JP3297482B2 - Method of manufacturing polycrystalline silicon-based substrate for liquid jet recording head - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polycrystalline silicon-based substrate used in a liquid jet recording head for performing recording by discharging a recording liquid from a discharge port by utilizing thermal energy. And a method for manufacturing the substrate. The present invention further relates to a liquid jet recording head and a liquid jet recording apparatus using the substrate.

(Background Art) A recording liquid such as ink is ejected and ejected from an ejection port by utilizing thermal energy, and paper,
A liquid jet recording method for performing recording by attaching a recording liquid to a recording medium such as a plastic sheet or cloth is a non-impact recording method, which has low noise and is particularly limited to a recording medium. There is an advantage that there is no color image recording and that a color image can be easily recorded.

[0003] An apparatus for implementing such a liquid jet recording method, that is, a liquid jet recording apparatus, has a relatively simple structure, the liquid jet nozzles can be arranged at a high density, and the speed of the recording apparatus can be increased. It has the advantage that it can be easily achieved. For these reasons, the above-described liquid jet recording method has attracted public attention, and many studies have been made on the recording method. Incidentally, some liquid jet recording apparatuses for performing the liquid jet recording method have been marketed and put to practical use.

FIG. 5A is a fragmentary perspective view of a recording head used in such a liquid jet recording apparatus.
FIG. 5B is a sectional view of a principal part taken along a liquid path of the recording head shown in FIG. 5A and perpendicular to the substrate.

As shown in FIGS. 5A and 5B, a recording head generally has a plurality of discharge ports 7 for discharging a recording liquid such as ink and the like, and corresponds to each of the discharge ports 7. The liquid path 6, a liquid chamber 10 for supplying a recording liquid to each liquid path 6, a heating resistor 2a for applying thermal energy to the recording liquid, and a wiring 3a for supplying an electric signal to the heating resistor 2a. , 3b are provided.

As shown in FIG. 5B, the substrate 8 for the liquid jet recording head is generally provided with a heating resistor layer 2 on a base 1 and has a good electrical conductivity on the heating resistor layer 2. A wiring layer 3 made of a material having the above-described structure is laminated, and a portion where the wiring layer 3 is not disposed becomes a heating resistor 2a. In this configuration, the wirings 3a,
When an electric signal is applied to the heating resistor 2a via 3b, the heating resistor 2a generates heat. Further, in the liquid jet recording head substrate 8, the wirings 3a,
A protective layer 4 can be provided for covering the heating resistor 3b and the heating resistor 2a. The protective layer 4 is provided with a heating resistor 2 a and a wiring 3 due to contact with a recording liquid or penetration of the liquid.
It contributes to prevention of electrolytic corrosion and electrical breakdown of the a and 3b.

As the substrate 1 constituting such a liquid jet recording head substrate 8, a plate-like member made of a material such as silicon, glass or ceramics can be used. Usually, however, substrates made of single-crystal silicon are used exclusively. The reason is as follows. That is, when glass is used as the base 1, the glass has poor thermal conductivity.
If the heat generation cycle (driving frequency) of is increased, the heat generated by the heat generating resistor in the base 1 is excessively accumulated, and as a result,
Due to the accumulated heat, the ink in the liquid jet recording head is heated, bubbles are generated, and ink ejection failure is likely to occur. When ceramics are used as the base 1, there is an advantage that a base having a relatively large size can be manufactured and a material having a higher thermal conductivity than glass can be selected. However, in the case of a ceramic substrate,
Generally, since raw material powder is fired, several μm to several tens μm
surface defects such as pinholes and small protrusions
Such surface defects tend to cause failures such as short-circuiting or disconnection of the wiring, which causes a reduction in yield. Also, the surface roughness is usually about Ra (center line average roughness) = 0.15 μm, and the optimum surface roughness for forming the heating resistance layer 2 having excellent durability performance cannot be obtained. For example, when a liquid jet recording head is manufactured using an alumina ceramic substrate, the heating resistance layer 2 may be peeled off from the substrate 1 or a part of the heating resistance layer disposed at a defective portion may be formed due to these causes. In addition, the cavities generated when the foamed foam disappears
However, there is a drawback that the heat generation resistance layer is disconnected and the durability life is shortened.

In order to solve these problems when using a ceramic substrate, the surface of the ceramic substrate 1 is polished and smoothed to improve the adhesion of the heating resistor layer 2 and the cavitation is reduced. There is a proposal to prevent early disconnection of the heating resistance layer caused by concentration on a part of the heating resistance layer. However, in this proposal, since alumina generally has high hardness, there is a limit in adjustment of the surface roughness, and this is not practical.

There is also a proposal to improve the above-mentioned problem by providing a glaze layer (a glassy layer is welded) on the surface of a ceramic substrate to form an alumina glaze substrate. However, the glaze layer cannot be formed to a thickness of 40 to 50 μm or less by a forming method that can be adopted, and a problem of heat storage occurs as in the case of a glass substrate. Not.

When silicon is used for the substrate 1, there is no problem of excessive heat storage when the above-mentioned glass or ceramics is used for the substrate 1. In particular, when a single-crystal silicon wafer is used, the surface property is extremely low. Therefore, there is almost no concern that the above-described problem such as disconnection of the wiring may occur. For this reason, for example, Japanese Patent Application Laid-Open No.
As can be seen in Japanese Patent Application Laid-Open No. H10-209, a single-crystal silicon wafer is used as a substrate for a liquid jet recording head utilizing the above-described thermal energy.

In recent years, in the field of recording using the liquid jet recording method, early provision of a recording apparatus capable of obtaining higher quality recording at higher speed is desired. From the viewpoint of responding to the demand for high-speed recording, in order to enable recording on a wide recording medium, intensive research has been conducted on a large recording head such as a so-called full line head having a width corresponding to the recording width. Has been established.

As a result of such research, as described above, a single-crystal silicon wafer is optimal as a substrate for a recording head as long as the recording head is relatively small, but is not suitable for increasing the size of the recording head. It is pointed out that the use of a single-crystal silicon wafer as a base causes the following inconveniences, and that there is a problem that needs to be solved before a single-crystal silicon wafer can be used as a base for a large recording head. ing.

[0013]

That is, when the recording head substrate is made of single-crystal silicon, the single-crystal silicon substrate, that is, the single-crystal silicon wafer is usually prepared from a single-crystal ingot manufactured by a single-crystal pulling method. It is formed by cutting. At present, the size of a single crystal ingot that can be manufactured by this single crystal pulling method is limited to a rod-shaped one having a diameter of 8 inches and a length of about 1 m. Therefore, there is naturally a limit to the single crystal substrate that can be obtained by cutting the obtained single crystal ingot. In addition, if it is attempted to cut out a long substrate as much as possible from such a single crystal ingot, the use efficiency of the ingot becomes extremely poor, so that the obtained crystal wafer becomes irreversibly expensive, and All this adds cost to the end product.

In the substrate for a liquid jet recording head, a heat storage layer for achieving a good balance between heat storage properties and heat dissipation properties is provided on the surface of the base for better transferring heat to the recording liquid. A lower layer). In this case, the substrate is thermally oxidized on the surface of the single-crystal silicon wafer cut out of the above-described single-crystal ingot to form a heat storage layer of an SiO ₂ layer, and after forming the above-described heat-generating resistance layer, wiring, and the like, It is manufactured by separating each recording head.

However, when the present inventor studied to obtain a large recording head, there was a problem that the substrate cut out from the end of the single crystal silicon wafer was deformed in an arc shape as shown in FIG. Was found to occur. And the deformation amount reaches a maximum of 60 μm to 90 μm, and when this deformation is forcibly corrected, there are many cases where the substrate is broken, and even if the deformation is small, the substrate continues after the cutting step of the substrate. Even in the polishing process, it is difficult to perform uniform polishing, the accuracy of patterning becomes poor when patterning wiring on the substrate, or the wiring and IC etc. It has been found that there is a problem that it is difficult to connect with high accuracy. Even if a liquid jet recording head can be manufactured using a substrate that has been bent, even if the substrate is bent, the bent position of the recording liquid causes a shift in the adhesion position of the recording liquid to the recording medium. It has been found that there is a problem that image quality is deteriorated such as omission or unevenness.
In addition, when the portion that causes this deformation, that is, the edge of the silicon wafer is not used as the recording head substrate,
It has been found that the manufacturing cost of the substrate itself is very high.

When the cause of such a deformation of the substrate has been intensively studied, no bending deformation of the substrate is observed in the substrate not provided with the above-mentioned thermal oxide layer as the heat storage layer. That is, it was found that the above-mentioned deformation was caused by the thermal oxidation process. The deformation occurs because the edge of the single crystal silicon wafer, particularly the four corners, is cooled most quickly when the single crystal silicon wafer is cooled after the heat treatment, as shown by the arrow in FIG. A tensile stress is generated at the outer edge of the base, and the stress is distributed in the base in a state as indicated by a sign (+) in FIG. 8B, and the stress is distributed from such a wafer as shown in FIG. 9A. It has been found that when a part is cut to form a substrate, a part of this stress is released to cause bending deformation.

Therefore, when a single-crystal silicon substrate is used as a substrate for a recording head substrate, there is naturally a limit in achieving a longer substrate. Therefore, when producing a long head for achieving higher-speed recording, it is required to connect and integrate a substrate for a shorter recording head. However, in this case, it is extremely difficult to adjust the joint portion of the substrate so as not to adversely affect the recorded image.

Accordingly, the shape of the substrate for a liquid jet recording head is not restricted by the manufacturing process, and high-speed, high-quality recording can be easily achieved without problems such as deformation of the substrate for a recording head due to enlargement. There is an urgent need to provide an inexpensive liquid jet recording substrate capable of performing such a process.

[0019]

SUMMARY OF THE INVENTION The main object of the present invention is to solve the above-mentioned problems with the conventional liquid jet recording head substrate and to obtain a specific material capable of obtaining a large recording head. It is an object of the present invention to provide a method for manufacturing a long substrate for a liquid jet recording head using a substrate knitted in the above.

