JP2013168465A - Target jig for calibration and semiconductor manufacturing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor manufacturing apparatus in which dust is prevented from being deposited to a distal end of an adsorbing collet by providing a target jig at a calibration position.SOLUTION: In a target jig 10, a cross-shaped target mark 12 is formed while protruding on a top face of a rectangular jig body 11, and the target mark 12 protrudes in such a manner that a width of the protruding portion thereof becomes 50 to 100 μm being smaller than the size of dust, and is brought into contact with a surface of a collet falling down from an upper side during a calibrating operation.

Description

  The present invention relates to a calibration target jig used in a die bonding process of a semiconductor chip and a semiconductor manufacturing apparatus for die bonding having an auto-calibration function, and more particularly to a calibration for securely bonding a semiconductor chip to a lead frame. The present invention relates to a target jig and a semiconductor manufacturing apparatus for die bonding using the target jig.

  In the manufacturing process of a semiconductor device, a die bonding apparatus (hereinafter referred to as a DB apparatus) is conventionally used as a semiconductor manufacturing apparatus for continuously bonding semiconductor chips to a lead frame.

  The DB device includes a heating stage that heats the lead frame and a feeding device such as a feed rail that continuously conveys the plurality of lead frames. On each lead frame, solder in a molten state on the heating stage is placed on a semiconductor element mounting portion such as an island and conveyed by a feeding device.

  The semiconductor chips are moved from the diced wafer set on the front side of the DB device, for example, to the DB device one by one using a vacuum suction collet, and die bonded to a predetermined position. At this time, when the semiconductor chip is pushed up from the back surface of the wafer sheet, it is vacuum-sucked by the suction collet from above the wafer and conveyed to the DB device. The semiconductor chip held by the suction collet is lowered to a predetermined position of the lead frame heated by the DB device and pressed there, thereby completing the mounting of the semiconductor chip via the solder layer.

FIG. 4 is a cross-sectional view showing a schematic configuration of a conventional semiconductor manufacturing apparatus.
The suction collet 1 moves in the horizontal direction to the DB device, and then descends by a controlled predetermined distance. At this time, the lead frame 2 is conveyed by a feed rail (not shown), and the semiconductor chip 4 can be mounted on the lead frame 2 at a position corresponding to the molten solder 3. The heating stage 5 holds the lead frame 2 at a predetermined temperature, and its upper surface is covered with a rail upper lid 6. The rail upper cover 6 prevents heat radiation of the solder 3 on the lead frame 2 and prevents atmospheric gas from scattering to the outside.

  An opening 6 a having a predetermined size is formed in the rail upper lid 6, and the suction collet 1 moves to the opening 6 a while holding the semiconductor chip 4. Thereafter, the semiconductor chip 4 is automatically lowered from the opening 6 a of the rail upper lid 6 to the position of the solder 3 on the lead frame 2, and the semiconductor chip 4 is fixed to a predetermined position of each lead frame 2. At that time, in the collet control means (not shown) on the DB device side that controls the conveyance of the suction collet 1, the surface of the solder 3 when the suction collet 1 transports the semiconductor chip 4 and reaches the top of the opening 6a. The distance is preset. Alternatively, the suction collet 1 may be brought into contact with the rail upper lid 6 in a state where the semiconductor chip 4 is not sucked, and the position of the rail upper lid 6 may be stored as a reference position.

  In the collet control means, the suction collet 1 is lowered toward the lead frame 2 in the Z-axis direction based on the distance preset in the collet control means, and the semiconductor chip 4 sucked by the suction collet 1 is moved to the lead frame. Move up two. At this time, the semiconductor chip 4 is mounted on the lead frame 2 by performing a pressure contact operation for pressing the semiconductor chip 4 against the lead frame 2 with a predetermined pressure.

  In order to securely mount the semiconductor chip 4 on the lead frame 2 and to stabilize the fixed state by the solder 3, as described above, a pressure contact operation for pressing the semiconductor chip 4 against the lead frame 2 with a predetermined pressure is required. It is necessary to control the movement distance of the suction collet 1 in the Z-axis direction so as not to cause insufficient pressurization or excessive pressurization.

