KR101967400B1 - Electro-luminescence Image Sensor for finger-print - Google Patents

Electro-luminescence Image Sensor for finger-print Download PDF

Info

Publication number
KR101967400B1
KR101967400B1 KR1020150093894A KR20150093894A KR101967400B1 KR 101967400 B1 KR101967400 B1 KR 101967400B1 KR 1020150093894 A KR1020150093894 A KR 1020150093894A KR 20150093894 A KR20150093894 A KR 20150093894A KR 101967400 B1 KR101967400 B1 KR 101967400B1
Authority
KR
South Korea
Prior art keywords
light
metal line
metal
metal lines
light emitting
Prior art date
Application number
KR1020150093894A
Other languages
Korean (ko)
Other versions
KR20170004064A (en
Inventor
박광수
남동욱
민병일
Original Assignee
주식회사 비욘드아이즈
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 주식회사 비욘드아이즈 filed Critical 주식회사 비욘드아이즈
Priority to KR1020150093894A priority Critical patent/KR101967400B1/en
Priority to PCT/KR2015/011208 priority patent/WO2016064222A1/en
Publication of KR20170004064A publication Critical patent/KR20170004064A/en
Application granted granted Critical
Publication of KR101967400B1 publication Critical patent/KR101967400B1/en

Links

Images

Classifications

    • G06K9/00013—
    • H01L27/323—

Abstract

A unit pixel of an EL (Electro-luminescence) fingerprint sensor is provided. The unit pixel includes a substrate on which a light receiving portion for detecting incident light is formed, a first to an n-th metal line which is located on the light receiving portion and defines a light incidence path of the incident light to the light receiving portion, A pixel protection layer having a through hole at a position corresponding to the light incidence path, a light emitting body formed by filling the inside of the through hole with a light emitting material so as to be in contact with the nth metal line, As shown in Fig.

Description

[0001] The present invention relates to an electro-luminescence image sensor,

The present invention relates to an electro-luminescence (EL) fingerprint sensor.

Image sensors are sensors that convert light into electrical signals. Representative image sensors include APS (Active Pixel Sensor) and PPS (Passive Pixel Sensor) using CMOS. A photodiode used in such an image sensor accumulates incident light and converts it into an electrical signal. In order to increase the amount of light incident on the photodiode, a microlens is generally provided on the top of the photodiode.

On the other hand, an optical fingerprint sensor detects an image of a fingerprint and converts it into an electric signal. In order to capture an image of a fingerprint, a conventional optical fingerprint sensor is provided with an optical system for irradiating the fingerprint to reflect the light. However, since an optical system such as a reflection mirror or a lens generally has a considerable volume, it is difficult to miniaturize a fingerprint recognition apparatus equipped with an optical fingerprint sensor.

It is desired to provide an EL fingerprint recognition sensor capable of generating a clear fingerprint image while enabling miniaturization.

According to an aspect of the present invention, there is provided a light emitting device including a substrate on which a light receiving portion for detecting incident light is formed, first to n-th metal lines which are located above the light receiving portion and define a light incident path of the incident light to the light receiving portion, A light emitting body formed by filling the inside of the through hole with a light emitting material so as to be in contact with the nth metal line, and a light emitting body formed on the upper part of the light emitting body, A unit pixel of an EL (Electro-Luminescence) fingerprint recognition sensor is provided which includes a contact electrode which contacts the light emitting body.

In one embodiment, the light emitting device may further include a dielectric layer interposed between the light emitting body and the contact electrode.

Here, the first through the n-th metal lines (n = 6) include first and second metal lines for forming an electric wiring for transmitting a light receiving unit control signal and an incident light detection signal, Third and fourth metal lines, which are dummy metal lines forming the light incidence path, formed on an upper portion of the line, a fifth metal line formed on the third and fourth metal lines, And a sixth metal line formed on the fifth metal line and connected to the AC power source to form an electric field inside the light emitting unit. In addition, a via may be formed around the light incident path to connect the third and fourth metal lines.

Here, the first to the n-th metal lines (n = 5) include first and second metal lines for forming an electric wiring for transmitting a light receiving unit control signal and an incident light detection signal, A fourth metal line formed on an upper portion of the third metal line and blocking the electric field, a second metal line formed on the fourth metal line, And a fifth metal line connected to the AC power source to form an electric field inside the light emitting unit. Meanwhile, the third metal line may be thicker than the remaining metal lines.

Also, the dummy metal line may be in the form of a flat plate having an opening defining the light incidence path.

Here, the light emitting body may be formed by filling at least a part of the light incidence path defined by the through-hole and the n-th metal line.

Here, the first to the n-th metal lines (where n = 4) include first and second metal lines for forming an electric wiring for transmitting a light receiving unit control signal and an incident light detection signal, A third metal line formed on an upper portion of the line and blocking an electric field, a fourth metal line formed on the third metal line, and a fourth metal line connected to the AC power source to form an electric field inside the light emitting unit . Meanwhile, any one of the first metal lane to the third metal lane may be formed thicker than the remaining metal lines.

Here, the first through the n-th metal lines (n = 6) include first and second metal lines for forming an electric wiring for transmitting a light receiving unit control signal and an incident light detection signal, A third metal line formed on the upper portion of the third metal line, the third metal line being a dummy metal line forming the light incidence path, a fourth metal line formed on the third metal line and blocking the electric field, A fifth metal line formed on the fifth metal line and connected to the AC power source to form an electric field in the light emitting body, and a sixth metal line formed on the fifth metal line and contacting the light emitting body, The metal line and the sixth metal line may be electrodes of a metal-insulator-metal (MIM) capacitor.