[0020]

[0021]

[0022]

Another object of the present invention is to form a thermally oxidized layer having good surface properties on the surface of a substrate made of polycrystalline silicon used for the above-described substrate for a liquid jet recording head. An object of the present invention is to provide a method for manufacturing a head substrate.

The present inventor has studied through the following experiments to solve the above-mentioned problems in the conventional liquid jet recording head substrate and to achieve the above object. As a result, the inventor has obtained the following knowledge. That is, when polycrystalline silicon is used as the base of the liquid jet recording head substrate,
(I) When the above-mentioned single crystal silicon wafer is used,
It is possible to eliminate a problem relating to the restriction on the size of the substrate and a problem relating to deformation, and to provide a recording head capable of recording a high-quality recording image at high speed at a low price. And (ii) forming a thermal oxidation layer on the surface of the polycrystalline silicon substrate, in the case of forming a thermal oxidation layer on the surface of the substrate, providing an oxygen diffusion barrier layer on the surface of the substrate and performing oxidation treatment. By carrying out the above, it has been found that the amount of oxygen diffused into the substrate can be controlled, and a thermal oxide film having good surface properties can be formed.

The present invention has been completed based on the above findings obtained by the present inventors through experiments.

[0026]

[0027]

[0028]

[0029]

[0030]

[0031]

According to the method of manufacturing a substrate for a liquid jet recording head of the present invention, a good thermal oxide film is formed while maintaining the flatness of the surface even though polycrystalline silicon having a rough surface is used as a substrate. This makes it possible to obtain a substrate having a surface oxide layer having a high durability performance and having no fear of disconnection of wiring or the like formed on the substrate.

(Experimental Example) Conventionally, polycrystalline silicon members on a plate have been used in the field of solar cells. If the polycrystalline silicon member is to be used as a substrate for a liquid jet recording head, it is necessary to provide a precise wiring or the like on the polycrystalline silicon member. It is said. However, unlike a single-crystal member, a polycrystalline silicon member has crystals of various orientations. Therefore, even if polishing for obtaining a mirror surface is performed, the desired surface property of a substrate for a liquid jet recording head is obtained. It is general recognition in the art that it is difficult to achieve, and therefore no attempt has been made in the field of liquid jet recording heads to use polycrystalline silicon as a substrate.

The inventor of the present invention, ignoring such recognition, attempted to use polycrystalline silicon as a substrate of a liquid jet recording head substrate through an experiment described below. As a result, they have found that polycrystalline silicon can be effectively used as a substrate of a substrate for a liquid jet recording head.

An experiment performed by the present inventors will be described below.

Experiment A In the case of a conventional single crystal wafer, mechanochemical polishing has been used because it is necessary to minimize the surface processing-affected layer as a semiconductor device. In the case of mechanochemical polishing, a polishing agent for polishing is obtained by adding various alkalis such as NaOH, KOH and organic amine to colloidal silica in the case of primary polishing, and a polishing agent obtained by adding ammonia to colloidal silica in the case of secondary polishing.

When the surface of a polycrystalline silicon substrate is processed by the above-mentioned polishing means, a step is generally generated. The following experiment was conducted on the assumption that the reason for this is that the amount of silicon etched by the alkali component in the polishing agent varies depending on the crystal orientation.

A single crystal substrate sample was prepared as follows. First, a boron oxide produced by crushing a high-purity polycrystalline rod having a residual impurity concentration of 1 ppb or less produced by a precipitation reaction by hydrogen reduction and thermal decomposition of SiHcl ₃ and then pulling it up in the <111> direction by the CZ method is manufactured. From a punt P type single crystal ingot (8 inch × 110 cm), it was shaped into a prism using a grinder, and cut into a plate using a multi-wire saw. Next, the surface layer was removed and flattened by about 30 μm by lapping.

On the other hand, as a sample of the polycrystalline silicon substrate, high-purity polycrystalline silicon produced by a precipitation reaction by hydrogen reduction and thermal decomposition used for production of single crystal silicon or crushed single crystal silicon is used. After heating and melting to 1420 degrees in a crucible, pour into a graphite mold,
It was cooled to form a 40 cm square ingot. Next, the ingot was cut into a plate shape using a multi-wire saw. Next, the surface portion was removed by about 30 μm by lapping to make it flat.

As described above, 300 mm × 150 mm ×
A plurality of samples each having a size of 1.1 mm (hereinafter abbreviated as 300 × 150 × 1.1 (mm) for simplicity) were prepared for each of single-crystal silicon and polycrystal silicon as shown in Table 1.

As a polishing apparatus, a single-side polishing machine manufactured by Speed Fam Co., Ltd. was used.

The polishing step was divided into primary polishing and secondary polishing under the conditions described below, and the presence / absence of alkali addition during the primary polishing and the surface finishing performance were evaluated.

The evaluation results are shown in Table 1.

[0044]

[Table 1] Primary polishing conditions: polishing cloth; polyurethane-impregnated polyester nonwoven fabric, abrasive; colloidal silica (particle diameter 0.06 μm), polishing pressure: 250 g / cm ² , polishing temperature: 42 ° C., processing speed: 0.7 μm / min secondary Polishing conditions: polishing cloth; suede-type foamed polyurethane, abrasive: silica fine powder (0.01 μm), polishing pressure: 175 g / cm ² , polishing temperature: 32 ° C., processing speed: 0.07 μm / min The results show that even if a polycrystalline silicon substrate is used, it is possible to obtain the same smoothness as a single crystal substrate by eliminating the addition of alkali during polishing, and that polycrystalline silicon can be used as a substrate for a liquid jet recording head. Do you get it.

Experiment B In this experiment, the difference in the amount of deformation between a single crystal silicon substrate and a polycrystalline silicon substrate when a long substrate was formed was examined.

A substrate sample of single crystal silicon was prepared as follows. That is, a crushed high-purity polycrystalline silicon rod with a residual impurity concentration of 1 ppb or less prepared by hydrogen reduction and thermal decomposition of SiHcl ₃ was melted and pulled up in the <111> direction by the CZ method. Borondo-Punt P-type single crystal ingot (8 inch × 110
cm), it was shaped into a prism using a grinder, and then cut out into a plate using a multi-wire saw. Next, after removing the surface layer and flattening it by about 30 μm by lapping,
After chamfering the end with a beveling machine, a final surface finish was performed by polishing to obtain a mirror-finished substrate having a surface roughness Rmax of 150 °.

Next, the substrate surface was thermally oxidized by a pyrogenic oxidation method (hydrogen combustion oxidation method) as schematically shown in FIG. The oxidation is performed, for example, as follows. That is, hydrogen and oxygen are separately introduced into the base quartz tube 73 which is thermally oxidized, and react in the quartz tube 73 to generate H ₂ O, and the remainder is burned. Quartz tube 73
Inside, a base 71 for performing a thermal acid oxidation treatment is disposed.
Heated by electric furnace 74.

The thermal oxidation of the prepared substrate is performed by the above-described oxidizing apparatus and method, and the gas pressure; 1 atm;
By introducing oxygen at 1150 ° C. for a treatment time of 14 hours, a thermal oxide layer of 3 μm was obtained.

In this way, five single crystal silicon substrate samples having the dimensions shown in Table 2 were prepared.

On the other hand, as the polycrystalline silicon substrate sample, a high-purity polycrystal manufactured by hydrogen reduction and a deposition reaction by thermal decomposition used for the production of a single crystal, or a crushed single crystal is used.
After heating to 1420 ° C. in a quartz crucible to melt, it was poured into a graphite mold and cooled to form a 120 cm 2 ingot. The higher the cooling rate is, the smaller the crystal grain size is. Therefore, the grain size becomes smaller on the outer side of the ingot in contact with the mold, and becomes larger near the center. A plate-like polycrystalline silicon was cut out of the ingot at a position where the average crystal grain size became 2 mm with a multi-wire saw.

Next, after lapping, the surface layer was removed and flattened by about 30 μm, the end was chamfered by a beveling machine, and then the final surface was finished by polishing to obtain a mirror surface with a surface roughness Rmax of 150 °. Finished on a substrate.

Next, a thermal oxidation layer was formed to a thickness of 3 μm by the above-mentioned pyrogenic method under the same conditions as those described above.

In this way, five polycrystalline substrate samples having the dimensions shown in Table 2 were prepared.

Next, an aluminum layer (4500.degree.) As a wiring, a hafnium; Hf layer (1500.degree.) As a heating resistor, and protection of the upper layer were formed on the respective surfaces of the single-crystal silicon substrate sample and the polycrystalline silicon substrate sample. A plurality of substrates were formed by laminating a Ti layer (50 °) as a layer for improving adhesion to the layers, and SiO ₂ (1.5 μm), Ta (5000 °), and polyimide (3 μm) as protective layers, respectively.

In the manufacturing process of the liquid jet recording head, in the next step, a 20 μm-thick negative dry film is laminated to form a flow path, and the flow path is patterned by exposing the flow path. In this case, if the substrate is warped, the focus position shifts, resulting in poor exposure. Therefore, the degree of warpage was evaluated for each of the obtained substrates. The degree of warpage was determined by placing the sample on a surface plate and measuring the maximum displacement using a dial gauge having a minimum scale of 1 μm. Table 2 shows the results.

[0056]

[Table 2]

The results shown in Table 2 are 300 × 150 ×
The maximum amount of warpage of a polycrystalline silicon substrate sample having a sample size of 1.1 (mm) is set to 1, and the other samples are relative values of the maximum amount of warpage.

As is evident from the results shown in Table 2, the polycrystalline silicon substrate sample showed only the same amount of warpage in all the sizes used in the experiment, whereas the single crystal silicon substrate sample did not. An increase in the amount of warpage was observed from a sample size of × 150 × 1.1 (mm), and 800 × 150
With a sample size of × 1.1 (mm), a warpage relative value of 3 is shown; with a warpage relative value of 2, when actual exposure is performed, exposure defects due to a shift in focus position considerably occur, In the case of the warpage relative value of 3, all of the exposures were defective; and in the case of the single crystal silicon substrate sample, 500 × 1
A sample size of 50 × 1.1 is the limit at which a liquid jet recording head can be manufactured.

