JP4841807B2 - Thin film integrated circuit and thin semiconductor device - Google Patents

Description

  The present invention relates to a thin film integrated circuit from which information can be read even when the integrated circuit is destroyed or counterfeited, and a thin semiconductor device having the thin film integrated circuit.

  In recent years, opportunities for seeing products mounted with chips formed from silicon wafers have increased. With a chip formed from a silicon wafer, various information can be recorded and provided to consumers and the like.

  Unlike a magnetic card, bar code, or the like, such a chip is excellent in that there is no fear that stored data can be read by a physical method and that the data is not easily tampered with.

  Further, as a countermeasure against forgery, there is a method in which a plurality of information points are arranged on a card base material, and a combination of the information points has information for specifying individual IC chips (for example, see Patent Document 1). Patent Document 1 describes that an IC card can be accurately identified even when an IC is destroyed, and illegally forged IC cards can be excluded.

In addition, an IC card composed of an IC module and a data display unit has been proposed for the purpose of providing an IC card capable of reproducing and restoring data even if the memory contents are destroyed or altered (see Patent Document 2). ). According to Patent Document 2, the data display section is a display section that can be recorded in a non-electrically visible manner, and displays the data display section even if the contents of the memory of the IC module are unreadable or destroyed. It is described that the contents can be checked.
JP 2000-113155 A JP-A-7-31826

  Patent Document 1 describes that information points are formed and a combination of information points has information for specifying individual IC chips. And as information points, materials that can be identified by the sensor are provided in a pattern, for example, an information string is provided by coating, electrophotography, ink jet, etc. on a base sheet, and then molded together with electronic components in an IC card It is described that they are integrated and information points are formed separately from the IC chip. When information points are formed in addition to the IC chip in this way, the information points are easily recognized due to the unevenness and color of the information points, and the design of the product is further deteriorated.

  Therefore, an object of the present invention is to provide a method for forming identification information by means different from the above-mentioned patent document.

Another object of the present invention is to provide means capable of reading information on an integrated circuit even when it is destroyed, on the premise of an integrated circuit having identification information, unlike Patent Document 2.

  In view of the above problems, the present invention forms a thin film integrated circuit (hereinafter also referred to as an IDF chip) having a semiconductor film having a thickness of 0.2 μm or less, typically 40 nm to 170 nm, preferably 50 nm to 150 nm, as an active region. An information source (hereinafter referred to as identification information) capable of being identified in the IDF chip in the chip manufacturing process is formed. Further, the identification information forms a character, a figure, a symbol, a number, or a combination thereof, and is configured by the character, a figure, a symbol, a number, or a combination thereof.

  As means for forming the identification information, there are a method of using a pattern such as a semiconductor film, an insulating film, or a conductive film, or a method of marking (marking) the pattern or a part of the substrate with a laser marker. Thus, the identification information of the present invention can be integrally formed inside the IDF chip. As a result, an IDF chip having identification information can be mounted on an article. Further, since the IDF chip of the present invention is thin, it is difficult to visually recognize the IDF chip in the mounted article. Such an IDF chip is difficult to be tampered with by a third party, and further, it becomes impossible to tamper with identification information formed in the IDF chip, and security can be improved.

  Further, the identification information may use a pattern such as a figure or the like, and can be constituted by coding a combination of minute dots. In this way, identification information obtained by coding a figure or the like in a two-dimensional combination can be formed within a predetermined minute range and can have more information.

  Furthermore, the present invention is characterized in that a visible display means is provided in a thin semiconductor device having the thin film integrated circuit. The display means may have a memory property, and for example, an electrochromic material or a ferroelectric liquid crystal material can be used.

  Further, as described above, since the IDF chip is formed to have a very thin semiconductor film, the IDF chip can be made thinner than a chip formed from a silicon wafer. The thickness of a specific IDF chip is 0.3 μm to 3 μm, typically about 2 μm, and can be dramatically reduced.

  Further, since the IDF chip of the present invention is formed on a substrate having an insulating surface (hereinafter referred to as an insulating substrate), it has a light-transmitting property unlike a chip formed from a silicon wafer. Therefore, the identification information formed in the IDF chip manufacturing process cannot be recognized visually. That is, the identification information is translucent or fine. As a result, it becomes difficult for a third party to falsify the identification information, and security can be improved.

  Furthermore, the IDF chip of the present invention may be formed on a flexible substrate (hereinafter also referred to as a flexible substrate). Since it is formed on a flexible substrate, it has higher flexibility and can be lighter than a chip formed from a silicon wafer.

  As described above, since the identification information of the present invention can be integrally formed inside the IDF chip, the IDF chip is not easily tampered with by a third party, and the identification information formed in the IDF chip cannot be tampered with. Thus, security can be improved.

  Further, since the identification information of the present invention can be integrally formed with the IDF chip, the design information of the mounted article is not deteriorated by the identification information. In addition, since the IDF chip on which the identification information is formed has translucency, the design of the mounted article is not deteriorated by the IDF chip.

  Further, the IDF chip of the present invention is very thin as compared with a chip formed from a silicon wafer, so that the design is not deteriorated even when mounted on an article. Such a thin film, lightweight, and highly flexible IDF chip is less likely to be damaged than a chip formed from a silicon wafer.

  Furthermore, since the IDF chip of the present invention is formed on an insulating substrate, there is no restriction on the shape of the base substrate as compared with a chip formed from a circular silicon wafer. Therefore, productivity of the IDF chip can be increased and mass production can be performed. As a result, cost reduction of the IDF chip can be expected. An IDF chip with a very low unit price can generate very large profits by reducing unit cost.

