JP3014095B1 - IC cutting method and device - Google Patents

Abstract

Abstract: [Object] To cut a package IC with a high cutting efficiency, no chips, and a smooth cut surface. A die holder is lowered, and a die fixed integrally with the die holder is lowered. At the corners of the gripping claws 30, the gripping claws 36, the gripping claws 42, and the gripping claws 60, the carrier 1
And hold down and fix the package. Dice 41
The distance between the tape carrier 1 and the punch 18 becomes smaller than the thickness of the tape carrier 1. The tape carrier 1 is displaced by the shearing force between the die 41 and the punch 18, and a cut crack 75 is generated. The tape carrier 1 and the package thereon are:
Since it is a relatively hard material and is easily broken, it is cut from this portion to complete one chip size IC4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for cutting an IC mounted on a carrier by a cutting blade. More specifically, a chip size IC cutting method and apparatus for cutting a carrier, a package, and the like using a cutting blade driven by a press, detecting the moment of the cut, and stopping the lowering of the press ram by this detection. About.

[0002]

2. Description of the Related Art In recent years, CSP (chip size package), MCP (mull)
A specification called ti chip package) has been proposed. According to this specification, a lead frame is not provided, an IC chip is mounted on a tape carrier, and a solder ball, which is a terminal called a BGA or the like, for connecting to a printed circuit board is arranged on the back surface. This type of IC
A tape carrier is mounted, but in many cases, a laminated carrier is used for wiring from an IC chip to a ball grid. The tape carrier is made of a film-like synthetic resin such as an epoxy resin, and is often used in a laminated state.

[0003] Recently, a device in which two IC chips are stacked and mounted has been proposed. The tape carrier is also laminated. Since the tape carrier is usually manufactured by mounting a plurality of IC chips on the basis of manufacturing efficiency, it is necessary to separate the tape carrier into individual chip size ICs in the final step. The laminated tape carrier and the package made of synthetic resin are cut by a grindstone or a cutting cutter.

However, since these resins are mainly thermosetting resins such as epoxy resins and phenols, the method of cutting with a whetstone or a cutting cutter causes cracks, chips or the like on the cut surface, resulting in an IC in the final step. Of defective products. To avoid this, the cutting speed must be reduced, resulting in poor productivity. Further, during the cutting operation, the laminated portion is peeled off, and over time, moisture stays in the peeled portion, and corrosion and current leak, resulting in defective I.
It also causes C. Further, since the cutting grindstone or the cutting cutter rotates at a high speed during the cutting operation, small chips are generated, which may cause a contamination of a manufacturing environment of an IC that requires no dust.

[0005]

SUMMARY OF THE INVENTION The present invention has been made under the above-mentioned technical background, and achieves the following objects. It is an object of the present invention to convert ICs on a carrier to individual ICs.
Another object of the present invention is to provide a method and an apparatus for cutting an IC which can be cut precisely. It is another object of the present invention to provide an I
An object of the present invention is to provide a method and an apparatus for cutting C. It is still another object of the present invention to provide a method and an apparatus for cutting an IC without chips. Still another object of the present invention is to provide
An object of the present invention is to provide a method and an apparatus for cutting an IC having a smooth cut surface.

[0006]

SUMMARY OF THE INVENTION According to the present invention, there is provided a method of cutting an IC, comprising the steps of: cutting an individual IC from a carrier having a plurality of ICs mounted thereon by a cutting blade driven by a ram of a press machine;
An IC cutting method for cutting and separating the cutting blade, detecting when the IC is cut by the cutting blade, stopping the cutting blade after the cutting, and stopping the cutting ram after stopping the cutting blade. It is characterized by being raised. When the detection of the cutting is detected by the pressing force of the cutting blade,
There is an advantage that this detection signal can be used for various controls of the press machine. If the stop position of the ram is a cutting edge advance position of the cutting blade which is only 10 to 30% of the thickness of the carrier, an optimum cut surface is obtained. The IC cutting apparatus according to the present invention uses a cutting blade driven by a ram of a press machine to separate individual ICs from a carrier on which a plurality of ICs are mounted.
C. An IC cutting device for cutting and separating into C.
A punch on which the C is placed, a die inserted relatively to the punch, a stripper disposed on the outer periphery of the punch and opposed to the die for pressing the IC, and the die And a pad for pressing the IC, which is disposed at a position facing the punch. The punch, the die,
A gripping claw, which is a projection for restraining and gripping the IC from both sides, is formed on the stripper and the pad. However, forming gripping claws only on one side of these,
The IC may be held. Preferably, the punch is disposed below the vertical direction, and the die is disposed above the vertical direction. When an inclined surface is formed on the gripping claw, the gripping function is good even if the thickness of the IC is incorrect. The cutting efficiency can be more effectively improved by combining an IC transport device for gripping the IC and cutting it into individual pieces and a cutting device for the IC.

