JPH08129292A - Charge generation control element for electrostatic image forming device and its production - Google Patents

Abstract

PURPOSE: To provide a charge generation control element for electrostatic image forming device with which a drastic reduction of line electrode size and an improvement in dimensional accuracy are made possible and a process for production thereof. CONSTITUTION: This charge generation control element is provided with a line electrode 302 consisting of aluminum formed on a quartz substrate 301, a titanium thin film 303 for preventing aluminum hillock formed on the line electrode 302 and a dielectric film 304 consisting of silicon oxide, etc., formed on the line electrode 30. The charge generation control element for the electrostatic image forming device is composed of a finger electrode 305 having finger hole 308 for forming charge in the central part and a screen electrode 307 having screen hole 309 in the central part formed on the finger electrode 305 via an insulating film 306 consisting of a polyimide, etc., having hole part for charge passage in the central part.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charge generation control element for an electrostatic image forming apparatus used for electrostatic printing and a method for manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, as a method of forming a latent image by electrostatic charges on a dielectric recording body by the principle of transferring charges directly onto the dielectric recording body and depositing it, a method utilizing corona discharge is particularly fair. No. 2-62862. FIG. 15 is a diagram showing a cross section of a part of the charge generator of the electrostatic image forming apparatus disclosed in the above publication. In the figure,
Reference numeral 100 denotes one charge generation control element of the charge generator. The charge generator is configured by arranging a large number of charge generation control elements 100 one-dimensionally or two-dimensionally. The charge generation control element 100 includes a line electrode 101 made of metal, a dielectric film 103, and the line electrode 10 via the dielectric film 103.
A finger electrode 105 made of metal, which is partially opposed to 1; an insulating film 107; and a screen electrode 109 made of metal, which is arranged so as to face the finger electrode 105 via a space. It is composed of.

Next, the operation of the charge generation control element 100 thus constructed will be described. In FIG.
By applying an AC voltage from the power supply 102 between the line electrode 101 and the finger electrode 105 which are arranged with the dielectric film 103 sandwiched therebetween, a charge group is generated on the side wall of the finger hole 104 due to a corona discharge phenomenon. Negative charges having high mobility in this charge group are used for latent image formation. When a positive potential higher than the potential applied to the finger electrode 105 is applied to the screen electrode 109 facing the finger electrode 105 with the insulating film 107 interposed, the negative charge generated by the corona discharge passes through the channel 106. It is extracted through the screen hole 108 formed in the screen electrode 109. The negative charges extracted from the screen holes 108 are accelerated toward the drum 110, which is a dielectric recording medium, and the drum 110
To form a latent charge image. On the contrary, when a negative potential is applied to the screen electrode 109 with respect to the finger electrode 105, extraction of negative charges from the screen hole 108 is blocked, and a latent image is not formed on the drum 110.

Next, a conventional method for manufacturing a charge generator will be described with reference to FIG.
Will be explained. FIG. 16 is a configuration diagram showing a laminated configuration of a conventional charge generator, broken down into layers. In FIG. 16, 201 is a container support (backbone) made of aluminum, and a charge generator is formed on this container support 201. 202 is a normal glass epoxy substrate, which is called an RF board in the conventional charge generator.
The surface of this glass epoxy substrate 202 has a thickness of about 5 μm.
The copper thin film is processed in advance by a wet etching method to form the line electrode 203 by patterning. Reference numeral 204 denotes a dielectric layer, which is formed of mica having a thickness of about 35 μm and has a relative dielectric constant of about 16.
205 is a stainless steel thin plate with a thickness of about 25 μm,
It is a finger electrode that has been previously patterned by wet etching. At the time of this etching, wet processing is performed from both sides of the thin plate,
The side holes of the finger holes are prevented from expanding due to side etching.

Reference numeral 206 denotes an insulating film called Bacquerel (generally called a photo-curable laminate film) sold by DuPont with a thickness of about 100 μm, which is also called a dynamask or a conform mask. ing. The patterning of the insulating film 206 is performed after the insulating film 206 is attached on the finger electrodes 205 as described later. 207 is a screen electrode formed by patterning a stainless steel thin plate having a thickness of about 25 μm in advance by the wet etching method. In this patterning process as well as the finger electrode forming process, wet processing is performed from both sides of the thin plate. By doing so, the size of the screen hole is prevented from expanding due to side etching.

