Y and Z are almost the same or the point Z is slightly later than the point Y, the output detection circuit of the optical coupling element can be obtained. The output signal of the Schmitt trigger circuit 37 (FIG. 4C) only when the output signal of FIG.
(B)) is also output as a High state from the AND circuit 39 (FIG. 4D), so that the through hole 26 of the collet 16 is formed.
Only the output signal corresponding to the light that has passed through can be reliably output. For this purpose, the width of the reflector 25 is set to the collet holder 2.
More desirably, it is smaller than the diameter of one. Alternatively, it is also possible to adjust the timing of the points Y and Z by setting an electrical delay time.

Further, in order to ensure the detection of the signal, an OFF delay circuit 40 for holding the peak output for a predetermined time may be added. In contrast to the output signal of FIG. 4D of the AND circuit 39 when the semiconductor chip 11 is not attracted to the collet 16, the output signal of FIG. 4E with a wider pulse is obtained from the OFF delay circuit 40. Signal detection is assured.

(Second Embodiment) FIG. 6 is an enlarged sectional view of the vicinity of the collet 16 when the die bonding apparatus according to the second embodiment of the present invention is viewed from the moving direction of the collet 16. In this embodiment, the light source 18 and the light receiving element 19 are fixed at a position away from the path along which the collet 16 of the die bonding apparatus moves, and the optical path from the light source 18 to the light receiving element 19 is formed by the optical fibers 51 and 52. The light-emitting end 53 and the light-receiving end 5 are guided to a predetermined position on a moving path.
2 are provided. The light emitted from the light source 18 is guided through the optical fiber 51 to the collet 16 from the light emitting end 19, and when the semiconductor chip 11 is not attracted to the collet 16, the light enters the light receiving end 54 and passes through the optical fiber 52 to the light receiving element. Reach 19. Even in such a configuration, it is possible to determine whether the semiconductor chip 11 is attracted to the collet 16 as in the first embodiment.

In the second embodiment, the light source 18, the light receiving element 1
9 can be installed at a position away from the moving path of the collet 16, so that the degree of freedom in designing the die bonding apparatus is increased. Further, a high performance fiber photoelectric sensor in which a light source, a light receiving element, an amplifier circuit, and the like are integrated is commercially available, so that a die bonding apparatus can be configured using these.

In the above description of the embodiment, the configuration in which the light source unit is disposed above the collet and the light receiving unit is disposed below the collet has been described. Also, an example in which a reflection type optical coupling element and a reflection plate are used as means for detecting the position of the collet has been described.
It is also possible to use a transmissive optical coupling element and a light shielding plate, or to use another position detecting means.

When it is confirmed that the peak of the output signal is obtained by the light from the through hole of the collet at the time of starting inspection of the apparatus, etc., it is confirmed that Ag, which is an adhesive, is present in the through hole of the collet.
It is possible to avoid a problem that a normal determination operation cannot be performed due to adhesion of a paste or the like.

[0038]

As described above, according to the present invention, there is no light source (or light receiving element) inside the collet in the die bonding apparatus for optically detecting whether the semiconductor chip is attracted to the collet. Wiring to this part is not required, so that even if the collet moves at high speed, the wiring does not break. Therefore, the operation rate of the apparatus is improved, and the moving speed of the collet can be further increased, so that the tact time in the manufacturing process can be reduced.

Further, it is possible to detect the timing at which the collet passes through the optical signal detecting section, and determine the presence or absence of chip suction in synchronization therewith. Further, by arranging components such as a condenser lens on the light source and the light receiving element, the detection sensitivity can be increased. Therefore, erroneous detection is eliminated and a stable operation can be realized, thereby improving the operation rate of the apparatus.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a die bonding apparatus according to a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view near a collet according to the first embodiment of the present invention.

FIG. 3 is a block diagram showing a circuit configuration for detecting and processing an output signal of a light receiving element.

FIG. 4 shows an example of an output signal obtained in each circuit when the collet does not adsorb the semiconductor chip.

FIG. 5 shows an example of an output signal obtained in each circuit when a collet is sucking a semiconductor chip.

FIG. 6 is an enlarged sectional view near a collet according to a second embodiment of the present invention.

FIG. 7 is a schematic view of a conventional die bonding apparatus.

FIG. 8 is a cross-sectional view of a conventional adsorbed object detection device.

[Explanation of symbols]

 Reference Signs List 11 semiconductor chip 12 adhesive sheet 13 ring 14 XY table 15 camera 16 collet 17 work 18 light source 19 light receiving element 20 suction port 21 collet holder 22 collet head 23 window 24 optical coupling element 25 reflecting plate 26 through hole 36 light receiving element circuit (amplifying circuit) 37 Schmitt trigger circuit 38 Optical coupling element output detection circuit 39 AND circuit 40 OFF delay circuit 51 Optical fiber 52 Optical fiber 53 Light emitting end 54 Light receiving end

Claims (7)

[Claims] 1. A die bonding apparatus having a collet for sucking a semiconductor chip and picking it up from a table and moving it to a work, wherein a through-hole provided at the collet and one end of which is closed by a window through which light passes; A die bonding apparatus comprising: a set of a light transmitting unit and a light receiving unit that are arranged to face each other at a position where a collet moves after adsorbing a semiconductor chip and a through hole of the collet passes therethrough. 2. The die bonding apparatus according to claim 1, further comprising a position detection unit including a member that moves with the movement of the collet and an optical coupling element that detects the member. 3. The die bonding apparatus according to claim 1, wherein the window has a lens function. 4. The light transmitting section comprises a light emitting section and a component having a lens function, or the light receiving section comprises a light receiving element and a component having a lens function. 4. The die bonding apparatus according to 3. 5. When a semiconductor chip is picked up from a table and moved to a work by a collet provided with a through hole whose one end is closed by a window through which light passes, a pair of the chips are arranged to face each other. Whether or not the semiconductor chip is attracted to the collet according to whether or not light transmitted from the light transmitting unit and the light transmitting unit of the light receiving unit passes through the through hole of the collet and is detected by the light receiving unit. In the method for detecting an adsorbate, the collet does not take out the output of the light receiving unit when the collet is not between the light transmitting unit and the light receiving unit. An adsorbed matter detection method, wherein the output of the light receiving unit is taken out only when the time is between them. 6. An optical coupling element that detects a position detecting means of the collet that moves with the movement of the collet, thereby determining that the collet is between the optical transmission unit and the light receiving unit. The method according to claim 5, wherein only the light passing through the through-hole is detected. 7. The method according to claim 5, wherein a pulse width of an output signal from the light receiving unit due to light passing through the through hole is extended by a delay circuit.