JP5381240B2 - IC chip and manufacturing method thereof - Google Patents

Description

  The present invention relates to an IC chip used for various IC media such as an IC card and an IC tag.

  Conventionally, as an ID card for recognizing an individual, a method of performing magnetic or optical reading has been widely used in employee ID cards, cash cards, credit cards, and the like. However, due to the popularization of technology, data tampering and counterfeit cards have become available, and the number of people who are actually damaged by counterfeit cards has increased. For this reason, in recent years, attention is attracting attention as managing personal data from the point of high security that an IC medium incorporating an IC chip can be loaded with information capacity and encrypted data.

  In particular, non-contact communication type IC media can be exchanged with an external read / write device in a portable state without requiring labor, and are being used in various fields. This is to drive an IC chip with an induced electromotive force excited in an antenna coil by electromagnetic waves from an external read / write device, and it is not necessary to have a battery power source inside the card, and it can be used in a portable state, for example. It is because it is excellent in activity.

  Conventionally, as shown in FIG. 4, such a non-contact IC medium is formed by flip-chip mounting an IC chip on an antenna sheet, and then sealing both surfaces with a resin to bond a reinforcing plate. In this case, an IC inlet having an IC chip thickness of about 200 μm, a reinforcing plate thickness of about 30 μm, and a total thickness of about 450 μm was employed.

JP 2005-84710 A

  However, since the IC chip portion becomes thick, this portion cannot follow the impact and bending, and the physical strength characteristics against the impact and bending of the card are inferior. There was a concern that the IC chip could be destroyed when stressed, and there was a problem with reliability.

  The present invention has been made to solve the above-mentioned problems, and the object of the present invention is to provide an IC chip having excellent physical strength characteristics while being thinned. A highly reliable IC medium having sufficient strength to prevent breakage without mounting the IC chip portion with resin when mounted on an antenna sheet and forming an inlet, and having excellent smoothness on the surface of the IC medium. It is to provide.

  In order to solve the above-described problems, the present invention includes a step of forming a laminated body in which a reinforcing plate is bonded to one side of a silicon wafer on which an integrated circuit is formed via an adhesive layer, and dicing the laminated body. An IC chip manufacturing method, wherein a laser is used for dicing at least the reinforcing plate among the steps of dicing the laminated body.

  The present invention also provides a method for manufacturing the IC chip, wherein a laser is used for dicing all of the silicon wafer, the adhesive, and the reinforcing plate in the step of dicing the laminate. .

  Further, the present invention provides the IC chip manufacturing method, wherein any one or more of the wavelength, output, and frequency of the laser is changed according to the dicing target member.

  According to the present invention, there is provided a method of manufacturing the IC chip, wherein the dicing of the laminated body is performed with one kind of laser.

  According to the present invention, the IC chip manufacturing method is characterized in that the laser is a water jet laser.

  Since the present invention is configured as described above, the following effects can be obtained.

  In other words, the IC chip manufacturing method of the present invention is a method in which a laminated body in which a reinforcing plate is bonded to one side of a silicon wafer on which an integrated circuit is formed via an adhesive layer is diced using at least a laser to form an IC chip. Since it is separated into individual pieces, it is possible to extend the life of the dicing blade and reduce the production cost. Further, when the IC chip obtained in this way is mounted on the antenna sheet, it is not necessary to seal the IC chip part with a resin and laminate a reinforcing plate, which contributes to a reduction in thickness of the IC chip part.

It is a figure explaining the embodiment of the manufacturing method of the IC chip in this invention. It is a figure explaining another embodiment of the manufacturing method of the IC chip in this invention. It is a figure which shows the embodiment example of the inlet which mounted the IC chip in this invention. It is a figure explaining the inlet in a prior art.

  Embodiments of the IC chip manufacturing method according to the present invention will be described below in detail with reference to the drawings.

  In the present invention, the IC chip is manufactured by dicing a laminated body formed by laminating a Si wafer, an adhesive layer, and a reinforcing plate (SUS) into individual IC chips.

  First, a silicon wafer on which an integrated circuit and connection terminals are formed is ground. The thickness of the silicon wafer is not particularly limited, but is preferably 45 μm to 100 μm, and is appropriately adjusted depending on the required thinness, strength, and the like.

