JP2001120519A - Semiconductor device for recognizing fingerprint and method for manufacturing the semiconductor device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device for recognizing a fingerprint and a manufacturing method therefor capable of improving reliability by preventing breaking by preventing discharge of static electricity and the occurrence of a crack at pressing time of a finger. SOLUTION: This semiconductor device has plural first electrodes 31 (SP) being formed side by side in a matrix shape on a base board 20 and accumulating electric charge, the constitution that the first electrodes connect a word wire 30 to one source drain area of a transistor being a gate electrode and plural semiconductor elements being formed under the first electrodes and reading out electric charge accumulated in the respective first electrodes, and comprises a protective film 21 including silicon nitride formed by covering the first electrodes and a clearance part of the first electrodes, a groove V formed on a surface of the protective film in the clearance part of the first electrodes and a second electrode 32 (NT) formed in a checker shape by being embedded in the groove and fixed to specific electric potential such as earth electric potential or power electric potential.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor device for fingerprint recognition used as a capacitance type fingerprint sensor and a method of manufacturing the same, and more particularly, to a method of discharging static electricity when a finger is pressed and cracking the fingerprint recognition surface. The present invention relates to a semiconductor device for fingerprint recognition in which destruction of a device is prevented and reliability of the device is improved.

[0002]

2. Description of the Related Art In recent years, fingerprint collation systems, which have often been used for entry / exit management and the like, have attracted attention in recent years as security systems on computer networks and personal identification tools in portable terminals and the like. Fingerprint detection methods using a fingerprint collation system include an optical detection method and a capacitance detection method as disclosed in Japanese Patent Application Laid-Open No. 4-231803. The capacitance detection method is a method of detecting a capacitance value (hereinafter, also simply referred to as a capacitance value) between an electrode of a fingerprint sensor and a finger. Since an easy-to-use capacitance type sensor is advantageous, the development of a capacitance type fingerprint sensor has been actively promoted.

FIG. 4A is a plan view of a semiconductor device for fingerprint recognition of a capacitance type, and FIG. 4B is a cross-sectional view taken along line XX 'in FIG. 4A. A gate electrode 30 serving as a word line is formed on a channel formation region of the semiconductor substrate 10 via a gate insulating film, and a source / drain diffusion layer (not shown) is formed in the semiconductor substrate 10 on both sides of the gate electrode 30. Thus, a transistor Tr is formed. One source / drain diffusion layer of the transistor is connected to a bit line.

[0004] An interlayer insulating film 20 made of, for example, silicon oxide is formed so as to cover the transistor Tr, and a sensor made of a laminate of a barrier metal layer made of, for example, Ti and an aluminum layer is formed thereon. The pad electrodes 31 (SP) are formed in a matrix. The sensor pad electrode SP is formed by a contact (not shown) connected to the other source / drain diffusion layer of the transistor Tr formed thereunder.

[0005] A sensor pad electrode 31 and a protective film 21 made of, for example, silicon nitride are formed on the entire surface so as to cover the gap between the sensor pad electrodes 31. Here, a groove V is formed on the surface of the protective film 21 in the gap between the sensor pad electrodes 31. As described above, the semiconductor device for fingerprint recognition has a structure in which the region where the sensor pad electrodes 31 (SP) are arranged in a matrix is used as the fingerprint recognition surface.

The operation of the above-described semiconductor device for fingerprint recognition will be described. As shown in FIG. 5A, when the finger 7 touches the fingerprint recognition surface of the fingerprint recognition semiconductor device, a capacitor is formed between the sensor pad electrode 31, the protective film 21, and the finger 7. The protective film 21 functions as a part of the capacitor insulating film. In the above, the distance d (for example, d ₁ , d ₂ ) between each sensor pad electrode 31 and the finger 7 fluctuates according to the unevenness 70 of the fingerprint. Therefore, since the capacitance of each capacitor formed by the sensor pad electrodes 31 arranged in a matrix on the fingerprint recognition surface is different, the electric charge accumulated in each sensor pad electrode 31 is transferred to the transistor formed on the substrate 10 or the like. It is possible to recognize a fingerprint by reading out and detecting by the semiconductor element described above. Here, each sensor pad electrode 31 constitutes a unit cell on the fingerprint recognition surface of the semiconductor device for fingerprint recognition.

