KR20020066972A - Ink jet recording device and method of manufacturing silicon structure - Google Patents

Abstract

PURPOSE: To provide a liquid drop jet apparatus which is equipped with liquid discharge openings having different depths in the same chip. CONSTITUTION: Large ink discharge openings 20 and small ink discharge openings 22 having different depths are formed to a layer end face 18 of an ink jet recording head 10. First, parts corresponding to the large ink discharge openings 20 are formed by wet anisotropic etching into grooves having a triangular section. Then, reactive ion etching(RIE) is carried out to parts corresponding to the large ink discharge openings 20 and the small ink discharge openings 22, whereby a channel substrate 14 including the large ink discharge openings 20 and the small ink discharge openings 22 is formed. The ink jet recording head 10 is manufactured in this manner. Eventually, channels can be worked accurately by the RIE and grooves having different depths can be efficiently formed by the wet anisotropic etching. The productivity of the ink jet recording head 10 is also improved.

Description

Droplet injection recording device and method of manufacturing silicon structure {INK JET RECORDING DEVICE AND METHOD OF MANUFACTURING SILICON STRUCTURE}

The present invention relates to a droplet ejection recording apparatus and a method for manufacturing a silicon structure in which energy is applied to a liquid held in a liquid flow passage and ejected from a nozzle.

Conventionally, a method of manufacturing a droplet ejection recording head by forming a desired shape by etching a silicon substrate and laminating the silicon substrate has been proposed.

For example, Japanese Patent Laid-Open No. 11-227208 (hereinafter referred to as Conventional Example 1) can produce a print head chip having a throttle shape with good manufacturing accuracy before and after the bubble generation region, and has high injection energy efficiency and high resolution. It is disclosed that a droplet ejection recording apparatus capable of responding to a fire can be manufactured.

This conventional example 1 is demonstrated using FIGS. 16-21.

As shown in FIG. 16, the head chip 100 is formed by stacking the heating element substrate 102 and the flow path substrate 104. As shown in FIG. 17, the ink supply formed on the flow path substrate 104 is shown. Ink supplied from the sphere 106 enters the individual flow path 110 through the common liquid chamber 108 having the stepped portion 107, is heated by the heat generating element 112, and ink droplets from the ink discharge port 114. Is discharged as. In addition, the front throttle 116, the rear throttle 118, and the concave portion 132 are formed in the individual flow path 110 so that ink droplets are discharged efficiently by heating by the heat generating element 112.

The manufacturing method of the flow path board | substrate 104 which comprises this head chip 100 is demonstrated with reference to FIGS.

On the Si substrate 120 (see Fig. 18A) to be the flow path substrate 104, a SiO ₂ film 122 is formed as a first anti-etch masking layer by thermal oxidation (Fig. 18 (Fig. 18 (A)). b)), the portion to be the individual flow path 110 including the nozzles of the SiO ₂ film 122 and the portion to be the common liquid chamber 108 are patterned by the photolithography method and the dry etching method (Fig. 18 (c)). Reference). As shown in Fig. 19 (a), the mask pattern formed by the SiO ₂ film 122 is connected to the portion that becomes the common liquid chamber 108 and the stepped portion 107 and the portion that becomes the individual flow path 110. The front throttle shape 124 used as the front throttle 116 of the individual flow path 110 and the rear throttle shape 126 used as the rear throttle 118 are provided. Subsequently, a SiN film 128 is formed as a second etch-resistant masking layer by reduced pressure CVD (Chemical Vapor Deposition) (see Fig. 18 (d)). With respect to the SiN film 128, the portion that becomes the common liquid chamber 108 and the stepped portion 107 and the portion that becomes the concave portion 132 provided in the individual flow path 110 are used by the photolithography method and the dry etching method. Patterning is performed (see Fig. 18 (e)). The SiN film 128 serves as a mask for preliminary processing for forming the shape of the depth direction to be the recess 132 in the individual flow path 110, and the SiN film (at the portion of the recess pattern 130) ( 128) is removed (see Fig. 19 (b)). In addition, in this example, since the stepped portion 107 is formed together with the recessed portion 132, the SiN film 128 of the portion that becomes the common liquid chamber 108 and the stepped portion 107 is removed.

Subsequently, a SiO ₂ film 134 serving as a phosphoric acid etching protective film (third etching resistant masking layer) is formed by a reduced pressure CVD method (see Fig. 18 (f)). The SiO ₂ film 134 is patterned using a photolithography method and a dry etching method (see Fig. 18 (g)). The SiO ₂ film 134 is formed to cover the SiN film 128.

Subsequently, a second SiN film 136 serving as a fourth etching resistant masking layer is formed by a reduced pressure CVD method (see Fig. 18 (h)). The area | region used as the common liquid chamber 108 with respect to this SiN film 136 is patterned using the photolithographic method and the dry etching method (refer FIG. 18 (i)). As shown in Fig. 19 (c), only the portion that becomes the common liquid chamber 108 is removed and the common liquid chamber pattern 138 is formed.

