JPH08132629A - Ink jet head and production thereof - Google Patents

Abstract

PURPOSE: To obtain an inexpensive ink jet head of high quality and high accuracy. CONSTITUTION: A heat accumulation layer 17 composed of SiOx, etc., a resistor layer 13 composed of polycrystalline silicon, etc., an interlaminar insulating film 18 composed of BPSG, etc., indivisual electrodes 11 composed of Al, etc., a common electrode 12 composed of Al, etc., a heater protecting layer 14 composed of SiNx, etc., a heater protecting layer 15 composed of Ta, etc., and an electrode protecting layer 16 composed of PSG, etc., are successively formed on a heater wafer 1 by patterning. These layers are not formed on the part of a grinding position 8 for forming an emitting orifice 7. Then, a photosensitive resin layer 5 is formed by patterning. Since a fragile material such as SiOx, SiNx, BPSG, PSG or the like and a metal material such as Al, Ta or the like are not present at the grinding position, a ground surface containing the emitting orifice 7 of good quality can be obtained in a grinding process.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet head and a method for manufacturing the same, and more particularly, to a method for manufacturing a large number of inkjet heads on a large-sized substrate and obtaining individual inkjet heads by cutting or grinding. The present invention relates to the manufactured inkjet head.

[0002]

2. Description of the Related Art As a method of manufacturing an ink jet head, various methods have been proposed. Among them, as a method that is suitable for mass production and can be manufactured at low cost and with stable quality, a large number of heads are formed on a large area substrate,
There is a method of cutting and separating. In particular, a manufacturing method for obtaining a large number of uniform inkjet heads by sticking two silicon wafers together and cutting or cutting them is a very useful method in mass production, cost reduction, and quality stabilization. Such a manufacturing method is disclosed in, for example, Japanese Patent Laid-Open No.
It has already been proposed in JP-A 1-230954, JP-A-1-166965, and the like.

FIG. 2 is a partial cross-sectional view of a conventional ink jet head. In the figure, 1 is a heater wafer, 5 is a photosensitive resin layer, 7 is a discharge port, 8 is a grinding position, 11 is an individual electrode, 12 is a common electrode, 13 is a resistor layer, 14 and 15 are heater protection layers, and 16 is An electrode protective layer, 17 is a heat storage layer, 18 is an interlayer insulating film, and 19 is an ink flow path. Silicon oxide (SiOx) is formed as the heat storage layer 17 on the heater wafer 1 which is one of the two silicon wafers, and thereafter, the resistor layer 13 made of polycrystalline silicon or the like, phosphorus and boron are sequentially contained. An interlayer insulating film 18 made of silicon oxide (BPSG), an individual electrode 11 and a common electrode 12 made of aluminum, a heater protection layer 14 made of silicon nitride (SiNx), a heater protection layer 15 made of tantalum, silicon oxide containing phosphorus (PSG). The electrode protection layer 16 and the photoreceptor resin layer 5 are formed and patterned.

In the ink jet head having such a structure, the ink jet head is cut out by cutting or grinding (hereinafter referred to as grinding or dicing). That is, in FIG. 2, grinding is performed at the grinding position 8 to separate the inkjet heads. At this time, the discharge port 7 and the nozzle surface including the discharge port 7 are processed and formed by grinding. The shape and processing state of the ejection port 7 greatly affect the ink droplet ejection directionality. In addition, this processing also determines the ink flow path length, which greatly affects the ejection characteristics, particularly the ink droplet volume and ejection stability. for that reason,
Particularly, the grinding process of this portion has an important influence on the characteristics of the inkjet head.

As a method of grinding the nozzle surface described above, for example, as described in Japanese Patent Application Laid-Open No. 2-184451, the peripheral speed determined by the diameter of the grindstone (blade) and the rotational speed is kept above a certain level. Is being ground. Further, for example, in Japanese Unexamined Patent Publication No. 5-57897, before joining two substrates, grooving is performed in a portion around the nozzle opening, and then the substrates are joined and separated. Further, Japanese Patent Application No. 6-223757 proposes a process for correcting the shape of the grinding wheel (blade) and a grinding volume, and a method of supplying the grinding fluid. are doing. All of these techniques are intended to economically manufacture an inkjet head having good dimensional accuracy without causing defects in the nozzle openings or the like of the inkjet head manufactured in the same manner as in the past.

