JPH10339985A - Charge generator for electrostatic image forming device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charge generator constituted so that a 2nd hard dielectric film for improving durability and a line electrode lead-out wiring are easily formed on a 1st dielectric film. SOLUTION: A line electrode 2 and the 1st dielectric film 3 are formed on the upper part of an insulating substrate 1. In a wiring part, a line electrode lead-out wiring contact 4 is formed on the 1st dielectric film 3 on the upper part of the line electrode 2 so as to provide the lead-out wiring 5. Next, an oxidation preventing film 6 for the lead-out wiring is formed on the entire upper part, and an alumina film 7 being the 2nd dielectric film by a mask sputtering method is provided only on a charge generating control element part. A finger electrode 8 is formed on the alumina film 7 and an electrode pad 12 is formed at the end of the wiring 5. Then, a 1st insulating film 9 and a screen electrode 10 are formed, and finally a screen hole 11 and a pad hole 13 are formed, whereby a charge generating control element chip for a charge generator is constituted.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a charge generator for an electrostatic image forming apparatus used for electrostatic printing.

[0002]

2. Description of the Related Art Conventionally, a charge generator using a corona discharge has been used as a method of forming a latent image by electrostatic charge on a dielectric recording medium based on a principle of transferring and depositing electric charges directly on a dielectric recording medium. Japanese Patent Publication No. 2-62862 discloses a technique for forming such a charge generator with high definition using semiconductor fine processing technology.
No. 08567.

FIG. 8 is a sectional view showing a configuration example of a charge generation control element constituting a conventional charge generator for an electrostatic image forming apparatus. In FIG. 9, reference numeral 100 denotes one charge generation control element, and the charge generator includes a plurality of charge generation control elements 10.
0 are arranged one-dimensionally or two-dimensionally. The charge generation control element 100 includes a substrate 101 made of quartz or glass, a line electrode 102 made of metal, a first dielectric film 103, and a finger electrode 104 made of metal.
, A first insulating film 105, and a screen electrode 106. The finger electrode 104 and the screen electrode 106 have finger holes 107 and a screen hole 108, respectively.

The charge generation control device 100 having the above-described configuration
Are formed by forming a resist pattern on a metal film formed by a method such as a sputtering method or a vacuum evaporation method, and then removing portions not covered by the resist pattern by etching. For the first dielectric film 103, a material having a high electrostatic withstand voltage such as a silicon oxide film formed by a method such as a CVD (chemical vapor deposition) method or a sputtering method is used. Also the first
The insulating film 105 is made of a resin having high heat resistance, such as polyimide, and is formed by a spin coating method or a screen printing method.

Next, the operation of the thus-configured charge generation control device 100 will be described. In FIG.
By applying an AC voltage of several hundreds of volts between the line electrode 102 and the finger electrode 104 disposed with the first dielectric film 103 interposed therebetween, a charge group is generated in a region of the finger hole 107 by a corona discharge phenomenon. I do. Negative charges having a large mobility in the charge group are used for latent image formation. The first insulating film 105 is opposed to the finger electrode 104.
When a potential more positive than the potential applied to the finger electrode 104 is applied to the screen electrode 106 formed with the
It is extracted from a screen hole 108 formed in 106. The negative charge extracted from screen hole 108 is
It is emitted toward the drum 109, which is a dielectric recording medium, and is deposited on the drum 109 to form a charge latent image. Conversely, when a negative potential is applied to the screen electrode 106 with respect to the finger electrode 104, the extraction of negative charges from the screen hole 108 is prevented, and no latent image is formed on the drum 109.

[0006]

When the conventional charge generation control device shown in FIG. 8 is driven, a plasma CVD with a high electrostatic breakdown voltage is applied between the line electrode and the finger electrode.
Even if the first dielectric film made of a silicon oxide film or the like is formed thick by the method, the surface of the dielectric film is subjected to ion irradiation or the like by corona discharge generated in the finger hole, and the surface of the dielectric film is shaved by sputtering. Eventually, a breakdown occurs between the line electrode and the finger electrode.

For this reason, a very hard film (a second dielectric film such as an alumina film) which is not hardened by ion irradiation is used as the uppermost layer of the first dielectric film exposed to corona discharge. Is desirable. However, such a very hard film is difficult to process using semiconductor technology, and when wet etching or dry etching is used, it is difficult to select a mask material, an etching solution, or a reactive gas type. Therefore, although an etching method using a physical action such as an ion milling method was also used, it was difficult to determine an etching end point and to select a mask material, and a steep step was formed due to disappearance of the mask and excessive etching, and FIG. As shown in (1), it often causes disconnection of the finger electrode wiring. In FIG. 9, 201 is a substrate, 202 is a line electrode, 203 is a first dielectric film, 204 is a hard second dielectric film such as an alumina film, and 205 is a reduction in the thickness of the second dielectric film 204 due to excessive etching. Reference numeral 206 denotes a finger electrode, and 207 denotes a disconnection of the finger electrode 206 due to a step at an edge of the second dielectric film (alumina film) 204.