The capacitor formed by each of the sensor pad electrodes 31 has d = ∞ in all the unit cells on the fingerprint recognition surface of the fingerprint recognition semiconductor device when the finger is not in contact with the fingerprint recognition surface, and accordingly, the total capacitance is d = ∞. Capacitance value C in unit cell
_s = 0. On the other hand, when the finger is in contact with the fingerprint recognition surface, as shown in FIG. 5B, in the n-th unit cell, the capacitance value between the sensor pad electrode 31, the protective film 21, and the finger 7 is increased. A capacitor of C _sn is formed. The capacitance value C _sn above is expressed as _{C sn = ε · ε 0 ·} S / d n. Here, S is an area contributing to the capacitor of each electrode, d _n is the distance between the electrode and the fingers of the n-th unit cell (e.g. d _1, d _2), n is the number of the unit cells (n =
1, 2,...).

The capacitance value C _sn of each unit cell described above
, A capacitor formed between the sensor pad electrode 31, the protective film 21, and the finger 7 of each unit cell is, for example, a transistor having a word line WL (WL ₁ , WL ₂ ,...) As a gate electrode. Are connected to one of the source / drain diffusion layers, and the other source / drain diffusion layer is connected to the bit line BL (BL ₁ , BL ₂ ,...). It is assumed that the capacitor of _B is connected. In the above configuration, when a finger contacts the bit line BL in a state where V _CC is applied (V _CC precharge), it is represented by ΔV _n = [C _Sn / (C _B + C _Sn )] · V _CC. A change in the potential of the bit line BL occurs. By detecting the potential change ΔV _n in each cell, the capacitance value C _sn of each unit cell is calculated, and image recognition is performed to perform fingerprint recognition.

[0009]

However, since the human body is generally charged, the conventional fingerprint recognition semiconductor device as shown in FIG. When a person charged on the fingerprint recognition surface approaches a finger, static electricity is discharged to the fingerprint recognition surface (indicated by ESD in the figure), and there is a problem that the fingerprint recognition semiconductor device may be damaged. .

[0010] Similarly, as shown in FIG. 6, in the above-described conventional semiconductor device for fingerprint recognition, a groove V is formed on the surface of the protective film 21 in the gap between the sensor pad electrodes 31 on the surface of the fingerprint recognition surface. Therefore, there is a problem that the mechanical strength is insufficient, cracks C are formed from the protective film 21 in the grooves V when the finger is pressed, and the semiconductor device for fingerprint recognition may be damaged. .

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and accordingly, the present invention prevents the device from being destroyed due to the discharge of static electricity at the time of pressing a finger and the occurrence of cracks in the fingerprint recognition surface, thereby improving reliability. An object of the present invention is to provide a semiconductor device for fingerprint recognition that can be improved and a method for manufacturing the same.

[0012]

In order to achieve the above object, a semiconductor device for fingerprint recognition according to the present invention comprises a plurality of first electrodes formed on a substrate and accumulating electric charges, and A plurality of semiconductor elements formed below the electrodes and reading out the electric charges stored in each of the first electrodes, a protective film formed to cover a gap between the first electrodes and the first electrodes, The semiconductor device includes a groove formed on the surface of the protective film in a gap between the first electrodes, and a second electrode embedded in the groove and fixed at a constant potential.

The semiconductor device for fingerprint recognition of the present invention described above comprises
Preferably, the second electrode is fixed to a ground potential or a power supply potential.

