JP4352545B2 - IC card manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of manufacturing an IC card configured by sealing an IC chip reinforced by a reinforcing member, and in particular, when a wafer is diced to obtain an IC chip, chipping at the dicing portion of the IC chip can be prevented. It relates to what I did.
[0002]
[Prior art]
Cash cards, credit cards, and the like that are widely used now have a magnetic stripe attached to a plastic card so that information recorded on the card is read. Such a magnetic recording system has problems such that information can be easily decoded by a third party and the amount of information that can be recorded is small.
[0003]
Therefore, in recent years, an IC card in which an IC chip having functions such as a memory and a CPU is mounted in a card-like base has been developed and already put into practical use. This IC card usually has a three-layer structure consisting of a circuit sheet on which an IC chip is mounted, an intermediate sheet bonded on the circuit sheet, and a cover sheet bonded on the intermediate sheet to seal the IC chip. Is done.
[0004]
Such an IC card is stored in a wallet or carried in a pocket of clothing, so it is easier to handle a supple one than a hard one that is hard to bend. However, if it is supple, it is easy to bend. However, if the IC card is actually bent, the IC chip may be damaged depending on the degree of bending.
[0005]
[Problems to be solved by the invention]
In order to solve the problem of breakage of the IC chip due to the bending of the IC card, it is considered to bond a reinforcing member to the IC chip. In order to manufacture an IC card having a structure in which the IC chip is reinforced by a reinforcing member, first, the wafer is diced and divided into a number of IC chips, and the IC chips obtained by the division are mounted on a circuit sheet. Thereafter, an adhesive is applied to the IC chip on the circuit sheet, and a reinforcing member formed by cutting a large metal sheet is bonded to the IC chip. Thereafter, the intermediate sheet is bonded to the circuit sheet, and finally the cover sheet is bonded onto the intermediate sheet to complete the IC card.
[0006]
However, since the wafer is hard and brittle and is formed as thin as about 100 μm in order to reduce the thickness of the IC card, there is a problem that chipping (chipping) is likely to occur in the dicing process. If the IC chip is chipped, when the IC card is bent, the IC chip may be broken starting from the chipping portion. Also, since the IC chip is very thin and easily cracked, in order to prevent the IC chip after dicing from breaking before it is assembled to the circuit sheet, for example, the IC chip is attached to an adhesive tape stretched in the outer frame during transportation. However, this requires time and increases the cost.
[0007]
The present invention has been made in view of the above circumstances, and an object thereof is to provide an IC card manufacturing method capable of effectively preventing chipping and cracking of an IC chip during dicing.
[0008]
[Means for Solving the Problems]
According to the first aspect of the present invention, when the wafer is diced, since the wafer is integrated and reinforced with the reinforcing plate, there is no possibility that the IC chip is lost by cutting with the dicing blade. Further, since the IC chip obtained by dicing from the wafer is integrated with the reinforcing member, even if it hits another IC chip during conveyance, it does not break.
[0010]
In addition , when dicing the wafer, the IC chip and the reinforcing member are diced so that the sizes of the IC chip and the reinforcing member are different. Therefore, the size of the reinforcing member depends on the degree of reinforcement required for the IC chip and the surrounding conditions of the portion where the IC chip is placed. Ru can be selected is.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a first embodiment of the present invention will be described with reference to FIGS.
First, as shown in FIGS. 6 and 7, the IC card 1 includes a circuit sheet 2, an intermediate sheet 3 as an intermediate adhesive layer, and a cover sheet 4.
[0013]
The circuit sheet 2 is made of a plastic, for example, a polyester plastic, specifically, a PET (polyethylene terephthalate) sheet having a thickness of about 188 μm. A coil-shaped circuit pattern 5 is formed on one surface of the circuit sheet 2, and an IC chip 6 connected to the circuit pattern 5 is mounted. In this embodiment, the circuit pattern 5 is formed by screen printing means using a conductive paste, for example, a polyester-based silver paste, and the IC chip 6 is flip-chip mounted using, for example, an epoxy-based anisotropic conductive adhesive. .
[0014]
The coil-shaped circuit pattern 5 is for transmitting and receiving radio signals to and from an external device. In this embodiment, the operation power for memory, arithmetic processing, and the like that are configured in the IC chip 6 is used. Is also configured to be obtained from a radio signal transmitted from an external device.
