JPH04320848A - Substrate for ink jet recording head, ink jet recording head, ink jet recording device, and manufacture of substrate for ink jet recording head and ink jet recording head - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a substrate for an inkjet recording head, an inkjet recording head, an inkjet recording apparatus, a substrate for an inkjet recording head, and a method for manufacturing the inkjet recording head.

0002

[Description of Background Art] Conventionally, the configuration of a recording head is to form an electrothermal transducer array on a single crystal silicon substrate, and as a drive circuit for the electrothermal transducer, an electrothermal transducer such as a transistor array is provided outside the silicon substrate to drive the electrothermal transducer. The electrothermal conversion elements and the transistor array were connected using flexible cables, wired bonding, etc.

[0003] For the purpose of simplifying the structure considered for the above-mentioned recording head configuration, reducing defects occurring in the manufacturing process, and furthermore making the characteristics of each element uniform and improving reproducibility, An ink jet recording apparatus having a recording head in which an electrothermal conversion element and a functional element are provided on the same substrate, as proposed in Japanese Patent No. 57-72867, is known.

FIG. 20 is a sectional view showing an example of the base of the recording head having the above-described structure.

[0005] Reference numeral 901 is a semiconductor substrate made of single crystal silicon. 902 is a collector region of an N-type semiconductor, 903
904 is an ohmic contact region of N-type semiconductor with high impurity concentration, 904 is a base region of P-type semiconductor, and 905 is an emitter region of N-type semiconductor with high impurity concentration, which form a bipolar transistor 920. 906 is an interlayer film made of a silicon oxide layer as a heat storage layer and an interlayer insulating layer, 907 is a heating resistor layer, 908 is an aluminum (Al) electrode, and 909 is a protective layer made of a silicon oxide layer. A base body 930 is formed. Here, 910 is a heat generating part. A top plate and a liquid path are formed on this base 930 to constitute a recording head.

By the way, although the above-mentioned structure is excellent, in order to satisfy the high-speed drive, energy saving, high integration, low cost, and high reliability that are strongly required for recording devices in recent years, There is still room for improvement.

First of all, in order to achieve commercial success, a highly reliable recording head must be provided at a low cost. To achieve this, it was necessary to make improvements to the exposed end of the resistor, which determines the lifespan of conventional recording heads.

In other words, in the conventional recording head, when the wiring material of the electrode 908 made of Al or the like was removed by wet processing, the Al was removed isotropically, and the heating part had a shape as shown in FIG. . FIG. 21 is an enlarged view of the heat generating section 910. Furthermore, if the Al electrode 908 is removed by dry etching such as RIE, the Al side surface will further stand vertically. In this case, when the heat generating section 910 is driven, a driving current flows as shown at 801A and 801B in FIG. 20 by applying a voltage. This drive current 801A, 801
The current density of B reaches 8.2×10 7 A/cm 2 at the exposed end A or B of the heating resistor layer shown in FIG. This value indicates that the current density in the Al electrode 908 is 1.7×
106 A/cm2, central part C of heating resistor layer 907
This is an abnormally large value compared to the current density of 1.03 x 107 A/cm2. Exposed end A of heating resistor layer
Alternatively, it has been found that the concentration of current density at B cuts a part of the heating resistor layer 907, which determines the life of the recording head.

[0009] Therefore, the inventor of the present invention developed a heating resistor layer 907.
It was believed that alleviating the concentration of current density at the exposed end of the recording head would extend the life of the recording head and produce uniformity of the recording head.

[0010] Also, the end portion 940 of the conventional Al electrode 908
Because the film stands nearly vertically, the interlayer film 906 and the protective film 909 need to have a thickness of about 1.25 μm and 1.0 μm, respectively, in order to improve step coverage.

[0011]

SUMMARY OF THE INVENTION The conventional recording head described above has the following problems.

In other words, the interlayer film 90 is as thick as 1.25 μm.
6 significantly deteriorates the throughput of the device, which has become a bottleneck in reducing costs.

In addition, the protective film 909 as thick as 1.0 μm exists as a thermal resistance when the heat generated in the heat generating part 910 is transferred to the ink, and it is necessary to increase the driving power of the resistor, and due to the delay in thermal conduction. This caused the frequency characteristics to deteriorate.

In other words, due to the presence of this thick protective film 909, improvements in performance and reduction in power consumption of recording heads have been delayed in the past.

The present invention has been made in view of the problems of the above-mentioned conventional techniques, and by maintaining step coverage between the upper and lower layers and reducing the film thickness, it is possible to reduce costs and improve reliability. The present invention aims to provide a substrate for an inkjet recording head, an inkjet recording head, an inkjet recording device, and a method for manufacturing the substrate for an inkjet recording head and an inkjet recording head, which are capable of performing the following steps.

[0016]

[Means for Solving the Problems] The present invention provides a group of electrothermal conversion elements for generating thermal energy, and a group of electrothermal conversion elements electrically connected to each of the electrothermal conversion elements of the group of electrothermal conversion elements.
In an inkjet recording head substrate in which a functional element group for driving an electrothermal transducer element and a wiring electrode for connecting each of the electrothermal transducer element group and the functional element group are provided on the same substrate, the wiring The connection end surface of the electrode is formed in a stepped shape, and the side surface of the wiring electrode may be formed in a stepped shape.