Here, the Si substrate 120 is etched with a KOH aqueous solution using this SiN film 136 as an etching mask (see Fig. 18 (j)). This etching is performed until it passes through the Si substrate 120, and the through hole is used as the ink supply port 106. As shown in FIG. In this process, the sidewall is formed as a slope having a predetermined angle from the characteristics of wet anisotropic etching as in the prior art. In addition, the crystal orientation of the Si substrate 120 is the <100> plane. Since the processing is performed from one surface of the Si substrate 120 here, a through hole is formed in which the cross-sectional area becomes small toward the ink supply port 106.

Subsequently, the SiN film 136 is selectively etched away with an aqueous solution of phosphoric acid (see Fig. 18 (k)). At this time, since there is an SiO ₂ film 134 serving as a phosphoric acid etching protective film, the underlying SiN film 128 is not eroded.

Next, the SiO ₂ film 134 is selectively etched away with an HF solution (see Fig. 18 (l)). Subsequently, wet anisotropic etching with a KOH aqueous solution is performed on the Si substrate 120 using the SiN film 128 as an etching mask (see Fig. 18 (m)). This wet room processes only the desired depth so that it may not penetrate by etching. As shown in Fig. 19B, since the portions serving as the common liquid chamber 108 and the stepped portion 107 are removed from the SiN film 128, a step portion having a predetermined depth is formed on the sidewall portion of the common liquid chamber 108. As shown in FIG. Can be formed. Moreover, since the part which becomes the recessed part 132 in the individual flow path 110 of the SiN film 128 is removed, the part used as the recessed part 132 is also etched. As shown in Fig. 19B, the recess pattern 130 can be formed as a rectangular pattern. By wet anisotropic etching the SiN film 128 having such a pattern as an etching mask, a three-dimensional recessed portion 132 as shown in FIG. 20 is formed.

Subsequently, the SiN film 128 is selectively etched away with a phosphoric acid solution (see Fig. 18 (n)). Subsequently, RIE (Reactive Ion Etching) processing of the Si substrate 120 is performed using the SiO ₂ film 122 as an etching mask (see Fig. 18 (o)). In this RIE processing, etching can be etched evenly in the thickness direction other than the masked portion, regardless of the crystal orientation of Si as described above. In other words, the cross section of the individual flow paths 110 forms a substantially rectangular groove along the mask pattern shape shown in Fig. 19A, and the shape formed by the above steps is also etched as it is. For this reason, in the process shown in Fig. 18 (m), the concave portion formed at the position within the individual flow passage 110 is almost maintained in the shape of the concave portion 132 at the bottom of the groove which becomes the individual flow passage 110 as it is. Is formed.

Finally, the SiO ₂ film 122 is selectively etched away with a hydrofluoric acid solution to complete the processing of the Si substrate 120 serving as the flow path substrate 104 (see Fig. 18 (p)). Fig. 21 is a plan view showing an example of an Si substrate 120 to be a flow path substrate manufactured by this method. In addition, by dicing the Si substrate 120 along the dicing line, the end portions of the individual flow paths 110 open to form the ink discharge ports 114.

As described above, the manufacturing method is characterized by using the RIE method differently from the wet anisotropic etching, so that the individual flow path 110 having a planar complex shape including the front throttle 116, the rear throttle 118, and the like as shown in FIG. Can be processed with high accuracy, and the grooves formed by RIE processing have the same depth over the entire surface of the chip. Therefore, the ink discharge port 114 becomes a rectangle of the same depth (refer FIG. 16), and can secure desired injection characteristic.

Thus, the method of manufacturing the head chip | tip which has the same shape (same cross-sectional area) of the prior art example 1 is established.

In recent years, however, the function of ejecting droplets of different volumes from the same print head has been required for the printer. This can be used, for example, to "print black and white text by printing a large drop of ink, and to print color by printing a small drop of ink, and to print high quality by printing a small drop of ink." This is because "printing by ink droplets is used and when using high quality printing, small ink droplets are used."

In order to achieve these demands, a print head may be formed by combining head chips formed according to respective ink drop volumes, but the print head becomes large and the cost also becomes high.

In addition, in the thermal inkjet method, the ink droplet volume difference is slightly adjusted by adjusting the design dimension of the heat generating resistor that generates bubbles and the width of the nozzle, but the difference cannot be sufficiently large.

On the other hand, Japanese Patent Laid-Open No. 10-138483 discloses a configuration in which the ink temperature rise speed is changed by changing the driving voltage and pulse width applied to the heat generating resistor, and the ink discharge amount is changed by changing the ink amount contributing to foaming. have. In this method, since a plurality of driving voltages are applied to the heat generating resistor, the cost is high and the fluctuation range of the ink drop volume is small.

In addition, Japanese Patent Laid-Open No. 11-99637 proposes a driving method of a heat generating resistor for installing a plurality of heat generating resistors in the same flow path and controlling the ink drop volume. Further, Japanese Patent Laid-Open No. 10-16221 proposes a method in which a plurality of heat generating resistors are provided in the same flow path, and two heat generating resistors are driven in the case of a large drop, and only one of them is driven in the case of a small drop. Although these methods can also make an ink volume difference, the fluctuation range is small.

In addition, in the conventional example 1, although the individual flow path (ink discharge port) of a complicated shape can be made into the cross-sectional shape of predetermined depth with high precision by RIE, it is only necessary to form it in a constant depth, and the volume of ink droplets discharged from the same chip is fluctuated. You can't.