[0015]
The intermediate sheet 3 is formed of a sheet having a thickness of about 400 μm formed of a plastic material having a heat-melting property, such as a polyester-based hot melt adhesive, which is melted when heated. The intermediate sheet 3 protects the circuit pattern 5 and the IC chip 6 and has a function of adhering the circuit sheet 2 and the cover sheet 4 to each other. The intermediate sheet 3 covers the circuit pattern 5 and the IC chip 6 without a gap. And seal them. The cover sheet 4 is for protecting the relatively soft intermediate sheet 3, and is made of a sheet made of PET (polyethylene terephthalate) having a thickness of about 188 μm, for example, like the circuit sheet 2.
[0016]
Such an IC card 1 has flexibility and bends flexibly and flexibly when bending force is applied, and returns to the original flat shape when the bending force disappears. In the IC card 1, since the IC chip 6 may be damaged when the mounting portion of the IC chip 6 is bent, a reinforcing member 7 is provided on the IC chip 6 to prevent this. The reinforcing member 7 is formed of a metal material, for example, a thin plate of stainless steel having a thickness of about 50 to 200 μm, and is bonded to the surface of the IC chip 6.
[0017]
Here, a procedure for manufacturing the IC card 1 as described above will be described.
FIG. 5A shows the wafer 8 of the IC chip 6. On the other hand, FIG. 5B shows a stainless steel sheet (hereinafter referred to as a stainless sheet) 9 as a reinforcing plate, which is a material of the reinforcing member 7, and is formed in the same shape and the same size as the wafer 8. A large number of IC circuits of the IC chip 6 are formed on the wafer 8, and the IC chip 6 can be obtained by dicing and dividing the wafer 8.
[0018]
The wafer 8 is integrated with the stainless steel sheet 9 in a pre-process for dicing the wafer 8. This integration is performed by bonding the two together. As the adhesive J, a thermosetting adhesive is used, and is applied to at least one of the wafer 8 and the stainless sheet 9, in this embodiment, the stainless sheet 9.
[0019]
As shown in FIG. 4, the application of the adhesive J to the stainless steel sheet 9 is performed by placing the stainless steel sheet 9 on the rotating table 10 and rotating the rotating table 10 at a high speed. The adhesive J is dropped from the nozzle 11. Then, the adhesive agent J dropped onto the rotation center portion of the stainless steel sheet 9 spreads over the whole while flowing from the rotation center portion of the stainless steel sheet 9 to the outer periphery by centrifugal force. As a result, the adhesive J is thinly and uniformly applied to the entire surface of the stainless steel sheet 9. Since the adhesive J can be applied thinly and uniformly in this way, the total thickness of the IC chip 6 and the reinforcing member 7 can be reduced, and the thickness of the IC card 1 as a whole can be reduced.
[0020]
After the adhesive J is applied to the stainless steel sheet 9, as shown in FIG. 5C, the adhesive application surface of the stainless steel sheet 9 is aligned with the wafer 8, and in this state, the adhesive J is heated and cured to Bond and integrate. Thereafter, dicing is performed as shown in FIG.
[0021]
In order to perform this dicing, as shown in FIG. 3, the wafer 8 is stuck on the adhesive resin tape 13 stretched on the wafer frame 12 with the stainless steel sheet 9 facing upward. Then, the wafer frame 12 is set on a table of a dicing apparatus, and the stainless sheet 9 and the wafer 8 are cut along the street by a dicing blade attached to the tip of a spinner (not shown) that rotates at high speed.
[0022]
In this case, as shown in FIG. 1, two types of dicing blades are prepared: a dicing blade 14 for cutting the stainless steel sheet 9 and a dicing blade 15 for cutting the wafer 8. First, as shown in FIG. As shown, the stainless sheet 9 is cut by the dicing blade 14, and then the wafer 8 is cut by the dicing blade 15. The stainless steel sheet 9 is softer and tougher than the wafer 8, and conversely, since the wafer 8 is hard and brittle, when the stainless steel sheet 9 is cut with the dicing blade 15 for the wafer 8, the dicing blade 15 is clogged. On the other hand, when the wafer 8 is cut with the dicing blade 14 for the stainless steel sheet 9, the dicing blade 14 is worn out and cannot be cut. However, by preparing the two types of dicing blades 14 and 15 as described above and dedicated to the stainless steel sheet 9 and the IC chip 8, it is possible to cut well while preventing the occurrence of the above-mentioned problems. it can.