The present invention also provides an ink ejecting section having a plurality of ejection ports for ejecting ink, and an electric power source that generates thermal energy used to eject ink from each ejection port of the ink ejecting section. a thermal conversion element group, a functional element group for driving an electrothermal conversion element electrically connected to each electrothermal conversion element of the electrothermal conversion element group, and a combination of the electrothermal conversion element group and the functional element group. In an inkjet recording head comprising a base body provided with wiring electrodes for connecting the respective wiring electrodes, the connection end surface of the wiring electrodes of the base body is formed in a stepped shape, and the side surface of the wiring electrodes of the base body may be formed in a step-like manner.

Furthermore, the present invention has an ink ejection section having a plurality of ejection ports for ejecting ink, and generates thermal energy used for ejecting ink from each ejection port of the ink ejection section. an electrothermal transducer group, a functional element group for driving an electrothermal transducer electrically connected to each electrothermal transducer of the electrothermal transducer group, the electrothermal transducer group and the functional element group. an inkjet recording head comprising a base provided with wiring electrodes for connecting the two, and a recording member to be recorded with ink ejected from the ejection ports to the ink ejection portion of the inkjet recording head. In the inkjet recording apparatus, the connection end surface of the wiring electrode of the inkjet recording head is formed in a stepped shape, and the side surface of the wiring electrode of the inkjet recording head is formed in a stepped shape. In some cases, the inkjet recording head is a full-line type in which a plurality of ejection ports are formed over the entire width of the largest recording member.

The present invention also provides an electrothermal transducer group, a functional element group for driving an electrothermal transducer, which drives each of the electrothermal transducers of the electrothermal transducer group, and the function of the electrothermal transducer by photolithography. In a method for manufacturing an inkjet recording head substrate, in which a wiring electrode group for connecting each functional element of an element group and the electrothermal conversion element is formed on a substrate, a connecting end surface of each wiring electrode of the wiring electrode group. This method has a wiring electrode group etching step in which the mask photoresist is etched multiple times while etching backward to form a step-like pattern. In the case where the side surface is etched multiple times together with the end surface to form a stepped shape, the end surface etching step is performed by alternately dipping the etching solution for wiring electrodes and a tri-methyl ammonium hydroxide aqueous solution for etching photoresist for masks. In some cases, the material layer of each wiring electrode is etched, and in other cases, the material of the wiring electrode is aluminum.

Furthermore, the present invention provides an electrothermal transducer group, a functional element group for driving the electrothermal transducer that drives each of the electrothermal transducer elements of the electrothermal transducer group, and the functional element group by photolithography. a base creation step of creating a base by forming wiring electrode groups on the substrate to connect each of the functional elements and the electrothermal transducer; and an ejection section having a plurality of ejection ports for ejecting ink. and an ink jet recording head manufacturing step of creating an ink discharge portion on the substrate, wherein the substrate creation step includes etching a photoresist for a mask to retreat the connection end surface of each wiring electrode of the wiring electrode group. In the wiring electrode group etching process, the side surfaces of each wiring electrode of the wiring electrode group are etched multiple times to form a staircase shape. In the case where the wiring electrode group etching process is performed, the material layer of each wiring electrode is alternately immersed in an etching solution for wiring electrodes and an aqueous trimethyl ammonium hydroxide solution for etching photoresist for masks. In some cases, the wiring material is aluminum.

[0021]

[Function] The inkjet recording head substrate of the present invention has
Since the connection end surface of the wiring electrode for connecting the functional element and the electrothermal conversion element is formed in a stepped shape, the concentration of current density at the connection end is alleviated, and it is also used to protect the electrothermal conversion element. The step coverage of the protective film formed as an upper layer is improved, and the protective film can be made thinner.

The inkjet recording head of the present invention uses the above-described inkjet recording head substrate, and it is possible to reduce the thickness of the protective film that is interposed as a thermal resistance when the heat generated by the electrothermal transducer is transmitted to the ink. Therefore, the driving power of the electrothermal conversion element can be reduced and the frequency characteristics can be improved.

Since the inkjet recording apparatus of the present invention uses the above-described inkjet recording head, it is possible to increase the speed of recording and reduce power consumption.

The substrate for an inkjet recording head and the method for manufacturing an inkjet recording head of the present invention include etching the connecting end surface of each wiring electrode of the wiring electrode group multiple times while etching the photoresist for the mask back. As described above, this makes it possible to alleviate the concentration of current density at the connection end and to make the protective film thinner, as well as to reduce driving power and improve frequency characteristics.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings, but the present invention is not limited to the following embodiments, and any embodiments may be used as long as the objects of the present invention can be achieved.

FIG. 1 shows a base body 100 for an inkjet recording head formed on a recording head substrate according to the present invention.
FIG.

The base body 100 of this embodiment has an NPN structure including P type base regions 5, 8, N type collector buried region 7, and N type emitter regions 10, 11, similar to the conventional one described above.
A P-type silicon substrate 1 having a functional element consisting of a transistor is connected to a collector/base common electrode 12 which is a wiring electrode.
It is covered with a heat storage layer 101 made of an oxide film or the like on which an emitter electrode 13 and an isolation electrode 14 are formed, and an interlayer film 102 made of a silicon oxide film or the like is formed on top of the heat storage layer 101 by a PCVD method or a sputtering method. be.

Each of the electrodes 12, 13, 14 is made of aluminum or the like, and as shown in FIGS. 2(a) and 2(b),
The end face and the side wall, that is, the entire side face is formed in a stepped shape (14 is not shown). Since Al forming each electrode 12, 13, 14 has a step on the side surface, the interlayer film 102
The step coverage is very excellent, and the interlayer film 102 can be formed thinner than before without losing the heat storage effect. In addition, the interlayer film 102 is partially opened to electrically connect the collector/base common electrode 12, the emitter electrode 13, and the isolation electrode 14, and to form electrical wiring on the interlayer film 102. A wiring 104, which is a wiring electrode, is installed, such as Al. That is, after partially opening the interlayer film 102, a heat generating resistive layer 103 made of HfB2 or the like is formed by sputtering, and A is formed by vapor deposition or sputtering.
A heat generating section 110, which is an electrothermal transducing element, is provided with wiring 104 such as L.

