JP4865248B2 - Semiconductor device - Google Patents

Description

The present invention relates to a semiconductor device capable of transmitting and receiving data and a driving method thereof.

In recent years, development of semiconductor devices that transmit and receive data contactlessly using electromagnetic waves has been promoted, and these semiconductor devices are called RF (Radio Frequency) tags, wireless tags, electronic tags, transponders, and the like (for example, , See Patent Document 1). Most semiconductor devices currently in practical use have a circuit using a semiconductor substrate (also called an IC (Integrated Circuit) chip) and an antenna, and a memory and a control circuit are built in the IC chip. ing.
JP 2004-282050 A (pages 11-14, FIG. 5)

Semiconductor devices that can send and receive data without contact are in widespread use in some areas such as railway boarding cards and electronic money cards, but it is an urgent issue to provide inexpensive semiconductor devices for further spread. Met. In view of the above circumstances, an object of the present invention is to provide a semiconductor device including a memory having a simple structure, and to provide an inexpensive semiconductor device and a driving method thereof.

A semiconductor device of the present invention includes a phase change memory having a memory cell array including a plurality of memory cells, a control circuit for controlling the phase change memory, and an antenna, and the memory cell array has a bit extending in a first direction. And a plurality of word lines extending in a second direction perpendicular to the first direction, and each of the plurality of memory cells has a phase change layer provided between the bit line and the word line. Features. In the semiconductor device having the above structure, one or both of the conductive layer forming the bit line and the conductive layer forming the word line have a light-transmitting property.

The phase change layer includes a material that reversibly changes between a crystalline state and an amorphous state. For example, germanium (Ge), tellurium (Te), antimony (Sb), sulfur (S), tellurium oxide (TeOx). ), Tin (Sn), gold (Au), gallium (Ga), selenium (Se), indium (In), thallium (Tl), cobalt (Co) and silver (Ag). It is characterized by being.

The phase change layer includes a material that reversibly changes between the first crystal state and the second crystal state. For example, silver (Ag), zinc (Zn), copper (Cu), aluminum (Al ), Nickel (Ni), indium (In), antimony (Sb), selenium (Se), and tellurium (Te).

The phase change layer has a material that changes only from an amorphous state to a crystalline state. For example, tellurium (Te), tellurium oxide (TeOx), palladium (Pd), antimony (Sb), selenium (Se) and A material having a plurality selected from bismuth (Bi).

In addition, the semiconductor device of the present invention includes a DRAM (Dynamic Random Access Memory), an SRAM (Static Random Access Memory), a FeRAM (Ferroelectric Random Access Memory), a mask ROM (Read Only Memory ROM). (Electrically Programmable Read Only Memory), EEPROM (Electrically Erasable Programmable Read Only Memory), and one or more selected from a flash memory.

The semiconductor device according to the present invention includes one or more selected from a power supply circuit, a clock generation circuit, a data demodulation / modulation circuit, and an interface circuit.

In the semiconductor device having the above structure, the phase change memory and the control circuit are provided over a glass substrate. The phase change memory and the control circuit are provided on a flexible substrate. The control circuit includes a thin film transistor.

In the driving method of the semiconductor device having the above structure, data is written by changing the phase of the phase change layer by applying a voltage between the bit line and the word line, and the voltage is applied between the bit line and the word line. By applying, data is read by reading the phase state of the phase change layer.

Further, data is written by changing the phase of the phase change layer by irradiating light through the first conductive layer or the second conductive layer, and a voltage is applied between the bit line and the word line. Thus, data is read by reading the phase state of the phase change layer.

The present invention having the above structure can provide an inexpensive semiconductor device and a driving method thereof by providing a semiconductor device including a phase change memory having a simple structure.

Embodiments of the present invention will be described in detail with reference to the drawings. However, the present invention is not limited to the following description, and it will be easily understood by those skilled in the art that modes and details can be variously changed without departing from the spirit and scope of the present invention. Therefore, the present invention should not be construed as being limited to the description of the embodiments below. Note that in the structures of the present invention described below, the same reference numerals are used in common in different drawings.