  However, in such a DB apparatus, the feed rail or the like may fluctuate up and down due to thermal expansion due to the heating of the heater in the heating stage 5, and the height (distance in the Z-axis direction) of the lead frame 2 may change. Therefore, in order to continuously mount the semiconductor chip 4 held by the suction collet 1 on the lead frame 2 and stabilize the fixing state by the solder 3, the suction collet 1 transports the semiconductor chip 4 and opens the opening 6a. A calibration function for adjusting the distance from the position reaching the top to the surface of the solder 3 of the lead frame 2 is necessary. That is, the calibration function is a distance set in advance in the collet control means, that is, a distance from the position where the suction collet 1 transports the semiconductor chip 4 and reaches the top of the opening 6a to the surface of the solder. It is a function to correct when mounting.

  In order to perform calibration, the suction collet 1 does not hold the semiconductor chip 4 and its tip is brought into contact with the upper surface of the rail upper cover 6 or the fixed surface around the feed rail, so that the lowering of the suction collet 1 is lowered. The position in the vertical direction (Z-axis direction) can be corrected. Such an auto-calibration function is a general function conventionally attached to a DB apparatus.

  By performing such calibration, the distance from the position where the suction collet 1 transports the semiconductor chip 4 and reaches the top of the opening 6a to the surface of the solder can be corrected. Further, it is not necessary to change the pressing operation of pressing the semiconductor chip adsorbed on the adsorbing collet against the lead frame with a predetermined pressure before and after the thermal expansion of the rail or the like.

FIG. 5 is a cross-sectional view showing a state in which an adsorption collet is pressed against a rail upper lid of a conventional semiconductor manufacturing apparatus.
When adsorbing the semiconductor chip 4 from the diced wafer, feed from the side of the wafer (not shown) placed on the front side of the rail upper cover 6 so that dust such as silicon dust during dicing does not remain on the chip surface. Air blow is performed in the direction of the rail. At that time, dust 7 such as silicon scraps was blown off from the wafer side to the rail upper lid 6, and as shown in FIG. In addition to air blow, the semiconductor chip 4 is held and transported by the suction collet 1, so that silicon dust accompanying the dicing falls from the suction collet 1 or the semiconductor chip 4 itself as dust 7 onto the rail upper cover 6. .

  Patent Document 1 discloses an invention of a bonding apparatus and a method for manufacturing a semiconductor device that shortens the teaching time of the stage height in the bonding process and improves the working efficiency in the bonding process.

  The tool state detection device of Patent Document 2 detects a landing on a lead frame when bonding a held chip to a lead frame as a workpiece, thereby appropriately controlling a bonding load and the like. By effectively utilizing an existing landing sensor prepared for judging the landing state, the state of the bonding tool provided in the bonding head is detected.

  In the die bonder of Patent Document 3, the collet holder and the collet reciprocate between the pickup position (Pa) and the bonding position (Pc). When the collet holder and the collet arrive at the bonding position (Pc), supply piping The cooling fluid supply flow rate is increased to cool the collet holder and the collet. Thereby, a change in height position due to expansion and contraction of the collet holder and the collet can be reduced, so that pickup accuracy and bonding accuracy can be improved, and the semiconductor chip can be bonded without damage.

  The chip mounting apparatus described in Patent Document 4 is performed by lowering the first movable part with respect to the fixed part in order to make the collet contact the chip mounting target surface and the like to grasp its position. When the second movable part is lifted with respect to the first movable part, the amount of deviation is read by the accurate second height detection means, and the accurate height direction is obtained even if the chip thickness varies. The chip is mounted with a positional accuracy of.

  Patent Document 5 discloses a die bonder and a die bonding method capable of bonding chips with high accuracy even when there is a temperature fluctuation during operation. According to this invention, the correction control means compares the detected collet suction surface height (detected height) with the collet suction surface height (reference height) set by the basic control means. To do. The height detection means can detect the height of the collet suction surface at the bonding position (Q), and the control means determines the vertical height at the bonding position (Q) based on the detected height of the collet suction surface. The amount of direction movement can be controlled, and the reliability of correction of the amount of vertical movement at the bonding position (Q) is improved.

