JP2004128339A - Method of manufacturing semiconductor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce cracking or defective bonding of a chip when the chip is subject to die-bonding by using a collet. <P>SOLUTION: A semiconductor chip 2 is sucked and held by a collet 7A wherein a plurality of suction holes 7b of about 1mm or less in diameter are formed in a suction part 7a having almost the same area as the semiconductor chip 2, or a collet 7B wherein the suction part 7a is entirely made of porous material 7c, e.g. ceramic-based material or synthetic resin or the like. Then, the rear surface of the semiconductor chip 2 held by the collet 7B is pressed toward the main surface of a wiring board, thereby die-bonding the semiconductor chip 2. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a semiconductor device manufacturing technique, and particularly to a technique effective when applied to the manufacture of a semiconductor device including a die bonding step of attaching a semiconductor chip on which an integrated circuit is formed to a mounting base such as a wiring board or a lead frame. About.
[0002]
[Prior art]
In the process of assembling a semiconductor device, a semiconductor wafer on which an integrated circuit is formed is diced into individual semiconductor chips (hereinafter, simply referred to as chips), and each chip is die-bonded to a surface of a wiring board or a lead frame. Then, an operation of connecting the chip to a wiring board or a lead frame with an Au wire or the like is performed.
[0003]
More specifically, first, a dicing tape is attached to the back surface of the semiconductor wafer after the wafer process (pre-process) and the inspection process are completed, and the semiconductor wafer is diced using a diamond blade or the like, so that chips are singulated. . At this time, by not completely cutting the dicing tape, each of the individual chips is held as it is on the dicing tape.
[0004]
Next, the chips are pushed up one by one from the back side of the dicing tape using pins, and the main surface of the pushed-up chip is vacuum-adsorbed with a collet to peel off the chips from the dicing tape, thereby preparing a wiring board and a lead frame. To the completed die bonding process. Then, the chip adsorbed and held by the collet is pressed against a chip mounting area such as a wiring board or a lead frame, and an adhesive such as an Ag paste or an organic material previously applied to the chip mounting area is heated and hardened, thereby forming a chip. Die bonding is performed.
[0005]
Thereafter, a wire is bonded between the bonding pad of the chip and the conductor layer of the wiring board or the inner lead of the lead frame, and then the chip is sealed with a mold resin or a potting resin, so that the assembly is almost completed. .
[0006]
[Problems to be solved by the invention]
The present inventors have carried out chip transportation using a pyramid collet (or a peripheral collet) or a flat collet in the above-described semiconductor device assembling process. The pyramid collet has a structure in which the bottom surface is brought into contact with the peripheral edge of the top surface of the chip, and vacuum suction is performed in this state to suck and hold the chip. In addition, the flat collet is provided with one suction hole having a diameter smaller than one side of the chip at the center, and has a structure in which the suction portion is brought into close contact with the main surface of the chip to perform vacuum suction.
[0007]
However, in recent years, with the introduction of a multi-chip package structure in which a plurality of chips are stacked and mounted, and the like, the thinning of the chips is progressing, so that it is difficult to transport the chips by the above-described pyramid collet or flat collet. It has become.
[0008]
That is, when the thickness of the chip becomes 100 μm or less, the chip is drawn to the suction hole of the collet even if it is sucked and held by the collet, the chip is deformed, and the chip is pushed up from the back side of the dicing tape using the pin. This causes a problem that the chip is broken. Furthermore, when the chip that has been sucked and held by the collet is pressed against the chip mounting area such as a wiring board or lead frame and die-bonded, if the chip is deformed, a gap is created between the chip and the chip mounting area. Failures such as cracks and poor crimping occur.
[0009]
An object of the present invention is to provide a technique capable of reducing chip cracking and pressure bonding failure when die-bonding a chip using a collet.
[0010]
The above and other objects and novel features of the present invention will become apparent from the description of the present specification and the accompanying drawings.
[0011]
[Means for Solving the Problems]
The following is a brief description of an outline of typical inventions disclosed in the present application.
