JPH04320850A - Manufacture of substrate for recording head and recording head - Google Patents

Abstract

PURPOSE:To manufacture a substrate for a recording head and the recording head so that they have excellent durability, power consumption is lowered and performance is improved. CONSTITUTION:The material layer 34 of a wiring electrode is etched while a photo-resist 100 for a positive type mask is retreated by etching by using an alkaline solution mainly comprising tetra-methyl-ammonium-hydroxide in this example because aluminum is an amphoteric metal and is soluble in alkali and the photo-resist 100 for the mask represented by the mixture of an alkali- soluble phenol resin and naphthoquinone azide is also dissolved in a basically strong alkali aqueous solution. Accordingly, since the quantity of the material layer 34 of the wiring electrode etched in a region, in which the photo-resist 100 for the mask is retreated, changes approximately linearly, the shape of the edge section 241 of the wiring electrode 24 formed can be formed in a linear tapered shape.

Description

[Detailed description of the invention]

0001

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

0002

[Description of Background Art] In recent years, inkjet recording devices
It is beginning to be used in copiers, facsimile machines, word processors, and host computer output printers and video output printers.

FIG. 17 is a schematic diagram showing the structure of an inkjet recording head used in an inkjet recording apparatus.

The inkjet recording head 800 includes a substrate 801 made of silicon or the like, a plurality of electrothermal transducers 802 constituting an electrothermal transducer array, and functional elements for driving the electrothermal transducers 802 and the electrothermal transducers 802. (not shown)
3 and a plurality of nozzle walls 803 that isolate the electrothermal conversion element 802 , and the substrate 801 via the nozzle wall 803 .
and a top plate 804 provided to face each other, and the driving functional element conducts electricity to the electrothermal conversion element 802 through the wiring electrode 803 .
Ink droplets are ejected from the ejection port 808 by utilizing the energy of bubbling generated by heating the upper ink. The ink is supplied from an ink tank (not shown) to the common liquid chamber 807 via a supply pipe 805 and a connector 806, and the ink is supplied to the common liquid chamber 807 by capillary action. ).

However, this inkjet recording head 8
In 00, the driving functional element is arranged outside the substrate 801, and the connection between the electrothermal conversion element 802 and the driving functional element is made by connecting the wiring electrode 803 and the driving functional element with a flexible cable, wire bonding, etc. Since this is done by connecting the elements, there are some problems with simplifying the structure of the inkjet recording head, reducing defects that occur during the manufacturing process, making the characteristics of each element uniform, and improving reproducibility. Therefore, the applicant
In order to solve this problem, an inkjet recording head in which an electrothermal conversion element and a driving functional element are provided on the same substrate was proposed in Japanese Patent Laid-Open No. 72867/1983.

FIG. 18 is a schematic diagram showing a vertical structure of a portion of an inkjet recording head substrate according to the structure proposed in Japanese Patent Application Laid-Open No. 57-72867.

[0007] This inkjet recording head substrate 90
0 is a heat generating part 920 which is an electrothermal conversion element and a bipolar transistor 930 which is a driving functional element.
It is formed on a mold silicon substrate 901.

Here, bipolar transistor 930
are two highly doped N-type collector regions 911 formed on the P-type silicon substrate 901 via the N-type collector buried region 902 and the N-type collector buried region 902 , and the N-type collector buried region 902 and P Two high-concentration P-type base regions 908 are formed inside the high-concentration N-type collector region 911 via the type base region 905 , and high-concentration P-type base regions 908 are formed inside the high-concentration N-type collector region 911 via the N-type collector buried region 902 and the P-type base region 905 . It has the structure of an NPN transistor with a highly doped N-type emitter region 910 formed between a type base region 908, and a highly doped N-type collector region 911 and a highly doped P-type base region 908 form a collector-base common electrode. 912, it operates as a diode. Further, adjacent to the bipolar transistor 930, a P-type isolation buried region 903, a P-type isolation region 906, and a heavily doped P-type isolation region 909 are successively formed as element isolation regions. Further, a heat generating resistance layer 923 is formed on the P type silicon substrate 901 via an N type epitaxial region 904 , a heat storage layer 921 and an interlayer film 922 .
A heating section 920 is formed by cutting the wiring electrode 924 formed above. Note that the upper surface of the inkjet recording head substrate 900 is covered with a first protective film 925 , and the first protective film 925 on the side of the heat generating part 920 from the high concentration N-type emitter region 910 of the bipolar transistor 930 is It is covered with a second protective film 926. The inkjet recording head substrate 900 having such a structure can be manufactured by a known semiconductor manufacturing process using photolithography.