JP 2003-332363 A (see paragraph numbers [0002] to [0005]) Japanese Patent Laying-Open No. 2009-194047 (see paragraph numbers [0041] to [0055], FIGS. 2 to 5) JP 2003-174042 A (see paragraph numbers [0026] to [0038], FIGS. 1 to 3) JP 2004-273805 A (see paragraph numbers [0016] to [0026], FIGS. 3 to 6) JP 2009-188079 A (see paragraph numbers [0031] to [0053], FIGS. 1 and 2)

  In FIG. 5, when a calibration operation is performed in which the suction collet 1 is lowered and brought into contact with the rail upper lid 6 while the dust 7 remains attached to the upper surface of the rail upper lid 6, the dust 7 adheres to the tip of the suction collet 1. Resulting in. Therefore, if the suction collet 1 in such a state next sucks the semiconductor chip 4, the surface element of the semiconductor chip 4 may be damaged by the dust 7.

  FIG. 6 is a cross-sectional view showing a conventional semiconductor manufacturing apparatus in which a semiconductor chip is adsorbed in an inclined state. Like the semiconductor chip 4a shown here, the semiconductor chip 4 is attached in an inclined state with respect to the lead frame 2 if it is attached to the tip of the suction collet 1 while being inclined and mounted as it is. Alternatively, the solder 3 protrudes on the lead frame 2. That is, there is a problem in that it is difficult to reliably bond the semiconductor chip and a defect occurs in the semiconductor device.

  Each of the suction collets 1 shown in FIGS. 4 to 6 is a flat collet that comes into contact with the upper surface of the semiconductor chip 4 and vacuum-sucks. However, a circuit pattern surface may be formed on the upper surface of the semiconductor chip. When it is not desired to bring the suction collet 1 into contact therewith, the following pyramid type collet is used.

FIG. 7 is a view showing a state in which a semiconductor chip is sucked by a pyramid-shaped suction collet.
The pyramid-shaped suction collet 8 has a recess 9 surrounded by a plurality of (for example, four) inclined surfaces 8a at the lower end, and the outer periphery of the semiconductor chip 4a is positioned by these inclined surfaces 8a. Each inclined surface 8a is inclined so that the interval between the inclined surfaces 8a opposed gradually from the lower end to the upper side becomes narrower, and the vacuum holes 9a and the vacuum holes 9a are attracted and held in the recess 9 Communicate.

  If the dust 7 adheres to the inclined surface 8a of the suction collet 8 when the calibration operation is performed with such a suction collet 8, there is no risk that the dust 7 damages the surface element of the semiconductor chip 4a. The chip 4a is adsorbed in a tilted state. Therefore, even when the pyramid-shaped suction collet 8 is used, it is difficult to reliably bond the semiconductor chip 4 a on the lead frame 2.

The present invention has been made in view of such a point, and an object thereof is to provide a calibration target jig in which dust does not easily adhere to the tip of a collet.
Another object of the present invention is to provide a semiconductor manufacturing apparatus in which a target jig is provided at a calibration position such as a rail upper lid so that dust does not adhere to the tip of the collet.

  In the present invention, in order to solve the above problems, the plane on which the semiconductor chip is die-bonded is the XY plane, and the Z-axis direction distance orthogonal to the XY plane of the collet holding and transporting the semiconductor chip is corrected. In a calibration target jig for forming, a jig main body fixed in the XY plane of the collet, a protrusion protruding from the upper surface of the jig main body, and a contact with the tip end in the Z-axis direction of the collet A calibration target jig is provided.

  According to another aspect of the present invention, there is provided a semiconductor manufacturing apparatus having an auto-calibration function, wherein the semiconductor manufacturing apparatus for die bonding mounts a semiconductor chip on a lead frame, and heating means for heating the lead frame; The distance between the predetermined position of the collet and the chip mount surface of the lead frame in the Z-axis direction orthogonal to the collet that holds and transports the semiconductor chip and the plane on which the semiconductor chip is die-bonded is defined as the XY plane. A collet control means set in advance, and the calibration target jig described above, which is arranged at a position that fluctuates up and down in proportion to the fluctuation distance in the Z-axis direction on the chip mount surface caused by heat from the heating means. And moving the collet in the Z-axis direction to Click to contacting the Z-axis direction leading end portion of said collet, and corrects the distance between the chip mounting surface of the lead frame to a predetermined position of the collet which is preset in the collet control means.