  Embodiments of the present invention will be described below with reference to the drawings. However, the present invention can be implemented in many different modes, and it is easy for those skilled in the art to make various changes in form and details without departing from the spirit and scope of the present invention. Understood. Therefore, the present invention is not construed as being limited to the description of this embodiment mode. Note that in all the drawings for describing the embodiments, the same portions or portions having similar functions are denoted by the same reference numerals, and repetitive description thereof is omitted.

(Embodiment 1)
In this embodiment mode, a usage mode of a thin semiconductor device having identification information and a display portion will be described. In this embodiment mode, description will be made using a card (hereinafter referred to as an IDF card) on which an IDF chip is mounted as a thin semiconductor device.

  In FIG. 5A, an IDF chip 10 having identification information, an antenna 12, and display means 13 are provided on an insulating substrate 11. For the structure and manufacturing method of the IDF chip and the antenna, the following embodiments may be referred to.

An electrochromic material can be used for the display means. Since the electrochromic material has memory properties, only the display means can be used alone. Further, the electrochromic material is displayed by being sandwiched between opposing electrode layers. Further, a solid electrolyte layer may be laminated between the opposing electrodes. The electrode needs to be formed of a transparent conductive film. Examples of the transparent conductive film include indium tin oxide (ITO), IZO (indium zinc oxide) in which 2 to 20% zinc oxide (ZnO) is mixed with indium oxide, and 2 to 20% in indium oxide. ITSO mixed with silicon oxide (SiO ₂ ) or organic indium can be used.

Since the display means having such an electrochromic material is very thin, even if it is mounted on an IDF card together with an IDF chip, the design is not impaired. As a display means having the same effect, there is a ferroelectric liquid crystal material.

  Then, as shown in FIG. 5B, the first film 14 and the second film 15 are bonded together to complete the IDF card 20.

At this time, the IDF chip is preferably arranged at the center with respect to the card to be mounted, and the periphery of the IDF chip is covered with the base material of the article, which is the first and second films in this embodiment. As a result, the mechanical strength of the IDF chip can be increased. Specifically, the position where the IDF chip is sandwiched (the center of the IDF chip): X satisfies (1/2) · D−30 μm <X <(1/2) · D + 30 μm, where D is the card thickness. may If you placed in.

  In this embodiment, the case where an IDF chip having an antenna formed on a substrate is used is described. However, an IDF chip on which an antenna is mounted may be used, and the IDF chip satisfies the above position. preferable.

  FIG. 6A shows a system block diagram of the IDF card. The IDF chip having identification information is connected to a communication unit and a power supply (generation) unit. The communication means and the power supply (generation) means correspond to the antenna in FIG. The IDF chip is connected to display means. A circuit for controlling the display means (control circuit) may be formed integrally with the IDF chip.

  FIG. 6B shows a circuit block diagram of the IDF chip. First, the IDF chip 10 includes an antenna 12 and a capacitive element 52, and includes a demodulation circuit 53, a modulation circuit 54, a rectifier circuit 55, a microprocessor 56, a memory 57, and a switch 58 for applying a load to the antenna. ing. These circuits and the microprocessor can be formed by a thin film integrated circuit. Note that the memory 57 is not limited to one, and may be a plurality.

  In the IDF chip, a signal transmitted as a radio wave from the reader / writer device is converted into an AC electrical signal by electromagnetic induction in the antenna 12. The demodulating circuit 53 demodulates the alternating electrical signal and transmits it to the subsequent microprocessor 56. The rectifier circuit 55 generates a power supply voltage using an alternating electrical signal and supplies it to the microprocessor 56 at the subsequent stage.

  The microprocessor 56 performs various arithmetic processes according to the input signal. The memory 57 stores programs and data used in the microprocessor 56, and can also be used as a work area during arithmetic processing. The signal sent from the microprocessor 56 to the modulation circuit 54 is modulated into an alternating electrical signal. The switch 58 can apply a load to the antenna 12 in accordance with an alternating electrical signal from the modulation circuit 54. The reader / writer device can read the signal from the microprocessor 56 as a result of receiving the load applied to the antenna 12 by radio waves.

  Since the IDF chip formed in this way has identification information, the information can be read even when it is destroyed or counterfeited. For example, the reader / writer device is provided with means for reading the identification information, and the identification information is stored. Then, when the identification information is coincident with the reader / writer device when it is damaged, the IDF chip information can be output to the display unit that the reader / writer device has or is connected to. As a result, even if the path read from the IDF chip is destroyed, the IDF chip information can be read as soon as the identification information matches.

  In addition, the display means can record information by a route different from the route for recording information in the memory of the IDF chip, and can further hold the display. Therefore, even if the route for reading information from the IDF chip is destroyed, the information on the IDF chip can be read. At this time, for example, personal information or the like may be displayed on the display means. Therefore, the identification information may be used to output to a display unit included in or connected to the reader / writer device.

(Embodiment 2)
In this embodiment, an IDF chip that forms identification information will be described.

  As shown in FIG. 1A, a thin film transistor (also referred to as a TFT) includes a semiconductor film 107, a conductive film 110 functioning as a gate wiring, a signal line, or the like, and the semiconductor film 107 forms identification information 113a. The identification information is composed of characters, figures, symbols or numbers, or a combination thereof, and is formed in a part of the IDF chip. Moreover, you may form the code | symbol for information like a barcode as identification information.

  FIG. 1B illustrates the case where a thin film transistor includes a semiconductor film 107, a conductive film 110 functioning as a gate wiring, a signal line, or the like, and identification information is formed by the conductive film 110.

  At this time, the identification information, that is, the conductive film can be formed by drawing by a droplet discharge method. The droplet discharge method is a method for selectively discharging (jetting) a droplet (also referred to as a dot) of a composition mixed with a material such as a conductive film or an insulating film. Depending on the method, an inkjet method is used. Also called.

  In addition to the droplet discharge method, it can be formed by any one of a sputtering method, a printing method, a plating method, a photolithography method, a vapor deposition method using a metal mask, or a combination thereof.