An enlarged view of the heat generating section 110 is shown in FIG.
Shown in (b).

[0030] The wiring 104 constituting the heat generating portion 110 also has an end face and a longitudinal side wall formed in a step-like shape, similar to the electrodes.

Materials constituting the heating resistance layer 103 include Ta, ZrB2, Ti-W, Ni-Cr, and Ta-Al.
, Ta-Si, Ta-Mo, Ta-W, Ta-Cu, T
a-Ni, Ta-Ni-Al, Ta-Mo-Al, Ta
-Mo-Ni, Ta-W-Ni, Ta-Si-Al, T
Examples include a-W-Al-Ni.

Furthermore, as shown in FIG.
A protective film 105 made of iO2, SiN, SiON, etc., and a protective film 106 made of Ta, etc. are provided.

Here, as mentioned above, since the end face and side wall of the wiring 104 are formed on a staircase, the coverage of the protective film 105 is extremely good, and compared to the conventional one.
The film thickness of 0,000 Å can be reduced to 6,000 Å,
Heat generated in the heat generating section 110 can be efficiently and rapidly transferred. Furthermore, the throughput of the protective film deposition apparatus could be approximately doubled. Furthermore, as shown in FIG.
It was possible to reduce A/cm2 to 3.2×107 A/cm2, and it also became possible to improve durability.

Next, the basic operation of the functional element having the above-described configuration will be explained with reference to FIG.

FIG. 5 is a schematic diagram for explaining a method of driving the heat generating portion 110 of the base body 100 shown in FIG.

In this embodiment, as shown in FIGS. 1 and 5, the collector/base common electrode 12 corresponds to the anode electrode of the diode, and the emitter electrode 13 corresponds to the cathode electrode of the diode. That is, by applying a positive potential bias (VH1) to the collector-base common electrode 12, the NPN transistors in the cells (SH1, SH2) are turned on, and the bias current flows out from the emitter electrode 13 as a collector current and a base current. do. Also, as a result of shorting the base and collector,
Electrothermal conversion elements (RH1, RH
2) The heat rise and fall characteristics were good, and the occurrence of the film boiling phenomenon and the accompanying growth and contraction of bubbles were well controlled, and stable ink could be ejected. This is because in inkjet recording heads that use thermal energy, the characteristics of transistors are closely related to the characteristics of film boiling, and because the accumulation of minority carriers in transistors is small, switching characteristics are faster and rise characteristics are better than expected. It is thought that this is having an influence. Furthermore, it has relatively few parasitic effects, has no variation between elements, and can obtain a stable drive current.

In this embodiment, furthermore, by grounding the isolation electrode 14, it is possible to prevent charges from flowing into other adjacent cells, thereby preventing the problem of malfunction of other elements. It becomes.

In such a semiconductor device, the concentration of the N-type collector buried region 2 should be 1×10 18 cm −3 or more, and the concentration of the P-type base region 5 should be 5×10 14 to 5×10 14 .
5×10 17 cm −3 and furthermore, it is desirable to make the area of the bonding surface between the high concentration base region 8 and the collector/base common electrode 12 as small as possible. In this way, it is possible to prevent leakage current from flowing from the NPN transistor to the ground via the P-type silicon substrate 1 and the isolation region.

The method for driving the heat generating section 110 will be described in more detail.

FIG. 5 shows two semiconductor functional elements (cells).
Although only SH1 and SH2 are shown, in reality, the same number of such functional elements are arranged at equal intervals corresponding to, for example, 128 electrothermal conversion elements corresponding to the heat generating part 110, Electrically matrix-connected to enable block drive. Here, to simplify the explanation, driving of the electrothermal transducers RH1 and RH2 as two segments in the same group will be explained.

In order to drive the electrothermal transducer RH1, a group is first selected using the switching signal G1, and the electrothermal transducer RH1 is selected using the switching signal S1. Then, the functional element cell SH1 having a transistor configuration is positively biased, a current is supplied, and the electrothermal conversion element RH1 generates heat. This thermal energy causes a state change in the liquid, generates bubbles, and discharges the liquid from the discharge port. Similarly, when driving the electrothermal transducer RH2, the electrothermal transducer RH2 is selected by the switching signal G1 and the switching signal S2, and the functional element cell SH2 is driven to supply current to the electrothermal transducer RH2.

At this time, the P-type silicon substrate 1 is placed through the isolation regions 3, 6, and 9. By providing isolation regions 3, 6, and 9 for each semiconductor functional element (cell) in this manner, malfunctions due to electrical interference between the semiconductor functional elements are prevented.

The base body 100 configured in this manner has a liquid path 505 communicating with a plurality of discharge ports 500, as shown in FIG.
Liquid path wall member 5 made of photosensitive resin etc. for forming
01 and a top plate 502 having an ink supply port 503 are attached to form a recording head 600. In this recording head 600, recording liquid injected from an ink supply port 503 is stored in an internal common liquid chamber 504 and supplied to each liquid path 505, and in this state, by driving a heat generating section 110, the ejection port 500 The recording liquid is ejected from.

Next, the manufacturing process of the recording head 600 according to this embodiment will be explained with reference to FIGS. 7 to 15.

