Patent Grant
8240030
1. Field of the Invention
In this specification, a terminal structure including a conductor covered with an insulating film will be described. Further, an electronic device provided with a terminal having such a structure will also be described.
2. Description of the Related Art
A resin layer formed by curing a prepreg including a reinforcing material such as a glass fiber or a glass filler is applied to a support, an insulating film, a protective material, or the like of a printed wiring board, an electronic device, or the like (for example, see Patent Documents 1 to 4). Since a multilayer wiring is formed, an opening penetrating a resin layer formed using a prepreg is formed in this layer in order to form an electrical connection portion with the external.
For example, Patent Document 1 discloses that an insulating layer of a printed wiring board is formed using a prepreg and an opening is formed in the insulating layer with laser treatment, drilling, or punching-out.
Patent Documents 2 and 3 disclose that an opening is formed in a cured prepreg by performing a step of laser beam irradiation or a photolithography step in order to form a connection terminal for an electronic device sealed with the cured prepreg.
Patent Document 4 discloses that a support of an electronic component is formed using a prepreg and that a resin layer in which an electronic component and a conductor electrically connected to the electronic component are embedded is formed and a surface of the resin layer is grinded in order to expose the conductor.
By using a prepreg including a reinforcing material as a sealing film, an electronic element can be sealed with a resin film including the reinforcing material; therefore, the strength of the electronic element can be increased. Meanwhile, in the case where an opening is formed in the sealing film in order to expose an extraction terminal of an electronic element, the reinforcing material is also needed to be removed with the resin film. The reinforcing material is troublesome when the opening is formed in the resin film.
As disclosed in Patent Document 1, an opening is formed in a resin film formed using a prepreg with drilling, punching, and treatment with a laser beam. For formation of an opening in a resin layer with which an electronic element is sealed, drill treatment and punching treatment are not suitable. Treatment with a laser beam is employed in order not to damage the electronic element.
However, the step of forming an opening with the use of a laser beam takes much time and needs a skill because it is difficult to determine whether both the resin film and the reinforcing material are removed. Thus, depending on the skill of an operator, the resin film and/or the reinforcing material might be insufficiently removed and thus the areas of regions exposed in openings might vary. Accordingly, the values of connection resistance of two conductors electrically connected through an opening vary, which makes it difficult to manufacture an electric element having electric characteristics with a designed value.
In addition, in the case of employing the step of forming an opening with the use of a laser beam, a mechanical impact on an electronic element is small as compared to drilling or a punching; however, the possibility that performance of the electronic element is degraded by energy of a laser beam cannot be completely eliminated. In the study by inventors of the present invention, it is found that characteristics of an electronic element with a small size and a high-performance electronic element driven with low voltage are degraded due to laser beam irradiation in a step of forming an opening in a sealing layer in some cases.
A technical object in this specification is to provide a method for forming an opening with high accuracy in an insulating film formed by curing a prepreg including a reinforcing material, with the use of a means other than laser beam irradiation.
A method for manufacturing a terminal structure, according to an embodiment of the present invention, includes forming a protrusion formed using a conductor over an insulating surface, closely attaching a prepreg including a reinforcing material to the insulating surface and a surface of the protrusion to form a portion of a top surface of the prepreg, which protrudes due to the protrusion, curing the prepreg closely attached to the insulating surface and the surface of the protrusion to form an insulating film including the reinforcing material, and removing a protruding portion of a top surface of the insulating film together with the reinforcing material to form an opening in the insulating film. Note that part of the protrusion may be removed in the step of forming the opening.
According to this embodiment, an opening can be easily formed with high accuracy in an insulating film formed by curing a prepreg including a reinforcing material, with the use of a means other than laser beam irradiation. This is because according to this embodiment, the position where an opening is formed can be determined in a self-aligned manner depending on the position where a protrusion is formed, and the accuracy of the position where an opening is formed can be ensured by the accuracy of the position where the protrusion is formed and the shape and size of the opening can be controlled by changing the height and shape of the protrusion. Therefore, in the step of forming the opening, highly accurate alignment like determination of a position where laser beam irradiation is performed is not necessary.
By grinding an insulating film including a reinforcing material, an opening can be formed in the insulating film. As described above, the opening can be formed in the insulating film in a self-aligned manner. Therefore, by simply grinding the insulating film in a direction parallel to a horizontal surface, the opening can be formed in a self-aligned manner in the insulating film.
In the manufacturing method according to the above embodiment, an insulating film may be formed by curing an uncured resin film which does not include a reinforcing material instead of a prepreg including a reinforcing material. In that case, the above advantageous effect can also be obtained. As a reinforcing material, a sheet fiber can be used. After formation of an opening, a conductor closely attached to a protrusion may be formed.
A method for manufacturing an electronic device, according to an embodiment of the present invention, includes forming a conductive protrusion electrically connected to at least one of electronic elements, over a first insulating film, closely attaching a prepreg including a reinforcing material to a top surface of the first insulating film and a surface of the protrusion to form a portion of a top surface of the prepreg, which protrudes due to the protrusion, curing the prepreg closely attached to the top surface of the first insulating film and the surface of the protrusion to form a second insulating film including the reinforcing material, and removing a protruding portion of a top surface of the second insulating film together with the reinforcing material to form an opening in the second insulating film. Note that a part of the protrusion may be removed in the step of forming the opening.
Thus, in the method for manufacturing an electronic device, according to the above embodiment, as described above, an opening can be easily formed with high accuracy in an insulating film formed by curing a prepreg including a reinforcing material, with the use of a means other than laser beam irradiation.