Here, the first to the n-th metal lines (n = 5) include first and second metal lines for forming an electric wiring for transmitting a light receiving unit control signal and an incident light detection signal, A fourth metal line formed on the third metal line and connected to the AC power source to form an electric field inside the light emitting unit, And a fifth metal line formed on the line and contacting the light emitting body, wherein the fourth metal line and the fifth metal line may be electrodes of a metal-insulator-metal (MIM) capacitor.

Here, the light-receiving unit may be a photodiode or a transistor-type light-receiving unit of a floating gate structure.

According to another aspect of the present invention, there is provided an EL fingerprint recognition sensor including a first region formed by arraying unit pixels and a second region disposed at an outer periphery of the first pixel region and connected to a ground.

The EL fingerprint sensor and the unit pixel of the EL fingerprint sensor according to the embodiment of the present invention can produce a high resolution clear fingerprint image as the EL phosphor can be independent and miniaturized.

Hereinafter, the present invention will be described with reference to the embodiments shown in the accompanying drawings. For the sake of clarity, throughout the accompanying drawings, like elements have been assigned the same reference numerals. It is to be understood that the present invention is not limited to the embodiments illustrated in the accompanying drawings, but may be embodied in many other specific forms without departing from the spirit or essential characteristics thereof.
1 is a view schematically showing an EL fingerprint recognition sensor.
Figs. 2A to 2F are views showing, by way of example, a unit pixel sectional structure of an EL fingerprint recognition sensor. Fig.
3 is a view showing an exemplary structure of the fingerprint contact surface of the EL fingerprint recognition sensor.
FIG. 4 is a diagram illustrating an exemplary operation of the EL fingerprint recognition sensor.
FIG. 5 is a view showing an exemplary structure of a dummy metal line of the EL fingerprint recognition sensor.
6 is an exemplary diagram for illustrating the circuit diagram and the operation principle of the transistor type light-receiving portion of the floating gate structure shown in FIG. 2. FIG.
FIG. 7 is a diagram illustrating an exemplary manufacturing process of the EL fingerprint recognition sensor.
8A to 8C are views showing another example unit pixel cross-sectional structure of the EL fingerprint recognition sensor.

While the present invention has been described in connection with certain exemplary embodiments, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and similarities. It should be understood, however, that the invention is not intended to be limited to the particular embodiments, but includes all modifications, equivalents, and alternatives falling within the spirit and scope of the invention.

1 is a view schematically showing an EL fingerprint recognition sensor.

The EL (Electro-luminescence) fingerprint sensor 100 acquires a fingerprint using light generated by a light emitting body in electrical contact with the fingerprint of the finger 10. [ The EL fingerprint recognition sensor 100 shown in FIG. 1 has a structure in which a light emitting body is disposed at a lower portion of a contact electrode and a contact electrode in contact with a fingerprint. Here, the light emitting body is connected to the AC power source, and the contact electrode is grounded when it comes into contact with the fingerprint. When a ridge of the fingerprint contacts the contact electrode, an electric field is formed between the contact electrode and an AC power source connected to the light emitting body. The light emitting body located below the contact electrode generates light by the formed electric field. Thus, the light emitting body emits light in the same shape as the fingerprint.

In such a structure, the light emitting body generates not only straight light (hereinafter referred to as straight light) but also light having a slope (hereinafter referred to as oblique light). Therefore, in order to obtain a clear fingerprint image, the oblique light should be blocked as much as possible and only the straight light should be detected. A plurality of contact electrodes physically spaced from each other are formed on the upper portion of the EL fingerprint recognition sensor 100 in contact with the ridge of the fingerprint. Further, the light emitting bodies corresponding to the contact electrodes are also physically spaced from each other and formed at the bottom of each contact electrode. The patterned contact electrode and the patterned light emitting body can limit the position where the light emitting body generates light by the electric field. On the other hand, a light incidence path for shielding the oblique light is formed between the lower portion of the patterned illuminant and the upper portion of the light receiving portion. The height and width of the light incidence path can be determined according to the type of the light receiving unit.

Figs. 2A to 2F are views showing, by way of example, a unit pixel sectional structure of an EL fingerprint recognition sensor. Fig.

2A, a unit pixel of the EL fingerprint sensor includes a substrate 200 on which a light receiving unit 210 is formed, a plurality of metal lines 230, 235, 240, 245, 250, 255 forming a light incidence path 220 A patterned illuminator 270 located on top of the light incidence path 220, a dielectric layer 280 located on top of the illuminant and a patterned contact electrode 290 located on top of the dielectric layer 280.

The light receiving portion 210 is a transistor-type light receiving portion of a floating gate structure. The light receiving unit 210 can distinguish light and dark within a range that does not overlap with other adjacent unit pixels due to the viewing angle determined by the height and width of the light incident path shown in FIG. When the transistor-type light receiving portion of the floating gate structure is used for a unit pixel, the area of the light receiving portion with respect to the pixel pitch is small and structurally adjacent metal lines must be used, so that the width of the light incident path using the metal line can be further narrowed. 2A, if the height of the light incidence path is increased by using the plurality of metal lines 230, 235, 240, 245, 250, and 255, the light incidence path is formed into a narrow and long tunnel shape . As a result, the amount of light decreases due to an increase in the inclined light blocking rate, but a bright fingerprint image can be obtained even at a small light amount due to the high light sensitivity characteristic of the transistor type light receiving portion of the floating gate structure.

The plurality of metal lines 230, 235, 240, 245, 250 and 255 may include first and second metal lines 230 and 235 forming electrical wiring lines, third and fourth metal lines 240 and 240, 245), and fifth and sixth metal lines (250, 255) for guiding an electric field. The first to sixth metal lines 230, 235, 240, 245, 250, and 255 are electrically insulated from each other by an IMD (Inter Metal Dielectric). Also, the light incidence path defined by the first to sixth metal lines 230, 235, 240, 245, 250, 255 is also formed as IMD. Here, the cross section of the light incidence path may be formed in various shapes such as a polygonal shape and a circular shape.