(1) P-type silicon substrate 1 (impurity concentration 1
x 1012 to 1 x 1016 cm-3) surface, 8
After forming a silicon oxide film with a thickness of about 0.000 Å, the silicon oxide film in the portion where the N-type collector buried region 2 of each cell was to be formed was removed by a photolithography process. After forming a silicon oxide film, N-type impurities (for example, P
, As, etc.) and thermal diffusion to form an N-type collector buried region 2 with an impurity concentration of 1 x 1018 cm-3 or more.
was formed to have a thickness of about 2 to 6 μm, and the sheet resistance was as low as 30Ω/hole or less.

Next, after removing the oxide film in the area where the P-type isolation buried region 3 is to be formed and forming an oxide film of about 1000 nm, a P-type impurity (for example,
B, etc.) is ion-implanted, and the impurity concentration is reduced to 1× by thermal diffusion.
A P-type isolation buried region 3 having a thickness of 1015 to 1×1017 cm−3 or more was formed (see FIG. 7).

(2) After removing the silicon oxide film on the entire surface, N-type epitaxial region 4 (impurity concentration 1×101
3 to 1×10 15 cm −3 ) to a thickness of 5 to 20 μm (see FIG. 8).

(3) Form a silicon oxide film of about 1000 nm on the surface of the N-type epitaxial region 4, apply a resist, pattern it, and ionize P-type impurities only in the portion where the low concentration P-type base region 5 will be formed. Injected. After removing the resist, a low concentration P-type base region 5 is formed by thermal diffusion.
(impurity concentration of about 1×10 14 to 1×10 17 cm −3 ) was formed to a thickness of about 5 to 10 μm. After that, the oxide film is removed from the entire surface again, and a silicon oxide film with a thickness of about 8000 Å is formed.The oxide film is then removed from the part where the P-type isolation region 6 is to be formed, and a BSG film is deposited on the entire surface using the CVD method. Furthermore, by thermal diffusion, a P-type isolation region 6 (with an impurity concentration of 1×1018 to 1×1020 cm) is formed so as to reach the P-type isolation buried region 3.
-3) to a thickness of about 10 μm (see FIG. 9). At this time, it is also possible to form the P-type isolation region 6 using BBr3 as a diffusion source.

(4) After removing the BSG film and forming a silicon oxide film with a thickness of about 8000 Å, only the portion where the N-type collector region 7 is to be formed is removed, and then N-type solid phase diffusion and phosphorus ions are implanted. Or by thermal diffusion, N
It reaches the mold collector embedding area 2 and has a sheet resistance of 10Ω.
N-type collector region 7 with a thickness of 10 μm (impurity concentration 1×1018 to 1×1020c) has a low resistance of less than /
m-3) was formed.

Subsequently, a silicon oxide film with a thickness of about 12,500 Å was formed to form a heat storage layer 101. Thereafter, the oxide film in the cell region was selectively removed to form a silicon oxide film with a thickness of about 2000 Å.

Next, resist patterning was performed, and P-type impurities were implanted only into the portions where the high-concentration base region 8 and the high-concentration P-type isolation region 9 were to be formed. After removing the resist, the oxide film in the area where the N-type emitter region 10 and the high concentration N-type collector region 11 are to be formed is removed, a thermal oxide film is formed on the entire surface, N-type impurities are implanted, and thermal diffusion is performed. An N-type emitter region 10 and a highly doped N-type collector region 11 were simultaneously formed. Note that the thickness of the N-type emitter region 10 and the high concentration N-type collector region 11 is 1.0 μm or less, and the impurity concentration is 1×10 18 to 1×
It was set to about 1020 cm-3 (see Fig. 10 above).

(5) Furthermore, after removing the silicon oxide film at the connection points of some electrodes, Al or the like was deposited on the entire surface as a material layer for wiring electrodes, and the Al or the like was removed from areas other than some electrode areas (see the figure below). 11). At this time, unnecessary parts are removed by etching so that the edge part of the aluminum electrode is not vertical but stepped. However, in normal wet etching, the shape of the edge part of the aluminum electrode is not the same as that referred to in the conventional technique mentioned above. As shown in Figure 21, it is almost vertical, so A
I decided to etch the resist at the same time as I.

A method for removing Al will now be described with reference to FIG. 16.

A positive resist (
Apply photoresist) 121 to a thickness of 1.2 μm,
Perform patterning for electrode formation (FIG. 16(a))
). Next, wet etching of the Al portion is performed. The Al etching solution used at this time is phosphoric acid (H3
PO4), nitric acid (HNO3) and acetic acid (CH3
COOH) mixtures are well known. The etching solution temperature was 30°C to 50°C. Further, the etching of the Al part is performed to be about half of the total Al film thickness. At this time, the etching rate of the Al part was about 3000 Å/min, and the etching time was calculated from the value obtained by dividing about half the Al film thickness by the above etching rate ((b) in FIG. 16).
.

Next, in order to set back the positive resist 121, it is immersed in an aqueous solution of TMAH (trimethylammonium hydroxide). At this time, the concentration of the TMAH aqueous solution is 2% to 3%, and the liquid temperature is 30°C to 40°C. At this time, the amount of retreat can be adjusted to 0.5 by changing the liquid temperature.
It was controllable in the range of ~1.0 μm/min ((c) in FIG. 16).

Next, the remaining Al portion is etched. The etching solution used at this time is the same as described above. Further, the end point of etching is determined by a change in reflectance on the wafer surface ((d) in FIG. 16).

Next, the positive resist 121 is removed using an organic amine stripping solution (FIG. 16(e)).