When an inkjet head is actually manufactured using a large-area substrate, the area where the chip (inkjet head) is not arranged on the substrate is an electrode and a heater arranged on the substrate due to the design man-hour and mask cost. In general, an underlying layer such as a circuit element or a protective layer is left on the entire surface. For example, in the configuration shown in FIG. 2, the heat storage layer 1 made of silicon oxide is provided at the grinding position 8 for forming the discharge port 7.
7. An interlayer insulating film 18 made of BPSG, a heater protection layer 14 made of silicon nitride, and an electrode protection layer 16 made of PSG are present. All of these layer materials are brittle materials. These result in serious defects in the grinding process or overload. As described above, since the brittle material is exposed at the grinding position 8, the state of the grinding portion of the grindstone is deteriorated, and the quality of the nozzle surface is deteriorated due to the inclusion of the grinding layer of the brittle material. In order to prevent this, measures such as low-speed feed were taken, but the processing time became long and the productivity was reduced.

Further, like the heater protection layer 15 shown in FIG. 2, a thermal ink jet head or the like uses a hard-to-grind metal material such as tantalum. When these metals are placed in the grinding position, the grinding stone is crushed,
It causes deterioration of grinding quality. Similarly, in the case of a soft metal such as aluminum or an aluminum alloy used for electrical wiring, the grindstone is clogged, which causes deterioration of grinding quality. As described above, the processed surface has a great influence on the ink ejection performance, and these are important problems in the processing of an inkjet head that requires high quality.

For example, in Japanese Unexamined Patent Publication No. 4-234666, after pattern etching the resin layer portion at the nozzle opening portion in advance, the substrates are joined, and the cutting and separation are performed. However, the brittle materials and metal materials as described above remain as they are, and a problem remains in the grinding process.

Further, as another problem, particularly in the case of a circular substrate such as a silicon wafer, the processing start shape (incident angle of the grindstone) or processing end shape (exit angle of the grindstone) on the object to be ground in the grinding process is different. Since there is a change, there is a problem that bending of the grinding position in the vicinity thereof, deviation of the grinding position due to wobbling of the grindstone, deterioration of the quality of the ejection port, and lowering of the head removal amount.

FIG. 9 is an explanatory diagram of a grinding profile and stress during wafer grinding. 31 is a grindstone. Usually, in order to ensure the quality of the nozzle, a soft and thin grindstone is selected during the grinding process. When a wafer is processed using such a grindstone, as shown in FIG. 9A, a curved grinding profile is shown when the grindstone 31 enters and exits the wafer. This is because, as shown in FIG. 9B, the grindstone 31 receives a grinding stress from the object to be ground when processing the periphery of the wafer. This grinding stress is determined by the incident angle to the object to be ground with respect to the grinding direction, the grinding depth and the grinding speed. The smaller the incident angle, the larger the side stress on the grindstone and the larger the bending of the grinding profile. Then, when the incident angle is 90 °, the lateral stress becomes equal on the left and right sides, and bending does not occur. However, on a circular wafer, there are few grinding positions where the incident angle is around 90 °,
Bending will occur in many grindings. Further, if the side stress on the grindstone becomes large, the grindstone will eventually be damaged.

FIG. 10 is an evaluation graph of the distance from the wafer end and the amount of grinding position deviation. In the graph shown in FIG. 10, the horizontal axis represents the distance from the wafer edge, and the vertical axis represents the deviation amount from the ideal grinding position, showing the details of the grinding profile. The deviation amount graphs shown in (a), (b), and (c) show the grinding position deviation amounts due to different incident angles to the object to be ground, and the respective incident angles are (a) <
The relationship is (b) <(c). Here, FIG.
The deviation amount shown in 0 vibrates with a certain period L, its amplitude sharply decreases, and converges to the ideal position. The cycle L here has a relationship of I = (1/2) · L with respect to the contact distance I in the grinding direction of the object to be ground and the side surface of the wheel determined by the diameter of the wheel and the grinding depth. . This is because the force applied to the side surface of the grindstone is equal to the right and left, that is, when the grindstone is completely inside the object to be ground, the bending stress of the whole grindstone causes a force to return to the ideal position.