The first and second metal lines 230 and 235, which are lower metal lines, are positioned closest to the light receiving portion 210 among the plurality of metal lines. The first and second metal lines 230 and 235 transmit a light receiving unit control signal for controlling the operation of the light receiving unit 210 and an electric wiring for transmitting the incident light detecting signal generated by detecting the rectilinear light . In one embodiment, the first and second metal lines 230 and 235 may be disposed so as to surround the light incidence path above the light receiving portion 210. In another embodiment, metal lines of the first and second metal lines 230 and 235, which do not form the electric wiring, may be disposed so as to surround the light incidence path above the light receiving unit 210. The cross section of the light incidence path defined by the first and second metal lines 230 and 235 may be formed in various shapes such as polygonal, circular, and the like.

The third and fourth metal lines 240 and 245 are located between the first and second metal lines 230 and 235 and between the fifth and sixth metal lines 250 and 255. The third and fourth metal lines 240 and 245 which are dummy metal lines are formed by the first and second metal lines 230 and 235 and the fifth and sixth metal lines 250 and 255 And an opening formed at a position corresponding to the light incidence path 220. The openings formed in the third and fourth metal lines 240 and 245 define a light incidence path. The opening may be formed in various shapes such as a polygonal shape, a circular shape, and the like. 2A, the dummy metal lines need not necessarily be plural, and only one dummy metal line may be connected to the first and second metal lines (the first metal line and the second metal line) depending on the type of the light- 230, and 235 and the fifth and sixth metal lines 250 and 255, respectively.

The fifth and sixth metal lines 250 and 255, which are the upper and the uppermost metal lines, are located farthest from the light receiving unit 210 among the plurality of metal lines. The sixth metal line 255 is connected to the AC power source to form an electric field with the contact electrode 290 and the fifth metal line 250 is connected to the remaining metal lines 230, 235, 240, 245 to the ground. The fifth and sixth metal lines 250 and 255 are formed in a flat plate shape including an opening formed at a position corresponding to the light incidence path 220 formed by the first through fourth metal lines 230, As shown in FIG. In one embodiment, at least a portion of the top surface of the sixth metal line 255 may be in electrical contact with the light emitter 280. Here, at least a part of the upper surface of the sixth metal line 255 is the periphery of the light incidence path 220. At least a portion of the upper surface of the sixth metal line 255 and at least a portion of the side of the sixth metal line 255 located on the side of the light incidence path 220 may be in electrical contact with the light emitting body 280. [ The cross section of the light incident path defined by the fifth and sixth metal lines 250 and 255 may be formed in various shapes such as polygonal, circular, and the like. Meanwhile, in another embodiment, when one or more dummy metal lines are formed, the fifth metal line 250 may be omitted.

The passivation layer 260 is formed on the sixth metal line 255 and includes a groove formed at a position corresponding to the light incidence path 270. The cross section of the groove may be formed in various shapes such as a polygonal shape and a circular shape, and the light emitting body 270 is formed by filling the light emitting material inside the groove. The maximum width or maximum diameter of the groove may be greater than or equal to the width of the light incidence path 220.

The light emitting body 270 is formed by filling a light emitting material into a groove. The light emitting body 270 generates light by an electric field formed between the contact electrode 290 and the sixth metal line 255. The luminescent material may be selected from Group II-VI compounds such as, for example, ZnS, SrS, and the like. On the other hand, the light emitting material may be doped with a dopant such as Mn, Cu, Al, I, Tb, F, or the like to adjust the luminescence brightness and / For example, the sensitivity of the light-receiving portion composed of a photodiode is low with respect to blue while the sensitivity of the transistor-type light-receiving portion of the floating gate structure is high with respect to blue. Therefore, the light emitting material can be doped using a combination of dopants or dopants depending on which light receiving unit is applied to the unit pixel.

The dielectric layer 280 is formed on the upper side of the light emitting body 270. The dielectric layer 280 may be formed of a material such as HfO 2 , Al 2 O 3 , ZrO 2 , TaO 2 , Ta 2 O 5 , hafnium silicate, zirconium Silicates, combinations thereof, and the like. When the ridge of the fingerprint contacts the contact electrode 290, an electrical connection can be formed that generates an electric field inside the light emitting body 270 due to the high dielectric constant of the dielectric layer 280.

The contact electrode 290 is formed on top of the dielectric layer 280 and is in electrical contact with the light emitting body 270 through the dielectric layer 280. The contact electrode 290 may be, for example, a transparent electrode such as ITO (Indium Tin Oxide) or a metal electrode such as Cu, Au, or Ag. The contact electrode 290 may be formed in various shapes such as a circular shape. The maximum width or maximum diameter of the contact electrode 290 may be more than the maximum width or maximum diameter of the light emitting body 270. That is, both ends of the contact electrode 290 may extend in a horizontal direction on the upper surface of the dielectric layer 280.

2B, a unit pixel of the EL fingerprint sensor includes a substrate 200 on which a light receiving unit 210 is formed, a plurality of metal lines 230, 235, 247, 250 and 255 forming a light incidence path 220, A patterned illuminant 270 located on top of the light incidence path 220, a dielectric layer 280 located on top of the illuminant and a patterned contact electrode 290 located on top of the dielectric layer 280. Explanations overlapping with FIG. 2A will be omitted, and differences will be mainly described.