Experiment C In this experiment, the relationship between the crystal grain size and the deformation due to the warpage of the substrate was examined for a single crystal silicon substrate and a polycrystalline silicon substrate. In the same manner as in Experiment B, ten mirror-finished single-crystal silicon substrates (sample No. 1) each having a size of 300 × 150 × 1.1 (mm) were prepared. Separately, a plurality of mirror-surface polycrystalline silicon substrates having a size of 300 × 150 × 1.1 (mm) were prepared in the same manner as in Experiment B. At this time, since the crystal grain size of the substrate is selected from polycrystalline silicon ingots, since the crystal grain size increases from the surface in contact with the mold toward the center, an appropriate portion is selected when cutting out from the ingot. As a result, the sample No. A plurality of substrates having the average crystal grain diameters shown in the items 2 to 8 (Sample Nos. 2 to 8)
Were obtained 10 sheets each.

At this time, the average crystal grain size of the substrate was determined by JI
SG 0552 “Steel ferrite grain size test method”
Was measured by a crystal grain size measuring method according to the “cutting method” described in the section. Prepared single crystal silicon substrate (sample N
o. For each of 1) and the polycrystalline silicon substrate, a 3 μm-thick thermally oxidized layer was formed on the surface by pyrogenic oxidation in the same manner as described in Experiment B.

An integrated long liquid jet recording head is manufactured by cutting each head in a strip shape from the substrate, but as a problem at this time, there is a problem that only the heads cut out from both ends of the substrate bend like a bow. FIG. 9A shows a state in which bowing or bending occurs.

Incidentally, if the polished surface is warped in the polishing process, the distance between the heating element and the face surface cannot be made uniform, which causes a problem in printing quality.

Then, for the purpose of calculating the process yield in the polishing process, two samples for bending measurement were prepared from each end of the substrate by cutting them into strips each having a width of 10 mm with a slicer. The number of samples for each sample in Table 3 was 2
0 were created.

The prepared sample was placed on a precision XY table with a linear scale, and the maximum bending amount was measured.

FIGS. 9 (B), 9 (C) and 9 (D) are explanatory views of the bow / bend measurement method adopted in this case.

The points a and b in FIG. 9D are replaced with the X of the XY table.
The amount of bending in the Y direction was measured along the axis.

Samples that exceeded the allowable bending amount in the polishing step were rejected, and the pass rate under each condition was counted. Table 3
The sample No. Sample No. 8 has a pass rate of 1 for a sample having an average crystal grain size of 0.01 mm, and for other samples, Sample No. The relative value to the value of 8 was shown.

[0068]

[Table 3]

From the results shown in Table 3, it has been found that a polycrystalline silicon substrate is less deformed by warpage than a single crystal silicon substrate. Further, even in a polycrystalline silicon substrate, those having an average crystal grain size exceeding 8 μm have little advantage over single crystal silicon, and those having an average crystal grain size exceeding 2 μm and an average crystal grain size of 8 μm or less have a single crystal silicon. Although superior to crystalline silicon, it was found that it was inferior to those having an average crystal grain size of 2 μm or less. From this, it was found that the average crystal grain size of the polycrystalline silicon substrate is preferably 8 μm or less, more preferably 2 μm or less.

Experiment D The substrate constituting the substrate for the liquid jet recording head was as follows.
Since wiring is provided on the base, the surface of the base is required to be smooth to a desired state. Therefore, it is necessary to satisfy this requirement even when the substrate is made of polycrystalline silicon.

By the way, polycrystalline silicon is used in the field of solar cells. In this case, the surface condition of the substrate made of polycrystalline silicon depends on that of the substrate constituting the substrate for a liquid jet recording head. There is no severe requirement regarding surface smoothness as described above. Incidentally, a polycrystalline silicon substrate used for a solar cell usually contains inclusions. That is, a polycrystalline silicon ingot used for obtaining a polycrystalline silicon substrate for a solar cell is manufactured by melting silicon in a quartz crucible and cooling and solidifying the molten silicon. The silicon melt is chemically very active, and quartz as the constituent material of the crucible material is also Si
It reacts like O ₂ + Si → 2SiO. As a result, the silicon firmly adheres to the inner wall of the crucible during cooling and solidification.

When a strain is applied to the quartz and silicon due to a difference in thermal expansion coefficient between them, the crucible is easily cracked. Therefore, when the ingot is taken out of the crucible, a powdery release agent is applied to the inner wall surface of the crucible so that it can be easily taken out. Therefore, the release agent inevitably intervenes in the polycrystalline silicon ingot.

Such inclusions do not cause any problem in the solar cell. However, when wiring is applied on a substrate made of such polycrystalline silicon, if the surface of the substrate is first polished and mirror-finished, the inclusions become defects such as pits or projections of several tens of μm and remain on the surface of the substrate. . If such a defect is present, when wiring is patterned by photolithography technology, a portion where the resist cannot be applied or a portion where the resist accumulates may occur, resulting in disconnection or short circuit of the wiring. In some cases. Further, if such a defect is located at a position where the heating resistor is disposed, cavitation damage is concentrated at the time of bubble disappearance generated due to ink ejection, resulting in early disconnection.

In this experiment, the influence of the inclusions contained in the polycrystalline silicon when the substrate constituting the substrate for the liquid jet recording head was made of polycrystalline silicon was examined in the background described above. We examined from the quantitative viewpoint.

First, as in the case of the experiment B, 330 × 1
A single crystal substrate having a size of 50 × 1.1 (mm) is cut out,
Lapping and polishing, surface roughness is Rma
It was finished to a mirror substrate of x150 °. This substrate was used as Sample 1. At this stage, the surface condition of the substrate (sample 1) was observed by a substrate surface inspection apparatus (trade name: Scantech, manufactured by Nagase & Co., Ltd.) using a CCD reading method. As a result, since there was no inclusion of the release agent, the number of defects per area of the substrate was 1 / cm 2 or less at all measurement points in the range of the detection capability diameter of 1 μm or more. The results are shown in Table 4.

[0076]

[Table 4]

Separately from the above, silicon was melted in a quartz crucible in which a mold release agent was not applied to the inner surface, and then a 50 cm square polycrystalline silicon ingot was prepared. From this ingot, a polycrystalline silicon substrate having the same dimensions as that of the single crystal silicon substrate was cut out, and its surface was wrapped and polished to finish a mirror surface substrate having a maximum surface roughness of 150 mm. This substrate was used as Sample 2. In the same manner as in the case of the single crystal silicon substrate (sample 1),
The surface condition of the substrate was observed. As a result, since there was no inclusion of the release agent, the number of defects per area of the substrate was 1 at all measurement points in the range of the detection capability diameter of 1 μm or more.
Pcs / cm2 or less. The results are shown in Table 4.

Next, the same operation as in the preparation of Sample 2 was performed except that a release agent was used, and a plurality of substrates (Sample 3) were prepared.
To 6) were created. The amount of the release agent used was different for each sample. The obtained substrate (sample 3
The surface condition of each of the samples 6 to 6) was observed in the same manner as in the single-crystal silicon substrate (sample 1).

As a result, the number of defects in each of the samples 3 to 6 was 5 / cm 2 or less and 10 / cm 2 or less, respectively.
0 / cm2 or less and 100 / cm2 or less. Next, the surface of each of the substrates (samples 1 to 6) was subjected to a thermal oxidation treatment in the same manner as in the experiment B to obtain a 3 μm-thick thermally oxidized layer.

Next, as a test wiring pattern for detecting a disconnection or a short circuit due to inclusions, an Al film was formed on the thermally oxidized layer of each sample to a thickness of 4500 mm by a magnetron sputtering method. Then, a folded wiring pattern having a wiring width of 20 μm and a wiring interval of 10 μm was prepared. At this time, the number of folded wirings of each sample is determined by the wiring pattern of the liquid jet recording head.
Assuming that the wiring length is 8 mm and the number of wirings is 4736, the test pattern
And 20 test patterns were formed for each sample.

A continuity test was performed by bringing the probe pins into contact with the ends of each wiring. The continuity test was evaluated on the basis of a test in which no disconnection or short circuit was found. The evaluation result is the number of patterns for which no disconnection or short circuit occurred for 20 test patterns, that is, the number of passed patterns / 2.
0 test pattern was expressed as yield. The results obtained are as shown in Table 4.

From the results shown in Table 4, the following was found. That is, (i) polycrystalline silicon having no release agent inclusions exhibits the same yield as single crystal silicon; (ii) even polycrystalline silicon having release agent inclusions has a defect number of 1 μm or more in diameter. Those having 5 / cm2 or less show the same yield as single crystal silicon; (iii) 10 / cm2 or more defects having a diameter of 1 μm or more.
Yields lower than 5 cm2 / cm2 have a lower yield than those lower than 5 cm2 / cm2, but to a lesser extent; and (iv) yields of 50 μm / cm2 or less having a diameter of 1 μm or more It is not practical because the deterioration is large, and the diameter is 1 μm
Those having the number of defects of 100 defects / cm2 or less are not practical. From the findings, the following findings were obtained. That is, for a polycrystalline silicon member which can be effectively used as a substrate constituting a liquid jet recording head substrate, its surface is preferably smooth (smooth state), and the number of defects having a diameter of 1 μm or more is 10 / cm 2 or less. More preferably, the number of defects having a diameter of 1 μm or more should be 5 / cm 2 or less.

Experiment E In this experiment, a study was made from the viewpoint of eliminating the surface step caused by the polycrystalline silicon when the base constituting the substrate for the liquid jet recording head was composed of polycrystalline silicon. As described in the Background Art section above, when single crystal silicon is used as a substrate constituting a substrate for a liquid jet recording head, the heat radiation property of the substrate is used in order to obtain better characteristics as a liquid jet recording head. And balance heat storage
Generally, a heat storage layer is formed on the surface of a single crystal silicon substrate. As the heat storage layer, an SiO ₂ layer formed by thermally oxidizing the surface of the single crystal silicon substrate is usually used. The present inventor uses a polycrystalline silicon substrate in place of the single crystal silicon substrate, and thermally oxidizes the surface of the polycrystalline silicon substrate to form a SiO ₂ layer as a heat storage layer in the same manner as in the case of forming the heat storage layer. Then, the surface state of the SiO ₂ layer was observed. As a result, it was found that a maximum difference of about several thousand degrees was generated between crystal grains on the surface of the SiO ₂ layer.