  More specifically, the Si wafer on which the integrated circuit and the connection terminals (not shown) are formed is polished and processed to a predetermined thickness (for example, 80 μm), and after the polishing, the damaged layer damaged during polishing is removed. . For this reason, for example, a polishing process, which is mechanical polishing with a dry grindstone wheel having ultrafine abrasive grains, is performed. By this treatment, it is possible to release the stress generated by grinding, and it is possible to reduce the warpage of the Si wafer and increase the strength when the IC chip is used. In this polishing process, 2 to 3 μm of Si is removed.

  Next, a reinforcing plate (SUS) having a thickness of 50 to 200 μm is bonded to one side of the thinly finished Si wear using, for example, a die attach film (DAF) as an adhesive layer. For the reinforcing plate (SUS), a metal made of C, Si, Mn, P, S, Ni, Cr or the like alone or in combination is used.

  The IC chip in the present invention is diced after being bonded to the reinforcing plate on the Si wafer and separated into IC chips. Therefore, compared to the case where the Si wafer is diced alone, for example, mounting on an antenna sheet or the like thereafter. In this process, the handling is easy and the possibility of breakage of the IC chip can be reduced.

  The thickness and material of the reinforcing plate greatly affect not only the impact strength of the IC chip portion after being processed into an IC medium, but also the ease of dicing. In order to improve the impact strength, it is necessary to increase the thickness of the reinforcing plate and increase the hardness. However, in order to improve the workability at the time of dicing, it is necessary to adjust the hardness, which is 400 Hv or less. desirable.

  The film thickness of the adhesive layer is desirably 5 to 50 μm. The composition of the adhesive layer is not particularly limited, but a material that can be processed at a low temperature is desirable. The adhesive layer preferably has a low elastic modulus, and specifically, the elastic modulus is preferably 75 MPa or less. Thereby, the adhesive layer is soft and excellent in cushioning properties, and the adhesive layer can also play a role of reinforcing the strength of the thinned IC chip.

  Further, it is desirable that the temperature applied to the wafer when bonding is lower (˜60 ° C.). When bonding is performed at a high temperature, the wafer may be warped, and this warpage may cause a defect in a subsequent processing step.

  A laminator is used for bonding, but bonding in a vacuum atmosphere at this time can suppress problems such as voids and uneven bonding (bonding is also possible in an air atmosphere). The area of the reinforcing plate is preferably equal to or slightly larger than the area of the Si wafer. As a result, even if a slight deviation occurs when the reinforcing plate is bonded to the Si wafer, all the IC chips are covered with the reinforcing plate when separated into individual pieces, and further from the impact from the outer periphery. Also serves to protect the Si wafer.

  Then, the laminated body in which the reinforcing plate is bonded to the Si wafer is fixed on a dicing tape, and is diced using a laser or using a laser and a dicing blade, and is singulated into chip units to form an IC chip. . Dicing is generally performed along a scribe line provided on the Si wafer.

  The scribe line is a groove indicating a location where dicing is performed when the Si wafer is separated into IC chips, and is provided in advance on the Si wafer by the manufacturer of the Si wafer. In the current state of the art, the scribe line width is generally 50 to 120 μm, and in order to obtain an IC chip without any problem, it is necessary to dice narrower than the scribe line width. However, the scribe line width of the Si wafer in the present invention is not limited to the above, and an Si wafer provided with a scribe line of any width can be used.

  Although the dicing tape is composed of a base material and glue, the material of the base material is not particularly limited in the present invention, but generally PET, PO, PVC, etc. are used. For dicing a Si wafer, PO is used. And PVC are preferably used, and it is desirable to use PO in consideration of environmental suitability and the like. In addition to the above, a dicing tape dedicated to laser dicing can also be used.

  If the thickness of the dicing tape is too thin, the dicing tape is damaged during dicing. In addition, if the adhesiveness of the glue is weak, the laminate moves in a small amount during dicing, and processing failure may occur. Therefore, the adhesiveness that does not move the laminate is required.

  Since the reinforcing plate is high in hardness, dicing with a dicing blade shortens the life of the dicing blade, and the vibration generated during dicing is also large. In the present invention, at least the reinforcing plate is diced by using a laser in the present invention because there is a problem that the blade becomes considerably wider than the blade width.