[0012]
In the present invention, the step of dicing a semiconductor wafer having a main surface partitioned into a plurality of semiconductor chips to singulate the plurality of semiconductor chips, and the area of the suction portion is substantially equal to the area of the semiconductor chip. In addition, a collet provided with a plurality of suction holes in its suction part is prepared, and a semiconductor chip that has been singulated is sucked and held by the collet, and a back surface of the semiconductor chip sucked and held by the collet is mounted on the mounting base. And die bonding the semiconductor chip onto the main surface of the mounting base by pressing against the main surface of the mounting base.
[0013]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In all the drawings for describing the embodiments, members having the same functions are denoted by the same reference numerals, and repeated description thereof will be omitted.
[0014]
(Embodiment 1)
A method for manufacturing a multi-chip module according to the first embodiment will be described in the order of steps with reference to FIGS. FIG. 1 is a plan view of a semiconductor wafer, FIG. 2 is a cross-sectional view showing a dicing process of the semiconductor wafer, FIG. 3 is a cross-sectional view showing a state in which singulated chips are vacuum-adsorbed by a collet, and FIG. FIG. 5 is a cross-sectional view showing a collet for vacuum-sucking the chip, FIG. 6 is a cross-sectional view showing a chip pickup sequence, and FIG. FIG. 8 is a sectional view showing a die bonding step, and FIG. 8 is a sectional view of the semiconductor device.
[0015]
First, after a semiconductor integrated circuit is formed on a main surface of a semiconductor wafer (hereinafter simply referred to as a wafer) 1 shown in FIG. 1 according to a well-known manufacturing process, bonding of each of a plurality of chip forming regions 2A partitioned by scribe lines SL is performed. A wafer is inspected by applying a probe to the pad 3, and non-defective products and defective products are selected.
[0016]
Next, as shown in FIG. 2, the dicing tape 4 is attached to the back surface of the wafer 1, and the periphery of the dicing tape 4 is adhered and fixed to the carrier jig 5. Next, the chips 2 are diced by dicing the wafer 1 using a diamond blade 6 or the like. At this time, the dicing tape 4 is not cut completely in order to adhere the individual chips 2 to the dicing tape 4.
[0017]
Next, as shown in FIG. 3, the main surface side of the chip 2 is vacuum-sucked with a collet 7, and then, as shown in FIG. By pushing up the chip 2, the chip 2 is peeled off from the dicing tape 4. The chip 2 peeled off from the dicing tape 4 is sucked and held by the collet 7 and transported to the next die bonding step.
[0018]
FIG. 5 shows an enlarged cross-sectional view of the collet 7 and the push-up pin 8 which have been vacuum-adsorbed on the chip 2. The collet 7 has, for example, a substantially cylindrical outer shape, and is made of stainless steel or synthetic rubber having hardness.
[0019]
FIG. 5A shows a collet 7A of the first example. At least the suction portion 7a of the collet 7A that contacts the chip 2 has approximately the same area as the chip 2, and the suction portion 7a has a plurality of suction holes 7b. The diameter of each of the plurality of suction holes 7b is about 1 mm or less, and the entire main surface of the chip 2 can be almost uniformly vacuum suctioned by the collet 7A having the plurality of suction holes 7b. The push-up pin 8 and the suction hole 7b are arranged so as to be shifted from each other so that the push-up pin 8 does not push up the suction hole 7b.
[0020]
FIG. 5B shows a collet 7B of the second example. At least the adsorbing portion 7a of the collet 7B that comes into contact with the chip 2 has approximately the same area as the chip 2, and a porous material 7c, for example, a ceramic material or a synthetic resin, Is provided. The entire main surface of the chip 2 can be vacuum-adsorbed almost uniformly by the porous material 7c. Although the drawing shows the collet 7B in which the porous material 7c is provided in about 1/3 of the adsorbing portion 7a, the entire adsorbing portion 7a can be made of the porous material 7c.
[0021]
As described above, when the chip 2 is sucked and held by the collet 7 and transported to the die bonding step, at least the area of the suction portion 7a that comes into contact with the chip 2 is made substantially the same as that of the chip 2, and a plurality of small-diameter By using the collet 7A provided with the suction hole 7b or the collet 7B having the suction portion 7a as the porous material 7c, the entire main surface of the chip 2 can be suctioned almost uniformly in vacuum. Thereby, deformation of the chip 2 can be prevented, and a uniform pressure-bonded layer can be obtained between the collet 7 and the chip 2. In the collet 7A, the tip 2 can be prevented from being deformed or cracked by shifting the push-up pin 8 from the position of the suction hole 7b.