The semiconductor device 20 of the present invention has a function of communicating data without contact, and includes a power supply circuit 11, a clock generation circuit 12, a data demodulation / modulation circuit 13, a control circuit 14 for controlling other circuits, an interface circuit 15, A memory 16, a data bus 17, and an antenna (antenna coil) 18 are included (see FIG. 1A). The power supply circuit 11 is a circuit that generates various power supplies to be supplied to each circuit inside the semiconductor device based on an alternating electrical signal input from the antenna 18. The clock generation circuit 12 is a circuit that generates various clock signals to be supplied to each circuit in the semiconductor device based on the AC signal input from the antenna 18. A data demodulation / modulation circuit (a circuit including a demodulation circuit and a modulation circuit) 13 has a function of demodulating / modulating data communicated with the reader / writer 19. The control circuit 14 has a function of controlling the phase change memory 16. The antenna 18 has a function of transmitting and receiving electromagnetic waves. The reader / writer 19 controls communication and control with the semiconductor device and processing related to the data. The semiconductor device is not limited to the above-described configuration, and may be a configuration in which other elements such as a power supply voltage limiter circuit and hardware dedicated to cryptographic processing are added.

The antenna 18 converts electromagnetic waves into alternating electrical signals. The antenna 18 is subjected to load modulation by the data demodulation / modulation circuit 13.

The memory 16 includes a phase change memory. The memory 16 may include only the phase change memory, or may include a memory having another configuration. The phase change memory uses the phase change of the recording thin film, and the phase change of the recording thin film is generated by applying light (optical action) or electrical action.

Note that the memory having another configuration other than the phase change memory is, for example, one or more selected from DRAM, SRAM, FeRAM, mask ROM, PROM, EPROM, EEPROM, and flash memory.

Next, a structure of the phase change memory will be described (see FIG. 1B). The phase change memory includes a memory cell array 22 in which memory cells 21 are provided in a matrix, decoders 23 and 24, a selector 25, and a read / write circuit 26.

The memory cell 21 includes a first conductive layer constituting the bit line Bx (1 ≦ x ≦ m), a second conductive layer constituting the word line Wy (1 ≦ y ≦ n), and a phase change layer. Have. The phase change layer is provided between the first conductive layer and the second conductive layer. In FIG. 1B, a stack of the first conductive layer, the second conductive layer, and the phase change layer is indicated by a circuit symbol representing a resistance element.

Next, a top surface structure and a cross-sectional structure when the memory cell array 22 is actually formed will be described (see FIGS. 2A and 2B). The memory cell array 22 includes a first conductive layer 27 extending in a first direction and a second conductive layer extending in a second direction perpendicular to the first direction on a substrate 30 having an insulating surface. 28 and a phase change layer 29. The first conductive layer 27 and the second conductive layer 28 are formed in a stripe shape so as to cross each other. An insulating layer 33 is provided between adjacent phase change layers 29. An insulating layer 34 that functions as a protective layer is provided so as to be in contact with the second conductive layer 28.

As the substrate 30, a quartz substrate, a silicon substrate, a metal substrate, a stainless steel substrate, or the like is used in addition to a glass substrate or a flexible substrate. The flexible substrate is a substrate that can be bent flexibly, and examples thereof include a plastic substrate made of polycarbonate, polyarylate, polyethersulfone, and the like. The first conductive layer 27 and the second conductive layer 28 are formed using a known conductive material such as aluminum (Al), copper (Cu), or silver (Ag).

Note that when data is written by light, one or both of the first conductive layer 27 and the second conductive layer 28 have a light-transmitting property. The light-transmitting conductive layer is formed using a transparent conductive material such as indium tin oxide (ITO), or formed with a thickness that allows light to pass even if it is not a transparent conductive material. To do.

The phase change layer 29 includes a material that reversibly changes between a crystalline state and an amorphous state. Alternatively, the phase change layer 29 includes a material that reversibly changes between the first crystal state and the second crystal state. Alternatively, the phase change layer 29 includes a material that changes only from an amorphous state to a crystalline state. When a reversible material is used, data can be read and written. On the other hand, when an irreversible material is used, only data reading can be performed. Thus, depending on the type of material, the phase change memory can be a read-only memory or a read / write memory. Therefore, the material used for the phase change layer 29 is appropriately selected according to the use of the semiconductor device.

Materials that reversibly change between a crystalline state and an amorphous state include germanium (Ge), tellurium (Te), antimony (Sb), sulfur (S), tellurium oxide (TeOx), tin (Sn), A material having a plurality of materials selected from gold (Au), gallium (Ga), selenium (Se), indium (In), thallium (Tl), Co (cobalt), and silver (Ag), for example, Ge-Te _{-Sb-S, Te-TeO 2} -Ge-Sn, Te-Ge-Sn-Au, Ge-Te-Sn, Sn-Se-Te, Sb-Se-Te, Sb-Se, Ga-Se-Te, Ga-Se-Te-Ge, In-Se, In-Se-Tl-Co, Ge-Sb-Te, In-Se-Te, and Ag-In-Sb-Te-based materials can be given.