[0007]

[First Embodiment] Next, an embodiment of the present invention will be described. FIG. 1 shows a tape carrier 1 on which an IC chip 2 which is a semi-finished product before cutting is mounted.
FIG. 2 is a diagram showing the appearance of the chip size IC 4 cut out from the tape carrier. FIG. 3 is a cross-sectional view of FIG. On the tape carrier 1, IC chips 2 are arranged and mounted. In this example, six IC chips 2
Are packaged in a package 5 made of synthetic resin (see FIG. 1).

[0008] The IC chip 2 is mounted on the tape carrier 1 on which a laminated thin film of an epoxy-based thermoplastic synthetic resin is laminated. Tape carrier 1
Is formed by laminating a plurality of films 1a, 1b, 1c. Lead wires are formed on each of the films 1a, 1b, 1c by means of printing, etching, or the like, whereby the lead wires formed on each of the films 1a, 1b, 1c, etc. are connected by lamination to form a tape carrier. 1 is connected to a solder ball 3 formed on the back surface. The solder balls 3 are terminals and are formed of hemispherical solder.

A solder ball 3 is soldered and connected to an electronic circuit formed on a printed circuit board. An IC chip 2 is mounted on the upper surface of the tape carrier 1 and is covered with a package 5 made of a synthetic resin to protect the IC chip 2. Laminated tape carrier 1
And the package 5 are cut to obtain individual chip size ICs 4.
And Usually, since several to several tens of IC chips 2 are mounted on the tape carrier 1, the IC chips 2 are cut and cut to obtain individual chip size ICs 4 (see FIG. 2).

[Cutting Die 10] FIG. 4 is a half sectional view of a cutting die 10 for cutting the tape carrier 1 and the package 5 (used synonymously with punching in this specification). The cutting die 10 includes an upper die 11 and a lower die 12. A punch plate 16 is mounted on a punch holder 15 which is a rectangular plate material. Punch plate 1
A hole is formed in the center of 6 and a female screw 17 is formed in the hole. A male screw 19 formed at the lower end of a cylindrical punch 18 is screwed and fixed to the female screw 17.

On the other hand, the punch holder 15 and the punch plate 16 are formed with through holes 20 passing therethrough. A bolt 21 is slidably inserted into the through hole 20 from below. A stripper 22 is screwed to the upper end of the bolt 21. On the outer periphery of the bolt 21,
A coil spring 25 is provided, and the coil spring 25 is interposed between the stripper 22 and the punch plate 16. The stripper 22 includes the punch 18
Is arranged on the outer periphery.

On the outer periphery of the upper end of the punch 18, a gripper 30 is provided.
Are formed. As shown in FIG.
A corner 31 is formed on the outer peripheral edge, and an inclined surface 32 is inclined toward the center of the punch 18. The inclined surface 32 has an inclination angle θ of 2 to 9 degrees. A concave portion 33 is formed at a central portion following the inclined surface 32.

A gripper 36 is formed at the edge of the rectangular center hole 35 of the stripper 22. A corner 37 is formed on the inner peripheral edge of the gripper 36, and an inclined surface 38 that is inclined outward of the stripper 22. An inclined angle θ of 2 to 9 degrees is formed on the inclined surface 38. A plane 39 is formed continuously from the inclined surface 38.

On the lower surface of the die holder 40 of the upper mold 11,
Dice 41 is fixed. On the lower surface of the die 41,
A gripping claw 42 is formed on a surface facing the gripping claw 36 described above. The gripping claw 42 includes a corner 43 at an outer peripheral edge, and an inclined surface 44 that is inclined outward of the die 41. An inclined angle θ of 2 to 9 degrees is formed on the inclined surface 44. There is a step following the inclined surface 44, after which a flat surface 45
Are formed.

A rectangular hole 48 is formed in the center of the die 41. A step 46 is formed in the die 41. The pad 50 is inserted into the step 46, and the step 51 of the pad 50 is formed in the step 46 (see FIG. 4).

A spring insertion hole 55 is formed in the die holder 40. The spring insertion hole 55 has a female screw 5
6 is screwed. Spring set female screw 56 and pad 50
, A coil spring 57 is interposed.
Therefore, the pad 50 is pressed by the coil spring 57 and the step 51 of the pad 50 is
And is pressed against it.