If such a step is present on the base constituting the substrate for a liquid jet recording head, damage is concentrated on the step due to thermal shock of heating / cooling and / or cavitation generated at the time of discharging the recording liquid. In the case where a heating resistor is formed on the stepped portion, there arises a problem that reliability in terms of durability life is reduced. That is,
In particular, when the ejection of the recording liquid is repeated at a high speed, cavitation concentrates on the step portion, whereby the heating resistor is broken at an early stage.

As a measure for solving such a problem, the above S
After forming the iO ₂ layer, the surface of the SiO ₂ layer may be polished and flattened. However, this method does not provide a satisfactory solution to the problem.

[0086] That is, the surface level difference of the SiO ₂ layer in addition to those of several thousands Å, as described above, the SiO ₂
Since the layer is preferably several microns thick,
As another solution to the problem without inhibiting the function of the SiO ₂ layer through polishing, the Si 2
It is also conceivable to make the O ₂ layer considerably thick and to polish the surface on the surface as described above. In this case, however, there is a problem that such an excessively thick SiO ₂ layer does not function as a desired heat storage layer and it is economical. Not practical from a point of view. The inventor described the formation of the heat storage layer (that is, the SiO ₂ layer) by a vacuum film forming method, that is, a sputtering method, a thermal CV method.
Attempts were made in each of the D method, the plasma CVD method, and the ion beam evaporation method, but in any case, the film thickness was not uniform, it took a long time to form the film, Was mixed into the film, resulting in projections several microns in diameter that caused destruction by cavitation. It has also been found that the occurrence of such protrusions causes a current to leak therefrom, causing an electrical short circuit. For this reason, the vacuum film formation method uses the heat storage layer (that is, SiO ₂
Layer). The present inventor tried to form the heat storage layer (SiO ₂ layer) by employing each of the spin-on-glass method and the dip pulling method.
In any case, the film quality of the formed SiO ₂ layer is poor, it is difficult to achieve good film quality, and impurity particles may be mixed in the film. Turned out to be unacceptable.

The present inventor has studied the cause of the occurrence of steps on the surface of the SiO ₂ layer when the surface of the polycrystalline silicon substrate is thermally oxidized to form a SiO ₂ layer as a heat storage layer. As a result, since the respective crystal orientations of the plurality of crystal grains constituting the polycrystalline silicon are not constant but different from each other, the thermal oxidation rates of the respective crystal grains are different during the thermal oxidation treatment. Was found to occur.

As described above, there is no appropriate means for eliminating such a surface step, but the present inventor has proposed that the surface of the polycrystalline silicon substrate be thermally oxidized by SiO 2.
We tried to form _two layers (heat storage layer) indirectly, not directly. That is, the present inventor has a function equivalent to that of the heat storage layer (SiO ₂ layer) formed on the surface of the polycrystalline silicon substrate and is made of a material that allows oxygen to reach the surface of the polycrystalline silicon substrate. Layer (ie diffusion barrier layer)
And the surface of the polycrystalline silicon substrate was thermally oxidized by introducing oxygen through the diffusion barrier layer.

As a result, it was found that the SiO ₂ layer formed on the surface of the polycrystalline silicon substrate by the thermal oxidation according to this technique did not have the above-mentioned surface step on the surface. Hereinafter, the reason why the SiO ₂ layer formed when the surface of the polycrystalline silicon substrate is directly subjected to the thermal oxidation treatment has a surface level difference, and that the diffusion barrier layer is provided on the surface of the polycrystalline silicon substrate The present inventor conducted an experiment on the reason why a SiO ₂ layer having no surface step is formed on the surface of the polycrystalline silicon substrate when the surface of the polycrystalline silicon substrate is thermally oxidized indirectly via the diffusion barrier layer. What has been clarified will be described with reference to FIGS. 4A to 4C.

When the polycrystalline silicon substrate 11 as shown in FIG. 4A is thermally oxidized as it is, the volume increases at the time of thermal oxidation, and the thermal oxidization rate is increased due to the difference in the crystal orientation of the crystal plane of each crystal grain 12. Is different, as shown in FIG.
Experiments have confirmed that the thickness of the thermal oxide film 13 generated for each crystal grain 12 is different, and a step is generated on the surface. In FIG. 4B, a dashed line a indicates the position of the surface of the polycrystalline silicon substrate 11 before thermal oxidation. For example,
When a thermal oxide film (SiO ₂ film) 13 having a thickness of about 3 μm is formed on the surface of the polycrystalline silicon substrate 11, a step on the surface of the formed thermal oxide film is about 1000 °. Here, the thermal oxidation process on the surface of polycrystalline silicon will be examined. In the very early stage of thermal oxide film formation, the thermal oxide film 1
A linear law holds between the thickness of No. 3 and the oxidation rate. That is, the reaction of oxygen (O ₂ ) at the interface between silicon (Si) and silicon oxide (SiO ₂ ) constituting the thermal oxide film is rate-limiting. In this case, the oxidation rate of oxygen varies depending on the orientation of the crystal plane.

On the other hand, after the thermal oxide film 13 is formed to a certain thickness or more, the process of diffusing oxygen in the thermal oxide film 13 becomes rate-determining. It is considered that the diffusion rate of oxygen in the thermal oxide film 13 does not depend on the orientation of the crystal plane of the silicon crystal grains 12. Therefore, the step on the surface of thermal oxide film 13 for each crystal grain 12 of polycrystalline silicon substrate 11 is:
It occurs very early in the thermal oxidation step, and it may be considered that the step does not increase after the thermal oxide film 13 has been formed to some extent.

Here, diffusion barrier layer 14 for limiting the diffusion rate of oxygen to the surface of polycrystalline silicon substrate 11 before thermal oxidation is provided, and thereafter thermal oxidation treatment is performed. Since the rate at which oxygen diffuses and permeates the rate of the formation of the thermal oxide film, as shown in FIG. 4C, the thermal oxide film does not depend on the crystal plane orientation of the crystal grains 12 on the surface of the polycrystalline silicon substrate 11. 13 is constant. That is, by performing the thermal oxidation treatment after providing the diffusion barrier layer 14, the formation of steps on the surface of the formed SiO ₂ layer (heat storage layer) is suppressed. The inventor has
A verification experiment on the effect when the above-described diffusion layer was used was performed by preparing a substrate for a liquid jet recording head.

That is, first, a polycrystalline silicon ingot was formed by the casting method described above. A rectangular substrate is cut out from the obtained ingot at a position where the average crystal grain size is about 2 mm, lapping and polishing are performed, and a mirror surface having a size of 300 mm × 150 mm × 1.1 mm and a surface roughness of Rmax150 ° is obtained. The substrate was used as a polycrystalline silicon substrate. Next, a 0.04 μm-thick SiO ₂ layer (diffusion barrier layer) was formed on the entire surface of each polycrystalline silicon substrate by magnetron sputtering.

Next, the surface of the polycrystalline silicon substrate was thermally oxidized via the diffusion barrier layer in the same manner and under the same conditions as those shown in Experiment B. After the thermal oxidation, the diffusion barrier layer is
It was removed by a reactive ion etching method using CHF ₃ -C ₂ F ₆ -O ₂ gas.

The removal of the diffusion barrier layer was performed for the following reason. That is, as described above, the diffusion barrier layer (SiO ₂ film) is formed by the magnetron sputtering method, and S deposited on the inner wall of the film forming chamber during the formation.
There is a suspicion that the iO ₂ film is peeled off and becomes a particle and is mixed in the diffusion barrier layer.

By treating the polycrystalline silicon substrate as described above, a polycrystalline silicon substrate having a heat storage layer formed of a thermal oxide film (SiO ₂ film) on the surface was obtained. The layer thickness of the formed heat storage layer (that is, the SiO ₂ layer) is 2.9 μm
Met.

When the surface of the heat storage layer was examined using a stylus type roughness meter, no step was found on the surface of the heat storage layer.

Next, on the surface of the support thus obtained,
By photolithography, heating resistor consisting of HfB ₂ [Size: 20 μm × 100 μm, thickness: 0.16 [mu] m, wiring density: 16 pel (i.e. 16 / mm)] a plurality and to the heating resistors The connected electrodes (20 μm wide, 0.6 μm thick) made of Al were formed. Further, a protective layer made of SiO ₂ / Ta is formed by sputtering on the portion where the heating resistor and the electrode are formed, and FIG. 1 (A) and FIG.
A substrate for a liquid jet recording head having the configuration shown in FIG.

Subsequently, a liquid path and a liquid chamber are formed on the liquid jet recording head substrate by a dry film or the like, and a discharge port is formed by slicer cutting.
A liquid jet recording head having the configuration shown in FIG.

With respect to the prepared liquid jet recording head, 1.1 Vth (Vth is a foaming voltage) and a pulse width of 10 μm were applied to each heating resistor.
An s drive pulse (print signal) was repeatedly applied to eject ink from each ejection port, and an ejection durability test was performed. The number of integrated drive pulses is 1 × 10 ⁷ , 1 × 10 ⁸ , 3 × 10 ⁸
The durability of the liquid jet recording head was evaluated by obtaining the residual ratio of the heating resistors when the above conditions were satisfied, that is, the number of the heating resistors that were not disconnected with respect to the total number of the heating resistors. The results are shown in Table 5. As shown in column 3.

[0101]

[Table 5]

For comparison purposes, a liquid jet recording head was prepared in the same manner as in the above-described method and experimental example except that the polycrystalline silicon substrate was thermally oxidized without providing a diffusion barrier layer.
An ejection durability test was performed in the same manner as in the above example. The results are shown in Table 5. The results are shown in column 1.