In the method for manufacturing an electronic device, according to the above embodiment, a sheet fiber can be used as the reinforcing material. After formation of the opening, a conductor closely attached to the protrusion may be formed. The second insulating film may be formed by curing an uncured resin film which does not include a reinforcing material.
In the method for manufacturing an electronic device, according to the above embodiment, in the case where an electronic element is provided over a substrate used when the electronic element is formed, a step of separating the substrate from the electronic element may be performed. For example, this step is preferably performed with the electronic element sealed with the second insulating film after the second insulating film is formed. In that case, the substrate may be separated either before or after the opening is formed in the second insulating film.
In a method for manufacturing an electronic device, according to an embodiment of the present invention, the accuracy of the position where the opening is formed in an insulating film (cured prepreg) including a reinforcing material is ensured in a self-aligned manner by the accuracy of the position where a protrusion is formed and the shape and size of the opening can be controlled by changing the height and shape of the protrusion. Therefore, by applying this embodiment, an opening can be easily formed in an insulating film including a reinforcing material with high accuracy, with the use of a means other than laser beam irradiation.
Embodiments of the invention disclosed in this specification will be described with reference to the accompanying drawings. Note that in the drawings referred to in this specification, components denoted by the same reference numerals in different drawings represent the same components. Therefore, the description regarding such components, which is repetitive, will be omitted in some cases.
In addition, it is easily understood by those skilled in the art that modes of the invention disclosed in this specification are not limited to the description in the embodiments and can be modified in various ways. That is, the invention disclosed in this specification should not be interpreted as being limited to the description of the embodiments.
In this embodiment, a terminal structure covered with n insulating film formed from a cured prepreg which includes a reinforcing material or cured resin film and a method for manufacturing the terminal structure will be described. Further, in this embodiment, an electronic device provided with a terminal having such a structure and a method for manufacturing the electronic device will also be described.
Terminal Structure
The terminal structure of this embodiment includes a conductor, a resin film including a reinforcing material and covering the conductor, and an opening formed in a region of the resin film, which overlaps with the conductor. In this opening, the conductor is exposed at a surface of the resin film and thus, the conductor can be electrically connected to another conductor.
Description of Insulating Surface
In the terminal structure, a first conductor is formed over an insulating surface, for example. As the insulating surface, for example, a surface of an insulator such as an insulating film formed with a deposition method, e.g., a CVD method or a PVD method, oxidation treatment, or the like; a resin substrate; a resin film; a glass substrate; or a quartz substrate.
Description of Electronic Device
The electronic device of this embodiment includes one or more electronic elements, a conductor having a projecting portion or a recessed portion, which is electrically connected to at least one of the electronic elements, and a resin film including a reinforcing material and covering the electronic element and the conductor, and an opening formed in a region of the resin film, which overlaps with the conductor. In this opening, the conductor is exposed at a surface of the resin film and thus, the conductor can be electrically connected to another conductor.
A method for manufacturing the terminal structure of this embodiment and a method for manufacturing the electronic device of this embodiment and the structures of the terminal structure and the electronic device will be described with reference to
As illustrated in
Description of Electronic Element 110 (Transistor)
In
As the substrate 100, a substrate such as a semiconductor substrate, a glass substrate, a quartz substrate, a sapphire substrate, a ceramic substrate, a stainless steel substrate, or a metal substrate can be used. As a semiconductor substrate, a silicon wafer obtained by slicing an ingot, an SOI substrate in which a single crystal semiconductor layer is formed over a substrate with an insulating film therebetween, or the like can be used. Further, in the case where a semiconductor substrate such as a silicon wafer obtained by slicing an ingot is used as the substrate 100, the electronic element 110 including a semiconductor region is formed over the silicon wafer (the substrate 100).
Each of the insulating films 101 to 103 has either a single-layer structure or a layered structure. Insulating films used as the insulating films 101 to 103 are selected in consideration of the condition of a manufacturing process of the electronic element 110 and the functions of these films. For example, an insulating film containing silicon and/or germanium as its component, such as a silicon oxide film, a silicon nitride film, a silicon oxynitride film, a silicon nitride oxide film, a germanium oxide film, a germanium nitride film, a germanium oxynitride film, or a germanium nitride oxide film can be used. Further, the following may be used: an insulating film formed from oxide of metal, such as aluminum oxide, tantalum oxide, or hafnium oxide; an insulating film formed from nitride of metal, such as aluminum nitride; an insulating film formed from oxynitride of metal, such as aluminum oxynitride; or an insulating film formed from nitride oxide of metal, such as aluminum nitride oxide. Furthermore, a resin film formed from a resin material such as acrylic, polyimide, polyamide, polyimideamide, or benzocyclobutene may be used. Note that in this specification, oxynitride is a substance in which the content of oxygen is larger than that of nitrogen and nitride oxide is a substance in which the content of nitrogen is larger than that of oxygen.
There are the following typical examples of the method for forming these insulating films: a CVD method (chemical vapor deposition method) such as a PECVD (plasma-excited CVD) method or a thermal CVD method; a PVD method (physical vapor deposition method) such as a sputtering method or a vapor deposition method; an ALD method (atomic layer deposition method); a method for forming a film with a liquid or paste material, such as a spin-coating method, a droplet discharging method, or a dip-coating method; solid-phase oxidation treatment or solid-phase nitridation treatment with plasma or heat; and the like.