[0022]
FIG. 6 shows a pickup sequence when sucking and holding the chip 2 using the collet 7A. In the drawing, the collet 7A of the first example is described as an example.
[0023]
First, as shown in FIG. 6A, the collet 7A is arranged above the chip 2, and the vacuum suction piece 9 is arranged below the chip 2. Next, as shown in FIG. 6B, the collet 7A is lowered, and the main surface side of the chip 2 is attracted to the collet 7A. At this time, it is preferable that the suction portion 7a of the collet 7A be brought into direct contact with the chip 2, but it is not always necessary to make contact with the chip 2 if suction is possible.
[0024]
Next, as shown in FIG. 6C, a vacuum is drawn from the vacuum suction piece 9, and then, as shown in FIG. The chip 2 is peeled off from the dicing tape 4 by pushing up the chip 2 by using. Here, as the dicing tape 4, a tape having such an adhesive strength that the collet 7 </ b> A does not separate from the chip 2 even when sucked from the collet 7 </ b> A and the vacuum suction piece 9 is used.
[0025]
As described above, the chip 2 is first suctioned by the collet 7A and then suctioned by the vacuum suction piece 9, so that bending stress can be prevented from being applied to the chip 2. When the chip 2 is pushed up by the push-up pins 8, a compressive stress is applied to the chip 2. However, since the chip 2 made of, for example, silicon is relatively strong against the compressive force, the chip 2 is hardly deformed or cracked.
[0026]
Next, as shown in FIG. 7, the chip 2 is mounted on the wiring board 10 (mounting base). In the drawing, the collet 7A of the first example is described as an example. First, the adhesive 11 is applied to each chip mounting area on the main surface of the wiring board 10. As the adhesive 11, for example, a thermosetting resin-based adhesive is used. Instead of the adhesive 11, a double-sided adhesive tape (die-bonding film or die-attach film) cut to the same size as the chip 2 may be attached to each chip mounting area. Next, die bonding of the chip 2 is performed by pressing the back surface of the chip 2 sucked and held by the collet 7A against the chip mounting area of the wiring board 10 and then separating the collet 7A from the chip 2. At this time, if there is a gap between the chip 2 and the chip mounting area of the wiring board 10 due to the deformation of the chip 2, cracks or poor crimping will occur. In the first embodiment, however, the chip is not adsorbed and held by the collet 7A. Since the deformation of No. 2 does not occur, problems such as cracks and poor press bonding can be prevented.
[0027]
Next, another chip 2 peeled off from the dicing tape 4 is pressed against another chip mounting area of the wiring board 10 in the same manner as described above to perform die bonding. In this manner, the chips 2 peeled off from the dicing tape 4 are die-bonded one by one to each chip mounting area of the wiring board 10, and then the adhesive 11 is cured by heating. Complete.
[0028]
Next, as shown in FIG. 8, the bonding pads 3 of each chip 2 and the wirings 12 of the wiring board 10 are connected by Au wires 13a. The connection of the Au wire 13a is performed using, for example, a known wire bonder using both ultrasonic vibration and thermocompression bonding.
[0029]
Next, the chips 14 are die-bonded one by one on the respective chips 2 mounted on the wiring board 10 by the same method as the above-described chip 2.
[0030]
Next, after bonding pads 15 of each chip 14 and wires 12 of wiring board 10 are connected by Au wires 13b, the entire main surface of wiring board 10 is collectively resin-molded using a mold (not shown). Seal. The mold resin 16 for sealing the main surface of the wiring board 10 is made of, for example, a thermosetting epoxy resin in which silica is dispersed.
[0031]
Next, the solder bumps 18 are connected to the electrode pads 17 on the back surface of the wiring board 10. The connection of the solder bumps 18 is performed by, for example, supplying a solder ball made of a low melting point Pb-Sn eutectic alloy to the surface of the electrode pad 17 and then reflowing the solder ball. Thereafter, the wiring substrate 10 is cut along the scribe lines and singulated to complete the multi-chip module MCM of the first embodiment.