If a second dielectric film, such as an extremely hard alumina film, is formed on the entire surface of the substrate, not only is it difficult to form line electrode pads for the above-mentioned reasons, but also the film stress due to the subsequent heat treatment. There is a problem that cracks such as warpage and cracks of the substrate occur due to the difference in thermal expansion coefficient and the like.

When a charge generator is formed by using one charge generation control element chip composed of a large number of charge generation control elements formed on a substrate, an electrode lead-out wiring form as shown in FIG. What is necessary is just to form a hard second dielectric film such as an alumina film only on the charge generation control element portion by a mask sputtering method as conventionally conceivable. In FIG. 10, 301 is a finger hole, 30
2 denotes a second dielectric film (alumina film) formed by a mask sputtering method, 303 denotes a line electrode, 304 denotes a line electrode lead-out wiring, 305 denotes an electrode pad, and 306 denotes a finger electrode.

However, in the case of forming a long charge generator, in order to form each member to the length of the long charge generator,
Since a manufacturing apparatus corresponding to the size is required, the cost is high, and it is very difficult to obtain a required film thickness distribution, particularly in a thin film manufacturing technique. Therefore, a plurality of charge generation control element chips formed on a substrate are required. By forming a long charge generator by joining, there is no limit on the size of the charge generator, and by removing defective chips due to defects during manufacturing and joining good chips, it is better to combine The number of charge generators that can be formed can be greatly improved.

However, when a long charge generator is formed by connecting a plurality of chips, as described above,
It cannot be performed by a simple process such as the case of forming a chip, and the line electrode lead-out wiring 304 as shown in FIG.
It cannot be taken out in the direction AA 'of the joining surface shown in FIG. Therefore, as shown in FIG. 11, it is necessary to adopt a structure in which the line electrode lead-out wiring 304 is taken out from between the finger electrodes 306. As a result, it is necessary to provide a contact portion 307 on the first dielectric film on the line electrode 303 in the minute region between the finger electrodes 306 in the charge generation control element portion in order to obtain conduction. Of course, after the hard second dielectric film 302 such as an alumina film is formed, it is very difficult to perform etching for the above-described reason, and a contact portion cannot be formed.

Also, it is very difficult to form an alumina film (second dielectric film) 302 by mask sputtering only on the charge generation control element portion avoiding the contact portion 307 in consideration of mask alignment accuracy. If the alumina film is not sputtered at a portion where the alumina film is not sputtered from the contact portion 307 as shown by reference numeral 308 and the alumina film is sputtered at least on the contact portion 307, contact etching cannot be performed, resulting in a failure. As described above, when a portion where the alumina film is not sputtered is formed in the finger hole, a problem such as a decrease in durability occurs, and the charge generation control element lacks reliability.

The line electrode lead-out wiring 304 is shown in FIG.
When formed between the finger electrodes 306 as shown in 11,
The wiring capacitance between the finger electrode and the line electrode wiring increases, causing a problem that crosstalk occurs between the two.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems in the conventional charge generator for an electrostatic image forming apparatus, and comprises connecting a plurality of charge generation control element chips comprising a plurality of charge generation control elements. In order to improve durability when forming a long charge generator, a very hard second dielectric film such as an alumina film is formed on the uppermost layer of the first dielectric film. It is another object of the present invention to provide a charge generator for an electrostatic image forming apparatus, in which formation of a dielectric film and formation of line electrode lead-out wiring can be easily performed.

The purpose of each claim is as follows. That is, according to the first aspect of the present invention, the line electrode lead-out wiring can be easily arranged, and the very hard second dielectric film such as an alumina film formed by the mask sputtering method can be easily provided only on the bottom surface of the finger hole of the finger electrode. It is an object of the present invention to provide a highly durable charge generator for an electrostatic image forming apparatus which can be formed and thereby can output a high ion current at a low applied voltage. According to a second aspect of the present invention, in the charge generator for an electrostatic image forming apparatus according to the first aspect, a charge generator for an electrostatic image forming apparatus capable of forming a harder second dielectric film is provided. The purpose is to provide. According to the third, fourth and fifth aspects of the present invention, it is possible to easily dispose the line electrode lead-out wiring, and to use a very hard second dielectric film such as an alumina film formed by a mask sputtering method to form the first dielectric film on the charge generating portion. Provided is a charge generator for an electrostatic image forming apparatus that can be easily formed on a film, and further reduces the wiring capacitance between a line electrode lead-out wiring and a finger electrode to solve the problem of crosstalk. Aim. According to a sixth aspect of the present invention, the second dielectric film can be easily formed on the first dielectric film on the charge generating portion by the mask sputtering method, and the wiring between the line electrode lead wiring and the finger electrode can be formed. Provided is a charge generator for an electrostatic image forming apparatus that has reduced capacity, reduces crosstalk between the two, can be easily connected to a drive circuit wiring portion, and can reduce the size and size of the connection portion. The purpose is to do.