FIGS. 19A to 19E are schematic diagrams showing the process of etching the wiring electrode material layer 824 in the heat generating portion 920 by photolithography. A wiring electrode material layer 824 is formed on the entire surface of the wiring electrode material layer 923, a mask photoresist 1000 is applied on the entire surface of the wiring electrode material layer 824, and the mask photoresist 1000 is exposed using a mask. By developing the photoresist 1000 for the mask, the portion of the photoresist 1000 for the mask where the material layer 824 of the wiring electrode is to be etched is removed (see FIG.
A)). Thereafter, by etching the wiring electrode material layer 824 with a wiring electrode etching solution, the wiring electrode material layer 824 in the portion where the mask photoresist 1000 was removed is gradually etched, and the wiring electrode material layer 824 is cut to form a wiring electrode 924 ((B) to (D) in the same figure). After the wiring electrode 924 is formed, the remaining mask photoresist 10
00 is removed ((E) in the same figure).

0010

However, in the inkjet recording head substrate 900 described above, the edge portion 9241 of the wiring electrode 924 formed in the heat generating portion 920 is almost vertical as shown in FIG. 19(E). Because of the shape, the following problems arise.

(1) When a current is passed from the high concentration N-type emitter region 910 to the wiring electrode 924 in order to generate thermal energy in the heat generating part 920, the current from the wiring electrode 924 in the heat generating part 920 to the heat generating resistor layer 923 decreases. The flow is directed to the edge portion 9241 as shown by the arrow in FIG.
Concentrate below. That is, according to one experimental result, the current density below the edge portion 9241 is 8.2×10
7 A/cm2, the current density in the wiring electrode 924 is 1.7×106 A/cm2, and the heat generating part 920
This is an abnormally large value compared to the current density of 1.03×10 7 A/cm 2 at the center of the heating resistance layer 923 in FIG. As a result, it has been found that the concentration of current density below the edge portion 9241 causes a portion of the heat generating resistive layer 923 to be cut off and determines the life span of the inkjet recording head.

(2) In order to improve the step coverage in the heat generating part 920, the thickness of the first protective film 925 needs to be approximately 1.0 μm.
The protective film 925 intervenes as a thermal resistance when the thermal energy generated in the heat generating part 920 is transmitted to the ink, and the driving power of the heat generating resistance layer 923 must be increased, and the deterioration of frequency characteristics due to heat conduction delay is prevented. This has been one of the factors that hinders lower power consumption and higher performance of inkjet recording heads.

An object of the present invention is to provide a substrate for a recording head and a method for manufacturing a recording head that is excellent in durability, reduces power consumption, and improves performance.

[0014]

[Means for Solving the Problems] A method for manufacturing a recording head substrate of the present invention includes a method for manufacturing a recording head substrate by photolithography, which includes a plurality of electrothermal transducer elements and a plurality of driving functional elements for respectively driving each of the electrothermal transducer elements. , a method for manufacturing a recording head substrate in which a plurality of wiring electrodes connecting each of the drive functional elements and each of the electrothermal conversion elements are formed on the substrate, the main component being tetramethyl ammonium hydroxide. The wiring electrode is formed by etching the wiring electrode material layer using an alkaline solution to etch back the masking photoresist of the wiring electrode material layer.

[0015] Here, the concentration of tetra methyl ammonium hydroxide in the alkaline solution is 1.5 to
It may be 3.0%, or the material layer of the wiring electrode may be an aluminum layer.

A method for manufacturing a recording head according to the present invention includes a plurality of electrothermal transducers, a plurality of drive functional elements for respectively driving each of the electrothermal transducers, and
and a base forming step of creating a recording head base by forming a plurality of wiring electrodes on the substrate to respectively connect each of the driving functional elements and each of the electrothermal transducing elements, and a plurality of ejecting electrodes for ejecting ink. In the method for manufacturing a recording head, the method includes the step of creating an ink jetting part having an outlet on the base for the recording head, wherein the base creating step contains tetra-methyl ammonium hydroxide as a main component. The method includes a wiring electrode etching step of etching the material layer of the wiring electrode while etching back the masking photoresist of the material layer of the wiring electrode using an alkaline solution to form the wiring electrode.

[0017] Here, the concentration of tetra methyl ammonium hydroxide in the alkaline solution is 1.5 to
It may be 3.0%, or the material layer of the wiring electrode may be an aluminum layer.

[0018]

[Operation] The method for manufacturing a recording head substrate of the present invention uses an alkaline solution containing tetramethyl ammonium hydroxide as a main component to etch back the mask photoresist of the wiring electrode material layer while wiring the wiring. By etching the material layer of the electrode, the amount of etching of the material layer of the wiring electrode in the area where the photoresist for the mask recedes can be changed almost linearly, so the shape of the edge portion of the formed wiring electrode can be changed. It can be a straight taper.

Further, the method for manufacturing a recording head of the present invention includes:
The substrate creation process involves etching the wiring electrode material layer while etching the masking photoresist of the wiring electrode material layer using an alkaline solution containing tetra-methyl ammonium hydroxide as a main component. By including the wiring electrode etching step to form a wiring electrode, a recording head with excellent durability can be manufactured.