[0032]
As described above, according to the first embodiment, the collet 7A in which the plurality of suction holes 7b are provided in the suction portion 7a having substantially the same area as the chip 2 or the suction portion 7a is constituted by the porous material 7c. By sucking and holding the chip 2 using the collet 7B, a uniform pressure-bonded layer can be obtained between the collets 7A, 7B and the chip 2, and the deformation of the chip 2 can be prevented. Thereby, when bonding the chip 2, it is possible to reduce cracks and poor pressure bonding of the chip 2.
[0033]
(Embodiment 2)
In the second embodiment, a third example of a collet 7C for sucking and holding the chip 2 and transporting the chip 2 to the die bonding step will be described with reference to FIGS. FIG. 9 is a cross-sectional view showing a state in which a singulated chip is vacuum-sucked with a collet, FIG. 10 is a cross-sectional view showing a state in which a singulated chip is pushed up by a push-up pin, and FIG. It is sectional drawing which shows a process.
[0034]
First, as shown in FIG. 9, in the same manner as the collets 7A and 7B described in the first embodiment, the main surface side of the chip 2 is vacuum-adsorbed by the collet 7C, and then, as shown in FIG. The chip 2 is peeled off from the dicing tape 4 by pushing up the chip 2 from the back side of the chip 4 using a plurality of push-up pins 8.
[0035]
At least the suction portion 7a of the collet 7C that comes into contact with the chip 2 has substantially the same area as the chip 2, and one suction hole 7d having a diameter of about 1 mm or less is provided substantially at the center of the suction portion 7a. I have. By bringing the main surface of the chip 2 and the almost entire surface of the suction portion 7a of the collet 7C into close contact with each other, a suction force is generated between them, and the deformation of the chip 2 is reduced by reducing the diameter of the suction hole 7d in contact with the chip 2. Can be prevented. A plurality of push-up pins 8 are provided so that their positions do not coincide with the positions of the suction holes 7d.
[0036]
Next, as shown in FIG. 11, the chip 2 is mounted on the wiring board 10 in the same manner as in the first embodiment. At this time, if there is a gap between the chip 2 and the chip mounting area of the wiring board 10 due to the deformation of the chip 2, cracks and poor crimping may occur, but in the second embodiment, the chip is not adsorbed and held by the collet 7C. Since the deformation of No. 2 does not occur, problems such as cracks and poor press bonding can be prevented.
[0037]
As described above, the invention made by the inventor has been specifically described based on the embodiment of the invention. However, the invention is not limited to the embodiment, and can be variously modified without departing from the gist of the invention. Needless to say, there is.
[0038]
For example, in the above-described embodiment, a case where the present invention is applied to the manufacture of a laminated multi-chip module has been described. However, the present invention is not limited to this, and a die is mounted on a variety of wiring boards and lead frames using a collet. The present invention can be widely applied to the manufacture of a semiconductor device to be bonded.
[0039]
【The invention's effect】
The effects obtained by typical aspects of the invention disclosed in the present application will be briefly described as follows.
[0040]
When a chip is die-bonded using a collet, it is possible to reduce cracks and poor pressure bonding of the chip.
[Brief description of the drawings]
FIG. 1 is a plan view of a semiconductor wafer used in a method for manufacturing a semiconductor device according to a first embodiment of the present invention.
FIG. 2 is a sectional view showing a dicing step of the semiconductor wafer according to the first embodiment of the present invention;
FIG. 3 is a cross-sectional view illustrating a state in which the singulated semiconductor chip according to the first embodiment of the present invention is vacuum-sucked with a collet;
FIG. 4 is a cross-sectional view showing a state in which the singulated semiconductor chip according to the first embodiment of the present invention is pushed up by a push-up pin.
FIG. 5A is a cross-sectional view illustrating a first example of a collet for vacuum-sucking a semiconductor chip, and FIG. 5B is a cross-sectional view illustrating a second example of a collet for vacuum-sucking a semiconductor chip.
FIGS. 6A to 6D are cross-sectional views showing a semiconductor chip pickup sequence according to the first embodiment of the present invention.
FIG. 7 is a sectional view illustrating a die bonding step of the semiconductor chip according to the first embodiment of the present invention;
FIG. 8 is a sectional view of the semiconductor device according to the first embodiment of the present invention;
FIG. 9 is a cross-sectional view illustrating a state in which a singulated semiconductor chip according to the second embodiment of the present invention is vacuum-adsorbed by a collet.