A comparison between the experimental example (sample No. 3) and the comparative example (sample No. 1) shows that sample no. In the case of No. 3, cavitation rupture did not occur at all, and the residual ratio was 100 even after the driving pulse was repeated 3 × 10 ⁸ times.
% Of the sample No. having a step on the surface of the heat storage layer based on the conventional technology. In the case of 1, cavitation fracture occurred from an early stage, and the residual ratio was reduced. From the above results, by providing a diffusion barrier layer having an appropriate thickness on the surface of the polycrystalline silicon substrate and performing thermal oxidation through the diffusion barrier layer, a heat storage layer having no surface steps can be obtained. It was also confirmed that extremely good results were obtained in

Next, an experiment was conducted to form a desirable heat storage layer on a polycrystalline silicon substrate as a substrate constituting a substrate for a liquid jet recording head. That is, if the heat storage layer of the liquid jet recording head is too thick, the cooling becomes insufficient as in the case of the glass substrate, so that the ejection drive frequency cannot be increased,
If the thickness is too small, the heating resistor is unlikely to rise in temperature, so that large power is required. Therefore, the thickness is usually selected in the range of 1 μm to 3 μm. Therefore, the thickness of the heat storage layer was adjusted by variously changing the thickness of the diffusion barrier layer.

First, a surface was prepared in the same manner as in the verification experiment for the effect when the diffusion layer was used, and the surface roughness was Rmax1.
A 50 ° polycrystalline silicon substrate was obtained. Then, the entire surface of each polycrystalline silicon substrate was subjected to magnetron sputtering to a thickness of 0.004 μm, 0.1 μm, and 1 μm.
m, 10 μm, 20 μm and 50 μm SiO ₂ layers (diffusion barrier layers) were formed. In this case, the surface of the polycrystalline silicon substrate was thermally oxidized through the diffusion barrier layer in the same manner as in the above-described verification experiment on the effect when the diffusion layer was used. After thermal oxidation, the diffusion disorder layer was removed by reactive ion etching method using CHF ₃ -C ₂ F ₆ -O ₂ gas.

By treating the polycrystalline silicon substrate as described above, a polycrystalline silicon substrate having a heat storage layer made of a thermal oxide film (SiO ₂ film) formed on the surface was obtained. The thickness of the formed heat storage layer (that is, the SiO ₂ layer) is 3 μm,
2.8 μm, 2 μm, 1 μm, 0.5 μm, 0.3 μm
Met. Table 5 shows the relationship between the thickness of the diffusion barrier layer and the thickness of the obtained heat storage layer. These are shown in columns 2, 4, 5, 6, 7, and 8, respectively.

As a result, the sample No. 7 and sample no. In No. 8, the required thermal oxide layer thickness could not be obtained. Also, when the surface of the thermal oxidation layer was measured using a stylus type roughness meter,
Sample No. In the case of No. 2, in which the thickness of the diffusion barrier layer was 40 °, the occurrence of steps on the surface of the thermal oxide layer was observed. Other samples N
o. In Nos. 4, 5, 6, 7, and 8, no step was observed on the surface of the thermal oxide layer.

Therefore, the sample No. of the verification experiment on the effect when the above-described diffusion layer was used was used. 3, the thickness of the diffusion barrier layer is from 1 μm to 3 μm in the range of 0.04 to 10 μm.
A heat storage layer having no surface step of μm (that is, a thermal oxidation layer) was obtained. Next, the sample No. A liquid jet recording head was prepared in the same manner as in the verification experiment on the effect when the diffusion layer was used with the substrates 4, 5, and 6, and an ejection durability test was performed in the same manner as in the above example. The results are shown in Sample No. 4,
As shown in columns 5 and 6, no cavitation breakage occurred, and the residual ratio was 100% even after the driving pulse was repeated 3 × 10 ⁸ times.

The above results, and the sample No. of the verification experiment on the effect when the above-mentioned diffusion layer was used were used. By combining the results of Step 3 with the diffusion barrier layer having a thickness in the range of 0.04 μm to 10 μm on the surface of the polycrystalline silicon substrate and performing thermal oxidation, a heat storage layer having no surface steps can be obtained. It was also confirmed that extremely good results were obtained in

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The substrate for a liquid jet recording head provided by the present invention has a heating resistor for generating heat and a pair of wirings electrically connected to the heating resistor. A substrate provided with an electrothermal converter, wherein the substrate constituting the substrate is a substrate composed of a polycrystalline material such as polycrystalline silicon.

The liquid jet recording head provided by the present invention comprises a discharge port for discharging liquid, a heating resistor for generating thermal energy for discharging the liquid from the discharge port, and a heating resistor. A substrate for a liquid jet recording head, wherein the substrate is provided with an electrothermal transducer electrically connected and having a pair of wirings for supplying an electric signal for generating the thermal energy to the heating resistor; and A liquid jet recording head having a flow path for supplying a recording liquid in the vicinity of the electrothermal transducer, wherein the substrate constituting the substrate is composed of a polycrystalline material such as polycrystalline silicon. It is a substrate.

The liquid jet recording apparatus provided by the present invention comprises: (a) a discharge port for discharging liquid, a heating resistor for generating heat energy for discharging liquid from the discharge port, A substrate for a liquid jet recording head, wherein the substrate is provided with an electrothermal transducer electrically connected to a resistor and having a pair of wirings for supplying an electric signal for generating the thermal energy to the heating resistor; (B) a flow path for supplying a recording liquid in the vicinity of the electrothermal transducer of the substrate, wherein the substrate constituting the substrate (a) is made of a polycrystalline material such as polycrystalline silicon. It is characterized by being a constituted base.

A method of manufacturing a substrate for a liquid jet recording head provided by the present invention is directed to an electrothermal converter having a heating resistor for generating thermal energy and a pair of wirings electrically connected to the heating resistor. A method for manufacturing a substrate for a liquid jet recording head in which a substrate is formed on a substrate, wherein a substrate composed of a polycrystalline material such as polycrystalline silicon is used as the substrate constituting the substrate, and oxygen is deposited on the polycrystalline substrate. Forming an oxide layer on the surface of the polycrystalline substrate by thermally oxidizing the surface of the polycrystalline substrate through the diffusion barrier layer.

In the present invention, a substrate typically made of polycrystalline silicon (hereinafter simply referred to as a polycrystalline silicon substrate) used as a substrate constituting a liquid jet recording head substrate is a single crystal silicon substrate. Since deformation is less likely to occur, as described in the above experiment,
There is a remarkable effect that the length of the recording head, which is difficult to achieve when using a single crystal silicon substrate, can be easily achieved. In this regard, the oxide layer provided on the polycrystalline silicon substrate is an important requirement. That is, the surface of the polycrystalline silicon substrate is generally not flat because of its crystal grains, but as described in the above experiment, the oxide layer formed on the surface has a surface with steps. I will.

In the present invention, the oxide layer comprises:
Forming a diffusion barrier layer on the surface of the polycrystalline silicon substrate,
It is formed by thermally oxidizing the surface of the polycrystalline silicon substrate through the diffusion barrier layer. This eliminates the problem of the step. As is apparent from the above-described experiments and the like, it is considered that such a characteristic of the polycrystalline silicon substrate is that the crystal grain boundary of the polycrystalline silicon substrate becomes a resistance to slip deformation and suppresses the deformation of the substrate.

In the present invention, since such a polycrystalline silicon substrate is used as a component of a substrate for a liquid jet recording head, when the surface of the substrate is subjected to a thermal oxidation treatment,
Even if heating or cooling generates an internal stress due to uneven shrinkage of the substrate, the occurrence of deformation is suppressed to a level that does not actually cause a problem.

Further, since such a polycrystalline silicon substrate is used as a substrate constituting the substrate for a liquid jet recording head, the substrate can be easily made to have a desired length, and in this case, As described in Experiment B above, since the amount of warpage is smaller than that of the single crystal silicon substrate, a long recording head which is hardly affected by warpage can be easily achieved. In addition, the long recording head does not cause pixel disturbance that occurs when a plurality of small recording heads are integrally connected to form a long recording head.

Further, since a long recording head can be easily obtained, it is possible to obtain a recording apparatus capable of achieving higher-speed recording.

The amount of warpage is proportional to the size of the average crystal grain size of the polycrystalline silicon substrate as clarified in Experiment C described above. From the demand for improving the yield during the production of the recording head, the preferred average crystal grain size of the polycrystalline silicon as the base constituting the substrate for the liquid jet recording head is 8 μm.
m, and a more preferred average crystal grain size is 2 μm or less. When a polycrystalline silicon substrate having an average crystal grain size in such a range is used, there is no problem of warpage of the substrate, and a long liquid jet recording capable of obtaining a higher quality recorded image at a high speed. A head substrate can be easily achieved.

Since it is necessary to form a heating resistance layer, wiring, and the like on the polycrystalline silicon substrate constituting the liquid jet recording head substrate, it is desirable that there be no defects such as pits and projections. When many of these defects are present on the surface of the base, the defects may cause disconnection or short circuit in the heat-generating resistance layer formed on the base. As has been clarified in Experiment D described above, the polycrystalline silicon substrate used for the recording head substrate has a high production yield,
In order to obtain good recording characteristics, the number of defects having a diameter of 1 μm or more on the surface of the substrate is preferably 10 / cm ^2.
Or less, more preferably 5 / cm ² or less.

Incidentally, the polycrystalline silicon constituting the base is similar to the case of the single crystal silicon substrate, and may contain trace amounts of the same impurities as those contained in the single crystal silicon.

In order to thermally oxidize the surface of the polycrystalline silicon substrate constituting the substrate for a liquid jet recording head and to prevent a surface step occurring when an oxide film is formed, diffusion of oxygen on the polycrystalline silicon substrate is suppressed. A diffusion barrier layer is formed, and a thermal oxidation treatment is performed on the polycrystalline silicon substrate through the diffusion barrier layer. By forming a thermal oxide layer by this method, a polycrystalline silicon substrate having a thermal oxide layer with excellent smoothness can be obtained.