  Note that the identification information of the present invention may be formed by other patterns of the thin film transistor. For example, the identification information can be formed by an insulating film such as a gate insulating film or an interlayer insulating film.

  FIG. 1C shows a case where identification information 113c is formed on a substrate, a thin film pattern, or the like included in an IDF chip by a laser marker.

For example, when forming identification information on a glass substrate, a laser that is absorbed by the glass substrate, such as a CO ₂ laser, can be used. When forming identification information on a semiconductor film, a laser absorbed by the semiconductor film, for example, a YAG laser can be used. Needless to say, identification information may be formed on a part of the insulating film or the conductive film using a laser marker.

  A means that can draw identification information such as a droplet discharge method or a laser marker does not form a photomask or the like. As a result, the cost for the mask formation process and the mask pattern can be reduced.

  The identification information as described above can be recognized, for example, as a change in transmittance, reflection pattern, or absorption spectrum. The IDF chip specific information can be managed by the identification information. As a result, unauthorized use or forgery of the IDF chip can be prevented, and security can be improved by the identification information.

  Further, when the information on the IDF chip is to be read after destruction of the article on which the IDF chip is mounted, the identification information can be used to determine whether or not the access is legitimate. Since unique information of the IDF chip can be formed from the identification information, it is possible to determine whether or not the access is regular based on the identification information. As a result, even if it is destroyed or the like, it is possible to permit reading of the IDF chip information by obtaining identification information even if the person has a legitimate access right.

  By forming the identification information in the IDF chip in this way, it is possible to prevent forgery of the IDF chip and improve security. Further, since the IDF chip and the identification information have translucency, it is difficult for a third party to recognize the identification information, and as a result, it is difficult to falsify. Furthermore, the IDF chip is very thin, and identification information formed on a part of the chip can be mounted on an article without deteriorating the design.

  In more detail, the IDF chip includes a contactless IDF chip (also referred to as a wireless tag) in which an antenna is mounted, a contact IDF chip in which a terminal connected to an external power source is formed without mounting the antenna, There is a hybrid type IDF chip in which a contact type and a contact type are mixed. More specifically, there is a non-contact type in which an IDF chip and an antenna are separately formed and bonded together. Some antennas are integrated with an IDF chip. For example, the antenna can be formed integrally with a gate electrode of TFT, wiring, or the like. It is preferable to integrally form the antenna on the IDF chip because the cost and time required for bonding can be reduced.

  In the case where the IDF chip and the antenna are separately formed, the antenna may be formed on a surface different from the mounting surface of the IDF chip. If the mounting surfaces of the IDF chip and the antenna are different, there is no restriction on the mounting area, and the degree of freedom in design increases. The antenna in this case can be formed on a substrate (a substrate for forming an antenna is referred to as an antenna substrate) or directly on an article.

  The IDF chip of the present invention can form identification information as described above regardless of whether it is a contact type, non-contact type, or hybrid type IDF chip.

(Embodiment 3)
In this embodiment mode, a manufacturing process of an IDF chip having identification information formed using a semiconductor film is described.

  As shown in FIG. 2A, an insulating film 102 provided over an insulating substrate 100 with a separation layer 101 interposed therebetween, semiconductor films 107a and 107b patterned into a desired shape, and an insulating film functioning as a gate insulating film ( Hereinafter, thin film transistors 130n and 130p each having a conductive film (hereinafter referred to as a gate electrode) 106 functioning as a gate electrode provided via a gate insulating film 105 are provided, and identification information is obtained using part of the semiconductor film. 113 is formed.

  Examples of the insulating substrate include glass substrates such as barium borosilicate glass and alumino borosilicate glass, and quartz substrates. Other substrates having an insulating surface include plastics typified by polyethylene-terephthalate (PET), polyethylene naphthalate (PEN), and polyethersulfone (PES), and flexible synthetic resins such as acrylic. There is a substrate that becomes. In addition, a substrate in which an insulating film such as silicon oxide or silicon nitride is formed on the surface of a metal such as stainless steel or a semiconductor substrate can also be used. Such an insulating substrate is not limited in the shape of the base substrate and can reduce the cost of the IDF chip as compared with a case where the chip is taken out from a circular silicon wafer.

  The semiconductor film includes a channel formation region and an impurity region (including a source region, a drain region, a GOLD region, and an LDD region), and an n-channel thin film transistor 130n or p depending on the conductivity type of the impurity element added to the impurity region. It can be distinguished from the channel thin film transistor 130p. A wiring 110 is formed so as to be connected to each impurity region.

  In this embodiment mode, the identification information is formed using part of the semiconductor film. However, as shown in FIG. 8A, part of the gate electrode is used, and the wiring 110 is formed as shown in FIG. May be used to form identification information. That is, the identification information of the present invention is formed in the IDF chip, and the identification information can be formed by combining one of the patterns of the thin film transistor or a combination thereof.

  Further, identification information may be marked on the above-described insulating substrate using a laser marker. In addition, as shown below, an insulating substrate may peel. In such a case, identification information may be marked on the pattern of the thin film transistor using a laser marker.

  The identification information as described above may use a pattern such as a figure in addition to numbers and barcodes, or may be constituted by coding a combination of minute dots. For example, minute dots are formed from a region irradiated with a laser marker and a region not irradiated. One dot can correspond to 1 bit, and a lot of information can be provided by forming them in a matrix. The dots may be formed from a pattern of a thin film transistor, for example, a semiconductor film. In this way, identification information obtained by coding a figure or the like in a two-dimensional combination can be formed within a predetermined minute range and can have more information.

  The present invention is characterized in that the identification information is formed in the IDF chip, and is not limited to the form of the identification information.