In the description of the above materials, for example, Ge—Te—Sb—S means a material containing four of germanium (Ge), tellurium (Te), antimony (Sb), and sulfur (S), These four composition ratios mean that there is no particular restriction. Ge-Te-Sb-S may be expressed as a Ge-Te-Sb-S-based material or a germanium-tellurium-antimony-sulfur-based material.

Materials that reversibly change between the first crystalline state and the second crystalline state are silver (Ag), zinc (Zn), copper (Cu), aluminum (Al), nickel (Ni), indium ( In), antimony (Sb), selenium (Se), and tellurium (Te), a material having a plurality, such as Ag—Zn, Cu—Al—Ni, In—Sb, In—Sb—Se, In-Sb-Te is mentioned. In this material, the phase change takes place between two different crystalline states.

The material that changes only from the amorphous state to the crystalline state is a plurality selected from tellurium (Te), tellurium oxide (TeOx), palladium (Pd), antimony (Sb), selenium (Se), and bismuth (Bi). More specifically, a plurality of materials selected from tellurium (Te), tellurium oxide (TeOx), palladium (Pd), a material containing antimony and selenium (SbxSey), and a material containing bismuth and tellurium (BixTey) Examples thereof include Te—TeO ₂ , Te—TeO ₂ —Pd, and Sb ₂ Se ₃ / Bi ₂ Te ₃ .

In the above description of the material, Sb ₂ Se ₃ / Bi ₂ Te ₃ means that a layer containing Sb ₂ Se ₃ and a layer containing Bi ₂ Te ₃ are laminated.

Further, as a structure different from the above structure, a rectifying element may be provided between the first conductive layer 27 and the phase change layer 29 (see FIG. 2D). The element having a rectifying property is a transistor or a diode in which a gate electrode and a drain electrode are connected. Here, a case where a PN junction diode including the semiconductor layers 44 and 45 is provided is shown. One of the semiconductor layers 44 and 45 is an N-type semiconductor, and the other is a P-type semiconductor. Thus, by providing a diode having a rectifying property, current flows only in one direction, so that an error is reduced and a read margin is improved. Note that when a diode is provided, a diode having another structure such as a diode having a PIN junction or an avalanche diode may be used instead of a diode having a PN junction.

As described above, the phase change memory has a simple structure having a phase change layer between a pair of conductive layers. Therefore, a manufacturing process is simple and an inexpensive semiconductor device can be provided. In addition, since the phase change memory is a non-volatile memory, it is not necessary to incorporate a battery for holding data, and a small, thin, and lightweight semiconductor device can be provided. If an irreversible material is used for the phase change layer 29, data cannot be rewritten. Then, it is possible to provide a semiconductor device that prevents forgery and ensures security. s

Next, an operation when data is written to the phase change memory will be described. Data writing is performed by light or electrical action. First, the case of writing data by electrical action will be described (see FIG. 1B). In this case, one memory cell 21 is selected by the decoders 23 and 24 and the selector 25, and then data is written to the memory cell 21 using the read / write circuit 26. Specifically, data is written by applying a voltage between the first conductive layer 27 and the second conductive layer 28 to change the phase of the phase change layer 29.

Next, the case where data is written by light will be described (see FIGS. 2B and 2C). In this case, the phase change layer 29 is irradiated with laser light by the laser light irradiation means 32 from the light-transmitting conductive layer side (here, the second conductive layer 28). The phase change layer 29 undergoes a crystallographic phase change in its structure when irradiated with laser light. In this manner, data is written by utilizing the fact that the phase of the phase change layer 29 changes due to laser light irradiation.

For example, when data “1” is written, the phase change layer 29 is irradiated with laser light, heated to a temperature equal to or higher than the crystallization temperature, and then gradually cooled to bring the phase change layer 29 into a crystalline state. On the other hand, when writing the data “0”, the phase change layer 29 is irradiated with laser light, heated to a temperature higher than the melting point and melted, and then rapidly cooled to bring the phase change layer 29 into an amorphous state. To do.