First, the material constituting the diffusion barrier layer is required to have heat resistance to at least the thermal oxidation temperature. Normally, when a thermal oxide film is formed on a semiconductor substrate, the thermal oxide film is formed in a temperature range of 850 ° C. to 1000 ° C., but a thermal oxide film formed as a thermal storage layer on the surface of a substrate constituting a substrate for a liquid jet recording head Has a thickness of several microns, the formation of a thermal oxide film on the surface of the substrate is mainly performed from the viewpoint of shortening the formation time.
It is performed at a high temperature of 00C to 1250C. Therefore, it is important that the diffusion barrier has heat resistance at a temperature of at least 1000 ° C., preferably at a temperature of 1200 ° C. or more.

Second, in order to accurately suppress the diffusion of oxygen, it is necessary that the material be a material that can form a highly dense film. In the case where the diffusion barrier layer is formed of a porous film, direct contact between silicon and oxygen is made, so that the surface step cannot be completely eliminated.

Third, it is necessary that the material does not greatly change the amount of permeation of oxygen with time. In the case of a material whose oxygen permeation amount changes greatly with time, it is difficult to control the oxygen permeation amount, so that a thermally oxidized layer having a desired thickness may not be obtained or a surface step may occur. Or it is difficult to fulfill a sufficient function.

As the material constituting the diffusion barrier layer, any material can be used as long as it satisfies the above first to third conditions. In particular, the above conditions are satisfied because of the ease of formation. For example, inorganic oxides such as titanium oxide, cobalt oxide, and silicon oxide are desirably used. After the oxidation treatment, the diffusion barrier layer is usually removed by a method such as a selective etching method. However, if there is no particular inconvenience without removing, it may be left as it is without removing. That is, when forming the recording head substrate,
A typical example in which no problem occurs even if the diffusion preventing layer is not removed is a case where the diffusion preventing layer is made of silicon oxide.

Further, the diffusion preventing layer in the present invention can be formed by any method capable of forming a dense film. As such a film forming method, thermal CVD
Film formation methods, such as a CVD method, an optical CVD method, and a plasma CVD method,
A film forming method such as a sputtering method and a vapor deposition method can be given.

The thickness of the diffusion barrier layer is determined in consideration of the thickness of the thermal oxide layer formed on the above-mentioned polycrystalline silicon substrate and also of the surface of the thermal oxide layer so that no step is formed. The thickness of the thermal oxide layer is usually in the range of 1 μm to 3 μm. In consideration of this point, the thickness of the diffusion barrier layer that does not cause a step on the surface of the thermal oxidation layer formed is in the range of 0.04 μm to 10 μm, as clarified in the experiment E described above.

Hereinafter, embodiments of the substrate for a liquid jet recording head according to the present invention will be described.

FIG. 1A is a schematic plan view of an essential part of an example of the substrate for a liquid jet recording head of the present invention. FIG. 1 (B)
FIG. 2 is a cross-sectional view taken along line XX ′ of FIG. FIG. 2 is a schematic sectional view of a base constituting the substrate for a liquid jet recording head.

The liquid jet recording head substrate 8 comprises a heating resistor 2a for generating thermal energy for ejecting a recording liquid on the polycrystalline silicon substrate 1, and an electrical connection between the heating resistor 2a and the heating resistor 2a. It has an electrothermal converter composed of a pair of connected wires 3a and 3b.

The heating resistor 2a and the wires 3a and 3b are
A heating resistance layer 2 made of a material having a certain level of volume resistivity and an electrode layer 3 made of a material having good electrical conductivity are laminated on the base 1 by, for example, sputtering, and then a photolithography process is performed. Is formed by patterning into a predetermined shape.

Then, by applying an electric signal to the heating resistor via the wirings 3a and 3b, the heating resistor generates heat.

Desirable materials for forming the heating resistance layer 2 include hafnium boride (HfB ₂ ) and tantalum nitride (Ta).
₂ N), rubidium oxide (RuO ₂ ), Ta-Al alloy, Ta-Al-Ir
Various metals such as alloys, alloys, metal compounds, cermets and the like are used. Further, as a material forming the wiring layer 3, a metal having high conductivity, for example, aluminum or gold can be used. A protective layer 4 is provided on the liquid jet recording head substrate 8 so as to cover the wirings 3a and 3b and the heating resistor 2a. The protective layer 4 is provided for the purpose of preventing the heating resistor 2a and the wirings 3a and 3b from being electrically corroded or electrically broken down due to contact with the ink or penetration of the ink.

Such a protective layer can be made of an electrically insulating material such as SiO ₂ , SiC, Si ₃ N _{4 and the} like. The protective layer may have a multilayer structure. In that case, for example, a layer made of Ta or Ta ₂ O ₅ can be laminated on a layer made of the above-mentioned electric insulating material to form a protective layer.

If the diffusion barrier layer does not adversely affect the subsequent manufacturing process and the performance of the liquid jet recording head, the heat generation resistance layer 2 and the electrode layer are placed on the diffusion barrier layer without removing the diffusion barrier layer. 3 may be formed.

In the above-described liquid jet recording head, the direction in which the liquid is ejected from the ejection port is substantially the same as the direction in which the liquid is supplied to the heating resistor. For example, the two directions are different from each other (for example, substantially the same). Perpendicular) are included in the liquid jet recording head of the present invention.

Hereinafter, an embodiment of a liquid jet recording head using the above-described substrate will be described.

Although the main structure of the recording head has been described with reference to FIGS. 5A and 5B in the background of the invention, it will be briefly described again. A liquid path 6 for supplying ink as a recording liquid is formed in the vicinity of each of the heating resistors 2a by connecting the top plate 5 to a substrate. Then, the ink in the liquid path is heated by the respective heating resistors to generate air bubbles, and the ink is ejected from the ejection port 7 by the pressure of the air bubbles to perform printing.

FIGS. 5A and 5B show a liquid jet recording head having a one-to-one correspondence between the number of heating resistors and the number of discharge ports. The recording head of the present invention is not limited to this. That is, such a form that a plurality of heating resistors correspond to one discharge port,
Any embodiment to which the above-described substrate can be applied is an embodiment of the present invention. Further, FIGS. 5A and 5B show a recording head in which the substrate surface on which the heating resistor is disposed is substantially parallel to the direction in which ink is ejected, but the present invention is not limited to this. It goes without saying that the direction in which the ink is ejected and the substrate surface may intersect with each other without intersecting. Further, the liquid jet recording head of the present invention may be a recording head which is incorporated in the apparatus or is detachable from the recording apparatus, and which receives ink from an ink tank via a tube or the like. Alternatively, the recording head may be detachable from the recording device and detachably connected to the ink tank. Various recording liquids can be used as the recording liquid applicable to the recording head of the present invention.
A water-soluble organic solvent such as a (polyvalent) alcohol or polyalkylene glycol having an ink composition of 10 to 80 wt% and water of 10 to 90 wt% can be preferably used. As CI food black 23 wt%, diethylene glycol 25 wt%
%, N-methyl-2-pyrrolidone 20 wt%, water 52
wt%.

FIG. 6 is an external perspective view showing an example of an ink jet recording apparatus (IJRA) in which the recording head according to the present invention is mounted as an ink jet head cartridge (IJC).

In FIG. 6A, reference numeral 120 denotes a platen 1
24 is an ink jet head cartridge (IJC) including a nozzle group for discharging ink while facing the recording surface of the recording paper sent on the recording paper 24. Reference numeral 116 denotes a carriage HC that holds the IJC 120. The carriage HC is connected to a part of a drive belt 118 that transmits the driving force of the drive motor 117, and is slidable with two guide shafts 119A and 119B disposed in parallel with each other. By doing, IJC120
Reciprocating over the entire width of the recording paper.

In this embodiment, the ink jet head cartridge having a small recording head is taken as the recording head. However, the present invention is not limited to the full line type which can perform recording in accordance with the recordable width of the recording paper. Of course, it is possible to use a long recording head.When such a long recording head is used, there is almost no warpage as described above, and when a short recording head is used. It is possible to obtain a recording device that can further utilize the feature that there is no image disturbance and the feature that high-speed recording can be performed.

Reference numeral 126 denotes a head recovery device, and IJC1
It is disposed at one end of the 20 movement paths, for example, at a position facing the home position. The head recovery device 126 is operated by the driving force of the motor 122 via the transmission mechanism 123, and the IJC 120 is capped. IJC1 by the cap 126A of the head recovery device 126
20 in connection with the capping of the head recovery device 1
The ink is sucked by an appropriate suction means provided in the ink jet printer 26 or the ink is fed by an appropriate pressurizing means provided in the ink supply path to the IJC 120, and the ink is forcibly discharged from the discharge port to increase the viscosity in the nozzle. An ejection recovery process such as removal of ink is performed. Also, by performing capping at the end of recording or the like, IJC is protected.

A blade 130 is provided on the side of the head recovery device 126 and is made of silicone rubber and serves as a wiping member. The blade 130 is held in a cantilever form by a blade holding member 130 </ b> A, and similarly to the head recovery device 126, a motor 122 and a transmission mechanism 123 are provided.
And the engagement with the ejection surface of the IJC 120 becomes possible. Accordingly, the blade 130 is moved to the IJC 12 at an appropriate timing in the recording operation of the IJC 120 or after the ejection recovery processing using the head recovery device 126.
In this case, the projection is made to protrude into the movement path of the IJC 120 to wipe off dew condensation, wetness, dust and the like on the discharge surface of the IJC 120 with the movement of the IJC 120.

Further, the recording apparatus has an electric signal applying means for applying an electric signal for discharging ink to the recording head. Further, the recording apparatus is not limited to the above-described embodiment in which recording is performed on recording paper, but also includes a textile printing apparatus which records a pattern on cloth or the like. In this printing apparatus, since it is necessary to perform high-speed recording on a very wide cloth, it is particularly desirable to apply a long and good recording head of the present invention.

(Other Embodiments) The present invention brings about an excellent effect particularly in an ink jet recording head and an ink jet recording apparatus of a type in which ink is ejected by thermal energy among ink jet recording methods.