FIG. 10 is a cross-sectional view showing a state in which a singulated semiconductor chip according to a second embodiment of the present invention is pushed up by a push-up pin.
FIG. 11 is a sectional view illustrating a die bonding step of the semiconductor chip according to the second embodiment of the present invention;
[Explanation of symbols]
Reference Signs List 1 semiconductor wafer 2 semiconductor chip 2A chip forming region 3 bonding pad 4 dicing tape 5 carrier jig 6 diamond blade 7 collet 7A collet 7B collet 7C collet 7a suction portion 7b suction hole 7c porous material 7d suction hole 8 push-up pin 9 vacuum suction Piece 10 Wiring board 11 Adhesive 12 Wiring 13a Au wire 13b Au wire 14 Chip 15 Bonding pad 16 Mold resin 17 Electrode pad 18 Solder bump SL Scribe line MCM Multi chip module

Claims (5)

(A) dicing a semiconductor wafer whose main surface is partitioned into a plurality of semiconductor chips to singulate the plurality of semiconductor chips;
(B) A collet in which the area of the suction portion is substantially the same as the area of the semiconductor chip and a plurality of suction holes are provided in the suction portion is prepared. Adsorption and holding steps;
(C) a step of die-bonding the semiconductor chip onto the main surface of the mounting base by pressing the back surface of the semiconductor chip sucked and held by the collet against the main surface of the mounting base. Manufacturing method of a semiconductor device. (A) dicing a semiconductor wafer whose main surface is partitioned into a plurality of semiconductor chips to singulate the plurality of semiconductor chips;
(B) The area of the suction portion is substantially the same as the area of the semiconductor chip, and a collet whose suction portion is made of a porous material is prepared, and the separated semiconductor chip is sucked by the collet. , Holding step,
(C) a step of die-bonding the semiconductor chip onto the main surface of the mounting base by pressing the back surface of the semiconductor chip sucked and held by the collet against the main surface of the mounting base. Manufacturing method of a semiconductor device. (A) dicing a semiconductor wafer whose main surface is partitioned into a plurality of semiconductor chips to singulate the plurality of semiconductor chips;
(B) A collet in which the area of the suction part is substantially the same as the area of the semiconductor chip and in which one suction hole having a diameter of about 1 mm or less is provided in the suction part is prepared. Adsorbing and holding a semiconductor chip with the collet,
(C) a step of die-bonding the semiconductor chip onto the main surface of the mounting base by pressing the back surface of the semiconductor chip sucked and held by the collet against the main surface of the mounting base. Manufacturing method of a semiconductor device. (A) dicing a semiconductor wafer whose main surface is partitioned into a plurality of semiconductor chips to singulate the plurality of semiconductor chips;
(B) A collet in which the area of the suction portion is substantially the same as the area of the semiconductor chip and a plurality of suction holes are provided in the suction portion is prepared. Adsorption and holding steps;
(C) a step of die-bonding the semiconductor chip onto the main surface of the mounting base by pressing the back surface of the semiconductor chip sucked and held by the collet against the main surface of the mounting base;
A method of manufacturing a semiconductor device, wherein the diameter of the suction hole is about 1 mm or less. (A) attaching a dicing tape to a back surface of a semiconductor wafer whose main surface is divided into a plurality of semiconductor chips, and then dicing the semiconductor wafer to singulate the plurality of semiconductor chips;
(B) A collet in which the area of the suction portion is substantially the same as the area of the semiconductor chip and a plurality of suction holes are provided in the suction portion is prepared, and the separated semiconductor chip is sucked by the collet. , Holding step,
(C) peeling off the semiconductor chip from the dicing tape by pushing up the semiconductor chip sucked and held on the collet from the back side of the dicing tape using a plurality of push-up pins,
(D) a step of die-bonding the semiconductor chip onto the main surface of the mounting base by pressing the back surface of the semiconductor chip sucked and held by the collet against the main surface of the mounting base;
The method of manufacturing a semiconductor device according to claim 1, wherein the plurality of push-up pins push up the semiconductor chip while being displaced from positions of the plurality of suction holes provided in the collet.

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