The above-described members are sequentially bonded to each other with an adhesive to form a charge generator. First, the glass epoxy substrate 202 on which the line electrode 203 is formed and the dielectric layer 204 are combined with an ultraviolet curing epoxy adhesive. Stick together. At this time, it is important to suppress the generation of bubbles in the adhesive as much as possible. It is also necessary to apply the adhesive uniformly so that the dielectric layer 204 is as uniform as possible. Next, an adhesive called Densil (generally a silicon adhesive) manufactured by Denison is applied on the dielectric layer 204, and the finger electrodes 205 are attached. When attaching the finger electrodes 205, the glass epoxy substrate 202
Using the alignment marks of the finger electrode portions formed at the same position, the alignment marks formed in step 1 are pressed and bonded while positioning with a microscope.

Then, the insulating film 206 is formed on the finger electrode 205.
Laminate coat on top. Then, an opening corresponding to the channel 106 in FIG. 15 is made by exposure, phenomenon, and wet etching. In the exposure process when opening a channel, the alignment mark formed on the glass epoxy substrate 202 or the alignment mark formed on the finger electrode part is used, and the exposure mask is positioned using a microscope. I do. After that, a low-viscosity silicone adhesive is applied on the area of the insulating film 206 other than the charge generation portion,
The screen electrode 207 is attached. At this time, with respect to the alignment mark formed on the glass epoxy substrate 202, the alignment marks formed on the same positions are used to perform pressure bonding while positioning with a microscope. Finally, attach the glass epoxy substrate 202 to the body support 201,
It is designed to complete the charge generator.

[0008]

By the way, the conventional charge generator has various technical problems, and the problems will be described in the order of steps. First, as a problem related to the formation of the line electrode, the occurrence of non-uniformity of the film thickness of the dielectric film 103 shown in FIG. 15 can be mentioned. If the thickness of the dielectric film 103 is not uniform, variations in the generated charge amount due to non-uniformity occur between different pixels, and eventually fixed pattern noise occurs on the reproduced image, resulting in deterioration of the reproduced image quality. As described above, the dielectric film 10 shown in FIG.
The thickness of 3 is the sum of the thickness of the dielectric layer 204 of FIG. 16 and the thickness of the ultraviolet curing epoxy adhesive. Line electrode 10
The step difference of the line electrode 101 due to the thickness of 1 is about 5 μm. There is a manufacturing difficulty in that the dielectric film 103 must be bonded by filling the step and flattening the surface. Further, foaming at the time of applying the adhesive also poses a problem. Regarding foaming, the larger the step of the line electrode 101, the greater the probability of foaming.

The next problem is that the conventional charge generator requires a large driving voltage for corona discharge. As described in the conventional example, since the dielectric layer made of mica has a large thickness of 35 μm, the driving voltage for generating corona discharge is about 2500 V.
Large with _PP . According to Paschen's law, by reducing the thickness of the dielectric film, it is possible to reduce the drive voltage to about 700 V _PP in the atmosphere, but in the conventional charge generator manufacturing method, mica In reality, it is difficult to reduce the film thickness, and it is feared that the electrical breakdown voltage will be insufficient due to the film thickness reduction. Therefore, a high driving voltage is required in the conventional example.

Regarding the formation of the finger electrodes, there are the following problems. In the conventional charge generator, the plane shape of the finger electrode 105 of FIG. 15 as viewed from above the element is circular, and the diameter R thereof is 300 dpi (do
About 15 for an electrostatic imaging device with a resolution of t per inch)
It is about 75 μm at 0 μm and 600 dpi. In the conventional finger electrode manufacturing method, the electrode thickness is about 25 μm.
Since the finger electrodes are thick, and the finger electrodes are processed by the wet etching method, the finger hole diameter of about 75 μm eventually becomes the substantially minimum processing size. In other words, the resolution increase of the charge generator by the conventional method is limited to about 600 dpi. Depending on the application, the resolution is required to be 1000dpi or more, and conventional charge generators cannot be used for these applications.

Further, in the conventional charge generator, since the thickness of the finger electrodes is large, the variation in the finger hole diameter which occurs during the patterning process becomes large, and eventually the image quality is deteriorated. Furthermore, the dielectric film is pasted with an adhesive called dencil, but since the thickness of this dencil also contributes to the increase of the thickness of the dielectric film and its variation, the discharge voltage rises or the dencil film thickness increases. This causes deterioration in image quality due to variations. Further, when the finger electrodes are bonded together, they are pressure-bonded while performing alignment with a stereoscopic microscope or the like, but such a method has a problem that a large alignment error (deviation) occurs.