  The separation layer may be a film containing silicon, and the state may be any of an amorphous semiconductor, a semi-amorphous semiconductor in which an amorphous state and a crystalline state are mixed (also referred to as SAS), and a crystalline semiconductor. Good. Note that a SAS includes a microcrystalline semiconductor in which crystal grains of 0.5 nm to 20 nm can be observed in an amorphous semiconductor. These release layers can be formed by a sputtering method, a plasma CVD method, or the like. The release layer may have a thickness of 30 nm to 1 μm, and can be 30 nm or less if the thin film formation limit of the release layer deposition apparatus permits. In this embodiment mode, a SAS having a thickness of 30 nm to 1 μm, preferably 30 nm to 50 nm is used for the release layer, but the other materials described above may be used.

  In addition, since the TFT layer is not etched, an insulating film is preferably formed over the separation layer. The insulating film is made of silicon oxide (SiOx), silicon nitride (SiNx), silicon oxynitride (SiOxNy) (x> y), silicon nitride oxide (SiNxOy) (x> y) (x, y = 1, 2,... ) Or the like, or a single layer structure of an insulating film containing oxygen or nitrogen, or a stacked structure thereof.

  The insulating film described above can be formed as a base film, for example. That is, the base film may have a stacked structure, and in this embodiment mode, the base film includes the first insulating film 102a, the second insulating film 102b, and the third insulating film 102c. For example, a silicon oxide film is used as the first insulating film, a silicon oxynitride film is used as the second insulating film, and a silicon oxide film is used as the third insulating film. Further, a silicon oxynitride film is preferably used as the base film in consideration of impurity diffusion from the substrate or the like, but there is a concern that the silicon oxynitride film has low adhesion to a peeling layer or a semiconductor film. Therefore, when a silicon oxynitride film is provided as the second insulating film and a silicon oxide film having high adhesion with the separation layer, the semiconductor film, and the silicon oxynitride film is provided as the first insulating film and the third insulating film. Good.

  The semiconductor films 107a and 107b have a thickness of 0.2 μm or less, typically 40 nm to 170 nm, preferably 50 nm to 150 nm. The semiconductor films 107a and 107b may have any state of an amorphous semiconductor, a semi-amorphous semiconductor in which an amorphous state and a crystalline state are mixed (including a microcrystalline semiconductor), and a crystalline semiconductor. .

  In this embodiment, an amorphous semiconductor film is formed and a crystalline semiconductor film crystallized by heat treatment is formed. The heat treatment can be a heating furnace, laser irradiation, irradiation of light emitted from a lamp instead of laser light (hereinafter referred to as lamp annealing), or a combination thereof.

When laser irradiation is used, a continuous wave laser (CW laser) or a pulsed laser (pulse laser) can be used. As the laser, Ar laser, Kr laser, an excimer laser, YAG _laser, Y 2 _{O 3} laser, YVO ₄ laser, GdVO ₄ laser, a YLF laser, Y A lO ₃ lasers, glass lasers, ruby lasers, alexandrite wells laser, Ti : One or more of sapphire laser, copper vapor laser, or gold vapor laser can be used. By irradiating a fundamental wave oscillated from such a laser and a second to fourth harmonic laser of the fundamental wave, a crystal having a large grain size can be obtained. For example, the second harmonic (532 nm) or the third harmonic (355 nm) of an Nd: YVO ₄ laser (fundamental wave 1064 nm) can be used. Energy density of the laser is about 0.01 to 100 MW / cm ² (preferably 0.1 to 10 MW / cm ²⁾ is required. Then, irradiation is performed at a scanning speed of about 10 to 2000 cm / sec.

  At this time, for example, using an optical system as shown in FIG. 7A, crystallization can be performed using a CW laser. First, the CW laser beam emitted from the laser oscillator 290 is elongated by the optical system 291 and processed into a linear shape. Specifically, a cylindrical lens or a convex lens included in the optical system 291 can be processed into a linear shape when the laser beam passes. At this time, it is good to process so that the length of the long axis of a spot may be set to 200-350 micrometers.

  Thereafter, the laser beam processed into a linear shape is incident on the semiconductor film 107 which is an irradiation object via the galvanometer mirror 293 and the fθ lens 294. At this time, the linear laser is adjusted so as to form a laser spot 282 having a predetermined size on the semiconductor film. Further, the fθ lens 294 can make the shape of the laser spot 282 constant on the surface of the irradiated object regardless of the angle of the galvanometer mirror. A telecentric fθ lens may be used in place of the fθ lens, and the same effect is obtained.

  At this time, the device (control device) 296 that controls the vibration of the galvanometer mirror vibrates, that is, the angle of the mirror changes, and the laser spot 282 moves in one direction. For example, when the galvanometer mirror vibrates in a half cycle, the laser beam is adjusted so as to move a certain distance in the X-axis direction on the semiconductor film (outward path).

  Then, the semiconductor film moves by a certain distance in the Y-axis direction by the XY stage 295. Similarly, the laser spot moves in the X-axis direction on the semiconductor film by the galvanometer mirror (return path). By using such a reciprocating motion of the laser beam, the laser spot moves along the path 283, and laser annealing can be performed on the entire semiconductor film.

  At this time, as shown in FIG. 7B, laser annealing is performed so that the carrier moving direction 281 of the thin film transistor and the moving direction (scanning direction) 283 to the major axis of the laser beam are aligned (parallel). . For example, in the case of a semiconductor film having the shape shown in FIG. 7B, the source region 107 (s) formed in the semiconductor film so as to be parallel to the moving direction (scanning direction) 283 of the laser beam to the long axis, A channel formation region 107 (c) and a drain region 107 (d) are disposed. As a result, since the grain boundaries crossed by carriers can be reduced or eliminated, the mobility of the thin film transistor can be increased.

  Furthermore, the incident angle of the laser may be θ (0 <θ <90 degrees) with respect to the semiconductor film. As a result, laser interference due to reflected light or the like can be prevented.