  In the embodiment of the IC chip manufacturing method of the present invention shown in FIG. 1, a dicing blade is used for dicing the Si wafer and the adhesive layer, and a laser is used for dicing the reinforcing plate.

  Here, in the process of dicing the Si wafer and the adhesive layer, the remaining adhesive layer is diced simultaneously in the process of dicing the reinforcing plate.

  The dicing blade may be composed of a single blade base material, or may be one in which a large number of fine abrasive grains are provided on the surface of the blade base material. The cutting characteristics vary depending on the blade base material or the abrasive material. As the dicing blade used for dicing the Si wafer and the adhesive layer, it is preferable to use a blade substrate having abrasive grains provided on the surface thereof, and diamond is particularly preferably used as the abrasive grains provided on the surface.

  Due to the influence of machine performance, operation, etc., the actual cutting width of the member becomes wider than the blade width of the dicing blade. Therefore, the dicing blade for the Si wafer is required to be narrower than the scribe line width of the Si wafer, and specifically, it is preferably about 10 to 15 μm.

  The laser width of the laser used for dicing the reinforcing plate is also required to be narrower than the cutting width of the Si wafer formed by the dicing blade described above. This is because the reinforcing plate is diced by inserting a laser used for dicing the reinforcing plate into a groove formed by dicing the Si wafer. At this time, the laser contacts the Si wafer and cuts excessively. This is to prevent it.

  However, since the laser is less susceptible to mechanical vibration and the like than the dicing blade, there is no problem if the laser width is about 5 to 10 μm narrower than the width of the groove formed in the Si wafer.

  As the laser, a laser such as a YAG laser (wavelength: around 1064 nm), a UV laser (wavelength: around 355 nm), a green laser (around 532 nm) can be used. In the present invention, lasers having wavelengths other than those described above can be used, and are not particularly limited. The laser that can be used is determined by whether or not the target material has wavelength absorption, and a green laser or a UV laser is suitable for dicing the reinforcing plate. In addition, a water jet laser using the above laser can be particularly preferably used.

  The water jet laser is a technique for introducing a focused laser beam into a water jet formed by thinly jetting water, and guiding the laser beam by reflecting the laser beam in the water jet.

  The water jet laser has an effect of suppressing the heat generation of the medium to be cut due to the action effect of water, and it is possible to prevent the Si wafer and the reinforcing plate from being warped by heat generated during dicing.

  In addition, scraping of the Si wafer and the reinforcing plate occurs during dicing, and this adheres to the surface of the Si wafer, causing defective products. Therefore, when dicing, a coating agent is applied to the surface of the Si wafer and dicing is performed. Although it is necessary to take measures such as removing the coating agent later, the use of a water jet laser prevents the adhesion of shavings to the surface of the Si wafer due to the water cleaning effect without applying the coating agent. Is possible.

  In addition, since the water jet laser has a larger number of focal positions than a normal laser, the processable range is wide and the processing time is shortened.

  FIG. 2 is a diagram showing another embodiment of the IC chip manufacturing method according to the present invention. The manufacturing method of the IC chip shown in FIG. 2 is the same as the manufacturing method shown in FIG. 1 except that the dicing of the laminated body is all performed using a laser. As the laser, a normal laser, a water jet laser, or the like can be used as described above.

  In order to perform dicing of a laminated body made of a plurality of members made of different materials, such as a laminated body made of a Si wafer, an adhesive layer and a reinforcing plate in the present invention, using a laser, each dicing target member is supported. There are a case where a laser is used and a case where a whole is diced at once using a single laser. When dicing of each target member is performed in different steps, the dicing processing is improved, so that the dicing surface can be finished finely. On the other hand, if the whole is diced at once using one laser, the effect of shortening the processing time can be obtained.

  Specifically, the laser corresponding to each target member is preferably a laser having at least a suitable wavelength band, and this suitable wavelength band may differ for each target member. Appropriate wavelength band means that the target member efficiently absorbs the laser of the wavelength band.