The above-described semiconductor device for fingerprint recognition according to the present invention comprises:
Preferably, the first electrodes are formed in a matrix on the substrate. More preferably, in the gap between the first electrodes arranged in a matrix,
The second electrode is formed in a grid pattern.

The above-described semiconductor device for fingerprint recognition according to the present invention comprises:
Preferably, the protective film is a film containing silicon nitride.

The above-described semiconductor device for fingerprint recognition according to the present invention comprises:
Preferably, as the plurality of semiconductor elements for reading out the charges, the first electrode is connected to one source / drain region of a transistor having a word line as a gate electrode, and the other source / drain of the transistor The region is connected to the bit line.

The above-described semiconductor device for fingerprint recognition according to the present invention comprises:
A plurality of first electrodes formed in a matrix and arranged on a substrate and accumulating electric charges, and the first electrode is connected to one of source / drain regions of a transistor having a word line as a gate electrode; And a plurality of semiconductor elements formed below the first electrode to read out the electric charges stored in each of the first electrodes, such as a configuration in which the other source / drain region is connected to a bit line. Furthermore, a protective film containing silicon nitride or the like formed by covering the first electrode and the gap between the first electrodes, a groove formed on the surface of the protective film in the gap between the first electrodes, and a groove embedded in the groove. And a second electrode fixed to a fixed potential such as a ground potential or a power supply potential.

According to the semiconductor device for fingerprint recognition of the present invention described above, the second electrode which is embedded in the groove formed on the surface of the protective film and fixed at a constant potential is formed in the gap between the first electrodes. Therefore, even if the static electricity is discharged when the finger is pressed, the static electricity is quickly eliminated by the second electrode, and the electrostatic breakdown can be prevented. In addition, since the groove having low mechanical strength is embedded by the second electrode, the strength is reinforced, and it is possible to prevent cracks on the fingerprint recognition surface when a finger is pressed. As described above, the reliability can be improved.

According to another aspect of the present invention, there is provided a method of manufacturing a semiconductor device for fingerprint recognition, comprising: arranging a plurality of first electrodes for accumulating electric charges on a substrate; Forming a groove on the surface of the protective film in the gap between the first electrodes while covering the gap between the first electrodes to form a protective film; Forming a second electrode fixed to the substrate in a self-aligned manner.

In the method of manufacturing a semiconductor device for fingerprint recognition according to the present invention, preferably, a plurality of electric charges stored in the first electrodes are read out before the step of forming the first electrodes side by side. The method includes a step of forming a semiconductor element, and in the step of forming the first electrodes side by side, the first electrodes are formed by connecting to the semiconductor element from which the charges are read. More preferably, the step of forming the plurality of semiconductor elements for reading out the electric charges includes the step of forming a gate insulating film on a channel formation region in a semiconductor layer, and the step of forming a gate electrode serving as a word line on the gate insulating film. Forming a transistor, forming a source / drain region in the semiconductor layer on both sides of the gate electrode, and connecting and forming a bit line to one of the source / drain regions. In the step of forming the first electrodes side by side, the first electrodes are connected to the other source / drain regions of the transistor.

In the method of manufacturing a semiconductor device for fingerprint recognition according to the present invention, preferably, the step of forming the second electrode includes the steps of:
Forming a conductor on the entire surface of the protective film while filling the trench; and removing the conductor formed outside the trench.

In the method of manufacturing a semiconductor device for fingerprint recognition of the present invention described above, preferably, in the step of forming the first electrode, the first electrode is formed in a matrix on the substrate. More preferably, in the step of forming the second electrode, the second electrode is formed in a grid pattern in a gap between the first electrodes arranged in a matrix.

In the method of manufacturing a semiconductor device for fingerprint recognition according to the present invention, preferably, in the step of forming the protective film, a film containing silicon nitride is formed.