  According to the present invention, dust does not adhere to the tip of the collet when performing calibration. Therefore, it is possible to remove the trouble such as the semiconductor chip being attached to be inclined or the solder sticking out to the lead frame, and the semiconductor chip can be securely bonded onto the lead frame. Moreover, there is no possibility of scratching the surface of the semiconductor chip adsorbed by the collet.

BRIEF DESCRIPTION OF THE DRAWINGS It is a calibration target jig | tool which concerns on embodiment of this invention, Comprising: (A) is a top view, (B) is a sectional side view shown along a BB line. It is a top view which shows the semiconductor manufacturing apparatus for die bonding using the target jig | tool of this invention. It is sectional drawing for demonstrating the calibration operation | movement in the semiconductor manufacturing apparatus of this invention. It is sectional drawing which shows schematic structure of the conventional semiconductor manufacturing apparatus. It is sectional drawing which shows the state which pressed the suction collet against the rail upper cover of the conventional semiconductor manufacturing apparatus. It is sectional drawing which shows the conventional semiconductor manufacturing apparatus with which the semiconductor chip was adsorbed in the inclined state. It is a figure which shows the state which adsorb | sucked the semiconductor chip with the pyramid type adsorption collet.

  Embodiments of the present invention will be described below with reference to the drawings. 1A and 1B are calibration target jigs according to an embodiment of the present invention, in which FIG. 1A is a plan view and FIG. 1B is a side sectional view taken along line BB.

  The calibration target jig 10 is formed by projecting a “+” character target mark 12 on the upper surface of a rectangular jig body 11 having a width of about 10 cm and a length of about 1 to 2 cm. The thickness of the main body 11 is about 2 mm. Mounting holes 13a and 13b are formed in the jig body 11 near the ends in the left-right direction. This target jig 10 is fixed to the upper lid of a die bonding semiconductor manufacturing apparatus (DB apparatus) shown in FIG. 2, which will be described later, by means of mounting holes 13a, 13b, and an XY plane of a suction collet that holds and conveys the semiconductor chip. It is used for correcting the distance in the Z-axis direction.

  The target mark 12 of the target jig 10 is formed to protrude from the surface of the jig body 11. The height of the target mark 12 from the surface of the jig body 11 is set higher than the maximum dimension assumed by dust (see FIG. 3 described later) attached to the upper lid or the like of the DB device. For example, assuming that the maximum value of the size of dust is 200 [μm], the height of the target mark 12 from the surface of the jig body 11 is set to 500 [μm].

  In the example shown in FIG. 1, the target mark 12 is formed in a “+” character shape. At this time, the target mark 12 itself is subjected to curved surface (R) processing, and the projection width from the target mark 12 is formed narrower than the size of the dust dropped on the surface of the jig body 11. For example, “+” letter-like protrusions were formed in a width of 50 to 100 [μm]. As a result, the target mark 12 has a shape in which dust is difficult to get on the upper surface of the “+” character. In addition, although the jig | tool main body 11 is created by the method of cutting out from a metal plate, the target mark 12 of the surface can be formed by carrying out the electrical discharge machining of the jig | tool main body 11. FIG.

  Here, considering the case where the calibration operation is performed by bringing the pyramid-shaped suction collet 8 shown in FIG. 7 into contact with the target jig 10, the size of the target mark 12 is formed longer than the recess 9 of the suction collet 8. It only has to be. When the target mark 12 is shorter than the recess 9 of the suction collet 8, the target mark 12 enters the recess 9 formed at the lower end (Z-axis direction front end) of the suction collet 8, and the jig body 11 This is because the dust falling on the surface comes into contact with the inclined surface 8a.