[0016]

In order to solve the above-mentioned problems, the invention according to claim 1 is directed to an insulating substrate, a line electrode formed on the insulating substrate, and a line electrode formed on the surface of the line electrode. A first dielectric film, a second dielectric film formed on the first dielectric film, the second dielectric film being harder than the first dielectric film, and a charge generation unit formed on the second dielectric film. A finger electrode, and a screen electrode formed on the surface of the finger electrode via a first insulating film provided with a hole through which a charge passes in the center and having a hole for discharging charges in the center. In a charge generator for an electrostatic image forming apparatus, wherein a plurality of charge generation control element chips each including a plurality of charge generation control elements are connected, a line electrode is drawn out to said first dielectric film on said line electrode. Contact holes for It is to form a line electrode lead wires through the contact hole to connect the line electrode pads provided on the outer edge of the charge generation control device chip and the line electrodes on the surface of the first dielectric film.

In the charge generator for an electrostatic image forming apparatus configured as described above, the second dielectric film can be formed by the mask sputtering method after forming the line electrode lead-out wiring. When a control element chip is connected to form a charge generator, a hard second dielectric film can be easily pattern-formed only in the charge generation control element portion, and a finger is formed after the formation of the second dielectric film. Since the electrode is formed, the second dielectric film is formed only on the bottom surface of the hole of the finger electrode, and the side wall of the finger electrode hole is not covered with the second dielectric film. And a high ion current can be output. Further, since the second dielectric film can be formed by using the mask sputtering method, the pattern edge does not have a steep shape as formed by dry etching, but has a smooth slope. Disconnection of the electrode can be avoided. In addition, since the second dielectric film is partially formed from the beginning, a problem such as warpage or peeling of the substrate does not occur, and a highly reliable and highly durable charge generator can be formed.

According to a second aspect of the present invention, in the charge generator for an electrostatic image forming apparatus according to the first aspect of the present invention, there is provided a charge generation device for preventing oxidation at least between the line lead-out wiring and the second dielectric film. 3 is characterized by forming a dielectric film. In a charge generator for an electrostatic image forming apparatus, if a line electrode lead wiring formed of titanium or the like is exposed to the surface, it is oxidized by a heat treatment in a later step. As a result, there are problems that the effective film thickness is reduced and that titanium oxide is hardly etched and a contact is hardly obtained.
Therefore, by forming a third dielectric film for preventing oxidation by an oxide film or the like formed by a plasma CVD method which can be formed at a low temperature, at least on the surface of the line for leading out the line electrode, an oxidation preventing effect is provided, thereby providing the second dielectric film. The film quality can be improved to a harder film quality by heat-treating the film at a high temperature, and a charge generator with further improved durability can be realized.

It can be seen from the graph showing the results of X-ray diffraction as shown in FIG. 12 that the dielectric film can be hardened by high-temperature heat treatment. In other words, the heat treatment at around 500 ° C is the same as the film quality immediately after sputter deposition,
It can be seen that when the heat treatment is performed at a temperature of 00 ° C. or higher, a film having a strong crystal bond with a sharp bond peak is formed (a portion indicated by an arrow in FIG. 12). In FIG. 12, the horizontal axis indicates the reflection angle 2θ, the vertical axis indicates the X-ray intensity, and the bottom curve indicates the characteristics when no heat treatment is performed. The film having a strong crystal bond means a hard film, which indicates that a high-durability charge generator can be obtained by subjecting the second dielectric film to high-temperature heat treatment.

According to a third aspect of the present invention, there is provided an insulating substrate, a line electrode formed on the insulating substrate, a first dielectric film formed on a surface of the line electrode, and the first dielectric film. A second dielectric film harder than the first dielectric film formed thereon, a finger electrode formed on the second dielectric film and having a charge generating portion, Charge generation comprising a plurality of charge generation control elements having a screen electrode having a hole for discharging charges at the center formed through a first insulating film having holes through which charges can pass. In a charge generator for an electrostatic image forming apparatus formed by connecting a plurality of control element chips, a second insulating film is formed between the insulating substrate and a first dielectric film, and the line electrode is connected to the first dielectric film. 2 and the line electrode and the charge generation The line electrode lead wire for connecting the line electrode pads provided on the outer edge of the control device chip, and forms in a lower layer than the line electrodes.
According to a fourth aspect of the present invention, in the charge generator for an electrostatic image forming apparatus according to the third aspect, the line electrode lead-out wiring is formed on the insulating substrate. According to a fifth aspect of the present invention, in the charge generator for an electrostatic image forming apparatus according to the third aspect, the line electrode lead-out wiring is formed by being embedded in the insulating substrate. is there.

According to this structure, the second dielectric film such as an alumina film can be easily formed only on the first dielectric film of the charge generating portion by the mask sputtering method.
A long-lasting charge generator having high durability can be formed with a high yield. Further, since the line electrode lead-out wiring can be formed in advance below the line electrode, the second dielectric film such as an alumina film by the mask sputtering method can be easily charged without using the third dielectric film for preventing oxidation. It can be formed only on the generation part, and high-temperature heat treatment for hardening is possible.
Further, since the line electrode lead-out wiring is formed below the line electrode, the wiring capacitance between the line electrode lead-out wiring and the finger electrode is reduced, and crosstalk between the two can be reduced. Further, by forming the line electrode lead wiring embedded in the insulating substrate, disconnection of the line electrode formed in the upper layer can be effectively prevented.