Further, each of the conductive films 112 and 113 has either a single-layer structure or a layered structure. Each of the conductive films 112 and 113 can be formed using a metal film containing single metal such as tantalum, tungsten, titanium, molybdenum, aluminum, chromium, niobium, gold, silver, copper, or platinum, as its main component, an alloy film, a metal compound film, or the like. For example, as the metal film, a copper film, a pure aluminum film, and an aluminum film to which Si, Nb, or the like is added are given. As the alloy film, an aluminum-copper alloy film and an aluminum-neodymium alloy film are given. As the metal compound film, a metal nitride film such as a titanium nitride film or a tungsten nitride film, and a silicide film such as a nickel silicide film or a cobalt silicide film are given. These conductive films can be formed with a PVD method such as a sputtering method or a vapor deposition method; a method for forming a film with a liquid or paste material, such as a printing method, a droplet discharging method, or a dip-coating method; a soldering method; a plating method; or the like.
Next, as illustrated in
The insulating film 104 can be formed in a manner similar to those of the insulating films 101 to 103. For example, in the case where the insulating film 104 has a two-layer structure of a silicon nitride oxide film and a resin film, the insulating film 104 having openings can be formed as follows. First, a silicon nitride oxide film with a thickness of approximately 50 nm to 300 nm is formed over the insulating film 103 in a PECVD apparatus using SiH4, N2O, NH3, and H2 for a source gas. Then, a film formed from an uncured photosensitive epoxy-phenol resin material is formed over the silicon nitride oxide film with a printing method. Next, the uncured resin film is irradiated with light having an appropriate wavelength to be cured, so that the resin film with a thickness of approximately 1 μm to 30 μm is formed. At that time, a portion of the resin film, which is to be a conduction region between the conductive film 113 and the conductive film 114, is not cured. After that, a portion of the silicon nitride oxide film in a first layer, which is to be a conduction region, is etched, and thus, the insulating film 104 including the openings is completed.
Then, the conductive film 114 is formed over the insulating film 104. The conductive film 114 can be formed in a manner similar to those of the conductive films 112 and 113. For example, a titanium film is formed with a sputtering method and the titanium film is etched to form the conductive film 114.
Next, conductive protrusions 120 are formed over the insulating film 104 (an insulating surface) as illustrated in
The protrusion 120 is preferably formed using a conductive material having fluidity, such as conductive paste containing conductive microparticles or conductive powder or conductive liquid containing conductive microparticles or conductive powder. This is because when such a conductive material is used, the protrusion 120 can be formed with a droplet discharging method (including an ink-jet method, a dispensing method, and the like), a printing method such as a screen printing method, or the like. These methods allow formation of a projecting conductor at a portion where the projecting conductor needed to be formed, without a deposition step using a complex deposition apparatus such as a CVD apparatus or a sputtering apparatus and an exposure step for forming a photomask.
Description of Conductive Paste
The conductive paste and the conductive liquid are materials in which conductive particles or conductive powder are/is dispersed or conductive materials in which conductive particles or conductive powder are/is dissolved. For example, as a material of conductive powder or a conductive particle contained in the conductive liquid, metal such as Ag, Au, Cu, Ni, Pt, Pd, or Nb; an alloy of any of these metal materials (e.g., Ag—Pd); a conductive oxide material such as indium oxide or zinc oxide; and the like are given. Further, as a medium (a solvent or a disperse medium) in which conductive powder or conductive particles is/are dissolved or dispersed, for example, precursor materials of a photocurable resin and a thermosetting resin are given. As a UV curable resin, an acrylic resin and an epoxy resin are given. As a thermosetting resin, a polyimide resin is given.
The protrusion 120 may be formed using solder paste.
Here, the protrusion 120 is formed using commercially available silver paste. The silver paste is formed in a projecting shape with a printing method in a region where the protrusion 120 is to be formed. Then, the silver paste is baked in oven, so that the protrusion 120 containing silver is formed. The protrusion 120 protrudes from a top surface of the insulating film 104 as compared to any portion of the electronic element 110.
Attachment of Prepreg
Next, an uncured (incompletely cured) prepreg 130 including a reinforcing material 131 is prepared, and the uncured prepreg 130 (hereinafter referred to as the “prepreg 130”) is provided on the insulating film 104 side of the electronic device and is closely attached to surfaces of the insulating film 104 and the protrusions 120. The prepreg 130 is cured in such a state, and thus, the surfaces of the insulating film 104 and the protrusions 120 are covered with an insulating film 140 including the reinforcing material 131 (see
As illustrated in
As a resin material of the uncured resin 132 (hereinafter referred to as the “resin 132”), a thermosetting resin such as an epoxy resin, an unsaturated polyester resin, a polyimide resin, a bismaleimide-triazine resin, or a cyanate resin can be used. Alternatively, a thermoplastic resin such as a polyphenylene oxide resin, a polyetherimide resin, or a fluorine resin may be used. For example, when the resin 132 is formed from a polyimide resin, the resin 132 is cured to form a resin layer formed from a polyimide resin is formed. Note that the number of resin materials used for the resin 132 is not limited to one and a plurality of resin materials may be used.
Note that in this specification, an uncured resin layer and an uncured prepreg refer to both those in an uncured state and those in an incompletely cured state. The latter state is also referred to as a semi-cured state.
As the reinforcing material 131 used for the prepreg 130, fiber, a sheet fibrous body (also referred to as a fibrous sheet), a filler, and the like are given. The sheet fibrous body is a sheet substance formed using fiber and for example, a woven fabric and a nonwoven fabric each correspond to the sheet fibrous body. The way of weaving a woven fabric used for the sheet fibrous body is not particularly limited and for example, a plain-woven fabric, a twilled fabric, a satin-woven fabric, or the like can be used as the sheet fibrous body.
High-strength fiber is preferably used as fiber used for the reinforcing material 131. The high-strength fiber is specifically fiber with a high modulus of elasticity in tension or fiber with a high Young's modulus. As the high-strength fiber, a polyvinyl alcohol fiber, a polyester fiber, a polyamide fiber, a polyethylene fiber, an aramid fiber, a polyparaphenylene benzobisoxazole fiber, a glass fiber, a carbon fiber, and the like are given. As the glass fiber, glass fiber using E glass, S glass, D glass, Q glass, or the like is given. For example, a woven fabric formed from glass fiber is called glass cloth.