In the above-described method of manufacturing a semiconductor device for fingerprint recognition according to the present invention, after a transistor or the like is formed on a substrate as a plurality of semiconductor elements from which charges are read, charges are connected so as to be connected to the source / drain regions of the transistor. A plurality of first electrodes to be accumulated are formed in a matrix or the like. Next, the first electrode and the gap between the first electrodes are covered with the first electrode while forming a protective film made of silicon nitride or the like.
A groove is formed on the surface of the protective film in the gap between the electrodes. Next, the groove is filled with a conductor, and the second is fixed at a constant potential.
Electrodes are formed in a self-aligned manner on a grid or the like.

According to the method of manufacturing a semiconductor device for fingerprint recognition of the present invention, the second electrode fixed at a constant potential is embedded in the groove formed on the surface of the protective film in the gap between the first electrodes. It can be easily formed in a self-aligned manner.
Therefore, even if the static electricity is discharged when the finger is pressed, the static electricity is quickly eliminated by the second electrode, and the electrostatic breakdown can be prevented. Further, since the groove having a low mechanical strength is embedded in the second electrode, the strength is reduced. Can be prevented, cracks on the fingerprint recognition surface when a finger is pressed can be prevented, and a semiconductor device for fingerprint recognition that can improve reliability can be manufactured.

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of a semiconductor device for fingerprint recognition and a method of manufacturing the same according to the present invention will be described below with reference to the drawings.

FIG. 1A is a plan view of the semiconductor device for capacitive fingerprint recognition according to the present embodiment, and FIG. 1B is a sectional view taken along line XX 'in FIG. 1A. It is. A gate electrode 30 serving as a word line is formed on a channel formation region of the semiconductor substrate 10 via a gate insulating film, and a source / drain diffusion layer (not shown) is formed in the semiconductor substrate 10 on both sides of the gate electrode 30. Thus, a transistor Tr is formed. One source / drain diffusion layer of the transistor is connected to a bit line.

An interlayer insulating film 20 made of, for example, silicon oxide is formed so as to cover the transistor Tr, and a sensor made of a laminate of a barrier metal layer made of, for example, Ti and an aluminum layer is formed thereon. The pad electrodes 31 (SP) are formed in a matrix. The sensor pad electrode SP is formed by a contact (not shown) connected to the other source / drain diffusion layer of the transistor Tr formed thereunder.

A sensor pad electrode 31 and a protective film 21 made of, for example, silicon nitride are formed on the entire surface so as to cover the gap between the sensor pad electrodes 31. Here, a groove V is formed on the surface of the protective film 21 in the gap between the sensor pad electrodes 31. The charge eliminating electrode 32 (NT) composed of the TiN adhesion layer 32a and the tungsten layer 32b is formed in a grid pattern so as to be buried in the groove V. The static elimination electrode 32 (NT) is, for example, ground potential (GN)
It is connected to the static elimination electrode pad NTP fixed to D), and is fixed to the ground potential (GND). By fixing the charge removing electrode pad NTP to the power supply potential, the charge removing electrode 32
It is also possible to fix (NT) to the power supply potential. As described above, the semiconductor device for fingerprint recognition has a structure in which the region where the sensor pad electrodes 31 (SP) are arranged in a matrix is used as the fingerprint recognition surface.

The operation of the semiconductor device for fingerprint recognition according to this embodiment will be described. As shown in FIG. 2A, when the finger 7 touches the fingerprint recognition surface of the fingerprint recognition semiconductor device, a capacitor is formed between the sensor pad electrode 31, the protective film 21, and the finger 7. The protective film 21 functions as a part of the capacitor insulating film. In the above, the distance d (for example, d ₁ , d ₂ ) between each sensor pad electrode 31 and the finger 7 is:
It fluctuates according to the unevenness 70 of the fingerprint. Therefore, since the capacitance of each capacitor formed by the sensor pad electrodes 31 arranged in a matrix on the fingerprint recognition surface is different, the charge accumulated in each sensor pad electrode 31 is transferred to the substrate 1.
It is possible to recognize a fingerprint by reading and detecting with a semiconductor element such as a transistor formed at zero. Here, each sensor pad electrode 31 constitutes a unit cell on the fingerprint recognition surface of the semiconductor device for fingerprint recognition.