Regarding the formation of the insulating film subsequent to the formation of the finger electrodes, in the conventional manufacturing method, the insulating film called bakurel is laminated-coated. In such a laminate-coating method, an insulating film having a thickness of 100 μm is formed. When formed, it is known that in-plane film thickness nonuniformity of at least 20 μm occurs, and similar to the dielectric film forming process, the nonuniformity of the insulating film thickness causes deterioration of image quality. Include the problem. Also, in the step of forming the channel hole to be formed in this insulating film, a mask pattern for forming the hole is formed while performing alignment using a stereoscopic microscope, etc. Also in this, a great amount of alignment error (deviation) occurs.

Since the final screen electrode forming step is formed by a method substantially similar to the finger electrode forming step, it has the same problems as those included in the conventional finger electrode forming step.

The present invention has been made in order to solve the above problems of the conventional charge generator. The invention according to claim 1 can significantly reduce the size of the line electrode and improve the dimensional accuracy. Another object of the present invention is to provide a charge generation control element for an electrostatic image forming apparatus. Further, the invention according to claims 2 to 5 can prevent an aluminum hillock when the line electrode is formed of aluminum, and can prevent a decrease in reliability of the solid dielectric film, and a method of manufacturing the same. The purpose is to provide. It is another object of the present invention to provide a method of manufacturing a charge generation control element capable of preventing the reliability of the solid dielectric film from being lowered. It is another object of the present invention to provide a charge generation control element capable of preventing dielectric breakdown of the solid dielectric film due to electric field concentration at the end of the line electrode. It is another object of the present invention to provide a charge generation control element that facilitates connection with a bonding wire. Another object of the present invention is to provide a charge generation control element capable of preventing a decrease in the potential applied to the finger electrodes by reducing the voltage drop due to the wiring of the finger electrodes.
According to the invention of claim 11, in the case where a charge generator composed of a plurality of charge generation control elements are connected to each other to form a long charge generator, the arrangement of the charge generation control elements on the connection surface is disturbed. It is an object of the present invention to provide a charge generator for an electrostatic image forming apparatus that can be avoided. Another object of the present invention is to provide a charge generator for an electrostatic image forming apparatus capable of preventing crosstalk between line electrodes and / or line electrode wiring and finger electrodes.

[0015]

In order to solve the above problems, the invention according to claim 1 provides a line electrode formed on an insulating substrate, and a solid dielectric formed on the surface of the line electrode. A film, a finger electrode formed on the solid dielectric film and having a hole portion for charge generation in the center, and a solid insulator film having a hole in the center of the finger electrode for allowing charges to pass therethrough. In the charge generation control element comprising a screen electrode having a hole for discharging charges in the central portion formed through the above, the line electrode is made of aluminum formed by a semiconductor manufacturing process. As described above, by using aluminum, which has been established as a wiring material in the semiconductor manufacturing method, for film formation and fine processing in the line electrode, it is possible to reduce the size of the electrode and improve the dimensional accuracy.

According to a second aspect of the present invention, a thin film having a hardness higher than that of aluminum is formed between the line electrode and the solid dielectric film.
The high-hardness thin film is a thin film made of any one of titanium, molybdenum, tungsten, and titanium nitride, and the high-hardness thin film is a thin film made of alumina. According to a fifth aspect of the present invention, in the method of manufacturing a charge generation control element for an electrostatic image forming apparatus according to the fourth aspect, a resist pattern is formed on an aluminum film formed on an insulating substrate. A step of forming, a step of forming a hydrated oxide film up to the interface with the insulating substrate of the aluminum film in a portion not covered by the resist pattern by a hydration reaction with warm water, and removing the resist pattern again A step of forming a hydrated oxide film of aluminum on the surface of the remaining aluminum film by performing hydrated oxidation with warm water, And a step of changing to an alumina film by heating at the above temperature.
Thus, by forming a high hardness thin film made of titanium, molybdenum, tungsten or alumina on the surface of the line electrode formed of aluminum, it is possible to prevent aluminum hillocks growing on the surface of the line electrode, The decrease in reliability of the solid dielectric film is prevented.

The invention according to claim 6 is the same as claims 1 to 4.
In the method of manufacturing a charge generation control element for an electrostatic image forming apparatus according to the above, all or part of the solid dielectric film is
It is formed at a temperature of ° C or less, and the invention according to claim 7 uses silicon oxide or silicon nitride as the solid dielectric film. By lowering the deposition temperature of the solid dielectric film in this way, the movement of aluminum atoms in the line electrode made of aluminum is suppressed, so that aluminum hillocks growing on the surface of the line electrode are prevented, and the solid dielectric film is prevented. Improves reliability.