Although the phase change of the phase change layer 29 depends on the size of the memory cell 21, it is realized by laser light irradiation with a diameter of the order of μm. For example, when a laser beam having a diameter of 1 μm passes at a speed of 10 m / sec, the time during which the phase change layer included in one memory cell 21 is irradiated with laser light is 100 nsec. In order to change the phase within a short time of 100 nsec, the laser power is preferably 10 mW and the power density is 10 kW / mm ² .

The phase change layer 29 may be irradiated with laser light to all the memory cells 21 or selectively. For example, in the case where the phase change layer 29 just formed is in an amorphous state, the laser beam is not irradiated when the amorphous state is kept, and the laser beam is irradiated when the phase change layer 29 is changed into a crystalline state (FIG. 2 (C)). That is, data may be written by selectively irradiating laser light. In this manner, in the case of selectively irradiating laser light, a pulsed laser irradiation apparatus may be used.

As described above, the structure of the present invention in which data is written by laser light irradiation can easily produce a large number of semiconductor devices. Therefore, an inexpensive semiconductor device can be provided.

Next, an operation when data is read from the phase change memory will be described (see FIGS. 1B and 9). Here, the read / write circuit 26 includes a resistance element 46 and a sense amplifier 47. However, the configuration of the read / write circuit 26 is not limited to the above configuration, and may have any configuration.

Data is read by applying a voltage between the first conductive layer 27 and the second conductive layer 28 to read the phase state of the phase change layer 29. Specifically, the resistance value Ra when the phase of the phase change layer 29 is in an amorphous state and the resistance value Rb when the phase of the phase change layer 29 is in a crystalline state satisfy Ra> Rb. Data is read by electrically reading such a difference in resistance value. For example, when reading the data of the memory cell 21 arranged in the x-th column and the y-th row from the plurality of memory cells 21 included in the memory cell array 22, first, the decoder 23 and 24 and the selector 25 are used to read the data in the x-th column. The bit line Bx and the y-th word line Wy are selected.

Then, the phase change layer included in the memory cell 21 and the resistance element 46 are connected in series. As described above, when a voltage is applied across the two resistance elements connected in series, the potential of the node α becomes a resistance-divided potential according to the resistance value Ra or Rb of the phase change layer 29. The potential of the node α is supplied to the sense amplifier 47, and the sense amplifier 47 determines whether it has information “0” or “1”. Thereafter, a signal including information of “0” and “1” determined by the sense amplifier 47 is supplied to the outside.

According to the above method, the phase state of the phase change layer 29 is read as a voltage value using the difference in resistance value and resistance division. However, a method of comparing current values may be used. This is based on the fact that the current value Ia when the phase of the phase change layer 29 is in an amorphous state and the current value Ib when the phase of the phase change layer 29 is in a crystalline state satisfy that Ia> Ib. It is.

Data writing to the phase change memory included in the semiconductor device 20 of the present invention is performed by light or electrical action. When writing data by light, if a plurality of semiconductor devices 20 are formed on the flexible substrate 31 and then laser light is irradiated by the laser light irradiation means 32, data writing can be made continuously and easily. It can be carried out. In addition, when such a manufacturing process is employed, a large number of semiconductor devices 20 can be easily manufactured (see FIG. 3A). Therefore, an inexpensive semiconductor device 20 can be provided.

In addition, the phase change layer of the phase change memory has a first state (for example, an amorphous state) when heated to a temperature higher than the melting point and melted, and a second state (for example, a crystal) when heated to a temperature higher than the crystallization temperature. State) is obtained. That is, data writing can be performed by heat treatment if the heating temperature is properly used. Therefore, a manufacturing process using different heating temperatures may be used. For example, a flexible substrate 31 on which a plurality of semiconductor devices are formed is used as a roll 51 (see FIG. 3B). Then, data may be written by using the heating means 52 with different heating temperatures during the heat treatment. The heating means 52 is controlled by the control means 53.

The semiconductor device of the present invention is characterized in that data can be read and written in a non-contact manner, and the data transmission format is an electromagnetic coupling method in which a pair of coils are arranged to face each other and communicate by mutual induction, There are roughly divided into an electromagnetic induction system that communicates using an induction electromagnetic field and a radio system that communicates using radio waves, and any system may be used. There are two ways of providing the antenna 18 used for data transmission. One is when the antenna 18 is provided on the substrate 36 provided with a plurality of elements (see FIGS. 4A and 4C). Is a case where the terminal portion 37 is provided on the substrate 36 provided with a plurality of elements, and the antenna 18 is provided so as to be connected to the terminal portion 37 (see FIGS. 4B and 4D). Here, a plurality of elements provided on the substrate 36 are referred to as an element group 35.