  Note that continuous wave fundamental laser light and continuous wave harmonic laser light may be emitted, or continuous wave fundamental laser light and pulsed harmonic laser light are emitted. You may do it. Energy can be supplemented by irradiating a plurality of laser beams.

  In addition, it is a pulse oscillation type laser that oscillates laser light at an oscillation frequency that can irradiate the laser light of the next pulse after the semiconductor film is melted by the laser light and solidifies in the scanning direction. Crystal grains grown continuously can be obtained. That is, by using a pulse beam in which the lower limit of the oscillation frequency is set so that the period of pulse oscillation is shorter than the time until the semiconductor film is completely solidified after being melted, Continuously grown crystal grains can be obtained. The oscillation frequency of the pulse beam that can be actually used is 10 MHz or more, and a frequency band that is significantly higher than the frequency band of several tens to several hundreds Hz that is normally used is used.

  Note that laser light may be irradiated in an inert gas atmosphere such as a rare gas or nitrogen. Thereby, roughness of the semiconductor surface due to laser light irradiation can be suppressed, and variation in threshold value caused by variation in interface state density can be suppressed.

Alternatively, a microcrystalline semiconductor film may be formed using SiH ₄ and F ₂ , or SiH ₄ and H ₂ , and then crystallized by performing laser irradiation as described above. That is, regardless of whether the semiconductor film is amorphous, microcrystalline, or crystalline, laser irradiation can be performed to improve the crystalline state.

  As another heat treatment, when a heating furnace is used, the amorphous semiconductor film is heated at 500 to 550 ° C. for 2 to 20 hours. At this time, the temperature may be set in multiple stages in the range of 500 to 550 ° C. so that the temperature gradually increases. In the first low-temperature heating step, hydrogen or the like of the amorphous semiconductor film comes out, so that so-called hydrogen dipping that reduces film roughness during crystallization can be performed. Furthermore, it is preferable to form a metal element that promotes crystallization, such as Ni, on the amorphous semiconductor film because the heating temperature can be reduced. In addition, even if it is crystallization using such a metal element, you may heat at 600-950 degreeC. When high temperature treatment is required in this way, a quartz substrate with high heat resistance is preferably used.

  However, when a metal element is formed, there is a concern that the electrical characteristics of the semiconductor element may be adversely affected. Therefore, it is necessary to perform a gettering step for reducing or removing the metal element. For example, heat treatment may be performed so as to capture a metal element using an amorphous semiconductor film as a gettering sink.

Alternatively, a crystalline semiconductor film may be formed directly on the surface to be formed. In this case, a crystalline semiconductor film is directly formed on the surface to be formed using heat or plasma using a fluorine-based gas such as GeF ₄ or F ₂ and a silane-based gas such as SiH ₄ or Si ₂ H _6. Can be formed. In the case where a crystalline semiconductor film is directly formed as described above and high temperature treatment is required, a quartz substrate with high heat resistance is preferably used.

  It is considered that the peeling layer is affected by the heating process of the semiconductor film as described above. For example, when heat treatment is performed using a furnace, or when laser irradiation is performed using a wavelength of 532 nm, energy may reach the release layer. As a result, the release layer may be crystallized at the same time. The reaction rate can be improved by such a change in the crystallization state of the release layer.

  On the other hand, in order to efficiently crystallize the semiconductor film, the structure of the base film can be selected so that the energy of the laser does not reach the release layer. For example, the base film material, film thickness, or stacking order is selected.

A semiconductor film formed by any one of the means described above has more hydrogen than a chip formed from a silicon wafer. Specifically, hydrogen can be formed so as to have 1 × 10 ¹⁹ to 1 × 10 ²² / cm ³ , preferably 1 × 10 ^{19 to} 5 × 10 ²⁰ / cm ³ . This hydrogen can provide a so-called defect termination effect that alleviates defects in the semiconductor film. Moreover, the flexibility of the IDF chip can be increased by hydrogen. Further, the same effect can be obtained by forming the film with halogen instead of hydrogen.

A sub-shred coefficient (S value) of a thin film transistor having such a semiconductor film is 0.35 V / dec or less, preferably 0.09 to 0.25 V / dec. Further, the mobility of the thin film transistor is 10 cm ² / Vs or more.

  When a 19-stage ring oscillator is configured using such a thin film transistor, the oscillation frequency is 1 MHz or higher, preferably 100 MHz or higher at a power supply voltage of 3 to 5 V. At a power supply voltage of 3 to 5 V, the delay time per inverter stage is 26 ns, preferably 0.26 ns or less.

  Furthermore, by setting the ratio of the area occupied by the patterned semiconductor film in the IDF chip to 1 to 30%, it is possible to prevent the thin film transistor from being broken or peeled off due to bending stress.

  Although the above structure can function as a thin film transistor, the first interlayer insulating film 108 and the second interlayer insulating film 109 are preferably formed. Damage or defects of the semiconductor film can be repaired by hydrogen from the first interlayer insulating film. That is, a defect termination effect due to hydrogen can be achieved. As such a first interlayer insulating film, silicon oxide (SiOx), silicon nitride (SiNx), silicon oxynitride (SiOxNy) (x> y), silicon nitride oxide (SiNxOy) (x> y) (x, An insulating film containing oxygen or nitrogen such as y = 1, 2,.