The invention according to claim 8 is characterized in that the end portion of the line electrode is chamfered.
By chamfering the end of the line electrode in this way,
Electric field concentration is suppressed at the electrode ends, and dielectric breakdown of the solid dielectric film is prevented.

According to a ninth aspect of the present invention, a wire bonding pad for the finger electrode is provided, and the wire bonding pad is made of aluminum. Since the bonding pad is made of aluminum in this way, good bonding between the bonding wire and the pad is realized.

According to a tenth aspect of the present invention, the finger electrodes and the wire bonding pads are connected by a wiring made of aluminum. Since the wiring is made of aluminum with a low electric resistance in this way, the voltage drop due to the wiring is small, and when the charge generator is composed of a large number of charge generation control elements, the length of the wiring differs for each electrode. However, variations in the voltage applied to each element of the charge generator are reduced.

The invention according to claim 11 is the same as claims 1 to 4.
And the charge generation control elements according to any one of 8 to 10 are arranged one-dimensionally or two-dimensionally to form a charge generation control element part, and the wire bonding pads of the line electrodes and finger electrodes are used to generate the charge. Wirings that are arranged on one side or both sides of the control element section and connect the line electrodes and finger electrodes to the wire bonding pads are arranged in the same direction or in two opposite directions. By arranging the wire bonding pads in this manner, when connecting a plurality of charge generators composed of a plurality of charge generation control elements to form a long-sized charge generator, all the bonding pads are connected. Since it is possible to dispose the charge generation control elements at other locations, it is possible to avoid the disorder of the arrangement of the charge generation control elements at the connection portion.

According to a twelfth aspect of the present invention, in the charge generator for the electrostatic image forming apparatus according to the eleventh aspect, between the line electrodes and / or between the line electrode wiring and the finger electrodes,
It is provided with an electrode wire to which a fixed potential is applied.
By disposing the electrode lines to which the fixed potential is applied in this way, it becomes possible to prevent crosstalk between the line electrodes and / or between the line electrode wiring and the finger electrodes.

[0023]

【Example】

[First Embodiment] Next, an embodiment will be described. FIG. 1A is a plan structural view of a first embodiment of a charge generator including a plurality of two-dimensionally arranged charge generation control elements for an electrostatic image forming apparatus according to the present invention, 1B is a cross-sectional structural view taken along the line AB of FIG. In the figure, 301 is a quartz (glass) substrate, and 302 is a line electrode made of aluminum. 303 is a titanium thin film for preventing aluminum hillocks. 304 is a dielectric film formed by plasma CVD (Plasma Chemical Vapor Deposition), and is made of silicon oxide or silicon nitride having a thickness of several microns. 30
Reference numeral 5 is a finger electrode, and refractory metals such as titanium and molybdenum are used because heat is generated by corona discharge on its surface. The line electrode 302 and the finger electrode 30
Since an AC bias of about 1000 V is applied between 5 and 5, the dielectric film 304 is required to have a high electrostatic breakdown voltage. The finger electrode 305 is connected to the finger pad 310 by a contact hole 312 formed in the dielectric film 304. An insulating film 306 is made of a resin having high heat resistance such as polyimide. A screen electrode 307 is a single-layer metal film of titanium, molybdenum, aluminum, titanium nitride or the like, or a multi-layer metal film made of these materials. 308 and 309 are finger holes and screen holes, respectively.

Next, the manufacturing process of this embodiment will be described. 2A to 6A are plan structural views showing the order of manufacturing steps, and FIGS. 2B to 6B are shown in FIG.
FIG. 7A is a cross-sectional structural view taken along the line AB of FIG. First, as shown in FIGS. 2A and 2B, an aluminum film 402 and a titanium film 403 are sequentially formed on a quartz (glass) substrate 401 by a method such as sputtering or vacuum deposition, and then a titanium film 403 is formed. A resist pattern 404 is formed on the surface of the. Next, as shown in FIGS. 3A and 3B, the portions of the aluminum film 402 and the titanium film 403 that are not covered with the resist pattern 404 are removed by etching to remove the line electrode 40.
5, line electrode pad 409 and finger electrode pad 40
Form 6. Next, as shown in FIGS. 4A and 4B, after removing the resist pattern 404, a dielectric film 407 is formed on the entire surface by a method such as plasma CVD.