When the grinding process is performed with the curved grinding profile as described above, the surface including the ejection port becomes a curved surface depending on the ink jet head formed on the wafer, and the length of the ink flow path is not constant, so that it cannot be used. For example, in FIG. 9 (A), the ink jet head indicated by X cannot be used. Therefore, the take-off height of the inkjet head has been reduced. Further, other inkjet heads are also affected by the curved grinding profile, so that the quality and accuracy are deteriorated.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and provides an inexpensive, high-quality, high-accuracy inkjet head that significantly reduces the processing load of the inkjet head, particularly the grinding step. An object of the present invention is to provide a method for manufacturing an inkjet head that can be manufactured, and an inkjet head having a structure manufactured by such a manufacturing method.

[0014]

According to a first aspect of the present invention, in an ink jet head for recording by ejecting ink from a nozzle, a brittle material and a metal layer are formed on an end face where the nozzle is arranged. Is not exposed.

In the invention described in claim 2,
In a method of manufacturing an inkjet head in which a large number of inkjet heads are manufactured by using one or a set of substrates, and individual inkjet heads are obtained by cutting or grinding, in the step of laminating a protective layer, a heater layer, an electrode layer, etc. It is characterized in that a layer made of a brittle material and a metal layer are laminated except for at least the cutting or grinding portion of the substrate near the ejection port for ejecting ink droplets and the extension thereof.

Further, in the third aspect of the invention, in a method for producing an ink jet in which a large number of ink jet heads are produced using a substantially circular substrate and individual ink jet heads are obtained by cutting or grinding, ink droplets are formed. The substrate on the side of incidence on the substrate at least at the time of the discharge port cutting in a direction orthogonal to the direction of the discharge port cutting before the process of the discharge port cutting for performing the cutting or grinding at the discharge port position for jetting. It is characterized in that a pre-processing for removing a part of the above is performed in advance.

[0017]

According to the first aspect of the invention, since the brittle material and the metal layer are not exposed at least on the end face where the nozzle for ejecting the ink droplet is arranged, the position of the nozzle is defined and the nozzle is formed. In the cutting or grinding process, the quality of the ground surface does not deteriorate, and an inkjet head having a high quality nozzle end surface can be obtained.

According to the second aspect of the present invention, in the step of laminating the protective layer, the heater layer, the electrode layer, etc., the layer made of the brittle material and the metal layer eject at least ink droplets on the substrate. Except from the above-mentioned cutting or grinding portion and its extension line in the vicinity where This reduces the grinding surface due to the inclusion of the grinding pieces of brittle material,
Stable and high-quality ground surface (discharging port and discharging port surface) without clogging or crushing of the grindstone due to grinding of the metal layer
Can be obtained.

According to the third aspect of the present invention, when manufacturing a large number of ink jet heads using a substantially circular substrate, a step of cutting the discharge or performing the cutting or grinding at the position of the discharge opening for ejecting ink droplets. Before that, pre-processing is performed in a direction orthogonal to the direction of the discharge port cutting, in which at least a part of the substrate that is incident on the substrate during the discharge port cutting is removed in advance. As a result, even in the edge region of the substantially circular substrate, it is possible to obtain a highly accurate and high-quality grinding surface (ejection port and ejection port surface) and increase the take-off height of the inkjet head.

[0020]

EXAMPLE FIG. 3 is a process drawing showing an example of a method for manufacturing an ink jet head of the present invention. In the figure, 1 is a heater wafer, 2 is a channel wafer, 3a and 3b are alignment marks, 4,4a and 4b are head chips, 5 is a photosensitive resin layer, 6 is an adhesive, 8a, 8b and 8c are grinding positions,
9 is a cleaning liquid.