As described above, by repeating etching → resist retreat → etching, the end face and side wall of the Al electrode, that is, the entire side face can be formed into a stepped shape as shown in FIG. 16(e). Ta.

(6) Next, by sputtering, Si is formed to become the interlayer film 102 having the function of the heat storage layer 101.
An O2 film was formed to a thickness of about 0.6 to 1.0 μm over the entire surface. S
The iO2 film may be formed by CVD. Also,
It is not limited to the SiO2 film, but may be an SiO film or a SiON film.

Next, in order to make an electrical connection, a part of the interlayer film 102 above the emitter region 10 and the base/collector regions 8 and 11 is opened by photolithography to form a through hole (TH). (Figure 12 above).

(7) Next, H as the heating resistance layer 103
About 1000 fB2 was deposited through TH on the interlayer film 102 and on the emitter electrode 13 and collector/base common electrode 12 above the emitter region 10 and base/collector regions 8, 11 for electrical connection.

(8) A pair of wires 104, 104 of the heat generating part 110 and the cathode electrode wire 10 of the diode are placed thereon.
4. Deposit a material layer of approximately 5000 Å of Al material to form the anode electrode wiring 109, and deposit Al and H
fB2 was patterned to simultaneously form the heat generating portion 110 and wiring 104 for other connections. The patterning of Al is the same as the method (5) above (see Fig. 13).
).

(9) By sputtering or CVD, the protective film 105 of SiO2 film, which serves as the protective layer of the heat generating part 110 and the insulating layer between the Al wiring 104, is deposited with a thickness of about 60%.
After about 00 Å of Ta is deposited, about 20 Å of Ta is deposited on the upper part of the heat generating part 110 as a protective film 106 for anti-cavitation.
A thickness of about 0.00 Å was deposited. Further, the heat generating part 110, Ta, and the protective film 105 thus created were partially removed to form a bonding pad 107. Note that the protective film 105 is made of SiO2, but unexpectedly SiON or S.
iN may also be used (see FIG. 14 above).

(10) A liquid path wall member 501 and a top plate 502 for forming a discharge port 500 are arranged on the base body 100 having a semiconductor functional element formed as described above, and a liquid passage wall member 501 and a top plate 502 are provided inside them. A recording head 600 in which a liquid path 505 and a common liquid chamber 504 were formed was manufactured (see FIG. 15 above).

[0065] Regarding the recording head 600 manufactured in this way, recording and operation tests were performed by block driving the heat generating section 110. In the operation test, eight semiconductor diodes were connected to one segment, and each semiconductor diode had a
Although a current of mA (2.4 A in total) was passed, the other semiconductor diodes did not malfunction and good ejection could be performed. Furthermore, since the container recording head has good heat transfer efficiency, it requires only 80% of the driving power of conventional recording heads, and has excellent high frequency response. Furthermore, excellent characteristics in terms of life and uniformity were obtained.

[0066] Furthermore, when performing Al etching in two steps as shown in steps (5) and (8) above, the etching film thickness of the first (1st etching) and second (2nd etching) is controlled. By doing so, interlayer film 1
It became possible to optimally adjust the step coverage of 02. The results are shown in Table 1.

[0067]

[Table 1] *Step coverage: ○ - Good, × - Bad As is clear from Table 1 above, the step coverage of the interlayer film 102 is better when the difference in film thickness between the 1st etching and the 2nd etching is not large. It is.

[0068] Furthermore, Al shown in steps (5) and (8) above
When performing etching, Al etching → resist retreat →
By performing Al etching two or more times, such as Al etching → resist retreat → Al etching,
As shown in FIG. 17, the number of steps formed on the Al end face and side wall can be increased. FIG. 17 shows the cross-sectional shape of the end face of the Al wiring 104 when Al etching is performed in four steps.

[0069] This makes it possible to further improve the step coverage of the interlayer film 102.

By attaching the recording head 600 having the above-described configuration to the main body of the inkjet recording apparatus and applying signals to the recording head 600 from the main body of the apparatus, an inkjet recording apparatus capable of high-speed recording and high-quality recording is obtained. be able to.

An inkjet recording apparatus using the recording head of the present invention will now be described with reference to FIG. 18.

FIG. 18 is a schematic perspective view showing an example of an inkjet recording apparatus 700 to which the present invention is applied.

The recording head 600 is mounted on a gear ridge 720 that engages with a helical groove 721 of a lead screw 704 that rotates via drive force transmission gears 702 and 703 in conjunction with the forward and reverse rotations of a drive motor 701. and
The gear ridge 720 is driven by the power of the drive motor 701.
At the same time, it is reciprocated along the guide 719 in the directions of arrows a and b. Reference numeral 705 denotes a paper pressing plate for the recording paper P conveyed onto the platen 706 by a medium feeding device (not shown), and presses the recording paper P against the platen 706 in the gear ridge movement direction. 707 and 708 are photocouplers, which are connected to the lever 709 of the gear ridge 720;
This is a home position detection means for confirming the presence in this area and switching the rotational direction of the drive motor 701. 710 is a support member that supports the cap member 711 that caps the front surface of the recording head 600, and 712 is a suction means for sucking the inside of the cap member 711, and suction recovery of the recording head 600 is performed through the opening 713 in the cap. conduct. 714 is a cleaning blade, 715 is a moving member that allows this blade to move in the front and back direction,
These are supported by a main body support plate 716. Needless to say, the cleaning blade 714 is not of this type, and other known cleaning blades may be used. Reference numeral 717 is a lever for starting suction for suction recovery, which moves with the movement of the cam 718 that engages with the carriage 720, so that the driving force from the drive motor 701 can be transmitted by known transmission means such as clutch switching. Movement controlled. A print control section that applies signals to the heat generating section 110 provided in the recording head 600 and controls the drive of each of the mechanisms described above is provided on the apparatus main body side (not shown).