The lower surface of the pad 50 is provided with
A gripping claw 60 is formed on a surface opposing to zero. The gripping claw 60 includes a corner 61 on the outer peripheral edge and an inclined surface 62 that is inclined outward of the pad 50. The inclined surface 62 is
An inclination angle θ of 9 degrees is formed. There is a step following the inclined surface 62, after which a flat surface 63 is formed.

The cutting die 10 is mounted on a press machine, and the die holder 40 is driven to perform a cutting operation. FIG.
FIG. 4 is an external view when the cutting die 10 is mounted on a press machine 68. The press machine 68 is a press machine having the structure proposed by the present inventors. This press machine can stop at an arbitrary position in the middle of the downward movement of the ram of the press, not at the bottom dead center.

In this press machine 68, a shank 65 integrated with the die holder 40 of the cutting die 10 is clamped on a ram (not shown) of the press. Die holder 40
Are slidable up and down along the guide post 66. A guide bush 67 is interposed between the die holder 40 and the guide post 66. The lower end of the guide post 66 is fixed to the punch holder 15.

A pressure sensor 69 is attached to the shank 65. The pressure sensor 69 is a sensor such as a strain gauge, and measures a pressing force by a ram of a press machine. The tape carrier 1 on which the IC is mounted is transferred by a transfer device 71 mounted on a guide 70. The transfer device 71 can transfer to an arbitrary position on the plane (XY plane). Gripping claw 7 of transfer device 71
2 grips the end of the tape carrier 1. The one that grasps a plate-shaped workpiece and controls the movement to an arbitrary position
Since it is commonly used in a press machine, the description of the structure and function of the transfer device 71 will be omitted.

[Press Control Device 80] FIG. 6 is a functional block diagram schematically showing the press control device. The drive mechanism of the press machine 68 is a well-known mechanism, and may be any of a toggle mechanism and a crank mechanism. Press machine 6
No. 8 has already been proposed by the present inventor (see Japanese Patent Publication No. 3-33939). The press control device 80 receives commands from various sensors, various setting values, and the like, a sequence program stored in a RAM (not shown), a processing program, and the like. (CPU) (not shown) instructs the servo motor 83 to stop, forward rotation, reverse rotation, speed and the like via an amplifier (not shown).

The rotation of the servo motor 83 is detected by a pulse generator 84 which is linked to the output shaft, and the detected rotation is fed back as a pulse signal to the press controller 80 and counted. Accordingly, the press control device 80 can control the rotation speed and the angular position of the servo motor 83. On the other hand, the press control device 80 includes:
Pressure sensor 6 attached to shank 65 of cutting die 10
The signal of the pressing force detected by 9 is input.

The top dead center sensor 81 is for detecting the top dead center determined by the mechanism of the press machine 68.
The bottom dead center sensor 82 is for detecting a bottom dead center determined by the mechanism of the press machine 68. The function of the press control device 80 may be a general-purpose sequencer instead of a dedicated control device.

[Cutting Operation] FIGS. 7 (a) to 7 (c)
It is an operation | movement figure explaining the cutting | disconnection situation by the cutting | disconnection die at the time of cutting | disconnecting chip size IC4. First, the tape carrier 1 is transferred by the transfer device 71 to the cutting position of the cutting die 10. The ram of the press machine descends, the die holder 40 descends, and the die 41 fixed integrally therewith is lowered.

Each gripping claw 30, gripping claw 36, gripping claw 42,
The tape carrier 1 and the package 5 are pressed and restrained and fixed by the corners 31, 37, 43, and 61 of the gripper 60.

In the vicinity immediately before the ram bottom dead center, the die 4
The distance between the tape carrier 1 and the punch 18 becomes smaller than the thickness of the tape carrier 1. Therefore, the tape carrier 1 is displaced by the shearing force between the die 41 and the punch 18, and a cut crack 75 is generated. The tape carrier 1 and the package 5 thereon are cut from this part because they are relatively hard materials and are easily broken. This cutting by the cutting die 10 completes one chip size IC4.

The cutting depth of the cutting edge into the tape carrier 1, that is, the bite amount with respect to the plate thickness of the die 41 and the punch 18 is optimally 10 to 20% of the thickness of the tape carrier 1. When the ram returns, the chip size IC is taken out of the cutting die 10 and the cutting is completed.