According to a sixth aspect of the present invention, in the charge generator for an electrostatic image forming apparatus according to the third aspect, the insulating substrate is removed and the line electrode lead-out wiring is connected to the second insulating film. It is characterized by being formed on the back surface. With this configuration, the line electrode lead-out wiring can be drawn out from the back surface side, whereby the second dielectric film can be easily formed on the first dielectric film, and a plurality of charge generation control can be performed. Even in the case of forming a charge generator by connecting element chips, no lead wiring is formed on the front surface side, so a step of forming a wiring contact is not required, and no step in the contact portion or lead wiring is formed. In addition, disconnection of the finger electrode wiring can be reduced. Further, the connection between the lead wiring formed on the back surface side and the driving circuit wiring portion is facilitated, so that the reliability is improved and the size of the connection portion can be reduced.

In summary, according to the charge generator for an electrostatic image forming apparatus according to the present invention, an extremely hard alumina film or the like is formed only on the charge generation control element portion by the mask sputtering method. The second dielectric film described above can be easily formed not only in a single chip configuration but also in a multi-chip configuration, thereby making it difficult to perform etching and significantly reducing the yield. Can be solved. In addition, the second dielectric film can be easily hardened by high-temperature heat treatment while preventing the line electrode lead-out wiring from being oxidized, and the durability can be improved. Further, by forming the line electrode lead wiring below the line electrode, the wiring capacitance between the finger electrode and the line electrode lead wiring can be reduced, and the problem of crosstalk can be solved. Further, since the line electrodes can be led out from the back side and connected to the drive circuit wiring portion, the reliability of connection such as wire bonding can be improved, and the size of the device can be reduced.

[0024]

BEST MODE FOR CARRYING OUT THE INVENTION

(First Embodiment) Next, an embodiment will be described. FIG. 1A is a sectional view of a single charge generation control element in a charge generation control element chip constituting a first embodiment of a charge generator for an electrostatic forming apparatus according to the present invention. (B) is a sectional view of the line electrode lead-out wiring portion. In the figure, reference numeral 1 denotes an insulating substrate, on which a line electrode 2 and a first dielectric film 3 are sequentially formed on the insulating substrate 1, and in a wiring portion, a first dielectric film on the line electrode 2 is formed. 3, a line electrode lead wiring contact 4 is formed, and the line electrode lead wiring 5 is connected to the wiring contact 4. Then, an oxidation preventing film 6 of the lead-out wiring 5 is formed on the entire upper portion thereof, and an alumina film 7 as a second dielectric film is formed on the charge generation control element portion and the wiring contact portion 4 by the mask sputtering method. Have been. In the charge generation control element portion, a finger electrode 8 is formed on the alumina film 7, an electrode pad 12 is formed on an end of the line electrode lead wire 5, and a first insulating film 9 is formed on the entire upper portion thereof. In addition, a screen electrode 10 is formed, a screen hole 11 is formed on the charge generation control element portion, and a pad hole 13 is formed on the electrode pad 12 to form a charge generation control element chip. Reference numeral 14 denotes an insulating film serving as an etching mask layer for forming the pad hole 13 by etching the first insulating film 9.

With such a structure, patterning is performed after forming an alumina film (second dielectric film) as in the prior art, the electrode pad portion is etched, and the alumina film is formed only on the charge generation control element portion. An alumina film can be partially formed using a mask sputtering method without using a forming step, so that there is no warpage of a substrate or a problem of etching, etc., and the yield is improved and the reliability is improved for an electrostatic forming apparatus. A charge generator can be obtained.

Next, the manufacturing process of the charge generation control device chip shown in FIGS. 1A and 1B will be described with reference to the manufacturing process diagrams shown in FIGS. First, as shown in FIG. 2A, a titanium film having a thickness of about 0.5 to 1.0 μm is formed on an insulating substrate 21 such as quartz or alumina by a sputtering method or the like, and is coated with a resist pattern. A plurality of line electrodes 22 are formed by removing unexposed portions by isotropic or anisotropic etching.

Next, as shown in FIG. 2B, after removing the resist pattern, a first dielectric film such as monosilane (Si) is formed by a method such as a plasma CVD method.
H ₄ ) and nitrous oxide (N ₂ O) form a silicon oxide film 23. The silicon oxide film 23 needs to have a predetermined thickness (5 to 10 microns) that can withstand a high voltage applied between the line electrode 22 and a finger electrode described later. Thereafter, in order to form a lead wire connecting the line electrode 22 and the line electrode pad portion, a contact hole 24 is formed on the line electrode 22 by removing the silicon oxide film 23 by isotropic or anisotropic etching. Form.

Next, as shown in FIG. 2C, a titanium film having a thickness of about 3.0 μm is formed by a sputtering method or the like. Thereafter, a portion of the titanium film that is not covered with the resist pattern is removed by isotropic or anisotropic etching, thereby forming a lead-out wiring 25 connecting the line electrode 22 and the line electrode pad portion. Subsequently, a silicon oxide film of about 1.0 μm is formed on the entire surface of the substrate as an antioxidant film 26 of the lead wiring 25 of the line electrode 22 by a method such as a plasma CVD method.