In the process of FIG. 3A, the heater wafer 1 is manufactured. The heater wafer 1 is composed of a silicon wafer, and heaters, individual electrodes, common electrodes, protective layers and the like (not shown) are formed on the silicon wafer by the LSI process by the number of head chips 4a on the heater wafer side.
Further, in the step of FIG. 3 (B), after spin-coating a photosensitive polyimide resin, the photosensitive resin layer 5 is formed by exposing and developing to a desired pattern and baking (Cure).
The heater wafer 1 is completed. Examples of the photosensitive polyimide resin include Prob manufactured by Ciba-Geigy.
imide (registered trademark), Pyr manufactured by Du-Pont
alin PI2722, etc. can be used. The alignment mark 3a is also formed on the heater wafer 1 during the above process.

In the process of FIG. 3C, the channel wafer 2
Is prepared. The channel wafer 2 is also made of a silicon wafer, and ink channels, ink reservoirs, etc. corresponding to the heaters on the heater wafer 1 are formed by anisotropic etching. Further, the alignment mark 3b is also formed. As a result, the channel wafer 2 is completed.

After that, in the step of FIG. 3D, the adhesive 6 which is spin-coated on a PET film, for example, is thinly and uniformly applied to the adhesive side of the channel wafer 2 by transfer.

Next, in the step of FIG.
A heater wafer 1 manufactured in steps (A) and (B);
The channel wafer 2 manufactured in the steps of FIGS. 3C and 3D is aligned and bonded. The alignment is performed using the alignment marks 3a and 3b that are patterned in advance on the bonding surface side of each wafer, and is achieved with high accuracy by the alignment device while observing using an infrared microscope, for example. The two wafers are aligned and bonded, and then baked.

The process of FIG. 3F is a process of cutting and cutting and separating each head chip 4. In order to define the discharge port surface of the two wafers bonded in FIG. 3E and to regulate the flow path length, the dicing step of grinding at the grinding position 8b and the grinding at the grinding position 8c, each head chip In order to expose the bonding pad (not shown) provided on the heater wafer 1 in the cutting step of cutting and separating into
It consists of a grinding process for grinding. Here, the cutting is performed so as to form the groove in the dicing process, but the cutting may be performed so as to also serve as the cutting process.
By this step, the individual head chips 4 are cut and separated.

The process of FIG. 3G is a process of cleaning each head chip 4 cut and separated in the process of FIG. If chips, dust, etc. generated by the cutting shown in FIG. 3F remain in the head chip 4, defective ejection of ink or the like will occur and the image quality will deteriorate. Therefore, in this step, the chips and dust are washed away, and the head chip 4 is brought into a clean state.

The ink jet head manufactured by the steps shown in FIGS. 3A to 3G is die-bonded on the fixed substrate and electrically connected to complete the ink jet head.

FIG. 1 is a partial sectional view showing an embodiment of the ink jet head of the present invention. In the figure, the same parts as those in FIG. 2 are designated by the same reference numerals. FIG. 1 shows the layer structure of the head portion of the heater wafer 1. Silicon oxide (SiOx) is formed and patterned as the heat storage layer 17 on the heater wafer 1 made of silicon, and then the resistor layer 13, the interlayer insulating film 18, the individual electrodes 11 and the common electrode 12, and the heater protection are sequentially performed. The layers 14 and 15 and the electrode protection layer 16 are formed and patterned. Resistor layer 13
For this, polycrystalline silicon or the like is used. As the interlayer insulating film 18, silicon oxide containing phosphorus and boron (BP) is used.
SG) or the like is used. Individual electrode 11 and common electrode 1
Aluminum or the like is used as 2. Heater protection layer 14
For this, silicon nitride (SiNx) or the like is used.
As the heater protection layer 15, tantalum or the like is used.
As the electrode protection layer 16, silicon oxide containing phosphorus (PS
G) or the like is used. These heat storage layer 17 and resistor layer 1
3, interlayer insulating film 18, individual electrode 11 and common electrode 12,
The heater protection layers 14 and 15 and the electrode protection layer 16 are the discharge ports 7
Is not formed in the portion of the grinding position 8 for forming. Finally, the photoreceptor resin layer 5 is formed and patterned to manufacture the heater substrate 1.