The third metal line 247 is a dummy metal line and is located between the first and second metal lines 230 and 235 and the fourth and fifth metal lines 250 and 255 of the plurality of metal lines. The third metal line 247 is thicker than the remaining metal lines 230, 235, 250 and 255. If the third metal lines 247 are formed to have a large thickness, a height-width ratio that can be ensured by a plurality of dummy metal lines is realized, and the process can be omitted.

Referring to FIG. 2C, the unit pixel of the EL fingerprint sensor includes a substrate 200 on which a light receiving unit 210 is formed, a plurality of metal lines 230, 237, 250 and 255 forming a light incidence path 220, A patterned illuminant 270 located on top of the path 220, a dielectric layer 280 located on top of the illuminant and a patterned contact electrode 290 located on top of the dielectric layer 280. Explanations overlapping with FIG. 2A will be omitted, and differences will be mainly described.

The first and second metal lines 230 and 237, which are lower metal lines, are located closest to the light receiving portion 210 among the plurality of metal lines. The first and second metal lines 230 and 235 transmit a light receiving unit control signal for controlling the operation of the light receiving unit 210 and an electric wiring for transmitting the incident light detecting signal generated by detecting the rectilinear light . The second metal line 237 is thicker than the remaining metal lines 230, 250 and 255. If the second metal lines 237 are formed to have a large thickness, the process of forming the dummy metal lines can be omitted while realizing a height-width ratio that can be secured by one or more dummy metal lines.

2D, the unit pixel of the EL fingerprint sensor includes a substrate 200 on which a light receiving unit 210 is formed, a plurality of metal lines 230, 235, 251 and 255 forming a light incidence path 220, A patterned illuminant 270 located on top of the path 220, a dielectric layer 280 located on top of the illuminant and a patterned contact electrode 290 located on top of the dielectric layer 280. Explanations overlapping with FIG. 2A will be omitted, and differences will be mainly described.

The third and fourth metal lines 251 and 255, which are the upper and the uppermost metal lines, are located farthest from the light receiving unit 210 among the plurality of metal lines. The third metal line 251 is connected to the ground to prevent the formed electric field from affecting the remaining metal lines 230, 235, and 255 located below. The third metal line 251 is thicker than the remaining metal lines 230, 235, and 255. If the thickness of the third metal line 251 is increased, a step of forming a dummy metal line may be omitted while realizing a height-width ratio that can be secured by one or more dummy metal lines.

2E, the unit pixel of the EL fingerprint sensor includes a substrate 200 on which a light receiving unit 215 is formed, a plurality of metal lines 230, 235, 240, 245, 250, 255 forming a light incidence path 225 A patterned illuminant 270 located on top of the light incidence path 225, a dielectric layer 280 located on top of the illuminant, and a patterned contact electrode 290 located on top of the dielectric layer 280. Explanations overlapping with FIG. 2A will be omitted, and differences will be mainly described.

The light receiving unit 215 is a photodiode for photoelectric conversion. Since the photodiode requires a relatively large amount of light as compared with the transistor-type light-receiving portion of the floating gate structure in FIG. 2A, the height of the light incidence path 225 is the same, but the width of the light incidence path 225 must be increased. As the width of the light incidence path increases, the area of the light emitting body 270 contacting the sixth metal line 255 increases and the area of the light emitting body 270 exposed to the light incidence path 225 also increases, 225 is increased. Therefore, even if a photodiode having a low photoelectric conversion efficiency is applied, a sufficiently bright fingerprint image can be obtained.

Referring to FIG. 2F, the unit pixel of the EL fingerprint sensor includes a substrate 200 on which a light receiving unit 215 is formed, a plurality of metal lines 230, 235, 247, 250 and 255 forming a light incidence path 225, A patterned illuminant 270 located on top of the light incidence path 225, a dielectric layer 280 located on top of the illuminant and a patterned contact electrode 290 located on top of the dielectric layer 280. Explanations overlapping with Figs. 2A and 2F will be omitted, and differences will be mainly described.

The third metal line 247 is a dummy metal line and is located between the first and second metal lines 230 and 235 and the fourth and fifth metal lines 250 and 255. The third metal line 247 is thicker than the remaining metal lines 230, 235, 250 and 255. If the third metal lines 247 are formed to have a large thickness, a height-width ratio that can be ensured by a plurality of dummy metal lines is realized, and the process can be omitted.

3 is a view showing an exemplary structure of the fingerprint contact surface of the EL fingerprint recognition sensor.

Referring to FIG. 3, the upper surface of the EL fingerprint sensor includes a first region 310 for forming an electrical path between a finger for acquiring a fingerprint image and an AC power source, and a first region 310 for contacting a fingerprint, And a second region 320 that is arranged. The first region 310 and the second region 320 are electrically insulated.

The first region 310 is formed at the outer portion of the second region 320. The first region 310 is electrically connected to ground to form an electrical path between the finger to obtain the fingerprint image and the AC power source. The first region 310 is formed of a material having high electrical conductivity such as ITO or metal. The first region 310 may be formed at a portion of the second region 320.

In the second region 320, the array of unit pixels shown in Figs. 2A to 2F is arranged. The array of unit pixels may be arranged in different ways depending on the shape of the contact electrode. The contact electrode is formed of a square contact electrode 321, a circular contact electrode 322, a hexagonal contact electrode 323, and a rhomboidal contact electrode 324 . The square contact electrode 321 and the circular contact electrode 322 are arranged side by side in the same row or column. The hexagonal contact electrode 323 and the rhomboidal contact electrode 324 are arranged such that the centers of the contact electrodes located in adjacent rows or columns do not coincide.