There is no particular limitation on a yarn bundle (e.g., the cross-sectional shape or the processing method) used for the reinforcing material 131. The cross-sectional shape may be a circular shape, an elliptical shape, or a flat shape. A sheet fibrous body formed using a yarn bundle which has been subjected to fiber opening is preferably used for the reinforcing material 131 because the yarn bundle subjected to fiber opening has a large width, has a smaller number of single yarns in the thickness direction, and thus is easily flattened in cross section. Flattening the yarn bundle in cross section makes the thickness of the fibrous body small, which reduces the thickness of the reinforcing material 131. Accordingly, the uncured prepreg 130 can be thin.
In the case where the resin 132 is a thermosetting resin, a step of closely attaching the prepreg 130 to the surfaces of the insulating film 104 and the protrusions 120 and a step of curing the prepreg 130 can be performed using a vacuum heat press. The prepreg 130 is placed on the insulating film 104 side and the prepreg 130 and the substrate 100 are pressed as illustrated in
In the case where the resin 132 is a photocurable resin, the prepreg 130 may be cured as follows. The prepreg 130 and the substrate 100 are pressed with a vacuum press (or a vacuum heat press), whereby the prepreg 130 is closely attached to the surfaces of the insulating film 104 and the protrusions 120 as illustrated in
In this embodiment, as illustrated in
Next, as illustrated in
In this embodiment, the size and shape of the opening 143 can be controlled by changing the height and shape of the protrusion 120. Thus, instead of the protrusion 120, a protruding conductor like the protrusion 120 may be provided in a region where the opening 143 is to be formed. The conductor thus partly provided with a projecting portion includes a portion forming a terminal of the electronic device and a portion forming an electrode or a wiring.
Grinding treatment in this specification may be any treatment as long as an object can be grinded and includes, in its category, polishing treatment such as mechanical polishing treatment and chemical mechanical polishing treatment, dressing treatment, and lapping treatment.
The step of removing part of the insulating film 140 is not necessarily performed until portions of the insulating film 140, which protrude from the top surface of the insulating film 104, are completely removed. It is only necessary to expose all of the protrusions 120 provided over the substrate 100. For example, as illustrated in
By changing the grinding amount, the size of the opening 143 formed in the insulating film 140 (the area of a portion of the protrusion 120, which is exposed from the insulating film 140) can be controlled. Therefore, in this embodiment, variation in area of portions of the protrusions 120, which are exposed from the insulating film 140, can be reduced as compared to the step of forming the openings 143 with the use of a laser beam. Accordingly, variation in electric characteristics of the electronic device can be reduced, which increases reliability of the electronic device itself.
Thus, as the height of the protrusion 120 is increased, the allowable range within which the areas of the plurality of openings 143 on the substrate 100 vary can be broaden. As the size of the substrate is increased, the areas of the openings 143 of the insulating film 140 over the substrate 100 are likely to vary; therefore, increasing the height of the protrusion 120 is advantageously effective. In order to form the plurality of openings 143 in the insulating film 140 reliably, the height of the protrusion 120 may be set to be high and the grinding amount of the protrusion 120 may be increased. Alternatively, without change in the height of the protrusion 120, the grinding amount of the protrusion 120 is increased so that a top surface of the insulating film 140 is entirely grinded as illustrated in
Next, as illustrated in
Thus, in the electronic device, the terminal portion including the protrusion 120 and the conductor 121 is formed. Note that the conductor 121 may include not only a portion forming a terminal portion of the electronic device but also a portion forming a wiring or another electrode.
Note that in the case where electric connection with another electric device is possible with the use of the protrusion 120 without formation of the conductor 121, the conductor 121 is not necessarily formed. By forming the conductor 121, the terminal portion can protrude as compared to any other portion on the insulating film 140 side of the electronic device; therefore, reliability of an electric connection portion with another electric device can be increased, which is preferable.
Next, as illustrated in
As illustrated in
Before the stack formed over the substrate 100 is cut, the prepreg 130 including the reinforcing material 131 may also be attached to a surface of the substrate 100, which is not provided with the stack. After the attachment of the prepreg 130, the prepreg 130 is cured to form an insulating film 160 which covers the surface of the substrate 100, which is not provided with the stack, as illustrated in
As illustrated in
Then, as illustrated in
The step of separating the substrate 100 may be performed before the openings 143 are formed in the insulating film 140. In that case, steps up to and including the step in
The structure of the electronic device 153 is similar to that of the electronic device 151 in
As described above, in this embodiment, accuracy of the position where an opening is formed in an insulating film (resin film) including a reinforcing material is ensured in a self-aligned manner and the shape and size of the opening can be controlled by changing the height and shape of a protrusion. Therefore, by applying this embodiment, the opening can be formed in the insulating film including the reinforcing material with high accuracy and with great ease as compared to the case where a laser beam is used. Accordingly, a terminal structure and an electronic device can have higher reliability.
Note that the method by which an opening is formed in an insulating film formed using a prepreg including a reinforcing material is described in this embodiment; however, this embodiment can also be applied to the case where an opening is formed in an insulating film formed by curing an uncured resin film which does not include a reinforcing material, which brings a similar advantageous effect.
This embodiment can be combined with any of the other embodiments as appropriate.