Conventional Example 2 described heretofore has been made in view of such a problem, and its purpose is to provide a depth within the same chip while having the advantages of fine processing by RIE (high injection energy efficiency and high resolution). Is to form another nozzle. Specifically, nozzles having different depths are formed in the same chip by using two-step RIE processing. As a result, it is possible to form nozzles having different depths in the same chip, and as a result, it is possible to eject ink droplets having a large volume, and to provide a liquid ejection recording apparatus which can attain both high speed factor and high image quality at low cost.

Hereinafter, the present conventional example 2 will be described in detail. In addition, the same code | symbol is attached | subjected to the component similar to the conventional example 1, and the detailed description is abbreviate | omitted. 22 is a perspective view of the printhead chip of the prior art example 2. FIG.

The print head chip 100A includes a small ink ejection opening region 140 in which a small ink ejection opening 114A for ejecting relatively small ink droplets is arranged, and a large ink ejection opening region in which a large ink ejection opening 114B for ejecting large ink droplets is arranged. 142 divided by a large ink ejection opening 114B of a large ink ejection opening region 142 when ejecting large ink droplets, and a small ink ejection opening region 140 when ejecting small ink droplets. Printing is performed at the ink discharge port 114A. For example, by using black ink in the large ink ejection opening region 142, black character printing with a high density can be achieved, and high-quality color printing becomes possible by using color ink in the small ink ejection opening region 140. FIG.

23 is a perspective view of a print head chip 100B according to another example of the conventional example 2. FIG. Here, the small ink discharge port 114A and the large ink discharge port 114B are alternately arranged. In this case, when the high speed draft printing is performed, a signal with a large volume of ink may be printed by selecting a signal having an address corresponding to the large ink discharge port 114B. Since the volume of the ink droplets is large, sufficient printing concentration can be achieved without being completely overwritten. In the case of high quality printing, a small volume of ink droplets may be used by selecting a signal having an address corresponding to the small ink discharge port 114A.

Next, a method of manufacturing these chips will be described based on the conventional example 2 of Fig. 23 in which a large ink discharge port and a small ink discharge port are alternately arranged.

Specifically, a description will be given of a manufacturing process of a Si substrate in which a large ink discharge port of depth d3 and a small ink discharge hole of depth d2 are alternately side by side as shown in FIG. As a manufacturing process, process c and o of FIG. 18 (the manufacturing method of a prior art example 1) are changed. The manufacturing process of this prior art example 2 is shown in FIG. For the Si substrate 120 serving as the liquid flow path substrate 104 shown in Fig. 24A, a SiO ₂ film 122 was formed by the thermal oxidation method as the etching resistance masking layer by the film thickness t1 in Fig. 24B. do. In Fig. 24C, the portion of the SiO ₂ film 122, which becomes a large ink ejection opening, is patterned by the photolithography method and the dry etching method.

The crystal orientation of the Si substrate 120 used is the <100> plane. Subsequently, the portion where the SiO ₂ film 122 becomes a small ink ejection opening is patterned in Fig. 24C by photolithography and dry etching, except that the SiO ₂ film 122 is not etched away at all. The thickness is equal to t2. Between steps d through n in Fig. 24 is the same as step n through d in Fig. 18. Next, the Si substrate 120 in the portion which becomes a large ink ejection opening in Fig. 24 (o ') is RIE. the etch depth as d1 by law. in this case, Si substrate of a portion where the small ink ejecting openings do, is not etched because it is covered with the SiO ₂ film 122. However, this case is also slightly etched SiO ₂ film 122 Therefore, the film thickness decreases, the film thickness t1 becomes t1 ', and the film thickness t2 becomes t2'. Subsequently, in Fig. 24 (o "), the SiO ₂ film 122 is formed by the RIE method. Etching to completely remove the SiO ₂ film 122 that becomes a small ink ejection opening. However, for the other parts (parts of the film thickness t1 '), the film thickness is left as much as the film thickness t1 ". At this time, since the Si substrate of the part which becomes the large ink ejection opening is set under the condition that it is hardly etched, the depth of this part is Then, the Si substrate 120 is etched by the depth d2 by the RIE method, at which point the depth of the portion which becomes the small ink ejection opening becomes d2, and the depth of the portion that becomes the large ink ejection opening is d3. = d1 + d2 Finally, in Fig. 24 (p), the SiO ₂ film 122 is selectively etched away with a hydrofluoric acid solution to complete the processing of the Si substrate 120 serving as the liquid flow path substrate 1. As an advantage of the present manufacturing method, ( ₁ ) the material (SiO ₂ film 122) which serves as an etching mask of the Si substrate may be formed only once, and ( ₂ ) the Si substrate of the large ink discharge port portion is etched twice in order to deepen it. Align because the masks are the same This shape defect due to bit error does not occur, or the like is mentioned.

However, the conventional example 2 has a problem that the manufacturing cost increases because the number of processes increases compared with the conventional example 1.

Moreover, when the depth of the groove of the rectangular cross section is deepened, there is a problem that stress concentration is generated at the corners (corners) of the rectangular groove as the cross-sectional area increases, and there is a possibility that cracks enter the substrate.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and with the advantage of fine processing by RIE (high injection energy efficiency and high resolution), ink ejection holes having different depths in the same chip can be provided without increasing the number of processes. An object of the present invention is to provide a formed droplet ejection recording apparatus and a method for producing a silicon structure.