In the case of the former configuration (FIGS. 4A and 4C), the element group 35 and a conductive layer functioning as the antenna 18 are provided on the substrate 36. In the illustrated configuration, a conductive layer functioning as the antenna 18 is provided in the same layer as the second conductive layer 28. However, the present invention is not limited to the above configuration, and the antenna 18 may be provided in the same layer as the first conductive layer 27, or an insulating film is provided so as to cover the element group 35, and the antenna 18 is provided on the insulating film. May be provided.

In the case of the latter configuration (FIGS. 4B and 4D), the element group 35 and the terminal portion 37 are provided on the substrate 36. In the configuration shown in the figure, a conductive layer provided in the same layer as the second conductive layer 28 is used as the terminal portion 37. Then, a substrate 38 provided with the antenna 18 is bonded so as to be connected to the terminal portion 37. Conductive particles 39 and a resin 40 are provided between the substrate 36 and the substrate 38.

The material containing the conductive particles 39 and the resin 40 is called an anisotropic conductive material.

If a plurality of element groups 35 are formed on a substrate having a large area and then completed by being divided, an inexpensive element group 35 can be provided. Examples of the substrate used at this time include a glass substrate and a flexible substrate.

The plurality of transistors included in the element group 35 may be provided over a plurality of layers. That is, it may be formed in multiple layers. When forming the element group 35 extending over a plurality of layers, an interlayer insulating film is used. As the material of the interlayer insulating film, a resin material such as an epoxy resin or an acrylic resin, or a resin material such as a permeable polyimide resin is used. It is preferable to use a compound material made by polymerization of a siloxane polymer, a material containing a water-soluble homopolymer and a water-soluble copolymer, or an inorganic material.

A siloxane-based compound material is a material having a skeletal structure composed of a bond of silicon and oxygen and containing at least hydrogen as a substituent, or at least one of fluorine, an alkyl group, or an aromatic hydrocarbon as a substituent. The material which has is mentioned.

As a material of the interlayer insulating film, a low dielectric constant material may be used for the purpose of reducing parasitic capacitance generated between the layers. If the parasitic capacitance is reduced, high-speed operation is realized and low power consumption is realized.

The plurality of transistors included in the element group 35 may use any semiconductor such as an amorphous semiconductor, a microcrystalline semiconductor, a polycrystalline semiconductor, and an organic semiconductor as an active layer. An active layer crystallized using a metal element as a catalyst or an active layer crystallized by a laser irradiation method may be used. In addition, a semiconductor layer formed by plasma CVD using SiH ₄ / F ₂ gas or SiH ₄ / H ₂ gas (Ar gas), or a semiconductor layer irradiated with laser is used as an active layer. Good.

The plurality of transistors included in the element group 35 includes a crystalline semiconductor layer (low-temperature polysilicon layer) crystallized at a temperature of 200 to 600 degrees (preferably 350 to 500 degrees), or a temperature of 600 degrees or more. A crystalline semiconductor layer (high-temperature polysilicon layer) crystallized in (1) can be used. When a high-temperature polysilicon layer is formed on a substrate, a quartz substrate may be used because a glass substrate may be vulnerable to heat.

A concentration of 1 × 10 ¹⁹ atoms / cm ³ to 1 × 10 ²² atoms / cm ³ , preferably 1 × 10 ¹⁹ atoms / cm ³ to the active layer (especially a channel formation region) of the transistor included in the element group 35. Hydrogen or a halogen element is preferably added at a concentration of 5 × 10 ²⁰ atoms / cm ³ . If it does so, the active layer with few defects and being hard to produce a crack can be obtained.

In addition, a barrier film that blocks contaminants such as alkali metals may be provided so as to enclose the transistors included in the element group 35 or to enclose the element group 35 itself. Then, the element group 35 that is not contaminated and has improved reliability can be provided. As the barrier film, a silicon nitride film, a silicon nitride oxide film, a silicon oxynitride film, or the like can be given.

The thickness of the active layer of the transistor included in the element group 35 is 20 nm to 200 nm, preferably 40 nm to 170 nm, more preferably 45 nm to 55 nm, 145 nm to 155 nm, and still more preferably 50 nm and 150 nm. As a result, it is possible to provide the element group 35 that is unlikely to crack even when bent.