The typical configuration and principle are described in, for example, US Pat. Nos. 4,723,129 and 4,740.
It is preferable to use the basic principle disclosed in the specification of Japanese Patent No. 796. This method can be applied to both the so-called on-demand type and the continuous type. In particular, in the case of the on-demand type, liquid (ink)
By applying at least one drive signal corresponding to the recorded information and providing a rapid temperature rise exceeding nucleate boiling to an electrothermal transducer arranged corresponding to the sheet or liquid path in which , Heat energy is generated in the electrothermal transducer, and the film is boiled on the heat-acting surface of the recording head.
As a result, air bubbles in the liquid (ink) can be formed in one-to-one correspondence with the drive signal, which is effective.

The liquid (ink) is ejected through the ejection opening by the growth and contraction of the bubble to form at least one droplet. When the drive signal is formed into a pulse shape, the growth and shrinkage of the bubble are performed immediately and appropriately, so that the ejection of liquid (ink) having particularly excellent responsiveness can be achieved, which is more preferable. As the pulse-shaped drive signal, US Pat.
Those described in 463359 and 4345262 are suitable. In addition, US Pat. No. 4,431,131 of the invention relating to the rate of temperature rise of the heat acting surface.
If the conditions described in the specification of JP-A No. 24 are adopted, more excellent recording can be performed.

The configuration of the recording head may be a combination of a discharge port, a liquid path, and an electrothermal converter (a linear liquid flow path or a right-angled liquid flow path) as disclosed in the above specification. U.S. Pat. No. 4,558,333 and U.S. Pat.
A configuration using the specification of Japanese Patent No. 59600 is also effective for the present invention. In addition, Japanese Unexamined Patent Publication (Kokai) No. 123670/1984 discloses a configuration in which a common slit is used as a discharge portion of an electrothermal converter for a plurality of electrothermal converters, and an aperture for absorbing pressure waves of thermal energy. The present invention is also effective as a configuration based on Japanese Patent Application Laid-Open No. 59-138461, which discloses a configuration corresponding to a discharge unit.

Further, in a full-line type recording head having a length corresponding to the width of the maximum recording medium that can be recorded by the ink jet recording apparatus, the above-described effects can be more effectively exerted as described above.

In addition, the print head is exchangeable with a print head of the chip type, which can be electrically connected to the main body of the apparatus or supplied with ink from the main body of the apparatus, or is integrated with the print head itself. The present invention can also be applied to a case where a cartridge type recording head provided in a specific manner is used.

The recording mode of the ink jet recording apparatus is not limited to the recording mode of only the mainstream color such as black, but may be a single recording head or a combination of plural recording heads. The present invention is also very effective for an apparatus provided with at least one of full colors by color mixture.

In the embodiments of the present invention described above, the ink is described as a liquid. However, the ink is solidified at room temperature or lower, and is softened or liquid at room temperature. Generally, the temperature is controlled within the range of 70 ° C. or more and 70 ° C. or less to control the temperature so that the viscosity of the ink is in the stable ejection range. Therefore, the ink is in a liquid state when the recording signal for ejection is applied. I just want it. In addition, positively prevent the temperature rise due to thermal energy by using the energy of the state change of the ink from the solid state to the liquid state, or use ink that solidifies in a standing state to prevent evaporation of the ink. In any case, heat energy is applied by heat energy, such as one in which ink is liquefied and ejected as an ink liquid by application of heat energy according to a recording signal, or one which already starts to solidify when reaching a recording medium. The use of an ink that liquefies for the first time is also applicable to the present invention. In such a case, the ink is disclosed in JP-A-54-5.
No. 6,847, or Japanese Patent Application Laid-Open No. 60-71260, in which the porous sheet is opposed to the electrothermal converter while being held as a liquid or solid substance in the concave portions or through holes of the porous sheet. It is good.

[0155]

EXAMPLES The structure and effects of the present invention will be described below with reference to examples, but the present invention is not limited to these examples.

Example 1 (Adjustment of Polycrystalline Silicon Substrate Constituting Liquid Jet Recording Head Substrate) A polycrystalline silicon ingot as a starting material was prepared as follows. That is, using high-purity polycrystalline silicon produced by precipitation reaction by hydrogen reduction and thermal decomposition used for the production of single-crystal silicon, introduced into a quartz crucible, heated to 1420 ℃ and melted, then made of graphite The mixture was poured into a mold and cooled to prepare an 80 cm square polycrystalline silicon ingot. At this time, no release agent was used. Next, at a position where the average crystal grain size becomes 2 mm from the ingot, the sample No. in Table 6 was used. 1 to N
o. 4 in the form of a plate shown in the respective column.
The sheets were cut out with a multi-wire saw. The surface of each of the obtained four polycrystalline silicon plates was removed by lapping to remove about 30 μm and flattened, and then chamfered by an end beveling machine.

Thereafter, the surface was polished with a single-side polishing machine manufactured by Speed Fam Co., Ltd., and the surface roughness was Rmax1.
It was finished to a mirror substrate of 50 °. At this time, in order to prevent a surface step due to etching by an alkali component in the polishing agent having crystal orientation dependency, polishing was performed without adding an alkali.

Here, the surface roughness of each polycrystalline silicon plate, ie, the surface of the polycrystalline silicon substrate was measured by a substrate surface inspection apparatus in the same manner as in Experiment D. Was 1 / cm ² or less at all measurement points.

Further, the smoothness of the surface of each polycrystalline silicon substrate was measured using a non-contact type surface roughness meter manufactured by Lasertec Co., Ltd., and it was confirmed that no step was generated.

Next, an SiO ₂ film as a diffusion barrier layer was formed on the surface of each polycrystalline silicon substrate to a thickness of 0.04 μm by magnetron bias sputtering.

At this time, the film forming conditions were as follows.

Ultimate vacuum: 8 × 10 ⁻⁷ Torr Preheat: 300 ° C., 5 minutes Argon gas pressure: 10 mTorr Target power: 2
KW Pre-sputtering time: 1 minute Bias voltage: 10
Next, each of the polycrystalline silicon substrates provided with the diffusion barrier layers was subjected to a thermal oxidation treatment by a pyrogenic method to form an SiO ₂ film as a heat storage layer on the polycrystalline silicon substrates.

The thermal oxidation conditions at this time were as follows.

Thermal oxidation temperature: 1150 ° C. Furnace pressure: 1 atm Thermal oxidation time: 14 hours After the thermal oxidation treatment, the diffusion barrier layer was changed to CHF ₃ —C ₂ F ₆ —O
_It was removed by reactive ion etching using _two gases.

Thus, four polycrystalline silicon substrates for a liquid jet recording head having a thermal oxide layer (SiO ₂ layer) of 2.9 μm as a heat storage layer (samples No. 1 to No. 4) were completed.

Sample No. No. 1 to No. The surface smoothness of the heat storage layer was measured for each of the substrates 4 by Lasertec Co., Ltd.
And a non-contact type surface roughness measuring device. As a result, it was found that there was no surface step on any of the substrates.

Next, the sample No. No. 1 to No. A plurality of heating resistors made of HfB ₂ (size: 20 μm × 100 μm, thickness: 0.16 μm, heating resistance vs. pitch interval: 63.5 μm) using a photolithography technique for each of the four substrates.
And an electrode made of Al connected to each heating resistor (width 20μ)
m, a film thickness of 0.6 μm), and SiO ₂ / Ta (SiO ₂
A protective layer having a thickness of 1.3 μm and a thickness of Ta: 0.5 μm) is formed by sputtering on the portion where the heating resistor and the electrode are formed.
Four substrates for a liquid jet recording head having the configuration shown in (B) were prepared (Sample Nos. 1 to 4).

Next, for each of the four obtained substrates for a liquid jet recording head, when exposing a plurality of ink flow paths by photolithography using a photosensitive dry film as described below, the ink flow It was observed whether the path could be formed accurately and the pass rate of exposure was calculated.

That is, the sample No. Sample No. 1 was 8576 pieces per head. For sample No. 2, 7244 pieces per head, sample No. For No. 3, 5504 pieces per head, sample no. 4 for 4 per head
Pattern samples of a liquid jet recording head each having 288 ink discharge channels were prepared, 15 samples per substrate. Sample No. No. 1 to No. For each of No. 4, when the focus position is shifted due to the warpage of the substrate among the 15 pattern samples prepared, and even one of the patterns at the discharge port is chipped. The pass rate of exposure was calculated based on the criteria for rejecting the test, and determining that no pattern chipping occurred at all.

Table 6 shows the obtained results.

[0171]

[Table 6]

As is clear from the results shown in Table 6, Sample No. No. 1 to No. It can be seen that all four have a 100% exposure pass rate.

Comparative Example 1 (Adjustment of Single Crystal Silicon Substrate Constituting Substrate for Liquid Jet Recording Head) A single crystal silicon ingot was used as a starting material in the same manner as in Example 1 to obtain Comparative Sample No. 1 to No. Four mirror single-crystal silicon substrates (comparative samples No. 1 to No. 4) having the dimensions shown in the respective columns and having a surface roughness of Rmax 150 ° were prepared. In any case, when polishing,
Alkali was added. Next, in the same manner as in Example 1 except that the diffusion barrier layer was not formed, each single crystal was thermally oxidized by a pyrogenic method to form a 3.0 μm thermally oxidized heat storage layer, and four liquids were formed. Substrates for ejection recording heads (Comparative Samples No. 1 to No. 4) were prepared.

Next, the sample no. 1 to No. Example 1 using each of the single crystal silicon substrates of Example 4
In the same manner as in the above, four substrates for liquid jet recording heads (Comparative Samples No. 1 to No. 4) were prepared.

Next, the obtained sample no. 1 to No. 4
The pass rate of exposure was calculated for each of the liquid jet recording head substrates in the same manner as in the examples.

Table 7 shows the obtained results.

[0177]

[Table 7]

As is clear from the results shown in Table 7, Comparative Sample No. A decrease in the exposure pass rate was observed in Sample No. 2, and the majority of Comparative Sample Nos. 1 failed.

Example 2 (Preparation of a liquid jet recording head using a polycrystalline silicon substrate) In this example, the liquid jet recording head shown in Table 6 prepared in Example 1 was used.
Liquid jet recording head substrates (Sample Nos. 1 to N)
o. Using each of 4), four liquid jet recording heads having the configuration shown in the sectional view of FIG. 3 were manufactured by the following method.