  Further, the flatness can be improved by the second interlayer insulating film. Such a second interlayer insulating film can be made of an organic material or an inorganic material. As the organic material, polyimide, acrylic, polyamide, polyimide amide, resist, benzocyclobutene, siloxane, or polysilazane can be used. Siloxane has a skeletal structure with a bond of silicon (Si) and oxygen (O), and the substituent contains at least hydrogen, or the substituent has at least one of fluorine, alkyl groups, and aromatic hydrocarbons. Is formed as a starting material. Polysilazane is formed using a polymer material having a bond of silicon (Si) and nitrogen (N), that is, a liquid material containing so-called polysilazane as a starting material. Examples of inorganic materials include silicon oxide (SiOx), silicon nitride (SiNx), silicon oxynitride (SiOxNy) (x> y), silicon nitride oxide (SiNxOy) (x> y) (x, y = 1, 2,... An insulating film containing oxygen or nitrogen such as ()) can be used. In the case of using an inorganic material, an insulating film containing nitrogen is preferable because it prevents intrusion of alkali ions such as Na. A stacked structure of these insulating films may be used as the second interlayer insulating film. In particular, when the second interlayer insulating film is formed using an organic material, the flatness is improved, but moisture and oxygen are absorbed by the organic material. In order to prevent this, a stacked structure in which an insulating film including an inorganic material is formed over an organic material is preferable.

  More preferably, a fourth insulating film 111 is provided so as to cover the wiring 110. Since an article on which an IDF chip is mounted is often touched by hand, there is a concern about the diffusion of alkali ions such as Na. Therefore, it is preferable to form a fourth insulating film on the top surface of the IDF chip. As the fourth insulating film, silicon oxide (SiOx), silicon nitride (SiNx), silicon oxynitride (SiOxNy) (x> y), silicon nitride oxide (SiNxOy) (x> y) (x, y = 1, An insulating film containing oxygen or nitrogen such as 2 ...) can be used, but silicon nitride oxide (SiNxOy) is typically used.

  Although the IDF chip can be completed as described above, it is preferable to peel the insulating substrate in order to reduce the thickness. Alternatively, the insulating substrate may be polished by chemical-mechanical polishing (hereinafter referred to as CMP) to achieve thinning. In this embodiment, the case where an insulating substrate is peeled is described.

  Thereafter, a groove 114 is formed between the IDF chips. The groove can be formed by dicing, scribing, etching using a mask, or the like. In the case of dicing, a blade dicing method using a dicing apparatus (dicer) is generally used. The blade is a grindstone in which diamond abrasive grains are embedded, and has a width of about 30 to 50 μm. The TFT layer is separated by rotating the blade at a high speed. In the case of scribing, there are a diamond scribing method and a laser scribing method. In the case of etching, a mask pattern can be formed by exposure and development processes, and the TFT layer can be separated by a dry etching method, a wet etching method, or the like. In the dry etching method, an atmospheric pressure plasma method may be used.

  The groove is not necessarily formed between the IDF chips, and may be formed between a plurality of IDF chips.

  Next, as illustrated in FIG. 2B, the peeling layer is removed by introducing an etching agent 115 into the groove 114. As an etchant, a gas or a liquid containing a halogenated fluorine can be used.

In this embodiment, a low-pressure CVD apparatus is used, and ClF ₃ (chlorine trifluoride) is used as the halogenated fluorine. The release layer is removed under the conditions of temperature: 350 ° C., flow rate: 300 sccm, atmospheric pressure: 6 Torr, and time: 3 h, but is not limited to these conditions.
Moreover, the reaction rate of ClF ₃ can be increased by increasing the treatment temperature (for example, 100 ° C. to 400 ° C.). As a result, the amount of ClF ₃ used can be reduced.

ClF ₃ can be produced through the process of Cl ₂ (g) + 3F ₂ (g) → 2ClF ₃ (g) by reacting chlorine with fluorine at 200 ° C. or higher. Further, ClF ₃ may be a liquid depending on the temperature of the reaction space (boiling point 11.75 ° C.), and in this case, wet etching can be adopted as a liquid containing halogenated fluorine.

  By introducing such an etchant, the SAS as the release layer can be gradually retreated, and the insulating substrate can be removed as indicated by the arrow.

Further, as a gas containing other halogenated fluorine, a gas in which nitrogen is mixed with ClF ₃ or the like may be used. Further, an etchant that etches the release layer and does not etch the base film is not limited to ClF ₃ , and is not limited to halogenated fluorine. For example, a gas containing fluorine such as CF ₄ , SF ₆ , NF ₃ , F _2, etc. can be used as plasma. As another etching agent, a strong alkaline solution such as tetraethylammonium hydroxide (TMAH) may be used.

Further, in the case of chemical removal with a gas containing a halogenated fluorine such as ClF ₃ , if the condition that a material that is selectively etched is used as a peeling layer and a material that is not etched is used as a base film, the peeling layer and The combination of the base films is not limited to the above materials.

In such an etching process, an etching agent, a gas flow rate, a temperature, and the like are set so that each layer of the TFT is not etched. Note that ClF ₃ used in this embodiment has a property of selectively etching silicon, and thus selectively removes the SAS which is a separation layer. For this reason, a layer mainly composed of silicon typified by SAS is used for the peeling layer, and an insulating film containing oxygen or nitrogen is used for the base film, and the TFT layer is etched by ClF _3. There is no. Since the difference in reaction rate between the release layer and the base film is large, that is, the selectivity of the etch rate is high, the release layer can be removed while protecting the IDF chip.

  The etching time can also be adjusted depending on the crystal state of the release layer. It is preferable that the etching process time is short because the influence on each layer of the TFT is small. Further, it is preferable because the amount of the etching agent to be used can be reduced.

Each IDF chip may be connected by a semiconductor film, an insulating film, or a conductive film constituting the IDF chip so that the IDF chips are not separated apart by peeling of the insulating substrate.
In addition, after attaching a substrate over which an antenna is formed (hereinafter referred to as an antenna substrate), an insulating agent may be removed by introducing an etchant.

  Although the IDF chip can be completed through the above steps, a flexible substrate may be bonded as shown in FIG. In this case, identification information may be formed on the flexible substrate. FIG. 2C shows a cross-sectional view of the state in which the flexible substrate 150 is bonded with the adhesive 151.