[0020]

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.

FIGS. 1A to 1E are schematic diagrams showing the process of etching the material layer 34 of the wiring electrode to explain the first embodiment of the method for manufacturing a recording head substrate of the present invention. It is a diagram.

A wiring electrode material layer 34 made of aluminum is formed on the entire surface of the heating resistor layer 23, and a masking photoresist 100 (positive type) is applied to a thickness of 1.2 μm over the entire surface of the wiring electrode material layer 34. After exposing the mask photoresist 100 using a mask, the mask photoresist 100 is developed to remove the mask photoresist 100 in the portion where the wiring electrode material layer 34 is to be etched (see (A) in the same figure). )). After that, the wiring electrode material layer 34 and the mask photoresist 100 are
Improved adhesion with mask photoresist 100
Bake at 125℃ for 22 hours to remove the solvent etc.
After 5 seconds, the etching operation of the material layer 34 of the wiring electrode is started. Here, a mixed solution of phosphoric acid (H3PO4), nitric acid (HNO3) and acetic acid (CH3COOH) is generally known as a wiring electrode (aluminum) etching solution used for etching the wiring electrode 24 made of aluminum. However, with this mixed solution, the mask photoresist 10
0 cannot be etched. Therefore, it is important to note that aluminum is an amphoteric metal and is soluble in alkali.
00 is basically soluble in a strong alkaline aqueous solution, so in this example, an alkaline solution containing tetra methyl ammonium hydroxide (hereinafter referred to as "TMAH") as a main component was used to form the wiring electrode. The material layer 34 is etched. At the point when etching of the material layer 34 of the wiring electrode is started using the alkaline solution, only the material layer 34 of the wiring electrode is mainly etched (FIG. 3(B)), but as time passes, the mask photo Since the resist 100 is also etched, the material layer 34 of the wiring electrode is etched while the mask photoresist 100 is etched back (FIG. 3(C)).
). Therefore, since the etching amount of the wiring electrode material layer 34 in the region where the mask photoresist 100 has retreated changes approximately linearly, the wiring electrode material layer 34
When the etching operation is completed and the wiring electrode 24 is formed, the shape of the edge portion 241 of the wiring electrode 24 becomes a linear taper, as shown in FIG. When the wiring electrode 24 is formed as described above, the remaining mask photoresist 100 is removed (see FIG.
E)). In addition, in one experimental result in which the material layer 34 of the wiring electrode was etched for 10 minutes using the alkaline solution heated to 34° C., it was found that the mask photoresist 100
The etching regression amount (pattern dimension shift amount) is approximately 1.
The tapered angle θ of the edge portion 241 of the wiring electrode 24 shown in FIG. 2A (the angle with respect to the normal to the surface of the wiring electrode 24) was approximately 65 degrees.

Furthermore, when the wiring electrode material layer 34 is etched as shown in FIG.
The shapes of both side surfaces 242 (front and rear surfaces of the paper) are also linearly tapered, as shown in FIG. 2(B).

FIG. 3 is a schematic diagram showing the vertical structure of a portion of the inkjet recording head substrate 40 manufactured by the manufacturing method shown in FIG.

[0025] This inkjet recording head substrate 40
is the inkjet recording head substrate 90 shown in FIG.
0 is that the edge portion 241 and both side surfaces 242 of the wiring electrode 24 are linearly tapered, and the edge portions of the collector/base common electrode 12, the emitter electrode 13, and the isolation electrode 14,
The shapes of both side surfaces are also linearly tapered, as shown in FIGS. 4(A) and 4(B), respectively.

Therefore, in this inkjet recording head substrate 40, the current flow in the heat generating section 20 is as follows.
As shown in FIG. 5, there is no concentration below the edge portion 241 of the wiring electrode 24. For example, according to one experimental result, the current density below the edge portion 241 of the wiring electrode 24 was increased from 8.2×107 A/cm2 when the shape of the edge portion 241 was almost vertical to 2.6×107 A.
/cm2. As a result, it is possible to prevent the heating resistance layer 23 from being partially cut.
For example, according to the results of an experiment in which an inkjet recording head was constructed using the inkjet recording head substrate 40, the durability of the inkjet recording head was 7×107
It was possible to significantly extend the pulse from 1 x 109 pulses.

Furthermore, since the step coverage of the first protective film 25 (see FIG. 3) can be made extremely good, the thickness of the first protective film 25 can be adjusted to the edge portion 241.
is thinner than when the shape is almost vertical (for example, 1.0
μm to 0.6 μm). As a result, the thermal energy generated in the heat generating section 20 could be efficiently and quickly transferred to the ink, and the throughput of the apparatus for forming the first protective film 25 could be approximately doubled.

Next, the manufacturing process of the inkjet recording head substrate 40 shown in FIG. 3 will be explained.

