JP4525002B2 - Wireless recognition semiconductor device and method for manufacturing wireless recognition semiconductor device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to a technical field related to a structure for economically and highly reliably creating a semiconductor recognition device or a wireless IC tag that reads or writes a number in a semiconductor chip wirelessly.
[0002]
[Prior art]
In the conventional electrode forming method, as described in Patent Document 1, the electrodes are formed by a conventional technique of gold plating on the front surface or the back surface when the electrodes of the double-sided electrode chip are attached.
[0003]
Conventional conductive particles have a conductor on the particle surface as described in Patent Document 2.
[0004]
A conventional 128-bit memory has only a 7-bit address counter as described in Non-Patent Document 1, and has a separate control circuit.
[0005]
Conventional anisotropically conductive adhesive particles have been used in which the particle surface is a conductor as shown in Patent Document 2.
[Patent Document 1]
Japanese Patent Laid-Open No. 2001-144135 [Patent Document 2]
International Publication No. 00/36555 Pamphlet [Non-Patent Document 1]
Klaus Finkenzeller (Author), "RFID Handbook-Principle and Application of Contactless IC Card", Nikkan Kogyo Shimbun, February 2001, p. 212
[0006]
[Problems to be solved by the invention]
In the conventional electrode forming method, a process for plating growth is required.
[0007]
Conventional anisotropic conductive particles have a problem of causing a short circuit on the side of the semiconductor chip.
[0008]
In the conventional 128-bit memory, a control circuit having a large area is required separately from the counter.
[0009]
In order to cause a short circuit on the side of the semiconductor chip, the conventional anisotropic conductive adhesive particles have been covered with an insulating film.
[0010]
[Means for Solving the Problems]
First, in the conventional electrode forming method, a process for plating growth is required, but a means for attaching a vapor deposition film to the entire wafer surface is proposed.
Next, although the conventional anisotropic conductive particles have a problem of causing a short circuit on the side of the semiconductor chip, a means for forming anisotropic conductive particles having an insulating film on the surface is proposed.
[0011]
Next, in the conventional 128-bit memory, a control circuit having a large area is required separately from the counter, but means for connecting the control counters is proposed.
Next, in order to cause a short circuit on the side of the semiconductor chip, the particles of the anisotropic conductive adhesive used to cover the side of the semiconductor chip with an insulating film. Propose a means to make it unnecessary.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
First, a wireless recognition semiconductor device using double-sided electrodes will be described.
[0013]
Since the wireless IC chip is operated by electromagnetic waves, the wireless IC chip is characterized by supplying energy to the wireless IC chip and transmitting / receiving data. For this reason, the wireless IC chip includes a circuit for processing electromagnetic waves, a memory circuit, and a circuit for controlling these circuits. First, in a circuit for processing an electromagnetic wave, since the electromagnetic wave has an AC waveform, a rectifier circuit that converts the AC waveform into a DC waveform is used.
[0014]
Generally, there are two types of rectifier circuits, a full-wave rectifier circuit and a voltage doubler rectifier circuit. In the input part of the conventional full-wave rectifier circuit, the first electrode and the second electrode are on the surface of the device and are connected to the gates of the MOS transistors, respectively. In the full-wave rectifier circuit, the circuit is configured symmetrically at the terminal portion to which electromagnetic waves are input. Their input terminals are connected to the gates of the two transistors. Therefore, it is necessary to form two transistors on the surface of the silicon substrate, and it is necessary to take out electrodes from the same surface of the chip. Therefore, the silicon substrate has a potential different from those of the electrodes, and cannot be short-circuited with these electrodes. Further, the antenna cannot be mounted unless the electrodes are taken out from the same surface of the silicon substrate. In the full-wave rectifier circuit, the substrate potential is different from the input of the wireless IC chip.
[0015]
On the other hand, in the voltage doubler rectifier circuit, the substrate potential can be shared with the input of the wireless IC chip. Therefore, in the voltage doubler rectifier circuit, the back surface of the wireless IC chip having the same potential as the substrate can be used as an electrode.
[0016]
The input part of the voltage doubler rectifier circuit in a semiconductor device using double-sided electrodes forms, for example, a capacitor, and is composed of an upper electrode, polysilicon, an oxide film, a capacitor diffusion part, a lower electrode, and the like. The polysilicon is connected to the upper electrode. The wireless IC chip and the upper electrode are insulated by an oxide film. Further, the capacitor diffusion portion can be used as an electrode for constituting a capacitor via an oxide film. Since this capacitor is formed on a silicon substrate, the silicon substrate can be used as a ground terminal.