[0023]
Now, at the time of dicing, the cutting force by the dicing blades 14 and 15 acts on the wafer 8, and the cutting force is sometimes applied impactively. However, in this embodiment, the wafer 8 and the stainless steel sheet 9 are integrated to reinforce the wafer 8, and the total thickness of the integrated wafer 8 and the stainless steel sheet 9 is increased to increase the bending strength. Therefore, the chipping of the wafer 8 (IC chip 6) can be effectively prevented.
[0024]
Further, the cutting force by the dicing blades 14 and 15 acts so that the wafer 8 and the stainless steel sheet 9 are lifted from the table of the dicing apparatus when the rotating dicing blades 14 and 15 are separated from the wafer 8 and the stainless steel sheet 9. To do. In FIG. 2, when the dicing blades 14 and 15 are rotating in the direction of arrow A, the dicing blades 14 and 15 act to press the wafer 8 and the stainless steel sheet 9 against the table of the dicing apparatus at the right side portion. In the left part, the wafer 8 and the stainless steel sheet 9 act so as to float up from the table.
[0025]
When receiving a cutting force such that the wafer 8 is lifted from the dicing blades 14 and 15, if only the wafer 8 is received, there is nothing to receive on the wafer 8 and chipping is likely to occur. However, in this embodiment, since the stainless steel sheet 9 is bonded onto the wafer 8, even if the wafer 8 receives a force that causes the wafer 8 to be separated from the table by the dicing blades 14 and 15, there is a possibility that the wafer 8 will be chipped. Absent.
[0026]
After the wafer 8 is diced as described above, the wafer 8 is divided into a large number of IC chips 6. When the wafer 8 is fully cut in the dicing process, the wafer 8 is divided into a large number of IC chips 6 by dicing. In the case of half-cutting, the wafer 8 is then set in a braking device and the wafer 8 is divided along the half-cut grooves to obtain a large number of IC chips 6.
[0027]
The IC chip 6 obtained in this way is conveyed to a mounting process on the circuit sheet 2. At this time, since the IC chip 6 is integrated with the reinforcing member 7, there is no possibility that the IC chip 6 will break even if the IC chip 6 is not attached and transported to an adhesive tape stretched in the outer frame. Then, the IC chip 6 conveyed to the mounting process is mounted on the circuit sheet 2 so that the reinforcing member 7 is on top.
[0028]
After the IC chip 6 is mounted on the circuit sheet 2, the intermediate sheet 3 and the cover sheet 4 are sequentially stacked on the circuit sheet 2 and thermocompression bonded. Then, the hot-melt adhesive forming the intermediate sheet 3 is in a molten state, and covers the outside of the IC chip 6 and the reinforcing member 7 with no gap and is sealed. Thereafter, the hot melt adhesive in a molten state is cooled and solidified, whereby the circuit sheet 2, the intermediate sheet 3, and the cover sheet 4 are bonded and integrated into a three-layer state.
[0029]
In the IC card 1 as described above, the circuit sheet 2 and the cover sheet 3 are formed of PET, and the intermediate sheet 3 is formed of a polyester hot melt adhesive, both of which have flexibility. When bending force acts, the IC card 1 bends flexibly with elasticity.
[0030]
In this case, assuming that the portion where the bending force acts is the mounting portion of the IC chip 6, the reinforcing member 7 is bonded to the IC chip 6, so that the bending force is received by the highly rigid reinforcing member 7. Be able to. Therefore, in a normal use state, even if the IC card 1 is slightly bent at the mounting portion of the IC chip 6, there is no possibility that the IC chip 6 is bent so much that the IC chip 6 is damaged. It can be effectively prevented.
[0031]
Further, since the IC chip 6 and the reinforcing member 7 are formed in the same size, the reinforcing member 7 that is easily elastically deformed is different from the case where the reinforcing member 7 is formed larger than the IC chip 6, for example. It is possible to effectively prevent the occurrence of a problem that the portion protruding from the chip 6 is bent greatly, and as a result, the stress concentrates on the ridge corner portion of the IC chip 6 to cause cracking starting from chipping.