Next, as shown in FIGS. 5A and 5B,
The contact portion 408 between the finger electrode and the finger electrode pad 406, the line electrode pad 409, and the dielectric film 407 and the titanium film 403 on the finger electrode pad 406 are removed by etching. At this time, as the etching method, a method in which the underlying aluminum is not easily attacked is adopted. Next, a metal film of molybdenum, titanium, tungsten, or the like is formed on the surface of the dielectric film 407, and then etching is performed along the resist pattern in the same manner as the case of the line electrode 405. As shown in B), a finger electrode 410 having finger holes 411 is formed.
Then, by sequentially forming an insulating film and a screen electrode on the finger electrodes 410, as shown in FIG.
The charge generator having the structure shown in (B) is completed. As the electrode material of the line electrode 405, other material having low electric resistance such as copper can be used in addition to aluminum.

The titanium film 303 in this embodiment prevents the growth of aluminum hillock generated on the surface of the line electrode 302 during the formation of the dielectric film 304. In this example,
Titanium was used as the aluminum hillock growth inhibiting film, but other materials such as molybdenum, tungsten, or titanium nitride can be used as long as the material has high hardness.

Further, when the line electrode is composed of aluminum only, the surface of the line electrode is covered by 80 after forming the line electrode.
After immersing in warm water of about ℃ for hydration oxidation and heating at a temperature of 450 ℃ or more for several tens of minutes, an alumina film is formed on the surface of the line electrode, and this alumina film is also effective in preventing aluminum hillocks. . Further, instead of forming an aluminum hillock growth inhibiting film such as a titanium film, aluminum hillock can be prevented by setting the film forming temperature of the dielectric film 304 to 200 ° C. or lower.

In the present embodiment, since the line electrode is made of aluminum, it is possible to greatly reduce the element size by using the fine processing technique used for manufacturing the semiconductor device. Further, since aluminum has a very small electric resistance, the variation in impedance of the line electrodes is relatively small, and the uniformity of the reproduced image of the charge generator can be improved. Further, since the film having high hardness is formed on the surface of the line electrode, it is possible to prevent the generation of aluminum hillock on the surface of the line electrode during the element manufacturing process. Therefore, even when aluminum is used for the line electrodes, the electrostatic breakdown voltage between the line electrodes and the finger electrodes can be significantly improved. Also, since the bonding pads of each electrode are all made of aluminum regardless of the material of each electrode, when connecting the charge generator to another device by a gold wire or the like, finger electrodes or aluminum hillock blocking film are used. Whatever material is used, the reliability of the joint between the gold wire and the bonding pad is guaranteed.

[Second Embodiment] Next, a second embodiment will be described. FIG. 7 is a plan structure view of the charge generator of the second embodiment. The basic structure of this embodiment is similar to that of the first embodiment, but the line electrode 502 formed on the quartz (glass) substrate 501 is connected to the bonding pad 50 by the wiring 510.
Connected to 5. And the wiring 510 is a finger electrode
Since it is formed near 503, when a high voltage is applied to the wiring 510, there is a possibility that the potential of the electrode near it changes and the element malfunctions. In order to prevent such crosstalk between the electrodes, in this embodiment, the line electrodes 502 between the wiring 510 and the finger electrodes 503 and adjacent to each other are provided.
Ground electrodes 511 and 512 are formed between them. Ground electrode
The 512 and the ground electrode pad 508 are formed simultaneously with the line electrode 502 in the line electrode forming process, and the ground electrode 511 and the wiring 51 are formed.
0 is formed simultaneously with the finger electrode 503 in the finger electrode forming step. By adopting the configuration of this embodiment when connecting a plurality of charge generators composed of a plurality of charge generation control elements to form a long charge generator,
The charge generators can be connected to each other at their connecting portions without disturbing the arrangement of the charge generation control elements. FIG. 7
In the figure, reference numeral 506 is a wiring connected to the bonding pads 505 and 507. Although the wiring 506 is formed integrally with the bonding pads 505 and 507 in this embodiment, the wiring 506 and the bonding pad may be formed separately.

In the second embodiment shown in FIG. 7,
Although the line electrode 502 is connected to the bonding pad 505 by one wire 510, it may be connected by a plurality of wires 510 and 506, respectively, as shown in FIG.