1 is a perspective view of an ink jet recording head according to a first embodiment of the present invention.

2 is a cross-sectional view taken along the line A-A of FIG.

3 is a cross-sectional view taken along the line B-B in FIG.

4 is a manufacturing process diagram of a laminated end face position of a silicon substrate;

FIG. 5 is a manufacturing process diagram of the flow path substrate at the cross-sectional position along the line A-A in FIG. 1; FIG.

FIG. 6 is a manufacturing process diagram of the flow path substrate at the A-A line cross-sectional position of FIG. 1; FIG.

FIG. 7 is a manufacturing process diagram of the flow path substrate at the A-A line cross-sectional position in FIG. 1; FIG.

8A is a mask pattern of the SiO ₂ film 42, FIG. 8B is a mask pattern of the SiN film 48, and FIG. 8C is a mask pattern of the SiN film 54. FIG.

Fig. 9 is a plan view showing the positional relationship between mask patterns of substantial portions of the individual flow paths 30;

Fig. 10 is a plan view showing the positional relationship between mask patterns of substantial portions of individual flow paths 31;

FIG. 11 is a manufacturing process diagram of a flow path substrate in the cross section taken along the line D-D in FIG.

FIG. 12 is a manufacturing process diagram of a flow path substrate in the cross section taken along the line D-D in FIG. 10;

Fig. 13 is a plan view of a flow path substrate in which large grooves and small grooves are formed.

14 is an explanatory diagram showing a crack entering a groove of a rectangular cross section;

Fig. 15 is a perspective view of the ink jet recording head according to the second embodiment of the present invention.

16 is a perspective view of an ink jet recording head according to a conventional example 1. FIG.

FIG. 17 is a sectional view taken along the line H-H in FIG. 16; FIG.

FIG. 18 is a manufacturing process diagram of the flow path substrate at the H-H cross-sectional position in FIG. 16; FIG.

FIG. 19A shows a mask pattern of the SiO ₂ film 122, FIG. 19B shows a mask pattern of the SiN film 128, and FIG. 19C shows a mask pattern of the SiN film 136.

Fig. 20 is a broken perspective view of a portion of the Si substrate, which becomes the individual flow path 110 when the second wet anisotropic etching is performed.

Fig. 21 is a plan view of a flow path substrate constituting the ink jet recording head according to the conventional example 1.

22 is a perspective view of an ink jet recording head according to a conventional example 2. FIG.

23 is a perspective view of an ink jet recording head according to a conventional example 2. FIG.

24 is a manufacturing process chart of the flow path substrate of the prior art example 2. FIG.

(Short description of sign)

10 Inkjet recording heads (droplet ejectors)

12 heating element substrate (silicon substrate)

14 euro board (silicon board)

20 large ink eject ports

22 small ink eject port

24 Ink Supply Port (Liquid Supply Port)

28common liquid room

The first aspect of the present invention is achieved by stacking a plurality of silicon substrates, and the liquid ejection recording in which the liquid supplied from the liquid supply port reaches a plurality of individual flow paths and is ejected as droplets from the liquid discharge port formed at the tip of each individual flow path. The apparatus is characterized in that the liquid discharge port is composed of a groove having a cross-sectional chamfer formed on the surface of the first silicon substrate, and a second silicon substrate in contact with the first silicon substrate. The operation of the first aspect of the present invention will be described. The liquid ejection opening formed in the droplet ejection recording apparatus comprises a first substrate having a groove having a cross-sectional chamfer shape and a second substrate abutting (stacked) on the first substrate, but the cross section of the groove formed in the first substrate is a corner. Since it is in the shape of a chamfer that does not form, the stress can be concentrated in the corners of the corners and the cracks can be suppressed from entering the substrate.

According to a second aspect of the present invention, in the first aspect, the groove is formed by wet anisotropic etching to a silicon substrate followed by reactive ion etching.

The operation of the second aspect of the present invention will be described.

First, a groove of a cross-sectional triangle is formed by a wet anisotropic etching on a silicon substrate, and reactive ion etching is performed on the grooved portion, so that two vertical planes and a pair of vertical planes approximately parallel to the substrate surface are formed. The groove | channel of the chamfer shape which is not formed with the corner formed by the circular arc surface which connects a negative side is formed.

Therefore, it is possible to form grooves that can prevent crack generation due to stress concentration, while securing an advantage of fine machining by reactive ion etching.

According to a third aspect of the present invention, in the first aspect, the laminated end surface is also provided with a liquid discharge port having a rectangular cross-sectional shape.

The operation of the third aspect of the present invention will be described.

The droplet ejection recording apparatus has a liquid ejection opening having at least two types of cross-sections and a rectangular shape (cross section) on a laminated end surface of the stacked silicon substrates. Therefore, when an image is formed using ink in a liquid, the image formation can be switched to image quality priority or speed priority by selecting a liquid discharge port and discharging ink droplets. That is, high quality image formation can be performed by ejecting ink droplets from a liquid ejection opening having a small cross-sectional area, and image formation can be performed quickly by ejecting ink droplets from a liquid ejection opening having a large cross-sectional area.