In addition, the crystal forming the active layer of the transistor included in the element group 35 is preferably formed so as to have a crystal grain boundary extending in parallel with the carrier flow direction (channel length direction). Such an active layer may be formed using a continuous wave laser (which can be abbreviated as CWLC) or a pulse laser operating at 10 MHz or more, preferably 60 to 100 MHz.

The S value (subthreshold value) of the transistors included in the element group 35 is 0.35 V / decade or less (preferably 0.09 to 0.25 V / decade) and the mobility is 10 cm ² / Vs or more. Good. Such characteristics can be realized by forming the active layer with a continuous wave laser or a pulsed laser operating at 10 MHz or higher.

The element group 35 is a ring oscillator and has a characteristic of 1 MHz or more, preferably 10 MHz or more (at 3 to 5 V). Alternatively, the frequency characteristic per gate is 100 kHz or more, preferably 1 MHz or more (at 3 to 5 V).

In other words, the element group 35 has a characteristic that the delay time per one stage of the ring oscillator is 1 μsec or less, preferably 100 nsec or less (at 3 to 5 V).

The antenna 18 may be formed using a droplet discharge method with a conductive paste containing nanoparticles such as gold, silver, and copper. The droplet discharge method is a general term for a method of forming a pattern by discharging droplets such as an ink jet method or a dispenser method, and has various advantages such as an improvement in material utilization efficiency.

The substrate 42 provided with the element group 35 may be used as it is. However, in order to add value, the element group 35 on the substrate 42 is peeled off (see FIG. 5A), and the element group 35 is removed. May be bonded to the flexible substrate 43 (see FIG. 5B).

The element group 35 is peeled from the substrate 42 by (1) providing a metal oxide film between the substrate 42 and the element group 35 having high heat resistance, and weakening the metal oxide film by crystallization. (2) An amorphous silicon film containing hydrogen is provided between the substrate 42 having high heat resistance and the element group 35, and the amorphous silicon film is removed by laser light irradiation or etching, (3) The element group 35 is removed by mechanically removing or removing the substrate 42 having high heat resistance on which the element group 35 is formed by etching with a gas such as a solution or ClF _3. A method of cutting off the above may be used. The peeled element group 35 may be attached to the flexible substrate 43 using a commercially available adhesive, such as an adhesive using an epoxy resin adhesive or a resin additive.

The element group 35 is peeled from the substrate 42 by a method in which a peeling layer is provided between the substrate 42 and the element group 35 in advance, and the peeling layer is removed with an etching agent, or the peeling layer is removed. A method may be used in which the substrate 42 and the element group 35 are physically separated after being partially removed by an etching agent. Note that “physical peeling” means peeling due to external stress. The external stress corresponds to wind pressure or ultrasonic waves blown from a nozzle.

As described above, when the element group 35 is bonded to the flexible substrate 43, it is possible to provide a semiconductor device that is thin, light, and difficult to break even when dropped. Moreover, since the flexible substrate 43 has flexibility, it can be bonded on a curved surface or an irregular shape, and various uses can be realized. For example, a wireless tag which is one embodiment of the semiconductor device 20 of the present invention can be attached to a curved surface such as a medicine bottle (see FIGS. 5C and 5D). Furthermore, if the substrate 42 is reused, an inexpensive semiconductor device can be provided. This embodiment can be freely combined with the above embodiment modes and embodiments.

In this embodiment, a case where a flexible wireless tag is formed using a peeling process will be described (see FIG. 6A). The wireless tag includes a flexible protective layer 2301, a flexible protective layer 2303 including an antenna 2304, and an element group 2302 formed by a peeling process. An antenna 2304 formed over the protective layer 2303 is electrically connected to the element group 2302. In the illustrated configuration, the antenna 2304 is formed only over the protective layer 2303; however, the present invention is not limited to this configuration, and the antenna 2304 may be formed over the protective layer 2301. Note that a barrier film made of a silicon nitride film or the like is preferably formed between the element group 2302 and the protective layers 2301 and 2303. Then, a wireless tag with improved reliability can be provided without the element group 2302 being contaminated.

The antenna 2304 is preferably made of silver, copper, or a metal plated with them. The element group 2302 and the antenna 2304 are connected to each other by performing UV treatment or ultrasonic treatment using an anisotropic conductive film. However, the present invention is not limited to this method, and various methods can be used.