As shown in FIG. 6, a P-type silicon substrate 1 (
Impurity concentration approximately 1 x 1012 to 1 x 1016 cm-3)
After forming a silicon oxide film with a thickness of about 8000 Å on the surface, the silicon oxide film in the portions where the N-type collector buried region 2 of each cell (each bipolar transistor 30) was to be formed was removed by photolithography. After forming a silicon oxide film, N-type impurities (for example, P, As, etc.) are ion-implanted, and the impurity concentration is increased to 1×101 by thermal diffusion.
N-type collector buried region 2 of 8 cm-3 or more with a thickness of 2 to 6 cm
It was formed to have a sheet resistance of about 30 Ω/□ or less. Subsequently, the silicon oxide film in the region where the P-type isolation buried region 3 is to be formed is removed, and
After forming a silicon oxide film with a thickness of about 0.00 Å, P-type impurities (such as B) are ion-implanted, and a P-type isolation buried region 3 with an impurity concentration of 1×1015 to 1×1017 cm-3 or more is formed by thermal diffusion. Formed.

As shown in FIG. 7, after removing the silicon oxide film from the entire surface, the N-type epitaxial region 4 (with impurity concentration of approximately 1×10 13 to 1×10 15 cm −3 ) is formed to a thickness of 5 μm.
It was epitaxially grown to about 20 μm.

As shown in FIG. 8, a silicon oxide film with a thickness of about 1000 Å is formed on the surface of the N-type epitaxial region 4, a resist is applied, patterning is performed, and a low concentration P film is formed.
P-type impurity ions were implanted only into the portion where the type base region 5 was to be formed. After removing the resist, a low concentration P-type base region 5 (impurity concentration 5×1014 to 5×10
17 cm-3) with a thickness of about 5 to 10 μm. After that, the silicon oxide film was completely removed again to a thickness of 8,000 Å.
After forming a silicon oxide film to a certain extent, the silicon oxide film in the portion where the P-type isolation region 6 is to be formed is removed, a BSG film is deposited on the entire surface using the CVD method, and further,
By thermal diffusion, the P-type isolation region 6 (impurity concentration 1
×1018~1×1020cm-3) with a thickness of 10μ
It was formed about m. At this time, it is also possible to form the P-type isolation region 6 using BBr3 as a diffusion source.

As shown in FIG. 9, the BSG film is removed and 8
After forming a silicon oxide film with a thickness of approximately 000 Å and removing the silicon oxide film only from the portion where the N-type collector region 7 will be formed, the N-type collector is buried by solid-phase diffusion of N-type, implantation of phosphorus ions, or thermal diffusion. N-type collector region 7 (impurity concentration 1×1018 to 1×
1020cm-3) with a thickness of about 10 μm. Next, a silicon oxide film of about 12,500 Å is formed,
After forming the heat storage layer 21 (see FIG. 10), the silicon oxide film in the cell region was selectively removed to form a silicon oxide film with a thickness of about 2000 Å. 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 isolation region 9 were to be formed. After removing the resist, high concentration N type emitter region 10
Then, the silicon oxide film in the portion where the high concentration N-type collector region 11 is to be formed is removed, a thermal oxide film is formed on the entire surface, an N-type impurity is implanted, and the high concentration N-type emitter region 10 and the high concentration An N-type collector region 11 was formed at the same time. The thickness of the heavily doped N-type emitter region 10 and the heavily doped N-type collector region 11 is 1.0 μm or less, and the impurity concentration is 1.
It was set to about ×1018 to 1×1020 cm-3.

Next, as shown in FIG. 10, after removing the silicon oxide film at the connection points of some electrodes, Al (aluminum) is deposited on the entire surface to form the collector/base common electrode 1.
2, emitter electrode 13 and isolation electrode 14
Al was removed from areas other than the area. At this time, the shapes of the edges and both side surfaces of the collector/base common electrode 12, emitter electrode 13, and isolation electrode 14 are not perpendicular, but are at an angle of 30 degrees to 75 degrees with respect to the normal line.
As shown in FIG. 1, Al was etched while etching the resist back.

Subsequently, as shown in FIG. 11, a SiO2 film having a thickness of about 0.6 to 1.0 μm was formed on the entire surface by sputtering to serve as the interlayer film 22 which also functions as a heat storage layer. The SiO2 film may be formed by CVD. Further, the film is not limited to the SiO2 film, but may be an SiO film or a SiON film. Thereafter, in order to establish electrical connection, a part of the interlayer film 22 above the emitter electrode 13 and the collector/base common electrode 12 was opened by photolithography to form a through hole TH.