The inkjet recording apparatus 700 configured as described above has a platen 706
The recording head 600 performs recording while reciprocating over the entire width of the recording paper P that is conveyed upward, and the recording head 600 is manufactured using the method described above. This enables high-precision and high-speed recording.

Substrate 10 in the above-described recording head 600
In the case of 0, the connection end surface and side surface of the wiring 104 made of Al and the entire side surface of each electrode of the functional element were formed in a step-like shape, but this is not necessary, and at least the surface perpendicular to the direction of current flow ( In the case of the wiring 104, it is sufficient that the connection end surface of the heat generating portion 110 is formed in a stepped shape.

Regarding the method of forming such a step-like end surface, the case of the wiring 104 is taken as an example, and FIGS.
This will be explained with reference to e).

In the base body 100 described above, the heating resistance layer 1
After depositing a layer of HfB2 as 03 and an Al material as wiring 104, the heat generating resistor layer 103 and wiring 104 are formed by repeating the conventional photolithography process twice (
a).

At this time, the wiring 104 can be etched by a conventionally used wet etching method or a dry etching method using RIE using a Cl-based gas. By these methods, the longitudinal side surfaces of the wiring 104 have an angle substantially perpendicular to the surface of the heat generating resistor layer 103.

Next, the resist 111,
111' to cover the area other than the area corresponding to the heat generating part 110 (b
), the wiring 1 is removed by repeating etching and resist retreat while being immersed in a TMAH aqueous solution in the same manner as the Al removal described in the manufacturing process (5) of the recording head 600 described above.
The area corresponding to the heat generating part 110 of 04 is peeled off to form the heat generating part 1.
Form 10 (c). At this time, the two connecting end faces of the wiring 104 in the heat generating part 110 are formed in a stepped shape as described above (d), and the side faces are connected to the lower heat generating resistor layer 103.
(e).

This method can be similarly applied to each electrode of the functional element, and only the connecting end surface of each electrode can be formed in a stepped shape.

The present invention brings about excellent effects particularly in recording heads and recording apparatuses of the inkjet recording method, which utilizes thermal energy to eject ink, as proposed by Canon Corporation. be.

For its typical configuration and principle, see, for example, US Pat. Nos. 4,723,129 and 4,740.
Preferably, it is carried out using the basic principles disclosed in the '796 specification. This method is the so-called on-demand type.
It is applicable to both continuous types, but especially in the case of on-demand type, electrothermal conversion elements placed corresponding to the sheet holding the liquid (ink) and the liquid path, By applying at least one drive signal that corresponds to recorded information and provides a rapid temperature rise exceeding nucleate boiling, the electrothermal transducer generates thermal energy to cause film boiling on the thermally active surface of the recording head. As a result, bubbles in the liquid (ink) can be formed in one-to-one correspondence with this drive signal, which is effective. The growth and contraction of the bubble causes liquid (ink) to be ejected through the ejection opening to form at least one drop. It is more preferable to use this drive signal in a pulse form, since the growth and contraction of bubbles can be carried out immediately and appropriately, making it possible to eject liquid (ink) with particularly excellent responsiveness. This pulse-shaped drive signal is described in U.S. Pat. Nos. 4,463,359 and 434.
5262 is suitable. Further, if the conditions described in US Pat. No. 4,313,124 concerning the invention regarding the temperature increase rate of the heat acting surface are adopted, even more excellent recording can be performed.

The configuration of the recording head is a combination configuration of ejection ports, liquid paths, and electrothermal conversion elements (straight liquid flow path or right-angled liquid flow path) as disclosed in the above-mentioned specifications.
In addition, the structure disclosed in US Pat. No. 4,558,333 and US Pat. No. 4,459,600, which disclose a structure in which the heat acting part is disposed in a bending region, may be used. In addition, Japanese Patent Application Laid-open No. 123670 of 1982 discloses a configuration in which a common slit is used as a discharge part for a plurality of electrothermal transducers, and a hole absorbing pressure waves of thermal energy is disclosed. The present invention is also effective as a configuration based on Japanese Patent Application Laid-Open No. 138461 of 1981, which discloses a configuration in which a discharge portion corresponds to a discharge portion.

Furthermore, a full-line type recording head having a length corresponding to the width of the maximum recording paper that can be recorded by the recording apparatus can be produced by combining a plurality of recording heads as disclosed in the above-mentioned specification. Either a configuration that satisfies the length or a configuration as a single recording head formed integrally may be used, but the present invention can more effectively exhibit the above-mentioned effects.

In addition, a replaceable chip-type recording head that is attached to the apparatus main body enables electrical connection with the apparatus main body and ink supply from the apparatus main body, or a print head that is integrated into the print head itself. The present invention is also effective when a cartridge type recording head is used.

Further, it is preferable to add recovery means, preliminary auxiliary means, etc. for the recording head, which are provided as a configuration of the recording apparatus of the present invention, because the effects of the present invention can be further stabilized. Specifically, these include cleaning means for the recording head, pressure or suction means, preheating means using an electric heat exchange element or another heating element, or a combination of these, and a method other than recording. It is also effective to perform a preliminary ejection mode for ejecting ink to perform stable recording.

Furthermore, the recording mode of the recording apparatus is not limited to a recording mode for only mainstream colors such as black, but may also include a recording head that is configured integrally or a combination of multiple colors; The present invention is also extremely effective for devices equipped with at least one of the following: , full color by color mixing.