In addition, in all of the cases shown in FIGS. 7 and 8, all the wire bonding pads 505, 507,
Although 508 are arranged in the same direction, some pads may be arranged on the opposite side to the line electrode 502 as shown in FIG. 9, for example. In the illustrated example, the bonding pad 507 for the finger electrode and the bonding pad 508 for the ground electrode are formed on the upper part of the line electrode 502, and the bonding pad 505 for the line electrode is formed on the lower part.

In the second embodiment, it is possible to combine a plurality of charge generators to form a large charge generator. Since the generation rate of defective elements increases as the number of elements included in the charge generator increases, the yield can be improved by dividing into a plurality of small parts and creating only the good parts. Further, even if the finger electrode 503 and the bonding pad 507 are separated from each other, the potential applied to the bonding pad 507 can be efficiently applied to the finger electrode because the wiring 506 is made of aluminum having a low electric resistance.

[Third Embodiment] Next, a third embodiment will be described. FIG. 10 is a sectional view showing a manufacturing process of the charge generator of the third embodiment. First, as shown in FIG. 10A, an aluminum film 602 is formed on a quartz (glass) substrate 601 by a method such as sputtering or vacuum deposition, and then a resist pattern 603 is formed. Next, as shown in FIG. 10 (B), the hydrated oxide film 606 is formed by hydrating and oxidizing the exposed portion of the aluminum film up to the interface with the substrate 601 by immersing it in warm water of about 80 ° C. To do. Here, the aluminum film left without being hydrated and oxidized becomes the bonding pads 605 for the line electrodes 604 and finger electrodes. Next, as shown in FIG. 10C, after removing the resist pattern 603, a resist pattern 607 is formed on the portion other than the line electrode 604, and the resist pattern 607 is again immersed in warm water of about 80 ° C. A hydrated oxide film 606a is grown on the surface of 604. Next, as shown in FIG. 10D, heat treatment is performed at a temperature of 450 ° C. or higher to remove water from the hydrated oxide films 606 and 606a, thereby forming an alumina film 608.
Next, as shown in FIG. 10E, a dielectric film 609, a finger electrode 610, an insulating film 611, and a screen electrode 612 are sequentially formed on these layers to complete the charge generator. In this embodiment, not only aluminum hillocks are prevented by the high hardness thin film made of the alumina film 608 formed on the surface of the line electrode 604, but also the thickness of the alumina film 608 is close to the end of the line electrode where the electric field is concentrated. Since it is formed thicker, the durability of the element is further improved.

[Fourth Embodiment] Next, a fourth embodiment will be described. FIG. 11 is a sectional view showing a part of the manufacturing process of the charge generator of the fourth embodiment. First, as shown in FIG. 11A, after forming a resist pattern 703 on the surface of an aluminum film 702 formed on a quartz (glass) substrate 701,
As shown in FIG. 11B, the line electrode 704 is formed by removing the portion not covered with the resist pattern 703 by etching. Next, after removing the resist pattern 703, as shown in FIG. 11C, an aluminum film 705 having the same thickness as the thickness of the line electrode 704 is formed again on the entire surface. Next, as shown in FIG. 11D, the aluminum film 705 newly formed by anisotropic etching is removed. By these processes, the curved surface portion 706 is formed at the end portion of the line electrode 704. Similarly, a dielectric film, a finger electrode, an insulating film, and a screen electrode are sequentially formed on these upper layers to complete the charge generator. In the present embodiment, the electric field concentration at the end of the line electrode is alleviated, which has the effect of improving the electrostatic breakdown voltage between the line electrode and the finger electrode.

[Fifth Embodiment] Next, a fifth embodiment will be described. FIG. 12 is a sectional view showing a part of the manufacturing process of the charge generator of the fifth embodiment. First, as shown in FIG. 12A, a resist pattern 803 thicker than the aluminum film 802 is formed on the surface of the aluminum film 802 formed on the quartz (glass) substrate 801 by photolithography. here,
At the time of exposure, the focus position of the projection lens is shifted from the resist surface to form a curved surface 804 at the end of the resist pattern 803. Next, as shown in FIG. 12B, the line electrode 805 is formed by removing the portion not covered with the resist pattern 803 by anisotropic etching. Here, the curved surface 804 at the end of the resist pattern 803 is transferred to the end of the line electrode 805 by adopting the etching condition such that the etching rate of aluminum is the same as that of the resist. Next, as shown in FIG. 12C, the resist 806 left above the line electrode 805 is removed. A charge generator is completed by sequentially forming a dielectric film, a finger electrode, an insulating film, and a screen electrode on these upper layers. Also in this embodiment, the same effect as in the fourth embodiment can be obtained.