[0017]
In the voltage doubler rectifier circuit, it is not necessary to assemble the circuit symmetrically, and the substrate potential can be fixed to the ground. Therefore, it can be taken out from the back surface of the silicon substrate as an antenna terminal. Of course, it is possible to take out two terminals from the device surface, but the chip size is as small as 0.5 mm square, 0.3 mm square, 0.15 mm square, 0.1 mm square, 0.05 mm square, 0.01 mm square. As the two electrodes are removed from the same surface, the space is reduced. When a plurality of terminals are taken out from a narrow place, not only the electrode size is reduced, but also the space between the electrodes is reduced, so that connection with the antenna terminal becomes extremely difficult.
[0018]
The substrate of the wireless IC chip is divided into a P-type and an N-type, but a voltage doubler rectifier circuit can be formed with any substrate. Further, in the SOI (Silicon On Insulator) wafer, the back surface potential is floated, but by removing the silicon and oxide film on the back surface, it is possible to expose and connect the active surface. Next, a circuit for changing the input impedance of the wireless IC chip is incorporated in the rectifier circuit. When the input impedance changes, an unmatch occurs between the antenna impedance and the semiconductor device impedance, resulting in a change in reflectance. The change in reflectance can be read by the reader, and information can be received on the reader side. FIG. 9 shows a plan view pattern of the first antenna terminal 11, the semiconductor substrate 18, and the second electrode 16. Referring to FIG. 9, it will be described that the electrode and the tip are formed in a similar shape by the process of FIG. In FIG. 2, the antenna terminal 11 of FIG. 9 is specifically formed by the sputter layer 21 of FIG. The surrounding shape is determined to be similar by the etching unit 22. Next, the semiconductor substrate 18 of FIG. 9 is specifically formed of the silicon substrate 23 in FIG. The silicon substrate 23 has a pattern formed by the etching part 22 and is determined to be similar to the shape of the dry etching part 25 in FIG. Next, the second antenna terminal 16 of FIG. 9 is specifically formed of the back sputter layer 24 in FIG. The back sputter layer 24 is determined to be similar in shape by the scribe portion 26. Therefore, in the manufacturing process, the antenna terminal 11, the semiconductor substrate 18, and the second antenna terminal 16 of FIG. 9 are formed in a similar shape.
[0019]
FIG. 1 shows a double-sided electrode structure.
[0020]
FIG. 1A shows a circuit diagram of a double-sided electrode structure. The first antenna terminal 11 is connected to a capacitor 12, and this capacitor is connected to a first diode 13 and a second diode 15. The first diode is connected to the electronic circuit 14. The second antenna terminal is ground, which is connected to the second diode 15 and the electronic circuit.
FIG. 1B shows a cross-sectional view of a semiconductor chip having a double-sided electrode structure. The semiconductor chip is composed of a semiconductor substrate 18 and an element layer 17, and has a first electrode 11 on the main surface side and a second electrode 16 on the back surface side.
[0021]
FIG. 10 shows a configuration of a wireless recognition semiconductor device using double-sided electrodes. The antenna 101 exists in a pair with the ground point 102. The electromagnetic wave input from the antenna is rectified in the rectifier circuit 103 to generate a DC voltage. This voltage accumulates electric charge in the capacitor 104. The clock circuit 105 extracts a clock from a signal that has been carried on an electromagnetic wave. The power-on reset circuit 107 receives the clock signal and sets the initial value of the memory circuit 106. The memory circuit includes a counter, a decoder, a memory cell having memory information, a write circuit, and the like. These digital circuits operate in synchronization with a clock signal. The clock signal is generated by demodulating the electromagnetic wave modulated signal. The modulation method includes an ASK method that modulates by amplitude, an FSK method that modulates by frequency, and a PSK method that modulates by phase. A combination of these is also possible. There are capacitors and diodes in the rectifier circuit, and the AC waveform is rectified into a DC waveform.
[0022]
FIG. 3 shows an example of a conventional example. The conductive particles 31 are in the adhesive 39, and the first antenna conductor 32 is connected to the electrode 34 on the main surface on the silicon substrate 38 by the first connection conductor particles 33. In addition, the second antenna conductor 35 is connected to the electrode 37 on the back surface by the second connection conductor particles 36.
[0023]
FIG. 7 is a sectional view showing the step before FIG. 3 in the present invention. The first connection conductor particles 111 before being crushed and the second connection conductor particles 112 before being crushed are between the antenna conductor and the front and back electrodes, respectively. By applying pressure from the outside of the upper and lower antenna conductors, the state shown in the cross section of FIG. 3 is obtained.