Next, as shown in FIG. 12, the emitter electrode 13 and the collector/base common electrode 12 are
2 (SiO2 film), HfB2 was deposited to a thickness of about 1000 Å as a heating resistance layer 23 through a through hole TH. On the heating resistance layer 23, an Al layer, which is a material layer of wiring electrodes for forming a pair of wiring electrodes 24 (corresponding to the cathode wiring electrodes of the diode) and an anode wiring electrode 15 of the diode, of the electrothermal transducer element is formed to a thickness of about 5000 Å. After a certain amount of deposition, the shape of the edge portion 241 and both side surfaces of the wiring electrode 24 is not perpendicular, but is at an angle of 30 to 75 degrees with respect to the normal line.
As shown in FIG. 1, the Al layer was etched while etching the mask photoresist back so as to form an angle of .degree.

Thereafter, as shown in FIG. 13, a first protective film 25 (S
After depositing about 6,000 Å of Ta (iO2 film) to a thickness of about 6,000 Å, Ta was deposited to a thickness of about 2,000 Å on the heat generating portion 20 of the electrothermal converter as a second protective film 26 for anti-cavitation. The electrothermal transducer thus prepared and the Ta and SiO2 films were partially removed to form bonding pads P. Note that the first protective film 25 is made of SiO
In addition to 2, SiON or SiN may be used.

Next, the basic operation of the bipolar transistor 30, which is a functional element for driving the inkjet recording head substrate 40 shown in FIG. 3, will be explained using FIG. 14.

In the bipolar transistor 30, 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 transistor in the cell turns on and bias current flows out of the emitter electrode 13 as collector and base current. In addition, as a result of short-circuiting the base and collector, the heat rise and fall characteristics of the electrothermal transducer are good, and the film boiling phenomenon and the accompanying growth and contraction of bubbles are better controlled, resulting in stable ink. can be discharged. 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, which has a greater influence than expected. It is thought that this is the case. Furthermore, it has relatively few parasitic effects, has no variation between elements, and can obtain a stable drive current. Furthermore, by grounding the isolation electrode 14, it is possible to prevent charges from flowing into other adjacent cells, and the problem of malfunction of other elements can be prevented.

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 base region 5 should be 5×10 14 to 5×1
017 cm-3, and furthermore, it is desirable to make the area of the bonding surface between the high concentration base region 8 and the electrode 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.

In FIG. 14, two diode cells SH1
, SH2 are shown, but in reality, the same number of driving functional elements corresponding to, for example, 128 electrothermal conversion elements are arranged at equal intervals to enable block driving. Electrically matrix connected. Here, for the sake of simplicity, driving of the electrothermal transducers RH1 and RH2 as two segments in the same group will be described.

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 diode 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 (ink) to generate bubbles, causing the liquid to be ejected from the ejection 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 diode cell SH2 is driven to supply current to the electrothermal transducer RH2. . At this time, the P-type silicon substrate 1 is grounded via the isolation region. By grounding the isolation region of each semiconductor element (cell) in this way, malfunctions due to electrical interference between the semiconductor elements are prevented.

Next, an embodiment of the method for manufacturing a recording head of the present invention will be described.

In order to manufacture an ink jet recording head having the structure shown in FIG. 17 and having the ink jet recording head substrate 40 shown in FIG. Following the base fabrication process shown in FIGS. 6 to 13, which includes the wiring electrode etching step shown in FIG. 1 in which the material layer 34 of the wiring electrode is etched while etching the material layer 34 of the wiring electrode while retreating, a plurality of ejection ports for ejecting ink are formed. An ink ejection part creation step of creating an ink ejection part having a 17) and the step of providing the top plate 204), the step of providing the connector (see FIG. 17) on the top plate 204, etc. may be added.

[0044] Regarding the inkjet recording head manufactured in this manner, the electrothermal transducer was block driven,
Recording and operation tests were conducted. In the operation test, eight semiconductor diodes were connected to one segment, and a current of 300 mA (total 2.4 A) was passed through each semiconductor diode.
The other semiconductor diodes did not malfunction and were able to perform good ejection. Further, since the inkjet recording head has good heat transfer efficiency, it requires only 80% of the driving power of conventional inkjet recording heads, and has excellent high frequency response. Furthermore, excellent characteristics in terms of life and uniformity were obtained.

Table 1 shows the edge portion 241 of the wiring electrode 24.
An example of the evaluation results when an inkjet recording head was subjected to a durability test while changing the angle θ of the linear taper is shown below.

[0046]

[Table 1] From this evaluation result, it was found that the durability of the inkjet recording head was improved by setting the linear taper angle θ of the edge portion 241 of the wiring electrode 24 between 30 degrees and 75 degrees. .

Furthermore, Table 2 shows the results of an experiment in which the relationship between the TMAH concentration of an alkaline solution containing TMAH as a main component and the taper angle θ of the edge portion 241 of the wiring electrode 24 was investigated.

[0048]

[Table 2] From the experimental results shown in Table 2, it is possible to set the taper angle θ of the edge portion 241 of the wiring electrode 24 to a desired angle by changing the TMAH concentration of the alkaline solution containing TMAH as the main component. At the same time, the TMAH concentration of the alkaline solution containing TMAH as the main component is 1.5 to 3.
．． By setting it to 0%, the edge portion 24 of the wiring electrode 24
It has been found that the angle θ of the taper 1 can be between 30 degrees and 75 degrees.