[Sixth Embodiment] Next, a sixth embodiment will be described. FIG. 13 is a sectional view showing a part of the manufacturing process of the charge generator of the sixth embodiment. First, as shown in FIG. 13A, a resist pattern 902 is formed on a quartz (glass) substrate 901.
To form. Next, as shown in FIG.
When the aluminum film 903 is formed on the entire surface of the film by a method such as sputtering or vacuum deposition, the aluminum film 903 is constricted at the end of the resist pattern 902. Next, as shown in FIG. 13C, a resist pattern
By removing 902 together with the aluminum film formed on it, the line electrode 904 having a curved surface at its end is formed. Next, as shown in FIG. 13D, the entire surface of the line electrode 904 is removed by anisotropic etching to a slight extent, thereby removing the burr 905 left at the end of the line electrode 904. Then, a dielectric film, a finger electrode, an insulating film and a screen electrode are sequentially formed on these upper layers in the same manner to complete the charge generator. Also in this embodiment, the same effect as in the fourth embodiment can be obtained.

[Seventh Embodiment] The seventh embodiment will be described below. FIG. 14 is a sectional view showing a part of the manufacturing process of the charge generator of the seventh embodiment. First, as shown in FIG. 14A, after forming a resist pattern 1003 on the surface of an aluminum film 1002 formed on a quartz (glass) substrate 1001,
As shown in FIG. 14B, the line electrode 1004 is formed by removing the portion not covered with the resist pattern 1003 by etching. Next, after removing the resist pattern 1003 and heating to a temperature near the melting point of aluminum, it is cooled to room temperature.
As shown in 14C, a curved surface is formed at the electrode end portion due to the surface tension when the line electrode 1004 melts. Then, similarly, a dielectric film, a finger electrode, an insulating film, and a screen electrode are sequentially formed on these upper layers to complete the charge generator. Also in this embodiment, the same effect as in the fourth embodiment can be obtained.

[0038]

As described above on the basis of the embodiments,
According to the first aspect of the invention, it is possible to reduce the size of the electrodes and improve the dimensional accuracy, and it is possible to realize a charge generation control element for a high-definition electrostatic image forming apparatus having excellent image quality. . Further, according to the inventions of claims 2 to 5, it is possible to prevent aluminum hillocks growing on the surface of the line electrode, and it is possible to prevent a decrease in reliability of the solid dielectric film. Further, according to the inventions of claims 6 to 7, the charge generation control element in which the movement of aluminum atoms in the line electrode is suppressed to prevent the growth of aluminum hillocks and the reliability of the solid dielectric film is improved is manufactured. can do.

According to the eighth aspect of the invention, the electric field concentration at the end of the line electrode is suppressed, and the dielectric breakdown of the solid dielectric film can be prevented. According to the invention described in claim 9, it is possible to realize the charge generation control element in which the bonding wire and the pad can be well bonded. Claims
According to the invention described in 10, it is possible to obtain a high-definition charge generator having excellent image quality by reducing variations in voltage applied to each element constituting the charge generator. According to the invention of claim 11, in the case of connecting a plurality of charge generators composed of a plurality of charge generation control elements to form a long-sized charge generator, in the connection portion of the charge generators It is possible to realize a charge generator that avoids the disorder of the arrangement of the charge generation control elements. Further, according to the invention of claim 12, it becomes possible to prevent crosstalk between the line electrodes and / or between the wiring of the line electrodes and the finger electrodes.

[Brief description of drawings]

FIG. 1 is a diagram showing a planar structure and a cross-sectional structure of a charge generator for explaining a first embodiment of a charge generation control element of an electrostatic image forming apparatus according to the present invention.

2A and 2B are a plan view and a cross-sectional view showing a manufacturing process of the first embodiment shown in FIG.

FIG. 3 is a plan view and a cross-sectional view showing a manufacturing process that follows the process shown in FIG.

FIG. 4 is a plan view and a cross-sectional view showing a manufacturing process that follows the process shown in FIG.

FIG. 5 is a plan view and a cross-sectional view showing a manufacturing process that follows the process shown in FIG.

FIG. 6 is a plan view and a cross-sectional view showing a manufacturing process that follows the process shown in FIG.

FIG. 7 is a plan structural view showing a part of a second embodiment of the present invention.

FIG. 8 is a plan view showing a modification of the second embodiment.

FIG. 9 is a plan view showing another modification of the second embodiment.

FIG. 10 is a diagram showing a manufacturing process for explaining a third embodiment of the present invention.