The thickness of the element group 2302 sandwiched between the protective layers 2301 and 2303 is preferably 5 μm or less, preferably 0.1 μm to 3 μm (see FIG. 6B showing a cross-sectional structure). Further, when the thickness when the protective layers 2301 and 2303 are overlapped is defined as d, the thickness of the protective layers 2301 and 2303 is preferably (d / 2) ± 30 μm, more preferably (d / 2) ± 10 μm. And In addition, the thickness of the protective layers 2301 and 2303 is preferably 10 μm to 200 μm. Further, the area of the element group 2302 is 5 mm square (25 mm ² ) or less, and desirably has an area of 0.3 mm square to 4 mm square (0.09 mm ^{2 to} 16 mm ² ).

Since the protective layers 2301 and 2303 are formed of an organic resin material, they have a strong characteristic against bending. In addition, the element group 2302 itself formed by the separation process also has a stronger characteristic against bending than a single crystal semiconductor. Since the element group 2302 and the protective layers 2301 and 2303 can be in close contact with each other so that there is no gap, the completed wireless tag itself has a strong characteristic against bending. The element group 2302 surrounded by the protective layers 2301 and 2303 may be arranged on the surface or inside of another solid object, or may be embedded in paper.

The case where an element group formed by a separation process is attached to a substrate having a curved surface will be described (see FIG. 6C). In the drawing, one transistor selected from an element group formed by a peeling process is illustrated. This transistor is linear in the direction of current flow. In other words, the transistor is arranged such that the direction in which the current flows is perpendicular to the direction in which the substrate draws an arc. That is, the positions of the drain electrode 2305 to the gate electrode 2307 to the source electrode 2306 are linear. The direction in which the current flows and the direction in which the substrate draws an arc are arranged perpendicularly. With such an arrangement, even when the substrate is bent and an arc is drawn, the influence of stress is small, and fluctuations in characteristics of transistors included in the element group can be suppressed.

Further, in order to prevent destruction of active elements such as transistors due to stress, the area of the active region (silicon island portion) of the active elements is 5% to 50% (preferably with respect to the entire area of the substrate). Is preferably 5 to 30%). In a region where there is no active element such as a TFT, a base insulating film material, an interlayer insulating film material, and a wiring material are mainly provided. The area other than the active region such as a transistor is preferably 60% or more of the entire area of the substrate. In this way, it is possible to provide a semiconductor device that is easy to bend but has a high degree of integration. This embodiment can be freely combined with the above embodiment modes and embodiments.

Although the semiconductor device of the present invention has a wide range of uses, for example, a wireless tag which is one form of the semiconductor device 20 of the present invention is a banknote, a coin, securities, certificates, bearer bonds, packaging containers, books And recording media, personal items, vehicles, foods, clothing, health supplies, daily necessities, medicines, electronic devices, and the like.

Banknotes and coins are money that circulates in the market, and include those that are used in the same way as money in a specific area (cash vouchers), commemorative coins, and the like. Securities refer to checks, securities, promissory notes, etc. (see FIG. 7A). The certificate refers to a driver's license, a resident card, etc. (see FIG. 7B). Bearer bonds refer to stamps, gift certificates, various gift certificates, etc. (see FIG. 7C). Packaging containers refer to wrapping paper for lunch boxes, plastic bottles, and the like (see FIG. 7D). Books refer to books, books, and the like (see FIG. 7E). The recording media refer to DVD software, video tapes, and the like (see FIG. 7F). The vehicles refer to vehicles such as bicycles, ships, and the like (see FIG. 7G). Personal belongings refer to bags, glasses, and the like (see FIG. 7H). Foods refer to food products, beverages, and the like. Clothing refers to clothing, footwear, and the like. Health supplies refer to medical equipment, health equipment, and the like. Livingware refers to furniture, lighting equipment, and the like. Chemicals refer to pharmaceuticals, agricultural chemicals, and the like. Electronic devices refer to liquid crystal display devices, EL display devices, television devices (television receivers, thin television receivers, thin television devices), cellular phones, and the like.

Forgery can be prevented by providing wireless tags on bills, coins, securities, certificate documents, bearer bonds, and the like. In addition, it is possible to improve the efficiency of inspection systems and rental store systems by providing wireless tags for personal items such as packaging containers, books, recording media, personal items, foods, daily necessities, and electronic devices. it can. By providing wireless tags for vehicles, health supplies, medicines, etc., counterfeiting and theft can be prevented, and medicines can prevent mistakes in taking medicines. As a method of providing the wireless tag, the wireless tag is provided on the surface of the article or embedded in the article. For example, a book may be embedded in paper, and a package made of an organic resin may be embedded in the organic resin.