In the embodiments of the present invention described above,
Although the ink is described as a liquid, it is an ink that solidifies at room temperature or lower, but softens or becomes a liquid at room temperature, or is within the temperature range of temperature adjustment commonly performed in inkjet. ℃ or more 70℃
It may be one that becomes soft or liquid in the following temperature range. That is, it is sufficient if the ink is in a liquid state when the recording signal is applied. In addition, the temperature rise caused by thermal energy can be actively prevented by using it as energy for changing the state of the ink from a solid state to a liquid state, or ink that solidifies when left unused is used to prevent ink evaporation. In either case, the ink is liquefied by applying thermal energy in accordance with the recording signal and is ejected as liquid ink, or the ink has already begun to solidify by the time it reaches the recording paper. It is also applicable to the present invention to use ink that is liquefied only by the following steps. In such a case, the ink is JP-A-54-56
847 or Japanese Patent Application Laid-Open No. 60-71260, a form in which the porous sheet is held as a liquid or solid in the recesses or through holes and faces the electric heat exchange element. It's good as well. In the present invention, the most effective method for each of the above-mentioned inks is to implement the above-mentioned film boiling method.

[0089]

[Effects of the Invention] As explained above, the present invention provides the following effects.

According to the substrate for an inkjet recording head of the present invention, by forming the connection end surface of the wiring electrode in a step-like manner, the unevenness of the lower film caused by the wiring electrode can be formed smoothly, which is excellent. Because of the step coverage, it is possible to make the upper and lower protective films and interlayer films thinner.

Furthermore, since the wiring electrode and the electrothermal transducer were in contact with each other at the step-like connection end surface in the heat generating part, it was possible to significantly reduce current concentration at the end of the electrothermal transducer. Further, by making the film thinner, the heat conduction efficiency is increased, and a recording head with low power consumption and good frequency response can be realized at low cost. Furthermore, since current concentration can be alleviated, the life of the recording head can be extended and uniform characteristics can be obtained.

In other words, a recording head with high reliability and high uniformity could be obtained at low cost.

[0093] Furthermore, in the inkjet recording apparatus,
High-speed recording operation can also be achieved, with fast switching characteristics, improved rise characteristics, and less parasitic effects, making it possible to apply suitable thermal energy to the ink and improving the accuracy of recording operations.

[Brief explanation of drawings]

FIG. 1 is a schematic cross-sectional view showing an example of a substrate for an inkjet recording head of the present invention.

FIG. 2 is a diagram showing an example of an electrode of the inkjet recording head substrate of the present invention, (a) is a cross-sectional view thereof, (b)
is a plan view.

FIG. 3 is a diagram showing an example of a heat generating part of an inkjet recording head substrate of the present invention, in which (a) is a cross-sectional view thereof, and (b)
) is a plan view.

FIG. 4 is a cross-sectional view showing an example of the current flowing through the heat generating portion of the inkjet recording head substrate of the present invention.

FIG. 5 is a cross-sectional view for explaining the operation of the inkjet recording head substrate of the present invention.

FIG. 6 is a perspective view showing an example of an inkjet recording head of the present invention.

FIG. 7 is a sectional view showing an example of the manufacturing process of the inkjet recording head substrate and inkjet recording head of the present invention.

FIG. 8 is a cross-sectional view showing an example of the manufacturing process of the inkjet recording head substrate and inkjet recording head of the present invention.

FIG. 9 is a cross-sectional view showing an example of the manufacturing process of the inkjet recording head substrate and inkjet recording head of the present invention.

FIG. 10 is a cross-sectional view showing an example of the manufacturing process of the inkjet recording head substrate and inkjet recording head of the present invention.

FIG. 11 is a cross-sectional view showing an example of the manufacturing process of the inkjet recording head substrate and inkjet recording head of the present invention.

FIG. 12 is a sectional view showing an example of the manufacturing process of the inkjet recording head substrate and inkjet recording head of the present invention.

FIG. 13 is a cross-sectional view showing an example of the manufacturing process of the inkjet recording head substrate and inkjet recording head of the present invention.

FIG. 14 is a cross-sectional view showing an example of the manufacturing process of the inkjet recording head substrate and inkjet recording head of the present invention.

FIG. 15 is a sectional view showing an example of the manufacturing process of the inkjet recording head substrate and inkjet recording head of the present invention.

FIG. 16 is a cross-sectional view showing an example of the manufacturing process of the electrode of the inkjet recording head substrate of the present invention.

FIG. 17 is a sectional view showing another example of the heat generating portion of the inkjet recording head substrate of the present invention.

FIG. 18 is a perspective view showing an embodiment of an inkjet recording apparatus of the present invention.

FIG. 19 is a sectional view showing another example of the manufacturing process of the heat generating portion of the inkjet recording head substrate of the present invention.

FIG. 20 is a sectional view showing an example of a conventional inkjet recording head substrate.

FIG. 21 is a cross-sectional view showing a current flowing through a heat generating portion of a conventional inkjet recording head substrate.