The maximum width of the contact electrodes 321, 323 and 324 or the maximum diameter of the contact electrode 322 and the inter-electrode distance of the contact electrodes 321, 322, 323 and 324 can be optimized for fingerprint image acquisition. Ridge-ridge or bone-to-bone spacing fingerprint spacing may vary with age, sex, and race. It can be assumed that the fingerprint has a fingerprint interval of 0.2 to 0.8 mm and an average interval of 0.5 mm. Thus, the maximum width or maximum diameter may be between 0.2 mm and 0.5 mm.

The shape and arrangement of the contact electrodes 321, 322, 323, and 324 shown in FIG. 3 are merely examples, and are not limited thereto.

FIG. 4 is a diagram illustrating an exemplary operation of the EL fingerprint recognition sensor.

4, the EL fingerprint sensor includes a light receiving unit 410, a plurality of metal lines 430, 435, 440, 445, 450 and 455, a light emitter 470, a dielectric layer 480 disposed on an upper portion of the light emitter, And a plurality of unit pixels including a patterned contact electrode 490 located on the upper portion of the substrate 480. Here, dummy vias 441 and 442 may be further formed between adjacent two metal lines of the plurality of metal lines. The dummy vias 441 and 442 block the inclined light incident on the light incidence path 440 from being reflected toward other adjacent unit pixels.

An electric field 471 is induced between the sixth metal line 455 and the contact electrode 490 which is in contact with the ridge of the fingerprint among the arranged plurality of contact electrodes. A portion of the finger contacts a grounded second region 310 of FIG. 3, and the sixth metal line 455 is connected to an AC power source, so that an electric field 471 is induced in the light emitting body 470. Here, the AC power source may apply an alternating voltage between about 60 and about 600 volts to the sixth metal line 455. The light emitting unit 470 generates light by the induced electric field 471 and a part of the generated light is incident on the light incidence path 442 from the lower surface 472 of the light emitting unit 470. The incident light includes straight light and oblique light. In this case, the oblique light is blocked by the first to sixth metal lines 430, 435, 440, 445, 450, and 455 and the dummy vias 441 and 442 Reflection.

The linear light passing through the light incidence path is photoelectrically converted by the light receiving section 410 formed on the substrate 400. The light receiving unit 410 located at the lower portion of the contact electrode in contact with the ridge of the fingerprint outputs the incident light detection signal and the light receiving unit 410 located at the lower portion of the contact electrode located in the fingerprint of the fingerprint does not output the incident light detection signal.

FIG. 5 is a view showing an exemplary structure of a dummy metal line of the EL fingerprint recognition sensor.

Referring to FIG. 5, the dummy metal lines 540 and 545 may be flat plates having a plurality of openings 546 defining a light incidence path. A pair of dummy metal lines 540, 545 may be connected by a plurality of dummy vias 541, 542, 543. A plurality of dummy vias 541, 542, 543 are formed around the openings defining the light incidence path. The plurality of dummy vias 541, 542, and 543 formed around the opening prevent the inclined light entering the light incidence path from entering the light incidence path of the adjacent unit pixel. The number and shape of the dummy vias may vary depending on the shape of the opening. As shown in Fig. 5, when a square opening is formed in the dummy metal lines 540 and 545, the dummy via can be formed at a position adjacent to each side of the quadrangle.

FIG. 6 is a circuit diagram showing the transistor-type light-receiving portion of the floating gate structure shown in FIG. 2 and an example for explaining the operation principle thereof.

The unit pixel 600 photoelectrically converts light and outputs an incident light detection signal. To this end, the unit pixel 600 includes a PMOS 610 serving as a light receiving part for photoelectrically converting incident light, and an NMOS 620 connected to the PMOS 610 and serving as a switch. Here, the PMOS 610 controls the magnitude of the incident light detection signal flowing through the channel formed by the electric field source and the drain by the floating gate polarized by the incident light, and the NMOS 620 outputs the incident light detection signal as the select transistor Selects a unit pixel 600 and determines an exposure time. The NMOS 620 performs a switching operation by a SEL control signal applied to the control gate, and the SEL control signal may be a voltage signal that is higher than the power supply voltage VDD. Here, the NMOS may be a Native or Medium Vt transistor having a low Vth.

The source of the PMOS 610 is coupled to the power supply voltage VDD and the drain is coupled to the drain of the NMOS 620. The body of the PMOS 610 is formed of a floating body, and the body of the NMOS 620 is connected to the ground voltage GND. The body or P-well of the NMOS 620 in the pixel region may also be formed as a floating body. The source of the NMOS 620 outputs an incident light detection signal, and the outputted incident light detection signal can be applied to an IVC (I-V Converter). The PMOS 610 and the NMOS 620 may be implemented through a general MOSFET process.

The operation of the unit pixel 600 is as follows. When the power source voltage VDD is applied to the source of the PMOS 610 formed on the same substrate as the NMOS 620, a PN junction is formed in all regions where the N-well and the p-type substrate face each other, The depletion region is formed thick. Also, a power source voltage is a P-channel induced between the source and the drain of the PMOS 610 by an electric field. Thereafter, when light is incident on the PMOS 610 as a light receiving part, the photon is incident on the lower junction surface of the N-well in which the floating gate and the depletion region are generated, thereby generating an electron hole pair (EHP). In the floating gate of the PMOS transistor 610, the P-channel is formed between the N-well, that is, the drain and the source, located under the floating gate due to the polarization phenomenon. A voltage is applied to the gate of the NMOS 620 connected to the PMOS 610 and a channel is formed between the source and the drain formed in the NMOS 620 to receive the signal charge formed in the PMOS 610 and output an incident light detection signal. In the conventional CMOS image sensor, one photon produces one electron-hole pair, while the PMOS 610 of the unit pixel 600 induces a channel current of the PMOS in which one photon is amplified. Accordingly, it is possible to realize an image even in a low light level in which a current gain of an incident light detection signal reaches 100 to 1000 and a small amount of light is incident.