When the finger is not in contact with the fingerprint recognition surface, the capacitor formed by each sensor pad electrode 31 has d = ｄ in all the unit cells of the fingerprint recognition surface of the fingerprint recognition semiconductor device. Capacitance value C in unit cell
_s = 0. On the other hand, when the finger is in contact with the fingerprint recognition surface, as shown in FIG. 2B, in the n-th unit cell, the capacitance value between the sensor pad electrode 31, the protective film 21, and the finger 7 is increased. A capacitor of C _sn is formed. The capacitance value C _sn above is expressed as _{C sn = ε · ε 0 ·} S / d n. Here, S is the area of each electrode contributing to the capacitor,
d _n is the distance between the electrode and the fingers of the n-th unit cell (e.g., d
₁ , d ₂ ), n is the number of each unit cell (n = 1, 2,...)
・).

The capacitance value C _sn in each unit cell described above
, A capacitor formed between the sensor pad electrode 31, the protective film 21, and the finger 7 of each unit cell is, for example, a transistor having a word line WL (WL ₁ , WL ₂ ,...) As a gate electrode. Are connected to one of the source / drain diffusion layers, and the other source / drain diffusion layer is connected to the bit line BL (BL ₁ , BL ₂ ,...). It is assumed that the capacitor of _B is connected. In the above configuration, when a finger contacts the bit line BL in a state where V _CC is applied (V _CC precharge), it is represented by ΔV _n = [C _Sn / (C _B + C _Sn )] · V _CC. A change in the potential of the bit line BL occurs. By detecting the potential change ΔV _n in each cell, the capacitance value C _sn of each unit cell is calculated, and image recognition is performed to perform fingerprint recognition.

According to the semiconductor device for fingerprint recognition according to the present embodiment, the protective film 21 is formed in the gap between the sensor pad electrodes 31.
Electrode 32 buried in a groove V formed on the surface of the substrate and fixed at a constant potential such as a ground potential or a power supply potential.
Is formed, even if static electricity is discharged when a finger is pressed, static electricity is quickly eliminated by the static elimination electrode, electrostatic breakdown can be prevented, and a groove V having low mechanical strength is embedded by the static elimination electrode. Therefore, the strength is reinforced, the occurrence of cracks on the fingerprint recognition surface when the finger is pressed can be prevented, and the reliability of the device can be improved.

The semiconductor device for fingerprint recognition according to the present embodiment can be manufactured, for example, as follows. First, as shown in FIG. 3A, a gate insulating film is formed on a channel forming region of the semiconductor substrate 10, a gate electrode 30 serving as a word line is formed on the gate insulating film, and the gate electrode 30 is further formed. A source / drain diffusion layer (not shown) is formed in the semiconductor substrate 10 on both sides of the gate electrode 30 by ion implantation or the like as a mask, and a bit line is connected to one of the source / drain diffusion layers to form a transistor. Form. These transistors can be formed by a usual method.

Next, for example, CVD (Chemical Vapor Dep.)
Silicon oxide is deposited by an osition method to form an interlayer insulating film 20 covering the transistor. Next, a contact (not shown) which reaches the source / drain diffusion layer through the interlayer insulating film 20 is formed, and a layer of Ti or Ti / TiN / Ti is formed thereon by, for example, a sputtering method so as to be in contact with the contact. A film is formed, and aluminum or an aluminum alloy such as aluminum silicide is deposited by a sputtering method, and patterned into a matrix to form a sensor pad electrode 31 made of a laminate of a barrier metal layer and an aluminum layer. . Next, a protective film 21 is formed by depositing silicon nitride on the entire surface of the sensor pad electrode 31 and the gap between the sensor pad electrodes 31 by covering the upper layer and the sensor pad electrode 31 by, for example, a CVD method. At this time, a groove V is formed on the surface of the protective film 21 in the gap between the sensor pad electrodes 31.