In this embodiment, the step of forming the openings 143 in the insulating film 140 (see
[Structure Example 1 of Grinding Machine and Grinding Step]
Hereinafter, a structure of a grinding machine 201 in
As illustrated in
To perform the step in
[Structure Example 2 of Grinding Machine and Grinding Step]
Next, a structure of a grinding machine 202 in
As illustrated in
To perform the step in
In the step in
By forming the protrusion 120, the position of the opening 143 is determined in a self-aligned manner, and the shape and size of the opening 143 can be controlled by changing the shape and height of the protrusion 120. Thus, the opening 143 can be formed in the insulating film 140 with high accuracy with grinding treatment without complex operation of the grinding machine.
Therefore, even when the grinding machine 201 provided with the grinding surface plate 210 rotated in one plane, which is illustrated in
This embodiment can be combined with any of the other embodiments as appropriate.
In this embodiment, a sheet fibrous body which can be applied to the reinforcing material 131 of the prepreg 130 illustrated in
[Structure Example 1 of Sheet Fibrous Body]
As illustrated in
There is no particular limitation on a yarn bundle (the warp yarn 261 and the weft yarn 262) (e.g., the cross-sectional shape or the processing method) used for the sheet fibrous body 251. The cross-sectional shape may be a circular shape, an elliptical shape, or a flat shape. A yarn bundle which has been subjected to fiber opening is preferably used for the warp yarn 261 and the well yarn 262 because the yarn bundle subjected to fiber opening has a large width, has a smaller number of single yarns in the thickness direction, and thus is easily flattened in cross section. For example, as illustrated in
[Structure Example 2 of Sheet Fibrous Body]
As a means to increase the strength of a cured prepreg, reduction in area of a basket hole is given.
[Structure Example 3 of Sheet Fibrous Body]
A woven fabric used for a sheet fibrous body is not limited to a plain-woven fabric.
Further, to protect an electronic device with the use of a cured prepreg more effectively, the area of the basket hole 263 of each of the sheet fibrous bodies (251, 252, and 253) is preferably smaller than the area of a portion of the electronic device, which is locally pressed when the electronic device is used. For example, in the case where the electronic device is pressed with a tool having a sharp tip, like a writing implement such as a pen or a pencil, the shape of the basket hole 263 is preferably a quadrangle having sides each of which has a length of from 0.01 mm to 0.2 mm.
In the step of forming the openings 143 in Embodiment 1, by controlling the grinding amount of the insulating film 140, part of the insulating film 140 can be reliably removed together with part of the reinforcing material 131. Therefore, even when a sheet fibrous body such as glass cloth is used for the reinforcing material 131, the opening 143 can be formed with high productivity.
This embodiment can be combined with any of the other embodiments as appropriate.
In this embodiment, as an example, a structure of an electronic device which is capable of transmitting and receiving data through wireless communication and a manufacturing method of the electronic device will be described.
Carrier waves are a signal of AC waves which is also referred to as a carrier. In wireless communication, the frequency or amplitude of carrier waves is changed (modulated) in accordance with a signal representing data to generate modulated waves, and data is communicated through transmission and reception of the modulated waves. There are some kinds of methods for modulating carrier waves. A modulation method in which data is represented by the amplitude of carrier waves is called amplitude modulation. A modulation method in which data is represented by the frequency of carrier waves is called frequency modulation.
As a specific example of the electronic device 300, an IC chip (also referred to as a wireless chip) which can communicate data without contact can be given. In addition, a radio frequency identification (RFID) tag with which individual identification without contact is performed can also be given. The RFID tag is also referred to as an RF tag, a wireless tag, an electronic tag, or an IC tag.
An example of a structure of the electronic device 300 which can be used for an IC chip or an RFID tag will be described with reference to
First, the structure of the electronic device 300 in
The power source portion 311 is a device for supplying power to the electronic device 300 and includes, for example, a rectifier circuit 321, a power storage portion 322, and a constant voltage circuit 323. The rectifier circuit 321 is a circuit to generate a DC voltage from a signal (carrier waves) received by the antenna 301. The power storage portion 322 is a circuit to store the direct-current voltage generated by the rectifier circuit 321 and thus includes, for example, a plurality of capacitors. The constant voltage circuit 323 is a circuit to make the voltage generated by the rectifier circuit 321 constant.
The logic circuit portion 312 has a function of extracting data from the signal (the carrier waves) received by the antenna 301, a function of generating carrier waves, which represents data and is transmitted from the antenna 301, and the like. For example, the logic circuit portion 312 includes a demodulation circuit 331, a clock generation/correction circuit 332, a code recognition/judgment circuit 333, a memory controller 334, a memory device 335, an encoding circuit 336, and a modulation circuit 337.
The demodulation circuit 331 is a circuit to demodulate the carrier waves received by the antenna 301. The clock generation/correction circuit 332 is a circuit to generate a clock signal based on the signal output from the demodulation circuit 331 and to correct the clock signal.
The code recognition/judgment circuit 333 recognizes a code included in the carrier waves received by the antenna 301 and makes a judgment. Further, the code recognition/judgment circuit 333 has a cyclic redundancy check (CRC) function, for discriminating a transmission error. As the code recognized by the code recognition/judgment circuit 333, an end-of-frame (EOF) signal, a start-of-frame (SOF) signal, a flag, a command code, a mask length, a mask value, and the like can be given.
The memory controller 334 generates, based on the code recognized by the code recognition/judgment circuit 333, a signal for reading out data from the memory device 335. The memory device 335 includes at least a read-only memory (ROM). As an example of the ROM, a mask ROM and a PROM can be given. Further, the memory device 335 may include a memory circuit such as a random access memory (RAM), which is capable of rewriting data. As the memory circuit capable of rewriting data, for example, a DRAM, an SRAM, an FeRAM, an EEPROM, or a flash memory can be used.