  Specifically, a green laser or a UV laser is preferably used for dicing the Si wafer and the reinforcing plate. A YAG laser is optimal for the adhesive layer. Therefore, when dicing of each member is performed by dividing the process, these lasers may be switched. For example, after the silicon wafer is diced with a UV laser, the adhesive layer is diced with a YAG laser, and the reinforcing plate is diced with a UV laser. However, the dicing process with a laser in the present invention is not limited to this.

  In addition, since the adhesive layer can be diced using a green laser or a UV laser, it is preferable to use a green laser or a UV laser when dicing the entire laminate at once using one laser. .

  When dicing a plurality of members at a time, it is necessary to increase the laser output as compared to the case where each member is individually diced according to the thickness. Since there is a risk of damage, adjust the output accordingly.

  FIG. 3 is a view showing an embodiment of an inlet formed by mounting an IC chip according to the present invention on an antenna sheet. An antenna sheet is a member in which an antenna for non-contact communication is provided on a film by a coil or etching.

  The mounting of the IC chip antenna sheet may be performed through a resin composition such as an insulating resin film (NCF) or an anisotropic conductive resin film (ACF), or it may be ultrasonically mounted and the gap will be It may be filled with a fill, or may be performed by other known mounting methods, and the mounting method is not particularly limited in the present invention.

  Although not shown, the side surface of the IC chip may be sealed with a resin or the like within a range that does not affect the thickness of the IC chip portion in order to increase electrical stability.

  As shown in FIG. 3A, the IC chip obtained by using the IC chip manufacturing method of the present invention described with reference to FIGS. 1 and 2 has a thin Si wafer as described above. Furthermore, since the reinforcing plate is already laminated, when forming the inlet by mounting on the antenna sheet, it is not necessary to laminate the reinforcing plate on the resin seal, and the thickness of the IC chip portion of the inlet can be suppressed. It becomes possible.

  In the case of the mounting form shown in FIG. 3 (a), it is desirable to make the reinforcing plate thicker than the Si wafer. By adopting the structure of the present invention, the reinforcing plate can be made thin as a whole. Therefore, the strength of the IC chip portion can be improved.

  If further strength is required for the IC chip portion, a reinforcing plate may be laminated on the back side of the IC chip laminated portion of the antenna sheet via an adhesive layer as shown in FIG. . Even in this case, it is possible to make the IC chip portion thinner as compared with the conventional inlet in which the front and back surfaces of the IC chip portion are sealed with resin and a reinforcing plate is laminated.

  In the case of the mounting form shown in FIG. 3 (b), it is desirable to make the reinforcing plate on either the front or back side thicker than the Si wafer. Strength can be improved.

DESCRIPTION OF SYMBOLS 1 ... IC chip 2 ... Silicon wafer 3 ... Adhesion layer 4 ... Reinforcement plate 5 ... Dicing tape 6 ... Laser 7 ... Dicing blade 8 ... Antenna sheet 9 ...・ Sealing resin

  A 70 μm thick SUS plate as a reinforcing plate is formed on one side of an 80 μm thick silicon wafer on which an integrated circuit and connection terminals are formed and a scribe line having a width of 70 μm is provided via a DAF material having a thickness of 30 μm as an adhesive layer. Were laminated to form a laminate. Then, the laminated body is fixed on the dicing tape made of PO so that the reinforcing plate is in contact with the dicing tape, and the silicon wafer and the adhesive layer are bonded using a 60 μm thick dicing blade provided with diamond as abrasive grains. Dicing. Then, using a water jet laser in which a 10 W, 160 kHz UV laser was guided to a water jet with a water pressure of 10 Mpa, the reinforcing plate was diced in accordance with the dicing grooves of the silicon wafer to obtain individual IC chips. The obtained IC chip was not damaged and the dicing surface was smooth.

Claims (2)

Forming a laminate in which a reinforcing plate is bonded to one side of a silicon wafer on which an integrated circuit is formed via an adhesive layer;
Dicing the laminate and dividing it into IC chips,
Among the steps of dicing the laminate , a laser is used for dicing all of the silicon wafer, the adhesive layer, and the reinforcing plate,
An IC chip manufacturing method , wherein a green laser or a UV laser is used for dicing at least the silicon wafer and the reinforcing plate, and a YAG laser is used for dicing the adhesive layer . 2. The IC chip manufacturing method according to claim 1 , wherein the laser is a water jet laser.

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