In a third aspect of the present invention, in the third aspect, the liquid discharge port having a rectangular cross section is formed by bringing another silicon substrate into contact with a silicon substrate on which a groove is formed by reactive ion etching.

The function of the 4th aspect of this invention is demonstrated.

By performing reactive ion etching on the silicon substrate, a groove having a rectangular cross section can be formed, and a liquid discharge port having a rectangular cross section can be formed by bringing another substrate onto the substrate on which the groove is formed.

A fifth aspect of the present invention is the third or fourth aspect of the present invention, wherein the liquid discharge ports having different cross-sectional shapes are alternately arranged on the laminated end surface.

The operation of the fifth aspect of the present invention will be described.

With such a configuration, droplets having a relatively small volume are discharged from the liquid discharge port of the first shape having a small cross-sectional area, and droplets having a relatively large volume are discharged from the liquid discharge port of the second shape having a large cross-sectional area.

When ink is used for the liquid, since the volume of ink droplets discharged from the liquid discharge port of the second shape is large, sufficient printing concentration can be achieved without being completely overwritten. In addition, printing with a relatively small volume of ink droplet in the liquid discharge port of the first shape can achieve high quality printing.

According to a sixth aspect of the present invention, in the third or fourth aspect of the present invention, the liquid discharge ports having different cross-sectional shapes are provided, and the liquid discharge ports of the same cross-sectional shape are continuously arranged.

The operation of the sixth aspect of the present invention will be described.

With such a configuration, droplets having a relatively small volume are discharged from the liquid discharge port of the first shape having a small cross-sectional area, and droplets having a relatively large volume are discharged from the liquid discharge port of the second shape having a large cross-sectional area. Therefore, when ink is used for the liquid, the ink droplets having a relatively large volume can be discharged by discharging ink droplets having a relatively large volume from the continuously discharged second-shaped liquid discharge ports. On the other hand, high quality color printing becomes possible by discharging ink droplets of relatively small volume using color ink to the continuously discharged first shape liquid discharge ports.

In the seventh aspect of the present invention, the opening area of the liquid discharge port including the groove having the chamfered shape in the cross section is larger than the opening area of the liquid discharge port in the cross-sectional rectangle in any one of the third to sixth aspects. do.

The operation of the seventh aspect of the present invention will be described.

As the cross-sectional area of the groove increases, cracks tend to enter the substrate. In particular, when the cross section of the groove is formed into a corner shape such as a rectangle, the risk of cracking into the substrate from the corner is increased. However, in this invention, since the groove | channel with a large cross-sectional area was made into the chamfer shape without a corner in a cross-sectional shape, the possibility that a crack enters a board | substrate can be suppressed.

Further, for example, by studying the etching-etched mask shape on the same silicon substrate, after etching only a portion that becomes a chamfer-shaped groove by wet anisotropic etching, the portion and the rectangle that becomes a chamfer-shaped groove by reactive ion etching are etched. By etching both of the portions to be the grooves, the chamfered grooves can be made larger in cross-sectional area than the rectangular grooves. By increasing the cross-sectional area of the chamfered grooves in this manner, the manufacturing process of forming liquid ejection openings having different cross-sectional areas in the droplet ejection recording apparatus is simplified.

The eighth aspect of the present invention is characterized by forming a groove having a chamfered cross section in the silicon substrate by performing wet anisotropic etching and subsequent reactive ion etching on the silicon substrate.

The operation of the eighth aspect of the present invention will be described.

By performing wet anisotropic etching and reactive ion etching on a silicon substrate, the cross-sectional shape of a groove | channel becomes a chamfer without a corner. Therefore, since the corner is eliminated inside the groove, stress concentration can be prevented and crack generation to the silicon substrate can be prevented.

(First embodiment)

An ink jet recording head (droplet ejection apparatus) according to the first embodiment of the present invention will be described with reference to FIGS. 1 is a perspective view of the inkjet recording head, and FIGS. 2 and 3 are sectional views taken on line A-A and line B-B, respectively, in FIG.

As shown in Fig. 1, the inkjet recording head 10 includes a heat generating element substrate 12 and a flow path substrate 14 laminated via a protective film 16, and the two vertical surfaces facing the laminated end surface 18; The large ink discharge port 20 defined by the arcuate surface which connects the said vertical surface, and the small ink discharge port 22 which are shallower (the opening area is small) than the large ink discharge port 20 as a rectangle are alternately formed.

The ink supply port 24 is formed in the upper surface of the flow path substrate 14, and is connected to the common liquid chamber 28 which has the step part 26 formed inside (refer FIG. 2, FIG. 3). The common liquid chamber 28 communicates with the individual flow passage 30 for communicating with the large ink discharge port 20 and the individual flow passage 31 for communicating with the small ink discharge port 22. Each of the individual flow paths 30 and 31 is provided with a heat generating element 32 and a large pressure generating region 35 having a concave portion 34 and an ink discharge port having a reduced width with respect to the pressure generating region 35 ( A front throttle 36 on the side of 20 and 22 and a rear throttle 38 on the side of the common liquid chamber 28 are provided (see Fig. 13).

Therefore, the ink supplied from the ink supply port 24 into the inkjet recording head 10 flows into the individual flow paths 30 and 31 via the common liquid chamber 28 and generates pressure by heating the heat generating element 32. Bubbles are generated in the area 35 so as to discharge droplets of different volumes from the large ink discharge port 20 or the small ink discharge port 22.