In order to hold the tape carrier 1 before cutting, the inclined surfaces 32, 33, 38, 44, 62 surely hold the tape carrier 1. In this cutting, a cut surface that could not be obtained by conventional punching and cutting with a grindstone was obtained. The pressure sensor 69 detects the moment when the chip size IC 4 is completed, stops the lowering of the ram instantly, and immediately raises it. Thereafter, the completed chip size IC4 is taken out by an unloader (not shown). When the removal is completed, the transport device 71 is moved in the XY directions according to the program, and the individual chip size IC 4 is completed.

FIG. 9 is a diagram showing the trajectory of the ram of the press machine. The positions of the top dead center and the bottom dead center of the ram are determined by the mechanism of the press machine 68, and the positions cannot be changed by the press control device 80. Press machine 6
The ram reciprocates from the top dead center to the bottom dead center by rotating the servo motor 83 forward or backward. The “machining cycle start point” is located between the “cutting start point” and the “top dead center”. In the machining cycle, the ram is not moved to “top dead center” and “bottom dead center” as much as possible, especially to the position of “top dead center”.

The reason for this is to save as much as possible the machining cycle time by minimizing operations not involved in machining.
The “cutting start point” is a ram position at which the die 41 and the punch 18 start cutting the tape carrier 1 and the package 5. “Cutting end point” is a point where cutting has been completed. This moment is the position of the ram when the output of the pressure sensor 69 sharply drops. In this example, the interval from the “cutting start point” to the “cutting end point” is about 10 to 20 times the plate thickness of the object to be cut.
% Intervals.

If the servo motor 83 continues to rotate forward, the ram reaches the "bottom dead center" after the "cutting end point". Since this operation is a useless cycle for cutting,
When the "cutting end point" is reached, the servomotor 83 is immediately stopped or reversed without stopping and returned to the "machining cycle start point", and the cutting cycle is performed again. In addition,
The “cutting end point” and the “bottom dead center” determined mechanically may be substantially matched.

[Working Cycle of Press Control Device 80] FIG. 10 is a flowchart showing an outline of a cutting cycle operation of the above-described press control device. Hereinafter, the outline of the operation will be described. First, the “allowable ram pressure”, the “cutting start pressure”, and the “cutting end pressure” are preset in the RAM in the press control device 80. "Allowable ram pressure" refers to the cutting mold 10 or
When an abnormality occurs in the press machine 68, it can be detected as an abnormal load. In the normal operation range, the pressure at the time of cutting is within a certain pressure, and the range of idle operation is within a certain pressure. "Allowable ram pressure"
This is a set value for determining whether or not this range is normal. It is set based on experimental values and experience values.

The "cutting start pressure" is a set pressure at which the cutting of the tape carrier 1 and the package 5 (hereinafter, referred to as an object to be cut) by the die 41 and the punch 18 of the cutting die 10 is started. As understood from the above-described cutting mechanism, the "cutting end pressure" sharply reduces the pressing force of the ram when the cutting is completed. The end of cutting is detected from the rate of change of the pressing force at the time of the rapid decrease. The magnitudes of these set values are values determined by experimental values and empirical values. When these settings are completed, a start command is issued to the press control device 80.

The tape carrier 1 is transferred by the transfer device 71 to the cutting position of the cutting die 10. The ram of the press machine descends, the die holder 40 descends, and the die 41 fixed integrally therewith descends (S2, S3). The pressure of the ram during this period is measured to determine whether the pressure is within the allowable pressure. When the pressure is not within the allowable pressure, that is, when the cutting pressure is not normal, it is presumed that the mold is damaged, foreign matter is caught, and the press machine 68 is abnormal. Restore to a normal state.

If the pressure is within the allowable pressure, the operation is normal. If the ram is further lowered, the die 41 is lowered to a position where it comes into contact with the workpiece. When the die 41 starts to contact the object to be cut, the cutting pressure sharply increases. This sudden increase in pressure is used to determine the cutting start point based on the rate of change and the threshold value (S6). When cutting is completed, the pressure drops sharply.
This sudden drop in pressure is determined as the cutting end point based on the rate of change and the threshold (S7).

When it is determined that the cutting is completed, the rotation of the servomotor 83 is stopped to stop the movement of the die 41 (S
8). If the stop position of the die 41 is at the bottom dead center, the servo motor 83 is rotated forward. If it is not the bottom dead center, the servo motor 83 is rotated in the reverse direction to raise the die 41 to the cutting cycle start point (S9-S12). The reason for raising the die 41 immediately is to prevent the cut product from being damaged. In addition, since the cutting cycle can be shortened, there is an effect that productivity is improved.