Next, as shown in FIG. 2D, for example, a silicon substrate is etched with an aqueous solution of tetramethylammonium hydroxide using an oxide film as a mask to form a silicon mask 27 for mask sputtering in advance. deep. At this time, in consideration of the alignment accuracy of the mask, it is necessary to make a large opening so that the alumina film is completely sputtered on the charge generation control element portion. Subsequently, at the time of alumina sputtering, the substrate and the separately prepared silicon mask 27 are brought into close contact with each other, and sputtering is performed to form an alumina film 28 as a second dielectric film having a thickness of about 0.3 to 1.0 μm only on the charge generation section control element section. At this time, the alumina film 28
Has a gentle slope, it is possible to prevent disconnection of a finger electrode described later. Thereafter, a heat treatment is performed at a temperature of about 700 ° C. for about 1 hour to harden the film quality of the alumina film 28 formed by mask sputtering.

Next, as shown in FIG. 3A, the oxidation preventive film 26 on the region where the line electrode pad portion is to be formed is isotropically or anisotropically covered with the resist pattern. The openings 29 are formed by etching. Next, as shown in FIG. 3B, a titanium film having a thickness of about 3.0 to 5.0 microns is formed by a sputtering method or the like, and then the titanium film portion not covered with the resist pattern is removed. Each finger electrode can be removed by anisotropic or anisotropic etching.
30 and line electrode pads 31 are formed.

Next, as shown in FIG. 3C, a first insulating film 32 having a thickness of about 50 μm is formed by spin coating or screen printing or the like, and then the first insulating film 32 is formed. As an insulating film 33 serving as an etching stopper layer, an oxide film is formed to a thickness of about 1.0 μm by a method such as a plasma CVD method, and then a titanium film serving as a screen electrode is formed by a sputtering method or the like. Finally, the screen electrode 34 is etched by photolithography and the first insulating film 32 is etched to form a screen hole 35 and a pad hole 36, thereby completing the charge generation control element chip.

In the above manufacturing method, the line electrode pad is formed by laminating a line electrode lead-out wiring portion made of a titanium film and a line electrode pad 31 formed simultaneously with the finger electrode 30 made of a titanium film. However, the present invention is not limited to such a structure, and a thick pad structure using a titanium film for a line electrode may be used.

In the above manufacturing method, the line electrode, the finger electrode, and the screen electrode are formed by using a titanium film formed by a sputtering method or the like. Any metal film can be used as long as it can withstand Mo.
, W, etc. may be formed by using a sputtering method or a CVD method. Although a silicon substrate is used as a mask material during mask sputtering, the present invention is not limited to this silicon substrate, and mask sputtering may be performed using an insulator such as quartz or a metal mask.

Further, in this manufacturing method, a method is described in which an antioxidant film and an alumina film are formed after forming a line electrode lead-out wiring, and then a finger electrode is formed. However, the present invention is not limited to this manufacturing method. A finger electrode may be formed at the same time as the electrode lead-out wiring, or an antioxidant film may not be formed when the heat treatment of the alumina film is not performed.

Further, plasma CVD is used as the first dielectric film.
Although an example using a silicon oxide film by the method has been described, the present invention is not limited to this. For example, boron (B), phosphorus (P), aluminum (Al), silicon (Si), titanium (Ti), tantalum (Ta), Tungsten (W), zirconium (Zr), calcium (Ca), hafnium (Hf),
Vanadium (V), niobium (Nb), chromium (Cr),
Any of oxides, carbides, nitrides, and fluorides such as magnesium (Mg), lead (Pb), and tin (Sn) can be used, or a composite film of these compounds may be used.

As described above, in the first embodiment, even when a long charge generator is formed by connecting chips, it is easy to form the line electrode lead-out wiring as described above. Since a very hard second dielectric film such as an alumina film can be formed only on the charge generation control element portion by the mask sputtering method, a charge generation control element chip that does not impair durability can be formed. Further, since the second dielectric film is formed only on the bottom surface of the finger electrode hole and the side wall of the finger electrode hole is not covered with the second dielectric film, a large amount of corona discharge is generated at a low applied voltage, and the high ion A current can be output. In addition, since the antioxidant film is formed on the line electrode lead wiring, the alumina film serving as the second dielectric film can be hardened by high-temperature heat treatment, and the durability can be further improved. . Further, since there is no patterning step of the alumina film, a manufacturing method which can reduce the number of steps and improve the yield can be adopted.