  Therefore, in this example, the vertical and horizontal lengths of the target mark 12 are set to 8000 [μm]. In this way, the target mark 12 protruding from the jig body 11 of the target jig 10 reliably contacts the tip of the suction collets 1 and 8 (see FIGS. 4 to 7) that descend during the calibration operation. It is formed so that dust does not adhere to its tip.

FIG. 2 is a plan view showing a semiconductor manufacturing apparatus for die bonding using the target jig of the present invention.
This semiconductor manufacturing apparatus is a DB apparatus 20 having an auto-calibration function, and a semiconductor wafer 31 is arranged on the front side of the DB apparatus 20. The semiconductor wafer 31 is stuck and held on the wafer sheet 30 in a state of being divided into chips, for example, on a predetermined mounting table (not shown). The semiconductor wafer 31 is diced for each chip in an integrated state with the wafer sheet 30.

  The DB device 20 includes an inlet rail 21, a first heater block 22, a second heater block 23, and an outlet rail 24 that are arranged from the left to the right in the drawing. The DB device 20 is provided with five feed claws 25 a to 25 e along feed rails formed through the respective blocks 21 to 24, and is continuously supplied from the entrance rail 21. Is transporting.

  The first heater block 22 is a place where the lead frame 2 to which the semiconductor chip is bonded is preheated. The lead frame 2 is heated to a predetermined temperature here, and then supplied to the second heater block 23 by the feed claws 25b.

  The first and second heater blocks 22 and 23 are both covered with rail upper lids 22a and 23a for preventing heat dissipation. Two openings 6a and 6b are formed in the rail upper lid 23a of the second heater block 23. Molten solder is supplied from one opening 6a to the lead frame 2, and the other opening 6b is a semiconductor. Chip 4 is mounted on lead frame 2. At the exit rail 24, the lead frame 2 on which the semiconductor chip 4 is mounted is taken out.

  The target jig 10 is fixed on the rail upper lid 23a of the second heater block 23 between the two feed claws 25c and 25d. The mounting hole 13a of the target jig 10 is on the feed claw 25c side of the second heater block 23, and the target jig 10 is fixed on the rail upper lid 23a by positioning pins 26a for supplying solder. The positioning pins 26 a are used when determining the position for carrying in molten solder with respect to the lead frame 2. In addition, another attachment hole 13b is provided on the feed claw 25d side of the target jig 10, and another positioning pin 26b for determining the mounting position of the semiconductor chip with respect to the lead frame 2 is inserted into the attachment hole 13b. The

  In FIG. 2, arrows A1 and A2 written between the lead frame 2 and the wafer sheet 30 indicate the conveyance path in the XY plane of the suction collet 1 described above. Teaches the reference position in the Z-axis direction with respect to the chip mount surface of the lead frame 2. The semiconductor chip separated from the wafer sheet 30 is carried by the suction collet 1 from the semiconductor wafer 31 to the opening 6b of the second heater block 23 along the arrow A1. On the other hand, when the lead frame 2 is transported along the feed rail of the DB device 20, the second heater block 23 is positioned in the vertical direction (Z-axis direction) due to thermal expansion of its members (for example, a heating stage). There are fluctuations.

  Therefore, if the amount of variation is grasped in advance prior to the die bonding process and calibration for correcting the bonding reference position of the semiconductor chip 4 is not performed, inconveniences such as chip breakage or poor soldering occur. Therefore, the calibration function using the target jig 10 will be described next.

FIG. 3 is a cross-sectional view for explaining the calibration operation in the semiconductor manufacturing apparatus of the present invention.
After the suction collet 1 has moved to the opening 6b of the second heater block 23, the suction collet 1 is lowered by a predetermined distance (L) controlled together with the semiconductor chip 4, and the semiconductor chip 4 is automatically placed at a predetermined position on the lead frame 2. Place. At this time, the heating stage 5 also expands due to heating, and accordingly, the mounting position of the lead frame 2 varies in the vertical direction (Z-axis direction). Moreover, it takes about 15 to 20 minutes for the temperature to stabilize.

  As described above, the target jig 10 is fixed to the rail upper lid 23 a of the second heater block 23. For this reason, the surface position fluctuates with the second heater block 23. That is, when the DB device 20 expands due to heat from the second heater block 23, the target jig 10 fixed to the rail upper cover 23a moves up and down in proportion to the fluctuation distance at which the vertical position of the lead frame 2 changes.