In this manner, since the small ink ejection openings 22 and the large ink ejection openings 20 are alternately arranged, the inkjet recording head 10 corresponds to the heat generating element 32 of the individual flow path 30 when the high speed draft printing is performed. By selecting the address signal, a large volume of ink droplets may be ejected and printed from the large ink discharge port 20. This is because the ink droplets have a large volume, so that sufficient printing concentration can be achieved without being completely overwritten. On the other hand, by selecting the signal of the address corresponding to the heat generating element 32 of the individual flow path 31, high-quality printing can be performed by ejecting and printing a small volume of ink droplet from the small ink discharge port 22. FIG.

Next, the manufacturing method of the inkjet recording head 10 is demonstrated with reference to FIG. Fig. 4 shows the position cross section of the laminated end surface 18 (dicing) with respect to the manufacturing process of the flow path substrate 14, and Figs. 5 to 7 show AA lines (large) with respect to the manufacturing process of the flow path substrate 14; Ink discharge port) cross section. In addition, the same thing as a-s attached to FIGS. 4-7, 11, and 12 shows the same manufacturing process.

Specifically, a step of manufacturing a Si substrate (euro substrate 14) in which a large groove 62 having a depth d4 and a small groove 64 having a depth d5 are alternately side by side as shown in FIG. 4 (o). Explain. In addition, the crystal orientation of the Si substrate 40 is the <100> plane.

First, a SiO ₂ film 42 is formed as a first etch-resistant masking layer by a thermal oxidation method on the Si substrate 40 (see FIG. 5 (a)), which becomes the flow path substrate 14 (FIG. 5 (b). ) Reference).

Subsequently, portions of the SiO ₂ film 42, which become the individual flow paths 30 and 31 and the common liquid chamber 28, are patterned by the photolithography method and the dry etching method (see Fig. 5 (c)). The mask shape formed by this patterning is shown in Fig. 8A. That is, the Si substrate 40 of the part corresponding to the common liquid chamber 28 and the individual flow paths 30 and 31 is exposed.

As shown in Fig. 8A, the mask pattern formed by the SiO ₂ film 42 is connected to the portion that becomes the common liquid chamber 28 and the portion that becomes the individual flow paths 30 and 31, and the individual flow path 30 And the rear throttle shape 46 at the connection portion of the common liquid chamber 28 at the common liquid chamber 28, and the front throttle shape 44 near the front of the portion to be the ink discharge port, and the individual flow path 30 at the position to be the ink discharge port. The pattern is narrowed down.

Subsequently, a SiN film 48 is formed as a second etch-resistant masking layer by reduced pressure CVD (Chemical Vapor Deposition) (see Fig. 5 (d)). At this time, the thickness of the SiN film 48 formed may be about 300 nm, for example.

With respect to this SiN film 48, the part which becomes the common liquid chamber 28 and the step part 26, the part which becomes the part of the recessed part 34, and the ink discharge opening 20 in the individual flow path 30, and the individual The part which becomes the recessed part 34 in the flow path 31 is patterned using the photolithographic method and the dry etching method (refer FIG. 5 (e)). An example of the pattern of the SiN film 48 is shown in Fig. 8B. The recess patterns 50A and 50B formed in the SiN film 48 have recesses 34 and the large ink ejection openings 20 of the individual flow paths 30 and recesses 34 of the individual flow paths 31, respectively. It becomes a mask for preliminary processing for forming the shape of the depth direction to become.

That is, the concave portion pattern 50A corresponds to the ink ejection opening 20 larger than the mask pattern (in FIG. 9, broken line portion) corresponding to the individual flow paths 30 of the SiO ₂ film 42, as shown in FIG. It is a rectangular pattern with a constant width that extends to the part. On the other hand, as shown in Fig. 10, the recess pattern 50B corresponds only to the recess 34 with respect to the mask pattern (dashed line in Fig. 10) corresponding to the individual flow path 31 of the SiO ₂ film 42. It is a large rectangular pattern.

In the pattern of the SiN film 48 of this example, since the common liquid chamber pattern 51 is formed together with the concave portion patterns 50A and 50B, the portions serving as the common liquid chamber 28 and the stepped portion 26 are removed. have.

Subsequently, a SiO ₂ film 52 serving as a phosphoric acid etching protective film (third etch-resistant masking layer) is formed by a reduced pressure CVD method (see FIG. 5 (f)). At this time, the thickness of the SiO ₂ film 52 formed may be, for example, about 500 nm.

The SiO ₂ film 52 is patterned by photolithography and dry etching. The SiO ₂ film 52 is formed to cover the SiN film 48 (see Fig. 5G).

Subsequently, a second SiN film 54 serving as a fourth etching resistant masking layer is formed by a reduced pressure CVD method. At this time, the thickness of the SiN film 54 formed may be, for example, about 300 nm (see Fig. 6 (h)).

This SiN film 54 is patterned by using a photolithography method and a dry etching method to form the common liquid chamber 28 (see Fig. 6 (i)). An example of the pattern of the SiN film 54 is shown in Fig. 8C. The SiN film 54 is provided with a common liquid chamber pattern 56 in which only a portion of the common liquid chamber 28 is removed. At this time, the region from which the SiN film 54 is removed may be set smaller than the actual common liquid chamber 28 by a predetermined amount.