Next, as shown in FIG. 3B, a TiN adhesion layer 32a is formed on the entire surface by coating the inner wall surface of the groove V by, for example, a sputtering method. Next, FIG.
As shown in (c), a tungsten layer 32b is formed by, for example, a CVD method. Next, the TiN adhesion layer 32a and the tungsten layer 32b deposited outside the groove V are removed by etching back such as RIE (reactive ion etching) or polishing such as CMP (Chemical Mechanical Polishing) on the entire surface. Electrode 3 composed of TiN adhesion layer 32a and tungsten layer 32b
2 is formed, and further, a pad for a charge eliminating electrode connected to the charge eliminating electrode 32 is formed, whereby the semiconductor device for fingerprint recognition shown in FIG. 1 can be manufactured.

The above-mentioned semiconductor device for fingerprint recognition is fixed to, for example, a die pad of a lead frame, subjected to a wire binding process, and molded while exposing the fingerprint recognition surface to obtain a desired form of the semiconductor device for fingerprint recognition. can do.

Embodiments of the semiconductor device and the method of manufacturing the same according to the present invention are not limited to the above description. For example, a circuit having a configuration other than the circuit described in the above embodiment can be used as a circuit for reading out the electric charge stored in the sensor pad electrode of each unit cell. Further, the neutralizing electrode may be fixed to any potential other than the ground potential or the power supply potential as long as the potential is constant. Further, although the charge removing electrode is formed by filling the groove formed in the protective layer, it may be configured to protrude from the surface of the protective film.
In addition, various changes can be made without departing from the gist of the present invention.

[0039]

According to the semiconductor device for fingerprint recognition of the present invention, in the gap between the first electrodes, the groove is formed in the groove formed on the surface of the protective film, and is fixed at a constant potential such as a ground potential or a power supply potential. Since the second electrode is formed,
Even if the static electricity is discharged when the finger is pressed, the static electricity is quickly eliminated by the second electrode, and the electrostatic breakdown can be prevented. Further, since the groove V having low mechanical strength is embedded in the second electrode, the strength is reduced. Can be prevented, and the occurrence of cracks on the fingerprint recognition surface when a finger is pressed can be prevented, and the reliability of the device can be improved.

According to the method for manufacturing a semiconductor device for fingerprint recognition of the present invention, the second electrode fixed at a constant potential is embedded in the groove formed on the surface of the protective film in the gap between the first electrodes. It can be easily formed in a self-aligned manner. Therefore, even if static electricity is discharged when a finger is pressed, the static electricity is quickly eliminated by the second electrode, and electrostatic breakdown can be prevented.
Further, since the grooves having low mechanical strength are buried by the second electrode, the strength is reinforced, and the occurrence of cracks on the fingerprint recognition surface when a finger is pressed can be prevented, and reliability can be improved. A semiconductor device for fingerprint recognition can be manufactured.

[Brief description of the drawings]

FIG. 1A is a plan view of a semiconductor device for fingerprint recognition according to the present invention, and FIG.
It is sectional drawing in X '.

FIGS. 2A and 2B are a cross-sectional view and a circuit diagram illustrating an operation of recognizing a fingerprint in the semiconductor device for fingerprint recognition according to the present invention; FIGS.

FIGS. 3A and 3B are cross-sectional views illustrating a manufacturing process of a method for manufacturing a semiconductor device for fingerprint recognition according to the present invention, wherein FIG. 3A illustrates up to a process of forming a protective film, and FIG. (C) shows up to the step of forming a tungsten layer.

FIG. 4A is a plan view of a semiconductor device for fingerprint recognition according to a conventional example, and FIG.
It is sectional drawing in X '.