  Therefore, in order to die-bond the semiconductor chip 4 continuously by the DB device 20, it is necessary to perform a calibration operation by bringing the suction collet 1 into contact with the target mark 12 of the target jig 10. The above-described calibration operation for the suction collet 1 is performed using the target jig 10 when the suction collet 1 is returned in the direction of the semiconductor wafer 31 along the arrow A2 in FIG. With such a calibration operation, the fluctuation due to thermal expansion can be grasped immediately after the start of the operation for the distance (L) at which the adsorption collet 1 should descend.

  The target jig 10 has a “+” character-like protrusion having a height of 500 [μm], assuming that the maximum size of dust that drops and adheres to the rail upper lid 23a is 200 [μm]. A target mark 12 is formed. If the suction collet 1 is informed of the reference position of the die bonding in the vertical direction of the lead frame 2 from the target mark 12, the above-described inconvenience when the suction collet 1 holds the semiconductor chip can be solved. In consideration of the fact that the vertical position variation due to thermal expansion is large only during about 20 minutes after the DB device 20 starts the continuous operation, the calibration operation described above takes 3 to 3 minutes, for example, immediately after the start of the operation. It is preferable to carry out at a timing of about four times.

  The target mark in the target jig of the present invention is not limited to the “+” character shape. For example, a single line (-) or an asterisk (*) may be used. In order to prevent dust accumulation, a simple shape is better. Or the target mark which consists of a several point (dot) -shaped projection part may be formed so that a point contact may be carried out to the lowest part (part which contacts a target mark) of an adsorption | suction collet.

DESCRIPTION OF SYMBOLS 1,8 Adsorption collet 2 Lead frame 3 Solder 4, 4a Semiconductor chip 5 Heating stage 6, 22a, 23a Rail upper cover 6a, 6b Opening 7 Dust 8a Inclined surface 9 Recessed part 10 Target jig 11 Jig body 12 Target mark 13a, 13b Mounting hole 20 DB equipment (semiconductor manufacturing equipment for die bonding)
21 entrance rail 22 first heater block 23 second heater block 24 exit rail 25a-25e feed claws 26a, 26b positioning pins 30 wafer sheet 31 semiconductor wafer

Claims (5)

In the target jig for calibration for correcting the distance in the Z-axis direction perpendicular to the XY plane of the collet holding and transporting the semiconductor chip, the plane on which the semiconductor chip is die-bonded is the XY plane.
A jig body fixed in the XY plane of the collet;
A target mark formed by protruding from the upper surface of the jig body, and in contact with the tip end of the collet in the Z-axis direction;
A calibration target jig characterized by comprising:   The calibration target jig according to claim 1, wherein the target mark is formed so as to be in contact with a bottom end portion of the collet on an upper surface of the jig body.   The calibration target jig according to claim 1, wherein the target mark is formed at a height exceeding a size of dust falling on an upper surface of the jig body.   2. The calibration target jig according to claim 1, wherein the target mark is formed so as to make point contact with the bottom end of the collet at a plurality of locations on the upper surface of the jig body. In semiconductor manufacturing equipment for die bonding that has an auto-calibration function and mounts a semiconductor chip on a lead frame,
Heating means for heating the lead frame;
A collet for holding and transporting a semiconductor chip mounted on the lead frame;
A plane on which the semiconductor chip is die-bonded is an XY plane, and a collet control means that presets a distance between a predetermined position of the collet and a chip mount surface of the lead frame in the Z-axis direction orthogonal thereto;
The calibration target jig according to any one of claims 1 to 4, wherein the calibration target jig is disposed at a position that varies vertically in proportion to a variation distance in the Z-axis direction on the chip mount surface caused by heat from the heating means. ,
With
The collet is moved in the Z-axis direction to bring the tip end of the collet into contact with the target mark in the Z-axis direction, and a predetermined position of the collet preset in the collet control means and the chip mount surface of the lead frame A semiconductor manufacturing apparatus for correcting a distance.

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