The floating gate 613 may be formed of N-doped polysilicon and may be formed to have a thickness of 100 nm to 1 μm to widen the absorption wavelength band of light. When fabricated according to a general MOSFET process, the floating gate 613 is formed to a thickness of 200 to 300 nm, and most of short wavelengths of 400 nm or less are absorbed, but a long wavelength band of visible light, for example, 500 to 1,100 nm, is transmitted. Therefore, the thickness of the floating gate 613 can be increased to increase the absorption ratio of the long wavelength band having a high transmittance. The increase in the thickness of the floating gate 613 can increase the probability of EHP generation in the floating gate 613 due to light. Also, in a process that supports a polysilicon-insulator-polysilicon (PIP) capacitor method, polysilicon is stacked and vertically connected to each other as a gate, thereby providing the same effect as increasing the thickness of the floating gate 613. On the other hand, by increasing the thickness of the floating gate 613, it is possible to reduce the generation of EHP due to the light incident to the inside of the N-well and / or the P-type substrate.

The floating gate 613a shown on the left side shows the electron distribution in the state where no light is irradiated. The floating gate 613a is N- doped to form a buried channel between the PMOS source and the PMOS drain that minimizes the noise generation due to the surface current. Here, the left lower end faces the PMOS source side, and the lower right end faces the PMOS drain side.

The floating gate 613b shown at the center shows a state in which light is incident to generate EHP and electrons and holes are polarized and distributed by an external electric field. In the floating gate 613b, the electrons separated from the holes can freely move outside the grain boundary of the polysilicon, and due to the electric field effect of the PMOS source, they are located at the lower left of the floating gate 613b, It is concentrated. As electrons are concentrated, an electric field is formed in the lower left portion of the floating gate 613b, and the electric field becomes stronger as the number of concentrated electrons increases. On the other hand, the holes are pushed by the hole carriers of the PMOS source and the lower channel, and the carriers move to the upper right side of the floating gate 613b, that is, away from the PMOS source, and polarization occurs in the floating gate 613b . When the light disappears, the polarized electrons and holes recombine to become a thermal equilibrium state and become the same state as the left side (613a) again.

And the right side is a floating gate 613c in which a polarization phenomenon occurs. The larger the intensity of the incident light, the more EHP production is generated. If the electric field effect is applied to the lower surface of the floating gate 613c and the upper surface of the channel due to the polarization of the floating gate 613c, the charge of the lower surface of the floating gate 613c increases in accordance with the intensity of the incident light, Effect appears. As a result, the PMOS source and the PMOS drain channel expand and the amount of current flowing through the channel increases.

FIG. 7 is a diagram illustrating an exemplary manufacturing process of the EL fingerprint recognition sensor.

Referring to FIG. 7A, an N-well is formed by implanting N-type impurity into a P-type substrate 700, an N-well is composed of a source and a drain, and an N-well is formed with an insulation layer A PMOS light receiving portion 710 having a floating gate formed by deposition with polysilicon is formed. A first metal line 730 and a second metal line 735 are formed on an upper portion of the light receiving unit 710. A third metal line 740 and a fourth metal line 745 which are dummy metal lines for increasing the height of the light incidence path 720 are formed on the second metal line 735, A line 750, and a sixth metal line 755 connected to the AC power source are stacked in this order. The first to sixth metal lines 730, 735, 740, 745, 750 and 755 are insulated by the IMD and the light incidence path 720 is also formed by the IMD. A pixel protection layer 760 is stacked on the sixth metal line 755.

Referring to FIG. 7B, a groove 765 is formed by etching the pixel protection layer 760 at a position corresponding to the light incidence path 720. The width of the groove 765 may be larger than the width of the light incidence path 720. In one embodiment, the groove 765 is formed by etching to the top surface of the sixth metal line 755. In another embodiment, the groove 765 may extend to a portion of the light incidence path 720 defined by the sixth metal line 755. That is, the lower surface of the groove 765 may be formed to have a step toward the light incidence path 720 side. As a result, the luminescent material filling the groove 765 is also filled in at least part of the light incidence path 720 defined by the sixth metal line 755. The step on the bottom of the groove 756 may be formed by overetching the pixel protection layer 760.

Referring to FIG. 7 (c), the light emitting material is filled in the groove 765 to form the light emitting body 770. The luminescent material may be selected from Group II-VI compounds such as, for example, ZnS, SrS, and the like. On the other hand, the light emitting material may be doped with a dopant such as Mn, Cu, Al, I, Tb, F, or the like to adjust the luminescence brightness and / For example, the light emitting material in a powder form may be mixed with a binder such as a polymeric matrix and converted into a liquid phase, and then filled in the groove 765 by spin coating or the like. The viscosity of the liquid luminescent material mixed with the binder can be adjusted by the binder and can be filled into the groove 765 by spin coating or the like. On the other hand, the luminance and the AC power to be applied may vary depending on the particle size of the light emitting material. That is, as the particle size of the luminescent material becomes smaller, the luminance increases, and the AC power to be applied may be lowered. Thus, the luminescent material may be in the form of a nano powder. The filled luminescent material is cured through a heat treatment process to become a light emitting body 770. At this time, the liquid luminescent material may remain on at least a part of the upper surface of the pixel protection layer 760. Therefore, if the surface of the pixel protection layer 760 is subjected to a surface planarization process such as CMP or grinding after the heat treatment, the remaining luminescent material can be removed.

Referring to FIG. 7D, a dielectric layer 780 is formed on the pixel protection layer 760 where the light emitting body 770 is formed. The dielectric layer 780 is formed by mixing a binder with a dielectric material in powder form and coating a liquid dielectric on the upper surface of the pixel protective layer 760. A contact electrode 780 is formed on the upper portion of the dielectric layer 780 at a position corresponding to the light incidence path.