[0032]
When the IC chip 6 and the reinforcing member 7 are made to have the same size as in the first embodiment so that stress concentration does not occur at the ridge corners of the IC chip 6, for example, FIG. In this way, the peripheral side surface of the reinforcing member 7 is cut into an inclined surface that gradually becomes wider from the adhesive surface with the IC chip 6 upward, or the peripheral side surface of the reinforcing member 7 is changed as shown in FIG. You may make it cut | disconnect to the inclined surface which becomes gradually narrow from the adhesion surface with IC chip 6 upwards, and, in short, the IC chip 6 and the reinforcement member 7 should just be the same magnitude | size in a joining surface at least. .
[0033]
FIG. 10 shows a second embodiment of the present invention. The difference from the first embodiment is that the wafer 8 and the stainless steel sheet 9 are bonded using a double-sided adhesive sheet 16 as a double-sided adhesive. . In this way, compared with the case of bonding using a thermosetting adhesive, since there is no need for heat curing, the bonding process time can be shortened and bonding can be performed easily.
[0034]
FIGS. 11 to 13 show a third embodiment of the present invention. The difference from the first embodiment is that the sizes of the IC chip 17 and the reinforcing member 18 are different. In this embodiment, the reinforcing member 18 is formed larger than the IC chip 17, and the manufacturing method thereof is as follows.
That is, as shown in FIG. 12, the adhesive 8 is applied to one of the wafer 8 and the stainless steel sheet 9, for example, the wafer 8, at the center of the portion corresponding to the IC chip 6, and the stainless steel sheet 9 is adhered. . Thereafter, the stainless steel sheet 9 is cut along line B shown in FIG. 13, and then turned upside down to cut the wafer 8 along lines C1 and C2. Then, since the portion indicated by D in the wafer 8 is not bonded to the stainless steel sheet 9, the portion is separated from the stainless steel sheet 9 as an unnecessary portion. As a result, the larger reinforcing member 18 can be adhered to and integrated with the IC chip 17.
[0035]
The present invention is not limited to the embodiments described above and shown in the drawings, and can be expanded or changed as follows.
When dicing, the wafer frame 12 may not be used.
The reinforcing member 7 is not limited to stainless steel, and may be composed of another metal plate, and is not necessarily limited to a metal member.
The IC chip 6 may be larger than the reinforcing member 7.
[Brief description of the drawings]
1 is a cross-sectional view showing a dicing state according to a first embodiment of the present invention; FIG. 2 is a cross-sectional view taken along the line of FIG. 1. FIG. 3 is a wafer frame for dicing. FIG. 4 is a perspective view showing a state in which an adhesive is applied to a stainless steel sheet. FIG. 5 is a view showing a process of dicing a wafer. FIG. 6 is a view showing three sheets constituting an IC card. FIG. 7 is a sectional view of an IC card. FIG. 8 is a side view of an IC chip showing a modification of the first embodiment. FIG. 9 is an equivalent view of FIG. 8 showing another modification of the first embodiment. 10 is a perspective view showing a second embodiment of the present invention. FIG. 11 is a side view of an IC chip showing a third embodiment of the present invention. FIG. 12 is a perspective view showing an application state of an adhesive to the IC chip. FIG. 13 is a diagram showing a cutting position during dicing.
In the figure, 1 is an IC card, 6 is an IC chip, 7 is a reinforcing member, 8 is a wafer, 9 is a stainless steel sheet (reinforcing plate), 10 is a turntable, 12 is a wafer frame, 14 and 15 are dicing blades, 16 is A double-sided adhesive resin sheet (double-sided adhesive), 17 is an IC chip, and 18 is a reinforcing member.

Claims (1)

In an IC card configured by sealing an IC chip reinforced by a reinforcing member,
Integrated wafer and a reinforcing member formed by a number form an integrated circuit of the IC chip, when dicing the wafer in a state of being integrated with the reinforcing member, the at mating surfaces of the reinforcing member said IC chip The peripheral side surface of the reinforcing member is changed from the mating surface to the surface opposite to the mating surface so that the same size as the IC chip and a size different from the IC chip on the surface opposite to the mating surface. headed by dicing so as to gradually wider or narrower to become inclined surface, IC card manufacturing method, characterized in that to obtain an IC chip that is reinforced by the reinforcing member.

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