The encoding circuit 336 encodes data which is to be transmitted from the electronic device 300, such as data read out from the memory device 335, or the like. The modulation circuit 337 modulates the signal based on the data which has been encoded in the encode circuit 336 to generate carrier waves which can be transmitted from the antenna 301.
Next, the structure of the electronic device 300 in
The analog circuit portion 341 includes a resonance circuit 351 having a resonant capacitor, a constant voltage circuit 352, a rectifier circuit 353, a demodulation circuit 354, a modulation circuit 355, a reset circuit 356, an oscillator circuit 357, and a power supply control circuit 358.
The digital circuit portion 342 includes an RF interface 361, a control register 362, a clock controller 363, a central processing unit (CPU) 364, a CPU interface 365, an RAM 366, and an ROM 367.
The operation of the electronic device 300 in
The reset circuit 356 generates a signal which resets and initializes the digital circuit portion 342. For example, the reset circuit 356 generates a signal which rises after increase in a power supply voltage with delay as a reset signal. The oscillator circuit 357 changes the frequency and the duty ratio of a clock signal in accordance with a control signal generated by the constant voltage circuit 352. The demodulation circuit 354 is a circuit which demodulates a received signal, and the modulation circuit 355 is a circuit which modulates a signal so that data to be transmitted is included in carrier waves.
For example, when a modulation method by which a signal is processed in the electronic device 300 is an amplitude shift keying (ASK) method, which is one of amplitude modulation methods, the demodulation circuit 354 is preferably formed using a low-pass filter. The demodulation circuit 354 binarizes the received signal based on variation in amplitude. On the other hand, the modulation circuit 355 changes the resonance point of the resonance circuit 351, thereby changing the amplitude of the signal.
The clock controller 363 generates a control signal for changing the frequency and the duty ratio of a clock signal in accordance with a power supply voltage or a current consumed in the CPU 364. The power supply voltage is monitored by the power supply control circuit 358.
The signal received by the antenna 301 is demodulated by the demodulation circuit 354. The demodulated signal is decomposed into a control command, data, and the like by the RF interface 361. The control command is stored in the control register 362. The control command includes an instruction to a circuit included in the digital circuit portion 342, such as an instruction for reading out data from the ROM 367, an instruction for writing data to the RAM 366, or an arithmetic instruction to the CPU 364.
The CPU 364 accesses the ROM 367, the RAM 366, and the control register 362 via the CPU interface 365. The CPU interface 365 generates an access signal which allows the CPU 364 to access any of the ROM 367, the RAM 366, and the control register 362 in accordance with an address requested by the CPU 364.
There are several arithmetic processing methods of the CPU 364, and a method in which processing is performed by software is one of the methods. In this method, for example, the ROM 367 stores an operating system (OS) and the CPU 364 reads out a program stored in the ROM 367 to execute. Another method is a method in which processing is conducted by a dedicated arithmetic circuit, that is, a method in which processing is conducted by hardware. Another method is a method in which hardware and software are used. In this method, part of arithmetic processing is conducted by a dedicated arithmetic circuit and the other part of the arithmetic processing is conducted by the CPU 364 with the use of a program.
Next, an example of a method for manufacturing the electronic device 300 will be described. This embodiment will describe a manufacturing method including a step of separating a substrate which is used for manufacturing an electronic device. For example, in the manufacturing method described in Embodiment 1 as such a method, a separation film (e.g., a film including silicon) is formed between the substrate 100 and the insulating film 101 serving as a base and removed by etching, so that the electronic device can be separated from the substrate 100. Alternatively, the electronic device may be separated from the substrate 100 in such a manner that a separation film which includes a metal as its main component is formed between the substrate 100 and the insulating film 101 serving as a base and physical force is applied to the separation film in order to cause separation along the separation film.
An example of the manufacturing method of the electronic device 300, to which the latter method is applied, will be described below with reference to
First, as illustrated in
Before the separation film 402 is formed, a base film 403 is formed on and in close contact with the glass substrate 400. The base film 403 is a base film of the separation film 402 and is formed in order to improve adhesion between the separation film 402 and the glass substrate 400. The base film 403 can be formed using an insulating film with a single-layer structure or a layered structure. As the insulating film used to form the base film 403, a silicon oxide film, a silicon oxynitride film, a silicon nitride oxide film, a silicon nitride film, a metal oxide film, or the like can be used. Here, a silicon oxynitride film with a thickness of 100 nm is formed with a PECVD method.
Next, the separation film 402 is formed in contact with the base film 403. Here, as the separation film 402, a tungsten film with a thickness of 50 nm is formed with a sputtering method.
In this manufacturing method, separation is caused priorly inside the separation film 402 and/or at the interface between the separation film 402 and the base insulating film 401 by applying mechanical force to the separation film 402 so that the functional circuit 302 is separated from the glass substrate 400. In order that such separation may be caused, the separation film 402 is formed using a tungsten film, a molybdenum film, an alloy film of tungsten and molybdenum, an oxide film of tungsten and/or molybdenum, an oxynitride film of tungsten and/or molybdenum, a nitride oxide film of tungsten and/or molybdenum, or a nitride film of tungsten and/or molybdenum, for example. Further, the separation film 402 can be formed using a stack of films selected from the above. These films can be formed with a sputtering method, a PECVD method, a droplet discharging method, or the like.
The separation film 402 may be formed in such a manner that a tungsten film, a molybdenum film, or an alloy film of tungsten and molybdenum is formed as a first layer and an oxide film, an oxynitride film, a nitride oxide film, or a nitride film of the first layer is formed as a second layer. Alternatively, the separation film 402 may be formed in such a manner that a tungsten film, a molybdenum film, or an alloy film of tungsten and molybdenum is formed over the base film 403 and the film is subjected to oxidation treatment. As the oxidation treatment, thermal oxidation treatment, plasma oxidation treatment with oxygen or N2O plasma, surface treatment with a solution having strong oxidizing power, such as ozone water, or the like can be used.