8A to 8C are views showing an exemplary unit pixel cross-sectional structure of the EL fingerprint recognition sensor.

8A, a unit pixel of the EL fingerprint sensor includes a substrate 800 on which a light receiving unit 810 is formed, a plurality of metal lines 830, 835, 840, 850, and 855 forming a light incidence path 820, A patterned illuminant 870 located on top of the light incidence path 820, and a patterned contact electrode 890 located above the illuminant 870. The parts that are the same as those in FIG. 2A are omitted and the differences are mainly described.

The plurality of metal lines 830, 835, 840, 850 and 855 may include first and second metal lines 830 and 835 for forming electrical wiring, third to fifth metal lines 840 and 850 , 855). The first to fourth metal lines 830, 835, 840 and 850 are electrically insulated from each other by an IMD (Inter Metal Dielectric). A dielectric material having a high dielectric constant is interposed between the fourth metal line 850 and the fifth metal line 855 to form a metal-insulator-metal (MIM) capacitor. Also, the light incidence path defined by the first to fifth metal lines 830, 835, 840, 850, 855 is also formed as IMD. Here, the cross section of the light incidence path may be formed in various shapes such as a polygonal shape and a circular shape. On the other hand, the unit pixel may further include a dummy metal for increasing the height of the light incidence path. Here, the thickness of the dummy metal may be different from the thickness of the other metal lines.

The third to fifth metal lines 840, 850 and 855 are located above the first and second metal lines 830 and 835 and induce an electric field in the light emitter 870. The third metal line 840 is connected to ground to prevent the formed electric field from affecting the remaining metal lines 830 and 835 located below. The fourth metal line 850 and the fifth metal line 855 are electrodes forming the MIM capacitor 852. The fourth metal line 850 is a common electrode to which the AC power is applied and the fifth metal line 855 Is an individual electrode in which at least a part of the upper surface is in contact with the light emitting body 870. Here, the fourth metal line 850 may be formed in a flat plate shape including an opening formed at a position corresponding to the light incidence path 220.

In the unit pixel having the above-described structure, the AC power connected to the fourth metal line 850 is applied to the light-emitting body 870 by the MIM capacitor 852. Compared with the structure shown in FIG. 2A, since a MIM capacitor supported by a general semiconductor process is used, there is an advantage that a process of separately forming a dielectric layer before forming the contact electrode 880 is omitted. In other words, the effect of completely separating the unit pixel including the light emitting body is more effective than the method in which the dielectric layer is entirely deposited on the upper part, thereby increasing the resolution, adjusting the value of the capacitance, and adjusting the frequency of the AC power. The capacity can be manufactured to have high uniformity for all pixels.

8B, a unit pixel of the EL fingerprint sensor includes a substrate 800 on which a light receiving unit 810 is formed, a plurality of metal lines 830, 835, 840, 850, and 855 forming a light incidence path 820, A patterned illuminant 870 located on top of the light incidence path 820, a dielectric layer 880 located on top of the illuminant and a patterned contact electrode 890 located on top of the dielectric layer 880. The light emitting body 870 is electrically connected to the contact electrode 890 through the dielectric layer 885 and the fourth metal line 850 is electrically connected to the fourth metal line 850 through the MIM capacitor 852. [ .

8C, a unit pixel of the EL fingerprint sensor includes a substrate 800 on which a light receiving unit 810 is formed, a plurality of metal lines 830, 835, 840, 845, 850, and 855 forming a light incidence path 820 A patterned illuminant 870 located on top of the light incidence path 820 and a patterned contact electrode 890 located on top of the illuminant 870. The same description is omitted and only the difference is noted, the light emitting body 870 is directly connected to the contact electrode 89 and the sixth metal line 855. An AC power source is applied through the sixth metal line 855 to induce an electric field inside the light emitter 870 by the finger touching the contact electrode 890.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive.

It is intended that the present invention covers the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. .

200: substrate
210:
220: optical incidence path
230, 235, 240, 245, 250, 255: metal line
260: pixel protection layer
270:
280: dielectric layer
290: Contact electrode

Claims (15)