FIGS. 5A and 5B are a cross-sectional view and a circuit diagram illustrating an operation of recognizing a fingerprint in a semiconductor device for fingerprint recognition according to a conventional example.

FIG. 6 is a schematic diagram for explaining a problem of a semiconductor device for fingerprint recognition according to a conventional example.

[Explanation of symbols]

7 ... finger, 10 ... semiconductor substrate, 20 ... interlayer insulating film, 21 ...
Protective film, 30 gate electrode, 31 (SP) sensor pad electrode, 32 (NT) static elimination electrode, 32a TiN adhesion layer, 32b tungsten layer, 70 unevenness, V groove, T
r: transistor, NTP: static elimination electrode pad, ESD
... Electrostatic breakdown, C: Crack.

Claims (13)

[Claims] A plurality of first electrodes arranged on a substrate for storing electric charges; and a plurality of first electrodes formed below the first electrodes for reading the electric charges stored in each of the first electrodes. A protective element formed by covering the first electrode and the gap between the first electrodes; a groove formed on the surface of the protective film in the gap between the first electrodes; And a second electrode embedded in the semiconductor device and fixed at a constant potential. 2. The semiconductor device for fingerprint recognition according to claim 1, wherein said second electrode is fixed to a ground potential or a power supply potential. 3. The fingerprint recognition semiconductor device according to claim 1, wherein said first electrodes are formed in a matrix on said substrate. 4. The fingerprint recognition semiconductor device according to claim 3, wherein said second electrode is formed in a grid pattern in a gap between said first electrodes arranged in a matrix. 5. The fingerprint recognition semiconductor device according to claim 1, wherein said protective film is a film containing silicon nitride. 6. A plurality of semiconductor elements for reading out the charge, wherein the first electrode is connected to one source / drain region of a transistor having a word line as a gate electrode, and the other source / drain region of the transistor. 2. The semiconductor device for fingerprint recognition according to claim 1, wherein the drain region is connected to the bit line. 7. A step of arranging a plurality of first electrodes for accumulating electric charges on a substrate, and forming the protective film by covering a gap between the first electrodes and the first electrodes. Forming a groove in the surface of the protective film in a gap between one electrode; and filling the groove with a conductor to fix the groove at a constant potential.
Forming an electrode in a self-aligned manner. 8. A step of forming a plurality of semiconductor elements for reading electric charges stored in the first electrodes before the step of forming the first electrodes side by side, wherein the first electrodes are formed side by side. The method of manufacturing a semiconductor device for fingerprint recognition according to claim 7, wherein, in the step (b), the first electrode is formed by connecting to the semiconductor element from which the charge is read. 9. A method for forming a plurality of semiconductor elements from which electric charges are read out, comprising: forming a gate insulating film on a channel forming region in a semiconductor layer; and forming a gate electrode on the gate insulating film as a word line. Forming a transistor, forming a source / drain region in the semiconductor layer on both sides of the gate electrode, and connecting and forming a bit line to one of the source / drain regions. 9. The method for manufacturing a semiconductor device for fingerprint recognition according to claim 8, wherein in the step of forming the first electrodes side by side, the first electrodes are connected to the other source / drain regions of the transistor. 10. The step of forming the second electrode includes the step of forming a conductor on the entire surface of the protective film while filling the groove, and removing the conductor formed outside the groove. 8. The method of manufacturing a semiconductor device for fingerprint recognition according to claim 7, comprising the steps of: 11. The step of forming the first electrode, wherein the first electrode is formed in a matrix on the substrate.
A manufacturing method of the semiconductor device for fingerprint recognition according to the above. 12. The fingerprint recognition semiconductor device according to claim 11, wherein in the step of forming the second electrode, a grid is formed in a gap between the first electrodes arranged in the matrix. Production method. 13. In the step of forming the protective film,
The method for manufacturing a semiconductor device for fingerprint recognition according to claim 7, wherein a film containing silicon nitride is formed.