[0024]
FIG. 2 shows an embodiment of the present invention. 2 (a) is a conductor layer 21 made of sputtered layer or a metal such as In the top of the silicon substrate 23, also back conductor layer 2 4 made from the back sputtered layer 24 or the metal or the like on the back of the silicon substrate Therefore, the sputter layer 21 shows a cross-sectional view immediately after the step of being etched by the etching portion 22. The etching unit 22 coats a photoresist layer thereon with the sputter layer 21 on the entire surface of the wafer, then exposes the mask pattern, and removes the portion of the photoresist layer where the etching unit 22 is formed by development, and then wets it. Alternatively, the sputter layer is etched and formed by a dry process. FIG. 2B shows a cross-sectional view of the process after FIG. 2A, in which the silicon substrate is pasted on the support tape 27 and the silicon substrate is separated by the dry etch portion 25. A cross-sectional view immediately after is shown. The silicon substrate is separated by dry etching in a self-aligned manner by the etching portion 22 on the surface. FIG. 2C shows a cross-sectional view of the step after FIG. The scribe part 26 separates the back sputtering layer, and is separated in a self-aligned manner by mechanical stress. The mechanical stress can be generated by rubbing an uneven hard roller or the like from the outside of the support tape 27. The scribe part is created with a support tape. The support tape can be easily removed by a conventional method. That is, the support tape can be easily removed by adhering and fixing the surface having the sputtered layer to the adsorber in a vacuum so that the support tape is turned over. The inventor claims the following by the present invention. That is, in a wireless recognition semiconductor device having electrodes on both the main surface and the back side of a semiconductor chip and connecting an antenna to the electrode to wirelessly read information existing in the semiconductor chip, In the wireless recognition semiconductor device in which the size and shape of the semiconductor substrate of the wireless recognition semiconductor device are similar, the semiconductor substrate is dry-etched by self-alignment using the electrode material on the main surface as a mask. The wireless recognition semiconductor device is characterized by the above. As a result, the silicon substrate can be easily separated and the surface electrode area can be maximized. In FIG. 2, the front sputter layer 21 corresponds to the front electrode 11, and the back sputter layer corresponds to the back electrode 16.
[0025]
In the present invention, the inventor claims the following. That is, in order to produce a wireless recognition semiconductor device stably and economically and characteristically, it has electrodes on both the main surface and the back side of the semiconductor chip, and an antenna is connected to the electrode so that the inside of the semiconductor chip In the wireless recognition semiconductor device that wirelessly reads information existing in the wireless recognition semiconductor device, the size of the electrode is similar to the size and shape of the semiconductor substrate of the wireless recognition semiconductor device. That is.
[0026]
FIG. 4 shows another embodiment of the present invention. This figure is a detailed view of the conductive particles 31 shown in FIG. The conductive particles have a special structure and are characterized in that the insulator 41 is around the conductor 42. With this structure, even if there are conductive particles beside the semiconductor chip as shown in FIG. 3, the antenna conductor and the silicon substrate are not short-circuited. In the case of a crushed shape such as the first connection conductor particle 33 and the second connection conductor particle 35 in FIG. 3, the insulator in FIG. 4 is broken, and the internal conductor is exposed to expose the first antenna conductor. Can be stably connected to the electrode on the main surface and the second antenna conductor to the electrode on the back surface. The inventor claims the following in the present invention. That is, in a wireless recognition semiconductor device having electrodes on both the main surface and the back side of a semiconductor chip and connecting an antenna to the electrode to wirelessly read information existing in the semiconductor chip, In the wireless recognition semiconductor device in which the size and shape of the semiconductor substrate of the wireless recognition semiconductor device are similar to each other, an anisotropic conductive adhesive is used to connect the electrode and the antenna. When performing, the wireless recognition semiconductor device is characterized in that the surface of the conductive particles in the anisotropic conductive adhesive is covered with an insulator.
[0027]
FIG. 5 shows another embodiment of the present invention. The first counter 51 and the second counter are in the wireless recognition semiconductor chip, the control circuit 53 is connected to the first counter 51, and the memory circuit 54 is connected to the second counter. Further, the first counter and the second counter are connected, and the output of the last stage of the first counter becomes the input of the first stage of the second counter. Each counter may be a simple toggle counter. The inventor of the present invention claims the following in the present invention. That is, in a wireless recognition semiconductor device that connects an antenna to an electrode of a semiconductor chip and wirelessly reads information existing inside the semiconductor chip, the semiconductor chip has a plurality of counters, and the first counter Are output to the upper bits of the second and subsequent counters, the first counter is used for controlling the output of information of the semiconductor chip, and the second and subsequent counters are used for the semiconductor. The wireless recognition semiconductor device is used as an address of a memory in a chip. As a result, the control circuit and the control of the memory can be simply configured in conjunction with each other, so that the configuration of the wireless recognition semiconductor chip can be simplified, and the chip area can be reduced.