A substrate on which a light receiving portion for detecting incident light is formed;
First to n-th metal lines located above the light receiving unit and defining a light incidence path of the incident light to the light receiving unit;
A pixel protection layer formed on the nth metal line and having a through hole at a position corresponding to the light incidence path;
A light emitting body formed by filling at least a part of the light incidence path defined by the through hole and the nth metal line with the light emitting material so as to contact the nth metal line; And
And a contact electrode disposed on the light emitting body and contacting the light emitting body,
Wherein at least one of the first to n-th metal lines is a dummy metal for increasing a height of the light incidence path. The EL fingerprint recognition sensor according to claim 1, further comprising a dielectric layer interposed between the light emitting body and the contact electrode. The method of claim 2, wherein the first to the n-th metal lines (where n = 6)
First and second metal lines for forming an electric wiring for transmitting a light receiving unit control signal and an incident light detection signal,
Third and fourth metal lines formed on the first and second metal lines, which are dummy metal lines forming the light incidence path,
A fifth metal line formed on the third and fourth metal lines to block an electric field,
And a sixth metal line formed on the fifth metal line and connected to an AC power source to form an electric field inside the light emitter. The EL fingerprint recognition sensor according to claim 3, further comprising vias formed around the light incidence path and connecting the third and fourth metal lines. The method of claim 2, wherein the first to the n-th metal lines (n = 5)
First and second metal lines for forming an electric wiring for transmitting a light receiving unit control signal and an incident light detection signal,
A third metal line formed on the first and second metal lines, the third metal line being a dummy metal line forming the light incidence path,
A fourth metal line formed on the third metal line for blocking an electric field,
And a fifth metal line formed on the fourth metal line and connected to an AC power source to form an electric field inside the light emitting body. The EL fingerprint recognition sensor of claim 5, wherein the third metal line is thicker than the remaining metal lines. The EL fingerprint recognition sensor according to claim 3, wherein the dummy metal line is in the form of a flat plate having an opening for defining the light incidence path. delete A substrate on which a light receiving portion for detecting incident light is formed;
First to n-th metal lines located above the light receiving unit and defining a light incidence path of the incident light to the light receiving unit;
A pixel protection layer formed on the nth metal line and having a through hole at a position corresponding to the light incidence path;
A light emitting body formed by filling at least a part of the light incidence path defined by the through hole and the nth metal line with the light emitting material so as to be in contact with the nth metal line; And
And a contact electrode disposed on the light emitting body and contacting the light emitting body,
The first to the n-th metal lines (where n = 4)
First and second metal lines for forming an electric wiring for transmitting a light receiving unit control signal and an incident light detection signal,
A third metal line formed on the first and second metal lines to block the electric field,
And a fourth metal line formed on the third metal line and connected to an AC power source to form an electric field inside the light emitting unit,
Wherein any one of the first metal line to the third metal line is thicker than the remaining metal lines to increase the height of the light incidence path. delete The method of claim 1, wherein the first to the n-th metal lines (where n = 6)
First and second metal lines for forming an electric wiring for transmitting a light receiving unit control signal and an incident light detection signal,
A third metal line formed on the first and second metal lines, the third metal line being a dummy metal line forming the light incidence path,
A fourth metal line formed on the third metal line for blocking an electric field,
A fifth metal line formed on the fourth metal line and connected to an AC power source to form an electric field in the light emitting body,
And a sixth metal line formed on the fifth metal line and in contact with the light emitting body,
Wherein the fifth metal line and the sixth metal line are electrodes of a metal-insulator-metal (MIM) capacitor. delete delete delete delete
KR1020150093894A 2014-10-24 2015-07-01 Electro-luminescence Image Sensor for finger-print KR101967400B1 (en)

Priority Applications (2)

Application Number Priority Date Filing Date Title
KR1020150093894A KR101967400B1 (en) 2015-07-01 2015-07-01 Electro-luminescence Image Sensor for finger-print
PCT/KR2015/011208 WO2016064222A1 (en) 2014-10-24 2015-10-22 Unit pixel and el fingerprint recognition sensor

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
KR1020150093894A KR101967400B1 (en) 2015-07-01 2015-07-01 Electro-luminescence Image Sensor for finger-print

Publications (2)

Publication Number Publication Date
KR20170004064A KR20170004064A (en) 2017-01-11
KR101967400B1 true KR101967400B1 (en) 2019-04-10

Family

ID=57833009

Family Applications (1)

Application Number Title Priority Date Filing Date
KR1020150093894A KR101967400B1 (en) 2014-10-24 2015-07-01 Electro-luminescence Image Sensor for finger-print

Country Status (1)

Country Link
KR (1) KR101967400B1 (en)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111445785B (en) * 2019-01-16 2022-06-10 北京小米移动软件有限公司 Electronic equipment and screen module
KR20220017015A (en) 2020-08-03 2022-02-11 삼성디스플레이 주식회사 Fingerprint sensor and display device including the same

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100436376B1 (en) * 2002-03-29 2004-06-19 테스텍 주식회사 Slim Type Fingerprint Recognition Device Using Contact Light Emitting Device And TFT Fingerprint Input Device
KR100881200B1 (en) * 2007-07-30 2009-02-05 삼성전자주식회사 CMOS image device and fabrication method thereof

Also Published As

Publication number Publication date
KR20170004064A (en) 2017-01-11

Similar Documents

Publication Publication Date Title
US11348955B2 (en) Pixel structure for image sensors
US10985201B2 (en) Image sensor including silicon over germanium layer
US9735196B2 (en) Photosensitive capacitor pixel for image sensor
US10615228B2 (en) Image sensor
US9929194B2 (en) Image sensor including vertical transfer gate
US10367029B2 (en) Image sensors having a separation impurity layer
US9923006B2 (en) Optical detection element and solid-state image pickup device
US20090039397A1 (en) Image sensor structure
TWI740958B (en) Photogate for front-side-illuminated infrared image sensor and method of manufacturing the same
KR102542614B1 (en) Image sensor
KR20090040158A (en) Cmos image sensor having transparent transistors
US10199423B2 (en) CMOS image sensors including a vertical source follower gate
US9735188B2 (en) Image sensor with solar cell function
TW201712856A (en) Image sensor including vertical transfer gate
KR102320531B1 (en) Image sensor having vertical transfer gate and electronic device having the same
US20110001207A1 (en) Solid state image sensor and manufacturing method thereof
CN111435667A (en) Image sensor with a plurality of pixels
US20220246654A1 (en) Photosensing pixel, image sensor and method of fabricating the same
CN112243094B (en) Image sensing device
US11309348B2 (en) High density image sensor
KR101967400B1 (en) Electro-luminescence Image Sensor for finger-print
KR101967403B1 (en) Electro-luminescence Image Sensor for finger-print
US6998659B2 (en) Large area photodiode
WO2016064222A1 (en) Unit pixel and el fingerprint recognition sensor
US20150014806A1 (en) Image Sensor and Manufacturing Method Thereof

Legal Events

Date Code Title Description
A201 Request for examination
E902 Notification of reason for refusal
E701 Decision to grant or registration of patent right
GRNT Written decision to grant