FIG. 11 is a diagram showing a manufacturing process for explaining a fourth embodiment of the present invention.

FIG. 12 is a diagram showing a manufacturing process for explaining a fifth embodiment of the present invention.

FIG. 13 is a diagram showing a manufacturing process for explaining the sixth embodiment of the present invention.

FIG. 14 is a diagram showing a manufacturing process for explaining a seventh embodiment of the present invention.

FIG. 15 is a view showing a cross section of a part of a conventional charge generator for an electrostatic image forming apparatus.

FIG. 16 is an exploded perspective view for explaining a conventional method for manufacturing a charge generator.

[Explanation of symbols]

 301 Substrate 302 Line electrode 303 Titanium thin film 304 Dielectric film 305 Finger electrode 306 Insulating film 307 Screen electrode 308 Finger hole 309 Screen hole 310 Bonding pad for finger electrode 311 Bonding pad for line electrode 312 Contact hole

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kazuya Matsumoto 2-43-2 Hatagaya, Shibuya-ku, Tokyo Inside Olympus Optical Co., Ltd.

Claims (12)

[Claims] 1. A line electrode formed on an insulating substrate,
A solid dielectric film formed on the surface of the line electrode, a finger electrode formed on the solid dielectric film and having a hole for charge generation in the center, and a finger electrode surface and a center part. In a charge generation control element comprising a screen electrode having a hole for discharging electric charges at a central portion formed through a solid insulator film having a hole for allowing electric charges to pass, the line electrode is formed by a semiconductor manufacturing process. And a charge generation control element for an electrostatic image forming apparatus, which is made of aluminum. 2. A charge generation control element for an electrostatic image forming apparatus according to claim 1, wherein a thin film having a hardness higher than that of aluminum is formed between the line electrode and the solid dielectric film. . 3. The charge generation control element for an electrostatic image forming apparatus according to claim 2, wherein the high-hardness thin film is a thin film made of any one of titanium, molybdenum, tungsten, and titanium nitride. 4. The charge generation control element for an electrostatic image forming apparatus according to claim 2, wherein the high hardness thin film is a thin film made of alumina. 5. The method of manufacturing a charge generation control element for an electrostatic image forming apparatus according to claim 4, wherein a step of forming a resist pattern on an aluminum film formed on an insulating substrate, and hot water By a step of forming a hydrated oxide film up to the interface with the insulating substrate in a portion of the aluminum film that is not covered with the resist pattern by a sum reaction, and removing the resist pattern and performing hydration oxidation with warm water again. And a step of forming a hydrated oxide film of aluminum on the surface of the remaining aluminum film, and a step of converting the hydrated oxide film to an alumina film by heating the hydrated oxide film at a temperature of 450 ° C. or higher. A method of manufacturing a charge generation control element for an electrostatic image forming apparatus, comprising: 6. The method of manufacturing a charge generation control element for an electrostatic image forming apparatus according to claim 1, wherein all or part of the solid dielectric film has a temperature of 200 ° C. or lower. A method of manufacturing a charge generation control element for an electrostatic image forming apparatus, comprising the step of forming at a temperature. 7. The method of manufacturing a charge generation control element for an electrostatic image forming apparatus according to claim 6, wherein the solid dielectric film is formed of silicon oxide or silicon nitride. 8. The charge generation control element for an electrostatic image forming apparatus according to claim 1, wherein an end portion of the line electrode is chamfered. 9. A wire bonding pad for the finger electrode is provided, and the wire bonding pad is formed of aluminum.
9. A charge generation control element for an electrostatic image forming apparatus according to any one of items 8 and 8. 10. The charge generation control element for an electrostatic image forming apparatus according to claim 9, wherein the finger electrode and the wire bonding pad are connected by a wiring made of aluminum. 11. A charge generation control element section is formed by arranging the charge generation control elements according to any one of claims 1 to 4 and 8 to 10 in a one-dimensional form or a two-dimensional form, and a line electrode. And wire bonding pads of finger electrodes are arranged on one side or both sides of the charge generation control element portion, and wirings connecting the line electrodes and finger electrodes to the wire bonding pads are arranged in the same direction or in opposite directions. A charge generator for an electrostatic image forming apparatus characterized by being provided. 12. The charge generator for an electrostatic image forming apparatus according to claim 11, comprising electrode lines to which a fixed potential is applied, between the line electrodes and / or between the line electrode wirings and the finger electrodes. A charge generator for an electrostatic image forming device, characterized in that