  As the flexible substrate, a substrate made of the above-described plastic or a flexible synthetic resin such as acrylic can be used. Note that a substrate made of a constituent resin including plastic is used in this embodiment mode.

  As the adhesive, an adhesive such as a thermosetting resin, an ultraviolet curable resin, an epoxy resin adhesive, a resin additive, or a double-sided tape can be used.

  By adhering the flexible substrate, it is possible to increase the breaking strength of the IDF chip while achieving a reduction in thickness and weight as compared with the state formed on the insulating substrate.

Thereafter, as shown in FIG. 2D, each IDF chip is cut by dicing, scribing, or laser cutting to complete the IDF chip formed on the flexible substrate. For example, it can be cut using a laser that is absorbed by the glass substrate, for example a CO ₂ laser.

Thereafter, an organic resin such as an epoxy resin may be filled around the side surface of the IDF chip. As a result, the IDF chip is protected from the outside and is easy to carry. The size of the IDF chip formed in this way, 5 mm square (25 mm ²⁾ or less, preferably to a 0.3mm square (0.09 mm ²⁾ to 4 mm square (16 mm ^2).

  In addition, the IDF chip of the present invention is provided on an insulating substrate or peels off the insulating substrate, so that there is no concern about radio wave absorption and a highly sensitive signal reception compared to a chip formed from a silicon wafer. be able to.

  The IDF chip thus formed may be mounted on a desired article. As the adhesive used at this time, an adhesive such as a thermosetting resin, an ultraviolet curable resin, an epoxy resin adhesive, a resin additive, or a double-sided tape can be used.

  Although not shown, in order to protect the IDF chip, the side surface of the IDF chip may be covered with an insulating film containing resin or nitrogen. Covering with an insulating film containing resin or nitrogen improves the breaking strength of the IDF chip and facilitates carrying. This insulating film containing resin or nitrogen may be part of the material of the article on which the IDF chip is mounted.

  In the present embodiment, the case where the IDF chip connection terminal and the antenna connection terminal are mounted in a so-called face-down manner in which the connection terminal of the IDF chip and the antenna connection terminal face each other is described. You may mount by what is called a face up which does not face a terminal but faces the same direction. In the case of face-up, a wire bonding method can be used as a connection means.

  As mentioned above, after forming the thin film transistor on the insulating substrate, the embodiment in which the insulating substrate is peeled off and preferably transferred to the flexible substrate has been described, but the timing of peeling, the number of times of peeling, or the form in which the IDF chip is in a face-down state is The present invention is not limited to this embodiment. Further, it is possible to determine whether the IDF chip is in a face-up state or a face-down state depending on the number of times of transfer. The destination to be transferred is not limited to the flexible substrate, and may be an article to be mounted (mounting article).

  As described above, in the present embodiment, the IDF chip and the like are described as being thick for easy understanding, but in actuality, the shape is very thin.

(Embodiment 4)
In this embodiment, an antenna manufacturing method and an antenna mounting method will be described.

  An antenna manufacturing process will be described with reference to FIGS. Although FIG. 3 illustrates a case where an antenna wound in a rectangular shape on an antenna substrate is described, the shape of the antenna is not limited to this. For example, a circular or linear antenna may be used.

  The substrate for the antenna is a glass substrate such as barium borosilicate glass or alumino borosilicate glass, a quartz substrate, polyethylene-terephthalate (PET), polyethylene naphthalate (PEN), plastic typified by polyethersulfone (PES), A substrate made of a synthetic resin having flexibility such as acrylic can be used. Since the antenna substrate is preferably thin, a film-like substrate is preferable.

  3A shows the whole antenna substrate, and FIG. 3B is an enlarged view thereof. As shown in FIG. 3B, the antenna 162 is formed on the antenna substrate 161 by a droplet discharge method using a nozzle 180. The droplet discharge method is a method for selectively discharging (jetting) a droplet (also referred to as a dot) of a composition mixed with a material such as a conductive film or an insulating film. Depending on the method, an inkjet method is used. Also called. In addition to the droplet discharge method, it can be formed by any one of a sputtering method, a printing method, a plating method, a photolithography method, a vapor deposition method using a metal mask, or a combination thereof. For example, the first antenna is formed by any one of a sputtering method, a droplet discharge method, a printing method, a photolithography method, and a vapor deposition method, and a second antenna is formed so as to cover the first antenna by a plating method. A stacked antenna can also be formed. In particular, in the case where an antenna is formed by a droplet discharge method or a printing method, it is not necessary to pattern a conductive film, so that a manufacturing process can be reduced.

  In addition, a connection terminal region (hereinafter simply referred to as a connection terminal) 165 may be formed in the antenna. The connection terminal can be easily connected to the thin film integrated circuit. The connection terminal can be formed by increasing the number of droplets ejected from the nozzle or by fastening the nozzle. Note that the connection terminal is not necessarily provided and is not limited to the shape and arrangement of this embodiment.

  As the antenna material, a conductive material such as Ag (silver), Al (aluminum), Au (gold), Cu (copper), or Pt (platinum) can be used. When using Al or Au having relatively high resistance, there is a concern about wiring resistance. However, when the antenna is thick or the antenna formation area is large, the wiring resistance can be reduced by increasing the width of the antenna. Alternatively, a stacked antenna may be used and covered with a low resistance material. For a conductive material such as Cu that is likely to be diffused, an insulating film that functions as a protective film may be formed so as to cover the surface where the antenna is formed or the periphery of Cu.

  In this embodiment mode, the antenna 162 is formed by dropping Ag mixed in tetradecane as a solvent from the nozzle 180. At this time, in order to improve the adhesion of Ag, a base film made of titanium oxide (TiOx) may be formed on the antenna substrate.