In this way, the system can be improved in functionality by applying it to a system for managing and distributing goods. For example, there is a case where a reader / writer 95 is provided on the side surface of the portable terminal including the display portion 94 and a wireless tag 96 which is one mode of the semiconductor device of the present invention is provided on the side surface of the product 97 (see FIG. 8A). ). In this case, when the wireless tag 96 is held over the reader / writer 95, the display unit 94 displays information such as the raw material, the place of origin, and the history of distribution process. Conventionally, the information of the product 97 is limited to the information described on the label, but more information can be obtained by providing the wireless tag 96. Another example is the case where a reader / writer 95 is provided on the side of the belt conveyor (see FIG. 8B). In this case, the product 97 can be easily inspected. This embodiment can be freely combined with the above embodiment modes and embodiments.

A cross-sectional structure of the semiconductor device of the present invention will be described with reference to FIG. The semiconductor device of the present invention includes an element group 102 provided over a substrate 101, a phase change memory 104, and a conductive layer 105 functioning as an antenna. As described above, a semiconductor device in which the element group 102 including transistors, the phase change memory 104, and the conductive layer 105 functioning as an antenna are formed over the substrate 101 having an insulating surface is reduced in size, thickness, and weight. Can be realized.

The element group 102 includes a plurality of elements such as transistors, capacitors, and resistors, and constitutes a circuit such as a power supply circuit and a clock generation circuit. Phase change memory 104 includes a plurality of stacked layers of conductive layer 111, phase change layer 112, and conductive layer 113. Such a stacked body of the conductive layer 111, the phase change layer 112, and the conductive layer 113 may be referred to as a memory element 114.

10A and 10B, a plurality of transistors are illustrated as the element group 102. FIG. 10A shows a CMOS circuit 103 included in the element group 102, and the CMOS circuit 103 controls the operation of the phase change memory 104. 10B illustrates the transistors 106 and 107 included in the element group 102. Each of the transistors 106 and 107 controls the operation of the memory element 114.

8A and 8B illustrate a semiconductor device and a driving method thereof according to the present invention. 8A and 8B illustrate a semiconductor device and a driving method thereof according to the present invention. 6A and 6B illustrate a semiconductor device of the present invention. 8A and 8B illustrate an example of a manufacturing process of a semiconductor device of the present invention. 6A and 6B illustrate a semiconductor device of the present invention. 6A and 6B illustrate a semiconductor device of the present invention. 8A and 8B illustrate usage patterns of a semiconductor device of the present invention. 8A and 8B illustrate usage patterns of a semiconductor device of the present invention. 8A and 8B illustrate a semiconductor device and a driving method thereof according to the present invention. 6A and 6B illustrate a semiconductor device of the present invention.

Explanation of symbols

11 power supply circuit 12 clock generation circuit 13 data demodulation / modulation circuit 14 control circuit 15 interface circuit 16 memory 17 data bus 18 antenna 19 reader / writer 20 semiconductor device 21 memory cell 22 memory cell array 23 decoder 24 decoder 25 selector 26 read / write circuit 27 First conductive layer 28 Second conductive layer 29 Phase change layer

Claims (4)

A phase change memory on a glass substrate, an antenna, and a thin film transistor for controlling the operation of the phase change memory ;
The phase change memory includes: a first conductive layer extending in a first direction; a second conductive layer extending in a second direction intersecting the first direction; the first conductive layer; Having a phase change layer provided between the second conductive layers;
One of the first conductive layer or the second conductive layer under the phase change layer is translucent,
The other of the first conductive layer or the second conductive layer on the phase change layer is the same layer as the antenna,
In the phase change memory, data is written by irradiating the phase change layer with light through the glass substrate and one of the light-transmitting first conductive layer and the second conductive layer. A semiconductor device. In claim 1,
The phase change layer comprises a material that reversibly changes between a crystalline state and an amorphous state;
The semiconductor device includes a plurality of materials selected from germanium, tellurium, antimony, sulfur, tellurium oxide, tin, gold, gallium, selenium, indium, thallium, cobalt, and silver. In claim 1,
The phase change layer has a material that reversibly changes between a first crystalline state and a second crystalline state;
The semiconductor device includes a plurality of materials selected from silver, zinc, copper, aluminum, nickel, indium, antimony, selenium, and tellurium. In claim 1,
The phase change layer has a material that changes only from an amorphous state to a crystalline state,
The semiconductor material includes a plurality of materials selected from tellurium, tellurium oxide, palladium, antimony, selenium, and bismuth.

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