Next, a second embodiment of the method for manufacturing a recording head substrate of the present invention will be described.

In the embodiment shown in FIG. 1, the shape of both side surfaces 242 (see FIG. 2B) of the wiring electrode 24 is also linearly tapered, but only a reduction in the current density in the heat generating portion 20 is achieved. In order to achieve this, the shapes of both side surfaces 242 of the wiring electrode 24 may remain substantially vertical as shown in FIGS. 16(B) and 16(C), respectively.

In this case, etching of the wiring electrode material layer 34 to form the wiring electrode 24 and
Etching may be performed separately from etching of the edge portion 241 of the wiring electrode 24 to make the shape of the edge portion 241 of the wiring electrode 24 linearly tapered. That is, first, a resist is applied on the entire surface of the material layer 34 of the wiring electrode, and the material layer 34 of the wiring electrode is etched using a conventional wet etching method or a dry etching method such as RIE using a Cl-based gas. Wiring electrodes 24 are formed. At this time, the shapes of both side surfaces of the wiring electrode 24 are substantially vertical as in the conventional case. Thereafter, as shown in FIG. 16A, after covering the wiring electrode material layer 34 other than the heat generating part 20 with a masking photoresist 50, the wiring electrode 24 is etched by the method shown in FIG. As shown in Figures (B) and (C), the shape of the edge portion 241 of the wiring electrode 24 is linearly tapered.

In the above explanation, the substrate for an inkjet recording head and the inkjet recording head have been explained, but the substrate for a recording head and the recording head manufactured according to the present invention can also be applied to, for example, a substrate for a thermal head and a thermal head. It is possible. Furthermore, the materials constituting the heating resistance layer 23 shown in FIG. 3 include Ta, ZrB2, Ti-W, Ni-Cr, Ta-
Al, Ta-Si, Ta-Mo, Ta-W, Ta-Cu
, Ta-Ni, Ta-Ni-Al, Ta-Mo-Al,
Ta-Mo-Ni, Ta-W-Ni, Ta-Si-Al
, Ta-W-Al-Ni, etc.

FIG. 21 is a schematic configuration diagram showing an example of the configuration of an inkjet recording apparatus 700 equipped with an inkjet recording head (hereinafter referred to as "recording head") 510 manufactured by the recording head manufacturing method of the present invention. It is.

The recording head 510 is driven by a drive motor 701.
The driving force transmission gears 702, 703 are linked to the forward and reverse rotation of the
The carriage 720 is mounted on the carriage 720 which engages with the helical groove 721 of the lead screw 704 which rotates via the drive motor 701 , and moves along the guide 719 with the carriage 720 by the power of the drive motor 701 .
It is moved back and forth in direction b. A paper pressing plate 705 for the recording paper P conveyed onto the platen 706 by a recording medium feeding device (not shown) presses the recording paper P against the platen 706 in the carriage movement direction.

The photocouplers 707 and 708 are home position detection means for confirming the presence of the lever 709 of the carriage 720 in this area and switching the rotational direction of the drive motor 701. The support member 710 supports a cap member 711 that caps the entire surface of the recording head 510 described above. In addition, the suction means 712
The inside of the cap member 711 is suctioned, and the recording head 510 is recovered by suction through the opening 713 in the cap. The moving member 715 is the cleaning blade 714
This allows for movement in the front and rear directions. Moving member 71
5 and the cleaning blade 714 are supported by a main body support plate 716. It goes without saying that the cleaning blade 714 is not of this type, but any known cleaning blade can be applied to this example. In addition, the lever 717 for starting suction recovery moves with the movement of the cam 718 that engages with the carriage 720, and the driving force from the drive motor 701 is controlled by known transmission means such as clutch switching. be done. A print control section that applies signals to the heat generating section provided in the recording head 510 and controls the drive of each of the mechanisms described above is provided on the apparatus main body side (not shown).

In the inkjet recording apparatus 700 having the above-described configuration, the recording head 510 performs recording while reciprocating over the entire width of the recording paper P, which is conveyed onto the platen 706 by the recording medium feeding device. Since the recording head 510 is manufactured by the method described above, highly accurate and high-speed recording is possible.

The present invention particularly relates to an inkjet recording head (hereinafter referred to as a "recording head") that uses thermal energy to eject ink, which is proposed by Canon Inc. among inkjet recording methods, and an inkjet recording method. It brings about excellent effects in a device (hereinafter referred to as a "recording device").