As described above, in the structure of the above-described embodiment, brittle materials (SiOx, SiNx, BPSG, PS) such as glass, silicon oxide, and nitride are formed at the grinding position 8.
G) and metallic materials (Al, Ta, etc.) do not exist. Thereby, good ground surface quality can be obtained.

4 to 6 are explanatory views of an example of the wafer layout. In the figure, reference numeral 21 is a brittle material / metal material removal region. As shown in FIG. 1, when the brittle material or the metallic material is not formed in the portion of the grinding position 8 for forming the discharge port 7, for example, as shown in FIG.
It is conceivable that only the front surface of the is used as the brittle material / metal material removal region 21. Even with such a configuration, the surface including the discharge port 7 can be satisfactorily ground. However, in a usual grinding process, a circular grindstone is rotated at a high speed while the grindstone and an object to be ground are relatively moved, and by its nature, a region of a wafer where an inkjet head does not exist is ground. Therefore, when the state of the grinding portion of the grindstone deteriorates in the portion where the inkjet head does not exist, and the quality of the surface including the ejection port 7 is deteriorated by performing the grinding of the inkjet head portion while the grinding layer of the brittle material is caught. There is.

Therefore, as shown in FIG. 5, when grinding the surface including the discharge port of the wafer, the entire grinding area is designed to be the brittle material / metal material layer removal area 21. As a result, the head having a high quality nozzle surface can be processed in a short time without the above-mentioned problems.

Further, as shown in FIG. 6, in a grinding region that is substantially orthogonal to the grinding of the discharge port portion, a brittle material and metal material layer removal region 21 is provided to prolong the life of the grindstone and the ink jet head. Further higher reliability can be achieved. Furthermore, a pattern may be used in which all the regions on the wafer where the inkjet head is not arranged are the removal regions 21 of the brittle material and metal material layers. These removal patterns are added to the patterning mask of each layer, and the number of masks does not increase.

Next, cutting and separation of the ink jet head will be described. FIG. 7 is an explanatory diagram of an example of wafer pre-processing in the inkjet head of the present invention. Figure 7
FIG. 3A shows a state in which the heater wafer 1 and the channel wafer 2 are bonded in the step shown in FIG. After joining the two wafers in this way, the inkjet heads are cut and separated in the grinding step shown in FIG. 3F, but before that, a wafer pre-step is performed. In the pre-process, as shown in FIG. 7B, only the channel wafer 2 part of the part shown in FIG. 7A is separated by a grinding process. The heater wafer 1 may be separated in the same manner. Since the grinding step here hits the side surface of the inkjet head and does not require grinding quality, it can be performed at high speed using a hard grindstone (such as an electroformed blade) by rough alignment, so The processing time is several tens of seconds, which is hardly a factor to increase the cost.

FIG. 8 is an explanatory view of another example of wafer pre-processing in the ink jet head of the present invention. In this example, as shown in FIG. 8 (A), after the heater wafer 1 is completed, both sides of the wafer are separated by the grinding method described in FIG. Further, the channel wafer 2 is shown in FIG. 8B by forming a groove at a desired position along the outer shape in the anisotropic etching process performed when forming the flow path and then dividing the groove by applying force. It was processed into a shape like. FIG.
The heater wafer 1 shown in (A) and the channel wafer 2 shown in FIG. 8 (B) are bonded together as shown in FIG. 8 (C). Then, a grinding process is performed. By performing such pre-processing, as shown in FIG. 8D, when grinding the surface including the discharge port, the grinding profile accuracy is improved over the entire wafer, and a surface including the discharge port with high quality is obtained. I was able to. The bending range at the edge of the wafer was about 15 μm, but in this example it is 3 μm.
It was improved to about m. As a result, an area where an ink jet head cannot be conventionally obtained, for example, in FIG.
Even in the area indicated by the mark, a good inkjet head can be obtained, the take-off height of the inkjet head is increased, and an inexpensive inkjet head can be supplied. In addition, it is possible to use a soft and thin grindstone, which enables higher quality grinding.