If it has risen to the top dead center for some reason, the process returns to the first step and returns to the next cutting cycle (S13, S14). When the die 41 has reached the cycle start point, the die is temporarily stopped and the next cutting cycle is started again (S14). In this case, the next cutting cycle may be started immediately without stopping.

[Other Embodiments] The cutting die 10 of the above embodiment cuts one unit.
A plurality of ICs 6 may be cut at the same time.
The chip size IC referred to in the present invention does not mean that the dimensions are mechanically exactly the same, but any other size can be cut as long as it cuts a carrier or a package. Although the detection at the time of the cutting is performed by detecting the pressure, the detection may be performed by using a waveform such as a sound intensity and a frequency instead of the pressure.

Punch 18, die 41, stripper 2
2, and the pad 50 are formed with gripping claws 30, 42, 36, and 60 for gripping and restraining an object to be cut from both sides. However, the purpose can be achieved even if these constraints hold the object to be cut from one side and constrain it.

[0040]

In the above cutting, the die 4 is positioned at a position where the bottom dead center of the press machine has cut into about 20% of the thickness of the tape carrier 1.
It was set so that the position of the gripping claw 30 and the corner 31 of the punch 18 came. The angle of each inclined surface 32, 33, 38, 44 was 2 to 5 degrees.

[0041]

According to the present invention, since the IC can be cut at the operating speed of the press, efficient cutting can be performed. In addition, since the periphery of the IC cut from the laminated film is fixed and cut, the probability of occurrence of cracking, chipping, or peeling of the cut opening is reduced. Further, since the ram of the press machine is pulled up at the moment when the cutting is completed, the occurrence of defective products due to foreign matters such as cutting chips is small.

[Brief description of the drawings]

FIG. 1 shows the appearance of a tape carrier on which an IC chip which is a semi-finished product before cutting is mounted.

FIG. 2 is a diagram illustrating an appearance of a chip size IC cut out from a tape carrier.

FIG. 3 is a cross-sectional view of FIG. 1;

FIG. 4 shows a half sectional view of a cutting mold for cutting a tape carrier and a package.

FIG. 5 is an enlarged view of the shape of each gripping claw that presses the tape carrier and the package.

FIG. 6 is a functional block diagram of a press control device.

FIGS. 7A to 7C show chip size ICs.
FIG. 4 is an operation diagram illustrating a cutting situation by a cutting die when cutting 4; .

FIG. 8 is an external view of a press machine.

FIG. 9 is a diagram showing a trajectory of a ram of a press machine.

FIG. 10 is a flowchart showing an outline of a cutting cycle operation of the press control device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Tape carrier 2 ... IC chip 5 ... Package 10 ... Cutting die 11 ... Upper mold 12 ... Lower mold 15 ... Punch holder 16 ... Punch plate 18 ... Punch 22 ... Stripper 30,36,42,60 ... Grip claws 68 ... Press machine 71 ... Conveying device 80 ... Press control device 69 ... Pressure sensor

Claims (8)

(57) [Claims] An IC cutting method for cutting and separating individual ICs from a carrier on which a plurality of ICs are mounted by a cutting blade driven by a ram of a press machine, wherein the IC is cut by the cutting blades. A method of cutting an IC, comprising detecting a time of cutting, stopping the lowering of the cutting blade after the cutting, and raising the ram after stopping the cutting blade. 2. The method for cutting an IC according to claim 1, wherein the detection of the cutting is detected by a pressing force of the cutting blade. 3. The method of cutting an IC according to claim 1, wherein the stop position of the ram is a cutting edge advance position of the cutting blade by 10 to 30% of a thickness of the carrier. IC cutting method. 4. An IC cutting device for cutting and separating individual ICs from a carrier on which a plurality of ICs are mounted by a cutting blade driven by a ram of a press machine, comprising: a punch on which the ICs are mounted. A die that is relatively inserted into the punch, a stripper that is disposed on the outer periphery of the punch, and that is disposed at a position facing the die and presses the IC, and that is disposed inside the die. And an IC cutting device arranged at a position facing the punch to press the IC. 5. The IC cutting device according to claim 4, wherein the punch, the die, the stripper, and the pad are formed with gripping claws that are projections for restraining and gripping the IC. An IC cutting device, comprising: 6. The IC cutting device according to claim 4, wherein the punch is arranged below the vertical direction, and the die is arranged above the vertical direction. 7. The IC cutting device according to claim 5, wherein the gripping claw is formed on one surface of the punch, the die, the stripper, and the pad, and an inclined surface is formed. . 8. The integrated circuit according to claim 4, further comprising: an IC transport device for gripping and cutting the IC in units of one. Cutting device.