[0058] For its typical configuration and principle, see, for example, US Patent No. 4,723,129;
Preferably, this is done using the basic principles disclosed in US Pat. No. 740,796. This method can be applied to both so-called on-demand type and continuous type, but in particular, in the case of on-demand type, liquid (
At least one drive signal that corresponds to recorded information and provides a rapid temperature rise exceeding nucleate boiling is applied to an electrothermal transducer disposed corresponding to a sheet holding ink (ink) or a liquid path. This is effective because it generates thermal energy in the electrothermal transducer and causes film boiling on the heat-active surface of the recording head, resulting in the formation of bubbles in the liquid (ink) in one-to-one correspondence with this drive signal. be. Due to the growth and contraction of these bubbles, liquid (ink) flows 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, so that ejection of liquid (ink) with particularly excellent responsiveness can be achieved. As this pulse-shaped drive signal, those described in US Pat. No. 4,463,359 and US Pat. No. 4,345,262 are suitable. Furthermore, 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.

In addition to the configuration of the recording head that combines ejection ports, liquid paths, and electrothermal converters (straight liquid flow path or right-angled liquid flow path) as disclosed in the above-mentioned specifications, The present invention also includes configurations using U.S. Pat. No. 4,558,333 and U.S. Pat. No. 4,459,600, which disclose a configuration in which a heat acting part is arranged in a bending region. It is. In addition, Japanese Patent Application Laid-Open No. 123670 of 1981 discloses a configuration in which a common slit is used as a discharge part of a plurality of electrothermal converters, and an opening that absorbs 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 1982, which discloses a configuration corresponding to the discharge section.

Furthermore, a full-line type recording head having a length corresponding to the width of the maximum recording medium 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 a recovery means for the recording head, a preliminary auxiliary means, etc., 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 capping means, cleaning means, pressure or suction means, preheating means for the recording head using an electrothermal transducer or another heating element, or a combination of these, and recording and It is also effective to perform a preliminary ejection mode in which different ejection is performed in order to perform stable recording.

Furthermore, the recording mode of the recording apparatus is not limited to a recording mode of only mainstream colors such as black, but may also include a recording head that is configured integrally or a combination of a plurality of recording heads; 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, the ink is described as a liquid, but it is an ink that solidifies at room temperature or lower, and is softened or liquid at room temperature, or in the above-mentioned inkjet, the ink itself is Generally, the temperature is adjusted within the range of ℃ to 70℃ to keep the viscosity of the ink within the stable ejection range, so if the ink is in a liquid state when the recording signal is applied, good. In addition, the temperature increase due to thermal energy is actively prevented by using it as energy for changing the state of the ink from a solid state to a liquid state, or
In order to prevent ink evaporation, ink that solidifies when left unused is used, and in any case, the ink is liquefied by applying thermal energy in accordance with the recording signal and is ejected as liquid ink or reaches the recording medium. It is also applicable to the present invention to use inks that are liquefied only by thermal energy, such as those that already begin to solidify at this point. 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 electrothermal converter. You can also use it as In the present invention, the most effective inks for each of the above-mentioned inks are:
This implements the film boiling method described above.

[0065]

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

[0066] In the invention described in claims 1 to 3, the material layer of the wiring electrode is etched while the masking photoresist of the material layer of the wiring electrode is etched back to form the wiring electrode. Since the shape of the edge part can be made into a linear taper, concentration of current density in the heat generating part can be prevented, and
Step coverage in the heat generating section can be improved.

[0067] The invention according to claims 4 to 6 provides a wiring structure in which the substrate forming step is performed by etching the material layer of the wiring electrode while etching back the masking photoresist of the material layer of the wiring electrode to form the wiring electrode. By including the electrode etching step, it is possible to manufacture a recording head that has excellent durability, low power consumption, and high performance.

[Brief explanation of the drawing]

FIG. 1 is a schematic diagram showing a process in which a material layer of a wiring electrode is etched to explain a first embodiment of the method for manufacturing a recording head substrate of the present invention; FIG. Figures showing the state before etching the layer, (B) to (D
) is a diagram showing the state in the middle of etching the material layer of the wiring electrode, and (E) is a diagram showing the state when the material layer of the wiring electrode has been etched.

FIG. 2 is a diagram showing the shape of the formed wiring electrode;
A) is a sectional view taken along line AA in (B), and (B) is a plan view.

3 is a schematic diagram showing the vertical structure of a portion of an inkjet recording head substrate manufactured by the manufacturing method shown in FIG. 1. FIG.

FIG. 4 is a diagram showing the shapes of the edge portions and both side surfaces of the collector-base common electrode, emitter electrode, and isolation electrode shown in FIG. 3, and (A) is a cross section taken along line A-A in (B). FIG. 2B is a plan view.

FIG. 5 is a diagram showing the flow of current in the heat generating section shown in FIG. 3;

6 is a diagram showing a manufacturing process of the inkjet recording head substrate shown in FIG. 3. FIG.

7 is a diagram showing a manufacturing process of the inkjet recording head substrate shown in FIG. 3. FIG.