(Second Embodiment) Next, a second embodiment will be described. FIG. 4A is a cross-sectional view of a single charge generation control element in the charge generation control element chip according to the second embodiment, and FIG. 4B is a cross-sectional view of a wiring portion thereof. The same or corresponding members as those of the charge generation control element chip according to the first embodiment shown in FIGS. 1A and 1B are denoted by the same reference numerals. This embodiment is configured such that a line electrode lead-out line 5 and a line contact 4 connecting them are present below the line electrode 2. 4A and 4B, 1 is an insulating substrate, 2 is a line electrode, 3 is a first dielectric film, 4 is a line electrode lead wiring contact, 5 is a line electrode lead wiring, and 7 is an alumina film ( 8 is a finger electrode, 9 is a first insulating film, 10 is a screen electrode, 11 is a screen hole, 12 is a line electrode pad, 13 is a pad hole, 14 is an insulating film, and 15 is an insulating film. The line electrode 2 is a second insulating film interposed between the substrate 1 and the first dielectric film 3, the line electrode 2 is on the upper surface of the second insulating film 15, and the line electrode lead wire 5 is a second insulating film. It is formed on the lower surface, and the line electrode lead-out wiring contact 4 is the second
The insulating film 15 is removed by etching.

With such a structure, patterning is performed after forming an alumina film (second dielectric film) as in the prior art, and the electrode pad portion is etched to form the alumina film only on the charge generation control element portion. An alumina film can be partially formed using a mask sputtering method without using a forming step, so that there is no warpage of a substrate or a problem of etching, etc., and the yield is improved and the reliability is improved for an electrostatic forming apparatus. A charge generator can be obtained. Further, since the wiring capacitance between the line electrode lead-out wiring and the finger electrode is reduced, crosstalk between the electrodes can be reduced.

Next, a method of manufacturing the charge generation control element chip having such a configuration will be described with reference to manufacturing process diagrams shown in FIGS. First, as shown in FIG. 5A, a titanium film having a thickness of about 1.0 μm is formed on an insulating substrate 41 of quartz, alumina, glass, or the like by a sputtering method or the like, and is covered with a resist pattern. By removing the non-existing portion by isotropic or anisotropic etching, the line electrode lead-out wiring 42 is formed.

Next, as shown in FIG. 5B, a silicon oxide film 43 is formed as a second insulating film between a line electrode to be described later and the lead wiring 42 by a method such as a plasma CVD method. Formed on the order of microns. Thereafter, in order to establish conduction with the line electrode lead-out wiring 42, a contact hole 44 is formed at the intersection of the line electrode and the lead-out wiring 42 by removing the silicon oxide film 43 by isotropic or anisotropic etching. . Subsequently, a titanium film having a thickness of about 0.5 μm is formed by a sputtering method or the like, and a portion of the titanium film not covered with the resist pattern is removed by isotropic or anisotropic etching. , Line electrode 45 made of titanium film
To form

Next, as shown in FIG. 5C, after removing the resist pattern, the first dielectric film is
By a method such as the VD method, for example, monosilane (SiH ₄ )
Oxide film due to the reaction between hydrogen and nitrous oxide (N ₂ O)
Form at 46. This silicon oxide film 46 is
And a predetermined thickness (5 to 10 microns) that can withstand the high voltage applied between the finger electrodes described later. Next, as shown in FIG. 5D, an alumina film 47 is formed only on the charge generation control element portion by a mask sputtering method.
Is formed through a mask 48 to form an alumina film 47 having a thickness of about 0.5 μm. Subsequently, in order to further harden the alumina film 47, heat treatment is performed at a temperature of about 700 ° C. for about 1 hour. At this time, since the substrate is covered with the silicon oxide film 46 serving as the first dielectric film functioning as an antioxidant film, the line electrode 45 and the lead wiring 42 are not oxidized.
Further, since the alumina film 47 is formed only in the charge generation control element portion, the substrate does not warp due to the stress due to the heat treatment, and the silicon oxide film (first dielectric film) 46 does not crack.

Next, as shown in FIG. 5E, the silicon oxide film (first dielectric film) 46 and the second insulating film 43 on the electrode pad portion expected area of the line electrode lead-out wiring 42 are patterned. A pad hole 50 is formed in the electrode pad portion expected region by removing the isotropic or anisotropic etching. Subsequently, a titanium film having a thickness of about 3.0 to 5.0 microns is formed by a sputtering method or the like. Thereafter, the portion of the titanium film that is not covered with the resist pattern is removed by isotropic or anisotropic etching, so that the finger electrode 51 is removed.
Then, a line electrode lead-out wiring pad 52 is formed. Next, a first insulating film 53 having a thickness of about 50 μm is formed by a spin coating method, a screen printing method, or the like. Subsequently, the insulating film for etching stopper of the first insulating film 53 is formed.
54 is formed of an oxide film having a thickness of about 1.0 micron by a method such as a plasma CVD method. Subsequently, a titanium film serving as a screen electrode is formed by a sputtering method or the like.
Finally, a screen electrode 55 is formed by photolithography, the first insulating film 53 is etched using the screen electrode 55 and the insulating film 54 for an etching stopper as a mask, and a screen hole 56 and a pad hole 57 are formed. Complete the generation control element chip.