An organic material may be filled so as to cover the antenna thus formed. As a result, since the organic material is filled between the antennas, the strength of the antenna can be increased.

  More preferably, pressure is applied to the formed antenna to improve flatness. As a result, the antenna can be thinned. In addition to the pressurizing means, a heating means may be provided, and the pressurization process and the heat treatment can be performed simultaneously. In particular, when a droplet discharge method is used and heat treatment is required to remove the solvent, the heat treatment can be combined.

  Further, a groove may be formed in the antenna formation region of the antenna substrate, and the antenna may be formed in the groove. Since the antenna can be formed in the groove, the antenna substrate and the antenna can be thinned, and the strength of the antenna can be increased.

  The antenna can also be formed on both sides of the antenna substrate. As a result, since the antenna length can be extended, the communication distance can be increased. In that case, an antenna may be formed on the other surface of the antenna substrate by the same method as described above.

  Depending on the arrangement of the connection terminals, a part of the antenna may be formed on the other surface of the antenna substrate. For example, if the antenna is formed so as to be wound, it becomes necessary to overcome the antenna depending on the arrangement of the connection terminals. At this time, it is necessary to use an insulator so that the antennas do not short-circuit, but an antenna substrate may be used as the insulator.

  Then, as shown in FIG. 4, the antenna substrate on which the antenna is formed and the IDF chip bonded on the flexible substrate 150 are bonded together. FIG. 4A shows a top view in a bonded state, and FIG. 4B shows a cross-sectional view taken along line ab.

As an attaching means, there is an anisotropic conductor 163 in which the conductor 164 is dispersed.
The anisotropic conductor can be electrically connected in the region where the connection terminal 160 of the IDF chip and the connection terminal 165 of the antenna are provided, because the conductor is pressed by the thickness of each connection terminal. In other areas, the conductors are kept at a sufficient interval, and thus do not conduct. In addition to the anisotropic conductor, bonding may be performed using an ultrasonic adhesive, an ultraviolet curable resin, a double-sided tape, or the like.

  Further, the antenna substrate on which the antenna is formed may be attached to both surfaces of the IDF chip. As a result, the total distance of the antennas can be increased, and the sensitivity such as the communication distance can be increased. In such a case, the antenna substrate may be bonded instead of the flexible substrate. As a result, the strength of the IDF chip can be increased by the antenna substrate, and the sensitivity such as the communication distance can be further increased.

  Although the case where the IDF chip and the antenna are attached to each other has been described in this embodiment mode, the antenna may be directly formed over the IDF chip. For example, the antenna can be formed in the same layer as the gate electrode 106 or the wiring 110. At this time, in order to reduce the resistance of the antenna, it may be covered with Cu that can be formed by a plating method, for example, electroless plating. Cu, which is such a low resistance material, may adversely affect the electrical characteristics of the thin film transistor. Therefore, in order to prevent diffusion of Cu, an antenna having Cu may be formed over the fourth insulating film 111. At this time, the fourth insulating film is preferably an insulating film containing nitrogen.

  When the antenna is directly formed on the IDF chip as described above, it is possible to reduce costs and time for bonding, or defects due to bonding.

  In this embodiment mode, a non-contact type IDF chip having an antenna as an IDF chip has been described. However, since the present invention is characterized by forming identification information as described above, a contact type IDF chip and a hybrid type IDF are used. Any of the chips may be used.

  As described above, in the present embodiment, the IDF chip and the antenna substrate are described as being thick for easy understanding, but in actuality, the shape is very thin.

It is sectional drawing which showed the identification information formed in the thin film integrated circuit It is sectional drawing which showed the manufacturing process of the thin film integrated circuit It is sectional drawing which showed the manufacturing process of the antenna It is sectional drawing which showed the state which bonded the thin film integrated circuit and the antenna It is a perspective view of the card | curd which mounted the thin film integrated circuit and the display means. It is a system block diagram of a card on which a thin film integrated circuit and display means are mounted. It is the figure which showed the manufacturing process of a thin film integrated circuit It is sectional drawing which showed the manufacturing process of the thin film integrated circuit

Claims (8)

A thin film integrated circuit having a thin film transistor including a semiconductor film having a thickness of 40 nm to 170 nm,
In the preparation process of the thin film transistor, the semiconductor film, a gate electrode to which the thin film transistor having the wiring, a gate insulating film, and by using any one of the interlayer insulating film, characters, figures, symbols or numbers, or a combination thereof is formed identification information is formed,
The identification information is integrally formed in the thin film integrated circuit,
The identification information and the thin film integrated circuit are translucent. A thin film integrated circuit having a thin film transistor including a semiconductor film having a thickness of 40 nm to 170 nm,
In the manufacturing process of the thin film transistor , the semiconductor film of the thin film transistor is irradiated with a laser marker, and an area where the laser marker is irradiated and an area where the laser marker is not irradiated are arranged in a matrix Information is formed,
The identification information is integrally formed in the thin film integrated circuit,
The identification information and the thin film integrated circuit are translucent. According to claim 1 or claim 2, the thin film integrated circuit, wherein the thin film integrated circuit is 5mm square or less. In any one of claims 1 to 3, wherein the semiconductor film, a thin film integrated circuit, wherein the concentration of the hydrogen concentration or halogen is ^{1 × 10 19 ~5 × 10 20} / cm 3. In any one of claims 1 to 4, the thin film integrated circuit and the thin film integrated circuit is characterized by having an antenna formed on the same substrate. In any one of claims 1 to 5, wherein the thin film integrated circuit thin film integrated circuit, characterized in that formed on the insulating substrate, the insulating substrate after was peeled. A thin film integrated circuit according to any one of claims 1 to 6, a thin semiconductor device and having a connected display means to the thin film integrated circuit. 8. The thin semiconductor device according to claim 7 , wherein the display means includes an electrochromic material or a ferroelectric liquid crystal material.

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