[Explanation of symbols] 1 P-type silicon substrate 2 N-type collector buried region 3 P-type isolation buried region 4
N-type epitaxial region 5 P-type base region 6 P-type isolation region 7 N-type collector region 8 High concentration P-type base region 9 High concentration P-type isolation region 10
N-type emitter region 11 High concentration N-type collector region 12 Collector-base common electrode 13 Emitter electrode 14 Isolation electrode 100 Base 101 Heat storage layer 102 Interlayer film 103 Heat generating resistor layer 104 Wiring 105, 106 Protective film 107 Bonding pad 109 Anode electrode Wiring 110 Heat generating part 401 Drive current 500 Ejection port 501 Liquid path wall member 502 Top plate 503 Ink supply port 504 Common liquid chamber 505 Liquid path 600 Inkjet recording head 700
Inkjet recording device 701 Drive motors 702, 703 Drive force transmission gear 704
Lead screw 705 Paper press plate 706 Platen 707, 708 Photo coupler 709, 717 Lever 710 Support member 711 Cap member 712 Suction means 713 Opening in cap 714 Cleaning blade 715 Moving member 716 Main body support plate 718 Cam 719 Guide 720 Carriage 721 Spiral groove

Claims (15)

[Claims] 1. A group of electrothermal conversion elements for generating thermal energy; and a group of functional elements for driving the electrothermal conversion elements, which are electrically connected to each of the electrothermal conversion elements of the group of electrothermal conversion elements. , an inkjet recording head substrate in which wiring electrodes for connecting each of the electrothermal conversion element group and the functional element group are provided on the same substrate,
1. A substrate for an inkjet recording head, wherein a connection end surface of the wiring electrode is formed in a stepped shape. 2. The substrate for an inkjet recording head according to claim 1, wherein the side surface of the wiring electrode is formed in a step-like manner. 3. An ink ejection section having a plurality of ejection ports for ejecting ink, and a group of electrothermal conversion elements that generate thermal energy used to eject ink from each ejection port of the ink ejection section. and a functional element group for driving an electrothermal transducer electrically connected to each electrothermal transducer of the electrothermal transducer group, and connecting each of the electrothermal transducer group and the functional element group. 1. An inkjet recording head comprising: a base body provided with wiring electrodes for said base body, wherein a connecting end surface of said wiring electrodes of said base body is formed in a stepped shape. 4. The ink jet recording head according to claim 3, wherein the side surface of the wiring electrode of the substrate is formed in a stepped shape. 5. An electrothermal conversion device having an ink ejection section having a plurality of ejection ports for ejecting ink, and generating thermal energy used to eject ink from each ejection port of the ink ejection section. an element group, a functional element group for driving an electrothermal transducer electrically connected to each electrothermal transducer of the electrothermal transducer group, and each of the electrothermal transducer group and the functional element group. An inkjet recording head including a base body provided with wiring electrodes for connection and a recording member to be recorded with ink ejected from the ejection ports are transported facing the ink ejection section of the inkjet recording head. What is claimed is: 1. An inkjet recording apparatus comprising: a conveying means for transporting said inkjet recording head, wherein a connection end surface of a wiring electrode of said inkjet recording head is formed in a stepped shape. 6. The inkjet recording apparatus according to claim 5, wherein the side surface of the wiring electrode is formed in a stepped shape. 7. The inkjet recording head is of a full line type in which a plurality of ejection ports are formed over the entire width of the largest recording member.
The inkjet recording device described above. 8. An electrothermal transducer group and a functional element group for driving the electrothermal transducers that drive the electrothermal transducers of the electrothermal transducer group, respectively, by photolithography;
forming on a substrate a wiring electrode group for connecting each functional element of the functional element group and the electrothermal conversion element, respectively;
In a method for manufacturing a substrate for an inkjet recording head,
A substrate for an inkjet recording head, comprising a wiring electrode group etching step in which the connection end surface of each wiring electrode of the wiring electrode group is etched multiple times while etching a photoresist for a mask to form a stepped shape. manufacturing method. 9. The inkjet recording head according to claim 8, wherein in the wiring electrode group etching step, the side surface of each wiring electrode of the wiring electrode group is etched multiple times together with the connecting end surface to form a stepped shape. Method of manufacturing substrate for use. 10. In the wiring electrode group etching process, the material layer of each wiring electrode is etched by alternately immersing the wiring electrode in an etching solution for wiring electrodes and a tri-methyl ammonium hydroxide aqueous solution for mask photoresist etching. Claim 8 or 9 characterized in that
The method for manufacturing a substrate for an inkjet recording head as described above. 11. The method according to claim 8, 9 or 10, wherein the material of the wiring electrode is aluminum.
A method for manufacturing a substrate for an inkjet recording head. 12. An electrothermal transducer group, a functional element group for driving an electrothermal transducer that drives each of the electrothermal transducers of the electrothermal transducer group, and each functional element of the functional element group by photolithography. and the step of forming a base by forming a group of wiring electrodes on the substrate to connect the electrothermal transducer and the electrothermal transducer, respectively, and forming an ink ejection section having a plurality of ejection ports for ejecting ink on the substrate. In the method for manufacturing an inkjet recording head, the step of creating an inkjet recording head includes etching the connection end surface of each wiring electrode of the wiring electrode group multiple times while etching back the photoresist for the mask. 1. A method of manufacturing an inkjet recording head, comprising the step of etching a group of wiring electrodes to form a step-like pattern. 13. The inkjet recording head according to claim 12, wherein in the wiring electrode group etching process, side surfaces of each wiring electrode of the wiring electrode group are etched multiple times together with the connection end surface thereof to form a stepped shape. Production method. 14. In the wiring electrode group etching step, the material layer of each wiring electrode is etched by alternately immersing the wiring electrode in an etching solution for wiring electrodes and a tri-methyl ammonium hydroxide aqueous solution for mask photoresist etching. 14. The method of manufacturing an inkjet recording head according to claim 12 or 13, wherein the method comprises: 15. The method of manufacturing an ink jet recording head according to claim 12, 13 or 14, wherein the material of the wiring electrode is aluminum.