(Third Embodiment) Next, a third embodiment will be described. FIG. 6A is a cross-sectional view of a single charge generation control element in the charge generation control element chip according to the third embodiment, and FIG. 6B is a cross-sectional view of a wiring portion thereof. The same or corresponding members as those of the charge generation control element chips according to the first and second embodiments shown in FIGS. 1A and 1B and FIGS. 4A and 4B are denoted by the same reference numerals. Are shown. The charge generation control element chip according to this embodiment is different from the charge generation control element chip according to the second embodiment shown in FIGS. The other configuration is the same as that of the second embodiment.

With such a structure, the same operation and effect as those of the second embodiment shown in FIGS. 4A and 4B can be obtained, and the line electrode lead-out wiring 5 can be formed on the insulating substrate 1. Since it is embedded in the inside, disconnection of the line electrode 2 formed thereon can be prevented.

In the present embodiment, the line electrode lead-out wiring is formed by embedding it in the insulating substrate. However, the present invention is not limited to such a structure, and the second insulating layer formed between the lead-out wiring and the line electrode is formed. The film (silicon oxide film) may be subjected to a flattening process.
Flattening by an OG (spin-on-glass) film, flattening by a CMP (chemical mechanical polishing) method, or the like is used.

(Fourth Embodiment) Next, a fourth embodiment will be described. FIG. 7A is a cross-sectional view of the charge generation control element in the charge generation control element chip according to the fourth embodiment, and FIG. 7B is a cross-sectional view of a wiring portion thereof, and FIG. (A), (B), (A), (B) of FIG.
Members that are the same as or correspond to the charge generation control element chips according to the first to third embodiments shown in FIGS. 6A and 6B are denoted by the same reference numerals. The charge generation control element chip according to this embodiment is similar to that shown in FIGS.
(B), the insulating substrate in the third embodiment has been removed, and a line electrode lead-out wiring contact 4 is formed on the second insulating film (polyimide film) 15 on the back surface side of the line electrode 2; The lead wiring 5 is formed on the lower surface of the second insulating film 15 via the contact 4.

With this configuration, the same operation and effect as those of the second embodiment shown in FIGS. 4A and 4B can be obtained, and a plurality of charge generation control element chips are connected. Even when a charge generator is formed, no extraction wiring is formed on the front surface side, so that a step of forming an extraction wiring contact is not required. Further, since a step in the contact portion and the extraction wiring are not formed, finger electrode wiring is not formed. Can be reduced. Further, the connection between the lead wiring formed on the back surface side and the driving circuit wiring portion is facilitated, so that the reliability is improved and the size of the connection portion can be reduced. In other words, when the connection to the drive circuit wiring portion is performed on the front side of the charge generator, the distance between the upper surface of the charge generator and the opposing drum is limited, so that the connection wires cannot be sufficiently bonded and lack reliability. However, there is a problem that the distance between the drum and the opposing drum cannot be shortened due to the presence of the connecting wire. However, by providing the drawing wiring on the back side as in the present embodiment, these problems are solved, A charge generator capable of causing the ion output to reach the drum can be realized. In the configuration shown in FIG. 7, the lead-out wiring 5 is formed in the lateral direction from the contact 4, but the lead-out wiring 5 can be drawn out from the contact 4 in a direction directly below the contact 4.

In order to obtain the charge generation control element chip having the structure of the present embodiment, the charge generation control element chip is formed on an insulating substrate such as a silicon substrate, and then the insulating substrate is removed by etching. The insulating substrate used at this time is not limited to a silicon substrate, and any insulating substrate or metal substrate can be used as long as it can be selectively processed. In addition, a second layer serving as a stopper layer during substrate etching.
Although the insulating film described above is formed of a polyimide film, the present invention is not limited to this, and a second insulating film serving as a stopper layer may be formed of an inorganic insulating film. Further, not only the lead wire of the line electrode but also the lead wire of the finger electrode can be taken out from the back surface side.

[0049]

As described above with reference to the embodiments, according to the present invention, an extremely hard second insulating film such as an alumina film, which is difficult to pattern by using semiconductor technology, is formed by a mask sputtering method. Since a predetermined film thickness can be easily formed only in the charge generation control element portion, reliability can be reduced without lowering the yield when processing the second dielectric film (alumina film), which has conventionally been a problem. It is possible to form a charge generation control element chip having high performance. Even when a plurality of chips are connected to form a long charge generator, a mask sputtering method is used to form the second dielectric film by forming the line electrode lead-out wiring on the surface of the first dielectric film. A charge generator which can be applied and has high durability can be formed. In addition, by forming a third dielectric film as an antioxidant film on the line electrode lead-out wiring, high-temperature heat treatment of the second dielectric film can be performed, and a harder second dielectric film can be formed. The durability can be further improved. Further, by forming the line electrode lead-out wiring below the line electrode, it is possible to reduce the wiring capacity with the finger electrode and to solve the problem of crosstalk between the two electrodes. Furthermore, since the line electrode lead-out wiring can be easily taken out from the back side by providing a through hole in the insulating film after the substrate etching, it is not necessary to form the lead-out pad portion on the substrate. The size of the charge generator can be easily reduced. Similarly, by extracting the finger electrodes from the back side, a more reliable miniaturization of the charge generator can be realized.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a single charge generation control element portion of a charge generation control element chip and a wiring portion thereof in a first embodiment of a charge generator for an electrostatic image forming apparatus according to the present invention.