The effect of the above-described pre-process is further increased as the diameter of the wafer is increased because of the incident angle. Also, in the above example, the pre-processing is grinding, etching,
Although the method is performed by physical stress, various methods such as layout processing can be applied as another method, and the method is not limited to the above-described preprocessing method.

[0036]

As is clear from the above description, according to the present invention, it is possible to stably manufacture an inexpensive inkjet head with high precision, high quality. In addition, an inexpensive inkjet head manufactured with high precision by such a manufacturing method has uniform ink dots ejected from the ejection ports, so that high quality images can be obtained by recording using such an inkjet head. There is an effect that a recorded image can be obtained.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing an embodiment of an inkjet head of the present invention.

FIG. 2 is a partial cross-sectional view of a conventional inkjet head.

FIG. 3 is a process drawing showing an example of a method for manufacturing an inkjet head of the present invention.

FIG. 4 is an explanatory diagram of an example of a wafer layout according to the present invention.

FIG. 5 is an explanatory diagram of another example of a wafer layout according to the present invention.

FIG. 6 is an explanatory diagram of still another example of the wafer layout according to the present invention.

FIG. 7 is an explanatory diagram of an example of wafer pre-processing in the inkjet head of the present invention.

FIG. 8 is an explanatory diagram of another example of wafer preprocessing in the inkjet head of the present invention.

FIG. 9 is an explanatory diagram of a grinding profile and stress during grinding of a wafer.

FIG. 10 is an evaluation graph of a distance from a wafer edge and a grinding position shift amount.

[Explanation of symbols]

1 ... Heater wafer, 2 ... Channel wafer, 3a, 3b ...
Alignment marks, 4, 4a, 4b ... Head chip,
5 ... Photosensitive resin layer, 6 ... Adhesive agent, 7 ... Discharge port, 8, 8
a, 8b, 8c ... Grinding position, 9 ... Cleaning liquid, 11 ... Individual electrode, 12 ... Common electrode, 13 ... Resistor layer, 14, 15 ... Heater protective layer, 16 ... Electrode protective layer, 17 ... Heat storage layer, 18 ...
Interlayer insulating film, 19 ... Ink flow path.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Masa Suzuki, 2274 Hongo, Ebina, Kanagawa Prefecture, Fuji Xerox Co., Ltd. (72) Inventor Naoshi Kotake, 2274, Hongo, Ebina, Kanagawa Prefecture, Fuji Xerox Co., Ltd.

Claims (3)

[Claims] 1. An inkjet head for performing recording by ejecting ink from a nozzle, wherein an brittle material and a metal layer are not exposed on an end face where the nozzle is arranged. 2. A method for manufacturing an inkjet head, in which a large number of inkjet heads are manufactured by using one or a set of substrates, and individual inkjet heads are obtained by cutting or grinding, a protective layer, a heater layer, an electrode layer, etc. In the step of laminating, an inkjet head characterized in that a layer made of a brittle material and a metal layer are laminated by excluding from at least the cutting or grinding portion near an ejection port for ejecting ink droplets of the substrate and its extension line. Of manufacturing. 3. A method for manufacturing an inkjet method, in which a large number of inkjet heads are manufactured by using a substantially circular substrate, and individual inkjet heads are obtained by cutting or grinding, wherein the cutting or grinding is performed at a discharge port position for ejecting ink droplets. Before the process of cutting the discharge port
A method of manufacturing an ink jet head, characterized in that pre-processing is performed in advance in a direction orthogonal to the direction of discharge port cutting, in which at least a part of the substrate that is incident on the substrate during the discharge port cutting is removed in advance. .