Subsequently, the Si substrate 40 is etched with a KOH aqueous solution using the SiN film 54 as an etching mask (see FIG. 6 (j)). This etching is performed until the Si substrate 40 is penetrated, and the through hole is the ink supply port 24. This processing results in the sidewalls being formed as slopes with a predetermined angle due to the nature of wet anisotropic etching. Since the processing is performed from one surface of the Si substrate 40 here, a through hole in which the cross-sectional area becomes small toward the ink supply port 24 is formed. The wet anisotropic etching used here is faster in processing speed than RIE (Reactive Ion Etching), and is suitable for processing having a deep processing depth to penetrate the Si substrate 40.

Subsequently, the SiN film 54 is selectively etched away with an aqueous phosphoric acid solution (see Fig. 6 (k)). At this time, since there is a SiO ₂ film 52 serving as a phosphoric acid etching protective film, the underlying SiN film 48 is not eroded.

Next, the SiO ₂ film 52 is selectively etched away with an HF solution (see Fig. 6 (l)).

Subsequently, wet anisotropic etching with KOH aqueous solution is performed on the Si substrate 40 using the SiN film 48 (see FIG. 8 (b)) as an etching mask (see FIGS. 6 (m) and 9 (m)). . In this wet anisotropic etching, only a desired depth is processed so as not to penetrate. The processing depth can be, for example, about 200 µm. However, it should be set shallower than the depth to be completed. As shown in Fig. 8B, since the SiN film 48 has a common liquid chamber pattern 51 in which portions of the common liquid chamber 28 and the step portion 26 are removed, the sidewalls of the common liquid chamber 28 are removed. A stepped portion of a predetermined depth can be formed in the portion.

In addition, a recess pattern 50A in which a part of the recess 34 in the individual flow path 30 of the SiN film 48 and the portion that becomes the large ink discharge port 20 is removed, and a recess in the individual flow path 31. Since the recessed pattern 50B in which the part used as 34 is removed is formed, the part used as the recessed part 34 and the large ink discharge opening 20 of the individual flow path 30, and the recess of the individual flow path 31 are formed. The part which becomes the part 34 is also etched, and the shape of the depth direction of the individual flow path 30 is formed.

9, 10, and CC line cross-section positions, which are diced to form the laminated end surface 18, the large ink discharge port 20 is formed by the recess pattern 50A of the SiN film 48. FIG. Only the Si substrate 40 of the portion is exposed, and the grooves 62A having a triangular cross section are formed by wet anisotropic etching (see Figs. 4 (l) to 4 (m)).

On the other hand, in the recess formation position (FIG. 9, FIG. 10, DD line cross-section position), the Si substrate 40 of the same width | variety as the laminated end surface 18 is made from the SiN film 48 by the recess pattern 50A. The exposed portion is also provided with a groove 63A having a triangular cross section similar to the groove 62A (see Figs. 11 (l) to 11 (m)). On the other hand, at the position where the concave portion pattern 50B is formed, the Si substrate 40 having a width corresponding to the concave portion 34 is exposed from the SiN film 48, and the groove 65A having a triangular cross section is formed in the portion. 12 (l) to 12 (m).

Subsequently, the SiN film 48 is selectively etched away with a phosphoric acid solution (see Figs. 4 (n), 7 (n), 11 (n) and 12 (n)). As a result, the Si substrate 40 in the portion along the flow path shape is exposed from the SiO ₂ film 42. That is, not only the position where the large ink ejection openings 22 are formed, but also the Si substrate 40 of the portion where the small ink ejection openings 22 are formed is exposed from the SiO ₂ film 42 at the laminated end surface position (Fig. 4 (n). ) Reference). At the recessed position, the Si substrate 40 also exposes the Si substrate 40 from the SiO ₂ film 42 even at the position where the individual flow paths 30 are formed (see Fig. 11 (n)).

Next, the Si substrate 40 in the portion to be the individual flow paths 30 and 31 and the portion to be the common liquid chamber 28 is etched by the RIE method using the SiO ₂ film 42 as an etching mask (Fig. 4 (o), 7 (o), 11 (o), 12o). The processing depth can be about 20 µm, for example. In this RIE processing, etching can be performed evenly in the thickness direction other than the portion being masked without depending on the crystal orientation of Si. Therefore, the flow path can be formed with high accuracy along the mask pattern shape (solid line portion) shown in Fig. 8A.

As a result, the small groove 64 of the cross-sectional rectangle of depth d5 is formed by RIE processing at the small ink discharge port 22 formation position (refer FIG. 4 (n)-FIG. 4 (o)).

On the other hand, at the position where the large ink ejection openings 20 are formed, a triangular groove 62A is formed immediately after the wet anisotropic etching, but after RIE processing, the apex of the triangle is rounded to become a large groove 64 (FIG. 4 ( n) to Fig. 4 (o)). This is due to the fact that the polymer is thickly deposited at the apex at the time of etching, so that the supply of the etching gas at the initial stage of etching is inhibited at this portion. In addition, the depth d4 of the large groove 62 is deeper than the case where only the RIE processing is performed (depth d5 of the small groove 62) by etching the triangular groove 62A.