Next, the base insulating film 401 with a single-layer structure or a stacked-layer structure is formed in contact with the separation film 402. An insulating film which can endure later steps of manufacturing the electronic device 300 is selected as the base insulating film 401 and can be formed in a manner similar to that of the insulating film 101 in
Next, the functional circuit 302 is manufactured over the base insulating film 401. A plurality of functional circuits 302 is simultaneously manufactured over the glass substrate 400 in the same process. A process of manufacturing two functional circuits 302 each including an n-channel transistor and a p-channel transistor is illustrated in drawings.
As illustrated in
Next, a resist mask is formed over the semiconductor film 405 and the semiconductor film 405 is etched to have a desired shape using the resist mask, so that semiconductor films 420 and semiconductor films 430 are formed over the base insulating film 401 as illustrated in
Next, as illustrated in
Next, as illustrated in
Next, as illustrated in
In order to form these regions, first, resist masks which cover the semiconductor films 430 are formed. An impurity element which imparts n-type conductivity is added to the semiconductor films 420 with the use of the conductive films 441 as masks, so that the n-type low-concentration impurity regions 423 are formed in the semiconductor films 420. Regions in the semiconductor films 420, where the impurity element is not added in this step, become channel formation regions 421. Then, after the resist masks which cover the semiconductor films 430 are removed, resist masks which cover the semiconductor films 420 are formed. An impurity element which imparts p-type conductivity is added to the semiconductor films 430 with the use of the conductive films 442 as masks, so that the p-type high-concentration impurity regions 432 are formed in the semiconductor films 430. Then, the resist masks are removed. Regions in the semiconductor films 430, where the impurity element is not added in the step of adding the impurity element, become channel formation regions 431.
As for the steps illustrated in
In this embodiment, phosphorus (P), arsenic (As), or the like can be used as the impurity element which imparts n-type conductivity, and boron (B), aluminum (Al), gallium (Ga), or the like can be used as the impurity element which imparts p-type conductivity.
Next, as illustrated in
Next, the insulating film 407 and the insulating film 406 are subjected to etching. This etching step is performed by anisotropic etching mainly in a perpendicular direction. By such anisotropic etching, sidewalls formed using the insulating film 407 can be formed on side surfaces of the conductive films 441 and the conductive films 442 as illustrated in
Next, as illustrated in
Next, as illustrated in
The insulating film 408 can be formed in a manner similar to that of the insulating film 103 in
Next, in order that the conductive films 443 and the conductive films 444 are electrically connected to the n-type high-concentration impurity regions 422 and the p-type high-concentration impurity regions 432, respectively, the insulating film 408 is etched so that openings are formed. Then, a conductive film to be the conductive films 443 to 445 is formed over the insulating film 408. The conductive film can be formed in a manner similar to that of the conductive film 113 in
The conductive films 443 are electrically connected to the n-type high-concentration impurity regions 422 and each of them functions as a source electrode, a source wiring, a drain electrode, or a drain wiring of the n-channel transistor. The conductive films 444 are electrically connected to the p-type high-concentration impurity regions 432 and each of them functions as a source electrode, a source wiring, a drain electrode, or a drain wiring of the p-channel transistor. Further, the conductive film 445 forms a portion in which the functional circuit 302 and the antenna 301 are electrically connected to each other.
Through the above steps, electronic elements (n-channel transistors 491 and p-channel transistors 492) of the functional circuits 302 are completed. Next, an example of steps of forming a connection terminal of the functional circuit 302 and the antenna 301 is described with reference to
As illustrated in
Next, conductive films 451 which are electrically connected to the conductive films 445 are formed over the insulating film 409 and protrusions 452 are formed corresponding to the conductive films 451. Here, as the conductive films 451, a titanium film with a thickness of 100 nm to 300 nm is formed with a sputtering method.
Protrusions 452 can be formed in a manner similar to that of the protrusions 120 in
The conductive film 445, the conductive film 451, and the protrusion 452 form a terminal portion 450 of the functional circuit 302. Note that the terminal portion 450 may be formed using only the protrusion 452 without forming the conductive film 451.
Next, a prepreg 460 formed using an uncured resin 462 which includes a reinforcing material 461 is prepared. The one which is similar to the prepreg 130 in
Then, as illustrated in
The prepreg 460 is cured in such a state, so that an insulating film 465 including the reinforcing material 461 is formed as illustrated in
Here, a sheet-like fibrous body including a glass fiber is used for the reinforcing material 461 of the prepreg 460 and a thermosetting resin is used for a resin material of the resin 462 of the prepreg 460. The steps illustrated in
Next, portions of the insulating film 465, which are in the regions 464 and cover the protrusions 452, are removed. As a result, openings 466 are formed in the regions 464 so that the protrusions 452 (the terminal portions 450) are exposed as illustrated in
In this embodiment, a laser beam is not used for formation of the openings 466 in the insulating film 465, whereby the functional circuit 302 is not damaged by a laser beam. Accordingly, miniaturization and high performance of the electronic elements of the functional circuit 302 are easily achieved. Thus, the functional circuit 302 including the CPU 364 illustrated in
Through the above steps, the functional circuits 302 each provided with a terminal portion 450 are manufactured. Next, a step of separating the functional circuits 302 from the glass substrate 400 is performed. This separation step can be performed as follows, for example.