First, a plurality of ink flow paths were formed on a substrate for a liquid jet recording head by photolithography using a photosensitive dry film, and cut with a slicer to separate heads and form discharge ports. Next, the discharge port surface was polished to correct defects such as chipping generated during cutting.

In this way, 15 liquid jet recording head in-process products were prepared for each liquid jet recording head substrate. A heating resistor driving IC is connected to each of the fifteen in-process products using a flip-chip connection method, and the discharge port pitch is 63.5 μm.
m of a liquid jet recording head.

Thus, the sample No. No. 1 to No. Fourteen liquid ejecting recording heads were prepared for each of the liquid ejecting recording head substrates of No. 4 (hereinafter, a group consisting of 15 liquid ejecting recording heads obtained from each of Sample Nos. 1 to 4 was used as a sample). No. 1 ′, sample No.
2 ', sample no. 3, and sample no. 4 '. ).

Sample No. 1 'to No. 1 The manufacturing process yield of the 4 ′ liquid jet recording head was within a normal level that decreased in accordance with the increase in the number of nozzles.

In the column for evaluating the total yield of the manufacturing process in Table 8, the sample No. 1 'to No. 1 When the yield expected from the number of the discharge ports of 4 'was not exceeded, the symbol ○ was given as no problem.

Next, for sample no. 1 'to No. 1 For one liquid jet recording head randomly selected for each of 4 ', a drive pulse (print signal) having a pulse width of 1.1 Vth (Vth is a foaming voltage) and a pulse width of 10 μs is repeatedly applied to each of the heating resistors, so that each ejection port is formed. , And a discharge durability test was performed.

The evaluation in the durability test was performed as follows. That is, the integrated number of drive pulses is 1 × 10 ⁷ , 1
The durability of the liquid jet recording head is determined by calculating the residual ratio of the heating resistors when the heating resistors reach × 10 ⁸ and 3 × 10 ⁸ , that is, the number of the heating resistors that are not disconnected with respect to the total number of the heating resistors. evaluated. Table 7 shows the obtained results. As is evident from the results shown in Table 8, in all cases, the residual ratio was 100% even after the driving pulse was repeated 3 × 10 ⁸ times, which was a result having no problem in the discharge durability performance.

Next, the sample No. 1 'to No. 1 Using another liquid jet recording head randomly selected for each of 4 ', the printing dot spacing accuracy and density unevenness were evaluated as printing performance. The ink composition used is as follows.

Dye: C.I. I. Direct Black 19 3 wt% Diethylene glycol 25 wt% N-methyl-2-pyrrolidone 20 wt% Ion-exchanged water 52 wt% In this evaluation, all the nozzles ejected paper in which the variation of the ink bleed rate was within a predetermined range. Scanning was performed perpendicularly to the ejection direction of the liquid jet recording head in the above state, and a print sample having four types of print widths in the nozzle arrangement direction and a paper feed direction of 200 mm was obtained. At this time, when the paper feed speed is an ejection frequency of 1 KHz, the print dot interval in the paper feed direction is 63.5.
It was adjusted to be μm. The head driving conditions were set as follows.

Heating resistor applied voltage: 1.1 Vth, (Vth) is foaming voltage Driving frequency: 1 KHz (heating resistor applied interval) Pulse width: 10 μs (one pulse application time of heating resistor) Indicates the print width at the head.

[0190]

[Table 8]

The printing samples obtained here were evaluated for printing accuracy and printing density unevenness as described below.

Evaluation of Printing Accuracy Using a magnifying glass with a measuring scale, the printing dot interval (dot center interval) of the printing sample was measured, and the range of the variation was obtained. One measurement range was set to 2 cm square, and measurement was performed by selecting any 10 places on the print sample. X is the paper feed direction and the vertical direction, and Y is the paper feed direction.
Those having a dot interval in the Y direction within a range of 43.5 μm to 83.5 μm were regarded as acceptable. Sample No. All of 1 ′ to 4 ′ passed the printing accuracy.

Evaluation of Print Density Unevenness The print sample was measured for density unevenness using a Macbeth densitometer. The entire surface of the print sample was read by a CCD scanner, and the optical density was measured for each 1 cm width in the direction perpendicular to the paper feed direction.

[0194] A sample in which the optical density of an adjacent area on the entire surface of the print sample was within 0.2 was judged to be acceptable. Sample No. 1 '
All of the samples 4 to 4 'passed the print density unevenness.

Comparative Example 2 (Preparation of Liquid Jet Recording Head Using Single Crystal Silicon Substrate) Next, the liquid jet recording head substrate shown in Table 7 and the comparative sample No. 1 to No. Using 4,
In the same manner as in Example 2, the liquid jet recording head (Comparative Sample N
o. 1 'to No. 1 4 ').

Comparative sample No. 1 'to No. 1 For each of 4 ′, the yield was evaluated in the same manner as in Example 2. Table 9 shows the obtained results.

[0197]

[Table 9]

In the total yield evaluation column of the manufacturing process in Table 9, all evaluation results are shown based on the following evaluation criteria with respect to the yield assumed from the number of discharge ports of each sample.

X: No good liquid jet recording head was finally found.

Δ: A non-defective liquid jet recording head is very small and not practical.

：: When the yield expected from the number of nozzles is not exceeded.

From the results shown in Table 9, the following is understood: the comparative sample No. In the case of 1 ', a practically usable liquid jet recording head cannot be produced.

Comparative Sample No. In the case of 2 ′, the production yield of a practically usable liquid jet recording head is extremely low.

Comparative Sample No. 3 ′ and No. 4 'has no problem in production yield.

Next, the comparative sample No. 2 ′ to No. 4 '
For each of them, an ejection durability test and evaluation of printing accuracy and density unevenness were performed as printing performance in the same manner as in Example 2. As a result, a practically usable liquid jet recording head, that is, Comparative Sample No. 2 ′, No. 3 ′ and No.
Regarding 4 ′, the evaluation of printing accuracy and density unevenness as the discharge durability test and printing performance were all passed.

Comparative Example 3 (Preparation of Liquid Jet Recording Head Using Single Crystal Silicon Substrate)
A liquid ejection recording head unit having 8576 ejection ports using two liquid ejection recording heads of 4 'and integrally connecting the two heads (Comparative Sample No. 4'', see Table 10) It was created.

First, the head unit was prepared as follows. That is, an aluminum support member was used, and the first liquid jet recording head was fixed to one surface of the support member. Next, the second head was arranged and fixed on the other surface of the support member such that the arrangement interval of the ejection ports was as constant as possible over the entire length of the liquid jet recording head unit including the connection region.

For the comparative sample No. 4 ″ of the liquid jet recording head unit thus obtained, an ejection durability test and evaluation of printing accuracy and density unevenness were performed in the same manner as in Example 2. The ejection durability test passed, but the printing accuracy was rejected due to the assembling error of the connection portion between the two heads.

[0209] Density unevenness was rejected due to the difference in Vth (foaming voltage) between the two heads. Table 10 summarizes the results of these evaluations.

[0210]

[Table 10]

[0211]

According to the present invention as described above, it is possible to easily and inexpensively obtain and provide a substrate having no problem such as deformation even in a substrate used for a long liquid jet recording head. This substrate can be easily manufactured. This also makes it possible to provide a recording head with better image quality. Further, it is possible to obtain a recording apparatus having excellent image quality and capable of high-speed recording.

[Brief description of the drawings]

FIG. 1A is a schematic plan view of a main part of a substrate for a liquid jet recording head according to a position embodiment of the present invention, and FIG.
(A) It is principal part sectional drawing in the XX 'line | wire of a figure.

FIG. 2 is a schematic cross-sectional view of a base constituting a substrate for a liquid jet recording head.

FIG. 3 is a schematic cross-sectional view illustrating a production example of a liquid jet recording head.

FIGS. 4A to 4C are diagrams illustrating the formation of a thermal oxide film on the surface of a polycrystalline silicon substrate.

5A is a cutaway perspective view of a main part of the liquid jet recording head, and FIG. 5B is a vertical sectional view of the main part of the liquid jet recording head in a flow path direction.

FIG. 6 is a diagram illustrating an example of a recording apparatus including the liquid jet recording head according to the invention.

FIG. 7 is a diagram showing an example of a thermal oxidation device for thermally oxidizing the surface of a base constituting a substrate for a liquid jet recording head.

FIGS. 8A and 8B are diagrams for explaining a bow-and-bend mechanism generated in a base. FIG.

FIGS. 9A to 9C are diagrams for explaining a state of occurrence of bowing and bending occurring when the base is cut off;
(D) is an explanatory view of a method for measuring the degree of bowing or bending of the base.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Base 1a Polycrystalline silicon base 1b Storage layer 2 Heating resistance layer 2a Heating resistor 3 Wiring layer 3a, 3b wiring 4 Protective layer 5 Top plate 6 Liquid path 7 Discharge port 8 Liquid ejection recording head substrate 9 Liquid supply port 10 Liquid Chamber 11 Polycrystalline silicon substrate 12 Crystal grains 13 Thermal oxide layer 14 Diffusion barrier layer 116 Carriage 117 Driving motor 118 Driving belt 119A, 119B Guide shaft 120 Inkjet head cartridge 122 Cleaning motor 123 Transmission mechanism 124 Platen 126 Head recovery device 126A Cap part 130 Blade

Claims (2)

(57) [Claims] 1. A method of manufacturing a substrate for a liquid jet recording head, wherein an electrothermal converter having a heating resistor for generating thermal energy and a pair of wirings electrically connected to the heating resistor is formed on a substrate. In the above, a substrate composed of a polycrystalline substance is used as a substrate constituting the substrate, and is selected from any of silicon oxide, titanium oxide, and cobalt oxide that suppresses the diffusion rate of oxygen on the polycrystalline substrate. A method for manufacturing a substrate for a liquid jet recording head, comprising: providing a material diffusion barrier layer; and thermally oxidizing the surface of the polycrystalline substrate through the diffusion barrier layer to form an oxide layer on the surface. . 2. The method according to claim 1, wherein the substrate is a polycrystalline silicon substrate.