8 is a diagram showing a manufacturing process of the inkjet recording head substrate shown in FIG. 3. FIG.

9 is a diagram showing a manufacturing process of the inkjet recording head substrate shown in FIG. 3. FIG.

10 is a diagram showing a manufacturing process of the inkjet recording head substrate shown in FIG. 3. FIG.

11 is a diagram showing a manufacturing process of the inkjet recording head substrate shown in FIG. 3. FIG.

12 is a diagram showing a manufacturing process of the inkjet recording head substrate shown in FIG. 3. FIG.

13 is a diagram showing a manufacturing process of the inkjet recording head substrate shown in FIG. 3. FIG.

14 is a diagram for explaining the basic operation of a bipolar transistor, which is a functional element for driving the inkjet recording head substrate shown in FIG. 3. FIG.

FIG. 15 is a schematic cross-sectional view for explaining a method of manufacturing a recording head according to the present invention.

FIG. 16: Second method for manufacturing a recording head substrate of the present invention.
FIG. 2 is a diagram showing an example of the above, in which (A) is a diagram showing the state before etching the material layer of the wiring electrode, and (B) is a diagram showing the state after etching the material layer of the wiring electrode. - A cross-sectional view taken along line A, and (C) a plan view showing the state after etching the material layer of the wiring electrode.

FIG. 17 is a schematic configuration diagram showing the configuration of an inkjet recording head used in an inkjet recording apparatus.

FIG. 18 is a schematic diagram showing a vertical structure of a portion of an inkjet recording head substrate according to the configuration proposed in Japanese Patent Application Laid-Open No. 57-72867.

FIG. 19 is a schematic diagram showing the process of etching the material layer of the wiring electrode in the heat generating part by photolithography; (A) is a diagram showing the state before the material layer of the wiring electrode is etched; ) to (D) are diagrams showing the state in the middle of etching the material layer of the wiring electrode, and (E) is a diagram showing the state when the etching of the material layer of the wiring electrode is completed.

20 is a diagram for explaining the problem of the inkjet recording head substrate shown in FIG. 18. FIG.

FIG. 21 is a schematic configuration diagram showing an example of the configuration of an inkjet recording apparatus equipped with an inkjet recording head manufactured by the recording head manufacturing method of the present invention.

[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
High concentration N type emitter region 11 High concentration N type collector region 12 Collector/base common electrode 13 Emitter electrode 14 Isolation electrode 15 Anode wiring electrode 20 Heat generating part 21 Heat storage layer 22 Interlayer film 23 Heat generating resistor layer 24 Wiring electrode 241 Edge part 242 Side surface 25 First protective film 26 Second protective film 30 Bipolar transistor 34 Wiring electrode material layer 40 Inkjet recording head substrate 50,1
00 Photoresist for mask 204 Top plate 208 Discharge port TH Through hole P Pad RH1, RH2 Electrothermal conversion element SH1, SH2
Diode cells S1, S2 Switch signal G1 Switching signal VH1 Bias

Claims (6)

[Claims] 1. A plurality of electrothermal transducers, a plurality of driving functional elements that drive each of the electrothermal transducing elements, and each of the driving functional elements and each of the electrothermal transducing elements are formed by photolithography. In a method for manufacturing a recording head substrate in which a plurality of wiring electrodes to be connected to each other are formed on a substrate, an alkaline solution containing tetramethyl ammonium hydroxide as a main component is used to mask the material layer of the wiring electrodes. A method of manufacturing a recording head substrate, comprising etching a material layer of the wiring electrode while etching a photoresist to form the wiring electrode. 2. The concentration of tetra methyl ammonium hydroxide in the alkaline solution is 1.5 to 3.
2. The method for manufacturing a recording head substrate according to claim 1, wherein the content is 0%. 3. The method for manufacturing a recording head substrate according to claim 1, wherein the material layer of the wiring electrode is an aluminum layer. 4. A plurality of electrothermal transducers, a plurality of driving functional elements that respectively drive each of the electrothermal transducing elements, and each of the driving functional elements and each of the electrothermal transducing elements are formed by photolithography. A substrate creation step of forming a plurality of wiring electrodes to be connected on a substrate to create a recording head substrate, and an ink ejection portion having a plurality of ejection ports for ejecting ink on the recording head substrate. In the method for manufacturing a recording head, the substrate forming step includes forming a photoresist for a mask of the material layer of the wiring electrode using an alkaline solution containing tetramethyl ammonium hydroxide as a main component. A method for manufacturing a recording head, comprising a wiring electrode etching step of etching a material layer of the wiring electrode while etching backward to form the wiring electrode. 5. The concentration of tetra methyl ammonium hydroxide in the alkaline solution is 1.5 to 3.
5. The method for manufacturing a recording head according to claim 4, wherein the amount is 0%. 6. The method for manufacturing a recording head substrate according to claim 4, wherein the material layer of the wiring electrode is an aluminum layer.