Irradiation with a UV laser beam is performed from an insulating film 465 side so that a groove (not illustrated) is formed in a stack over the glass substrate 400 so as to reach the separation film 402. By formation of the groove, separation is caused inside the separation film 402 and/or at the interface between the base insulating film 401 and the separation film 402. Accordingly, the plurality of functional circuits 302 can be separated from the glass substrate 400 with relatively weak force (force that can be applied by a hand). Next, as illustrated in
Next, in order to protect the base insulating film 401 which is exposed due to removal of the glass substrate 400, a protective film which is formed using a prepreg including a reinforcing material is formed. Further, for formation of the protective film, the one which is similar to the prepreg 460 used for forming the insulating film 465 can be used. The prepreg 460 which has not been cured is attached to the base insulating film 401, and the prepreg 460 is cured by a vacuum heat press with the prepreg 460 closely attached to the base insulating film 401. As a result, as illustrated in
Next, the stack held by the film 470 is divided into the individual functional circuit 302. This step can be performed by dicing, scribing, or the like. Here, scribing with the use of a UV laser beam is performed. Irradiation with a UV laser beam is performed from the insulating film 467 side, so that a groove is formed in the stack held by the film 470. As illustrated in
Next, the antenna 301 is electrically connected to the functional circuit 302. Here, as the antenna 301, a film antenna including a film 500 formed using a resin such as polyester and a conductive film 501 formed over the film 500 is used. As the film 500, a film which has flexibility and is formed using an insulating material is preferably used. Since the functional circuit 302 has a structure in which the electronic elements are sealed with the insulating film 465 and the insulating film 467 each of which is formed using a resin, the functional circuit 302 is flexible and bendable. Therefore, when the antenna 301 is formed using a film antenna which is bendable, the electronic device 300 in
For example, as the film 500, a resin film such as a polyester film, a polycarbonate film, an acrylic film, or a polyimide film can be used. The conductive film 501 includes a portion forming a main body of the antenna and a terminal portion which is electrically connected to the functional circuit 302. A surface of the conductive film 501 is covered with a layer formed using an insulating material such as a resin, except for the terminal portion.
As illustrated in
The conductive film 501 may have a suitable structure (e.g., a shape, a size) in accordance with the frequency band of carrier waves transmitted and received by the electronic device 300, the communication distance, or the like. Three example of the structure of the antenna 301 (the conductive film 501) are described with reference to
For example, when the frequency band is from the 125 kHz band to the 135 kHz band or the 13.56 MHz band, a loop antenna, a coil antenna, or a spiral antenna may be used as the antenna 301.
In this embodiment, a laser beam is not used for formation of the openings 466 in the insulating film 465, whereby the functional circuit 302 is not damaged by a laser beam. Accordingly, miniaturization and high performance of the electronic elements of the functional circuit 302 are easily achieved. Thus, the functional circuit 302 including the CPU 364 illustrated in
In addition, the electronic device 300 of this embodiment may be embedded in paper or interposed between two plastic substrates, whereby an IC card can be manufactured. Further, the electronic device 300 in
Further, the electronic device 300 may be used by being fixed to a variety of goods and objects. As a method for fixing the electronic device 300 to the goods and objects, there are methods such as embedding the electronic device 300 in the goods and objects, and attaching the electronic device 300 to the surface of the goods and objects. Since the electronic device 300 of this embodiment has flexibility, the appearance of an object to which the electronic device 300 is attached is unlikely to be spoiled, and the electronic device 300 can be fixed to a curved surface. Further, as the goods and objects to which the electronic device 300 is fixed, for example, the following can be given: packaging containers (such as wrapping paper and bottles), recording media (such as Blu-ray Discs, DVDs, and USB memories), clothing and accessories (such as bags, glasses, and clothing), foods, plants, animals (such as livestock and pets), commodities, and shipping tags and labels on products and baggage. When the electronic device 300 is fixed to these goods and objects, inspection, distribution management, historical management of the objects, and the like are easily systematized.
For example, when the electronic device 300 is fixed to a shipping tag or a price tag of a product and data stored in the electronic device 300 is read with a reader/writer which is provided beside a conveyor belt, data on a manufacturing process, a distribution process, a delivery destination, and the like is obtained and thus product inspection and stock management can be performed with high efficiency.
Note that this embodiment can be combined with any of the other embodiments as appropriate.
In the method for manufacturing the electronic device 300, according to Embodiment 4, the step of forming the openings 466 in the insulating film 465 covering the protrusions 452 is performed and then the step of separating the glass substrate 400 from the functional circuits 302 is performed (see
First, the steps up to and including the step in
Next, as illustrated in
Next, the stack supported by the film 472 is cut into individual functional circuits 302. This step can be performed by treatment such as dicing or scribing, like the step in
Then, the film 472 is heated so that the functional circuit 302 is separated from the film 472, an antenna 301 is electrically connected to the functional circuit 302, and thus, the electronic device 300 is completed (see
This embodiment can be combined with any of the other embodiments as appropriate.
In the method for manufacturing the electronic device 300, according to Embodiment 4, the step of forming the openings 466 in the insulating film 465 covering the protrusions 452 is performed and then the step of separating the glass substrate 400 from the functional circuits 302 is performed (see
In the method for manufacturing an electronic device 300, according to Embodiment 5, the inspection step may be performed similarly. In the step in
Application of the manufacturing method according to this embodiment is not limited to application to Embodiments 4 and 5. This embodiment is the method for manufacturing an electronic device, in which a protrusion covered with a reinforcing material is exposed and then inspection is performed using the protrusion.
This application is based on Japanese Patent Application serial no. 2009-185126 filed with Japan Patent Office on Aug. 7, 2009, the entire contents of which are hereby incorporated by reference.
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