FIG. 2 is a diagram showing a manufacturing process of the charge generation control element chip shown in FIG.

FIG. 3 is a view showing a manufacturing process following the manufacturing process shown in FIG. 2;

FIG. 4 is a cross-sectional view showing a single charge generation control element portion of a charge generation control element chip and a wiring portion thereof in a second embodiment of the present invention.

FIG. 5 is a view showing a manufacturing process of the charge generation control element chip shown in FIG. 4;

FIG. 6 is a cross-sectional view illustrating a single charge generation control element portion of a charge generation control element chip and a wiring portion thereof according to a third embodiment of the present invention.

FIG. 7 is a cross-sectional view showing a single charge generation control element portion of a charge generation control element chip and a wiring portion thereof according to a fourth embodiment of the present invention.

FIG. 8 is a cross-sectional view showing a single charge generation control element unit constituting a conventional charge generator.

FIG. 9 is a diagram showing a problem when a second dielectric film (alumina film) is formed in a charge generation control element constituting a conventional charge generator.

FIG. 10 is a diagram showing a wiring structure of a conventional charge generator formed of a single charge generation control element chip.

FIG. 11 is a diagram showing a wiring structure of a conventional charge generator formed by a plurality of charge generation control element chips.

[Figure 12] Dielectric film (alumina film) due to difference in heat treatment temperature
FIG. 4 is a diagram for explaining a change in film quality of the present invention.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 insulating substrate 2 line electrode 3 first dielectric film 4 line electrode lead wiring contact 5 line electrode lead wiring 6 antioxidant film 7 alumina film 8 finger electrode 9 first insulating film 10 screen electrode 11 screen hole 12 electrode pad 13 pad Hole 14 Insulating film 15 Second insulating film 21 Insulating substrate 22 Line electrode 23 Silicon oxide film 24 Contact hole 25 Line electrode lead-out wiring 26 Antioxidant film 27 Silicon mask for mask sputtering 28 Alumina film 29 Opening 30 Finger electrode 31 Line electrode Pad 32 First insulating film 33 Insulating film for etching stopper 34 Screen electrode 35 Screen hole 36 Pad hole 41 Insulating substrate 42 Line electrode lead-out wiring 43 Silicon oxide film 44 Contact hole 45 Line electrode 46 Silicon oxide film (first dielectric film) ) 47 Alumina film 48 Click 49 alumina sputtering 50 pad hole 51 finger electrodes 52 pads 53 first insulating film 54 etched stopper insulating film 55 screen electrode 56 screen holes 57 pad hole

Claims (6)

[Claims] An insulating substrate; a line electrode formed on the insulating substrate; a first dielectric film formed on a surface of the line electrode; and a first dielectric film formed on the first dielectric film. A second dielectric film harder than the first dielectric film, a finger electrode formed on the second dielectric film and provided with a charge generating portion, and a hole in the center of the finger electrode for allowing charges to pass therethrough. A plurality of charge generation control element chips each including a plurality of charge generation control elements having a screen electrode provided with a charge outflow hole at the center formed through the first insulating film provided therein In the charge generator for an electrostatic image forming apparatus connected, a contact hole for drawing out a line electrode is provided in the first dielectric film on the line electrode, and the line electrode is connected to the charge generation through the contact hole. Control element chip A line electrode lead-out line for connecting to a line electrode pad provided on the outer edge of the
A charge generator for an electrostatic image forming apparatus, wherein the charge generator is formed on the surface of a dielectric film. 2. An electrostatic image according to claim 1, wherein a third dielectric film for preventing oxidation is formed at least between said line electrode lead-out wiring and said second dielectric film. Charge generator for forming equipment. 3. An insulating substrate, a line electrode formed on the insulating substrate, a first dielectric film formed on the surface of the line electrode, and a first dielectric film formed on the first dielectric film. A second dielectric film harder than the first dielectric film, a finger electrode formed on the second dielectric film and provided with a charge generating portion, and a hole in the center of the finger electrode for allowing charges to pass therethrough. A plurality of charge generation control element chips each including a plurality of charge generation control elements having a screen electrode provided with a charge outflow hole at the center formed through the first insulating film provided therein In the charge generator for an electrostatic image forming apparatus connected, a second insulating film is formed between the insulating substrate and the first dielectric film, and the line electrode is connected to the second dielectric film.
A line electrode lead-out line for connecting the line electrode to a line electrode pad provided at the outer edge of the charge generation control element chip is formed below the line electrode. A charge generator for an electrostatic image forming apparatus. 4. The charge generator for an electrostatic image forming apparatus according to claim 3, wherein said line electrode lead-out wiring is formed on said insulating substrate. 5. The charge generator for an electrostatic image forming apparatus according to claim 3, wherein said line electrode lead-out wiring is embedded and formed in said insulating substrate. 6. The charge generator for an electrostatic image forming apparatus according to claim 3, wherein the insulating substrate is removed, and the line electrode lead-out wiring is formed on a back surface of the second insulating film. A charge generator for an electrostatic image forming apparatus.