[0028]
FIG. 6 shows another embodiment of the present invention. In the present invention, the electrode 61 on the main surface is on the insulating film 62 and the electrode 63 on the back surface exists on the back surface of the etched semiconductor substrate 65. With this structure, even if the conductive particles 64 are attached as shown in the figure, the electrode and the substrate on the surface do not short-circuit even if the surface of the conductive particles is a conductor. This is because the shape is formed so that the semiconductor substrate recedes from the insulating film on the surface as shown in the figure. The present invention relates to a semiconductor chip that transmits and receives data wirelessly to and from the outside. The semiconductor chip has an electrode on the main surface side and an electrode on the surface opposite to the main surface. An external antenna of the semiconductor chip or an attached capacitor is formed by the first conductor and the second conductor that are connected to the first conductor and the second conductor outside the semiconductor chip. The inventor claims that the wireless recognition semiconductor device is characterized by the above. FIG. 8 is a drawing for explaining the manufacturing process leading to FIG. It is possible to obtain the state of the cross-sectional view of FIG. 8 through the steps of FIGS. 2A, 2B, and 2C according to the present invention. Once this shape is achieved, it is possible to easily etch the side of the semiconductor chip with a liquid that etches only the semiconductor substrate 121. Through this process, the shape of the cross-sectional view of FIG. 6 can be obtained. . The electrode 61 on the main surface in FIG. 6 has a function equivalent to that of the first antenna terminal 11 in FIG. 1, and the electrode 63 on the back surface in FIG. 6 has a function equivalent to that of the second antenna terminal in FIG.
[0029]
【The invention's effect】
First, in the conventional electrode forming method, a process for plating growth is required. However, an effect that the process can be simplified is generated by means of attaching a vapor deposition film to the entire surface of the wafer.
Next, the conventional anisotropic conductive particles have a problem of causing a short circuit on the side of the semiconductor chip, but even if a conductor contacts the surroundings by means of anisotropic conductive particles having an insulating film on the surface, the short circuit occurs. The effect that does not occur.
[0030]
Next, in the conventional 128-bit memory, a control circuit having a large area is required separately from the counter. However, the effect that the control circuit can be formed with a small area by means of connecting the control counter occurs.
[0031]
Next, in order to cause a short circuit on the side of the semiconductor chip, the particles of the anisotropic conductive adhesive used to cover the side of the semiconductor chip with an insulating film. An effect that the step of forming the insulating film can be omitted by the unnecessary means occurs.
[0032]
[Brief description of the drawings]
FIG. 1 is a diagram showing an embodiment of a circuit and device configuration according to the present invention.
FIG. 2 is a drawing showing an embodiment of processing a wafer according to the present invention.
FIG. 3 is a view showing an embodiment of connection with an antenna of the present invention.
FIG. 4 is a view showing an example of conductive particles of the present invention.
FIG. 5 is a diagram showing an embodiment of an internal circuit configuration of the present invention.
FIG. 6 is a drawing showing a device embodiment of the present invention.
FIG. 7 is a diagram showing an antenna connection embodiment of the present invention.
FIG. 8 is a diagram showing an antenna connection embodiment of the present invention.
FIG. 9 is a plan view showing a semiconductor chip embodiment of the present invention.
FIG. 10 is a drawing showing a circuit example of a semiconductor chip of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... 1st antenna terminal 12 ... Capacitor 13 ... 1st diode 14 ... Electronic circuit 15 ... 2nd diode 16 ... 2nd antenna terminal 17 ... Element layer 18 ... Semiconductor substrate 21 ... Sputtering layer 22 ... Etching part 23 ... Silicone substrate 24 ... Backside sputter layer 25 ... Dry etch part 26 ... Scribe part 27 ... Support tape 31 ... Conductive particles 32 ... First antenna conductor 33 ... First connection conductor particle 34 ... Main surface electrode 35 ... Second Antenna conductor 36 ... second connection conductor particle 37 ... back electrode 38 ... silicon substrate 39 ... adhesive 41 ... insulator 42 ... conductor 51 ... first counter 52 ... second counter 53 ... control circuit 54 ... memory Circuit 61 ... Main surface electrode 62 ... Insulating film 63 ... Back electrode 64 ... Conductive particles 65 ... Etched semiconductor substrate 101 ... Antenna 102 ... Ground point 1 3 ... rectifier circuit 104 ... first connecting conductor particles 112 ... second connecting conductor particles 121 ... semiconductor substrate before being crushed prior to capacitor 105 ... clock circuit 106 ... memory circuit 107 ... power-on reset circuit 111 ... crushed.

Claims (1)

A method of manufacturing a wireless recognition semiconductor device having electrodes on both sides,
Forming a conductor layer on the main surface of the silicon substrate;
Forming a backside conductor layer that functions as an etch stop on the backside of the silicon substrate;
Removing a part of the conductor layer by first etching;
Removing the silicon substrate under the conductor layer removed by the first etching by the second etching up to the back conductor layer;
Cutting the back conductor layer under the silicon substrate removed by the second etching;
A method for manufacturing a wireless recognition semiconductor device, comprising:

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