In this manner, the large grooves 62 and the small grooves 64 having different depths are formed in the Si substrate 40.

Finally, the SiO ₂ film 42 is selectively etched away with a hydrofluoric acid solution to complete the processing of the Si substrate 40 serving as the flow path substrate 14 (see Fig. 7 (p)).

By dicing the Si substrate 40 in which the large groove 62 and the small groove 64 are formed in this way along the dicing lines shown in FIGS. 7 and 12, the large groove 62 and the small groove having different depths ( 64 is opened in the end face, and the flow path substrate 14 is formed.

By stacking the flow path substrate 14 and the heat generating element substrate 12 via the protective layer 16, the large grooves 62 and the small grooves 64 become individual flow paths 30 and 31, respectively, and the laminated end surface. The openings in 18 serve as the ink discharge ports 20 and 22.

As described above, in the present embodiment, in the mask for forming the step portion 26 of the common liquid chamber 28, the recess pattern 50A is formed from the portion corresponding to the recess 34 to the portion corresponding to the large ink ejection opening 20. Since it is formed, a triangular groove 62A is formed in the formation portion of the large ink discharge port 20 of the Si substrate 40 in the wet anisotropic etching at the time of forming the stepped portion 26, and subsequently by the mask for forming the flow path. By etching by RIE, the triangular groove 62A becomes a large groove 62 having a deeper chamfer shape. On the other hand, since the part of the small ink discharge port 22 is etched only by RIE, the small groove 64 of a shallow cross section rectangle is formed compared with the large groove 62.

As described above, in the present embodiment, the mask shape is formed without increasing the conventional etching process, so that the large grooves 62 and the small grooves 64 having different depths can be formed in the Si substrate 40.

Therefore, while the flow path substrate 14 of the inkjet recording head 10 having the ink ejection openings having different cross-sectional areas is precisely processed using RIE processing, the deep ink ejection openings (large grooves 62) can be formed in a short time using wet anisotropic etching. Can be. Therefore, the productivity of the inkjet recording head 10 can be improved.

If the cross section of the groove 70 is rectangular, as shown in Fig. 14, there is a risk that the crack 72 enters the silicon substrate 40 at the corner of the corner due to stress concentration due to the increase in the cross-sectional area.

However, since the large groove 62 has a shape in which there is no corner formed as a vertical plane facing the cross-sectional shape inside the groove and an arc surface connecting this bottom portion, cracks can be prevented from entering into the corner by stress concentration. In addition, this crack prevention effect can be achieved if it is a chamfer shape without a corner, for example, the shape which made the groove shape round the top of a triangular groove, and is circular, and is not limited to the shape of a present Example. .

(2nd Example)

Next, an ink jet recording head according to a second embodiment of the present invention will be described with reference to FIG. The same components as those in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted. Since the difference from the first embodiment is only the arrangement of the individual flow paths of the flow path substrate 14, only a substantial portion thereof will be described.

As shown in Fig. 15, in the inkjet recording head 60, in the laminated end surface 18, the first region A1 in which the small ink ejection openings 22 are arranged, and the large ink ejection opening 20 are arranged. It is divided into two areas A2.

Therefore, printing is performed using only the second area A2 when injecting a large volume of ink droplets, and printing is performed using the first area A1 when injecting small ink droplets.

For example, by discharging black ink from the large ink discharge port 20 in the first area A1, black character printing with a high density can be achieved, and high quality color printing can be achieved by using color ink in the second area A2. It becomes possible.

By forming the ink ejection openings having different depths in the same chip without increasing the number of processes, a large-sized droplet ejection recording apparatus capable of ejecting large droplets of different ink droplets and achieving both high speed and high image quality is provided. Can provide.

Further, by assigning black ink to a large drop and color ink to a small drop, it is possible to provide a full color liquid ejection recording apparatus capable of high speed and high quality printing in a single head.

Further, by applying the present invention (processing by wet anisotropic etching and reactive ion etching) to all of the ink ejection openings, it is possible to process deep grooves in a short time, and the productivity of the inkjet recording head is improved.

Moreover, since the corner of the groove | channel of the board | substrate which comprises an ink discharge port can be rounded, the crack tolerance of a silicon substrate also improves.

Claims (8)

A droplet ejection recording apparatus which is formed by stacking a plurality of silicon substrates, in which a liquid supplied from a liquid supply port reaches a plurality of individual flow paths, and is sprayed as droplets at a liquid discharge port formed at the tip of each individual flow path, And the liquid discharge port comprises a groove having a cross-sectional chamfer formed on the surface of the first silicon substrate, and a second silicon substrate in contact with the first silicon substrate. The method of claim 1, And the groove is formed by wet anisotropic etching of the first silicon substrate followed by reactive ion etching. The method of claim 1, And the liquid ejection opening having a rectangular cross-sectional shape is provided on the laminated end surface. The method of claim 3, And the liquid discharge port having a rectangular cross section is formed by abutting another silicon substrate on a silicon substrate having a groove formed by reactive ion etching. The method according to claim 3 or 4, A liquid ejection recording apparatus, characterized in that liquid ejection openings having different cross-sectional shapes are alternately arranged on the laminated end surface. The method according to claim 3 or 4, A droplet ejection recording apparatus comprising liquid ejection openings having different cross-sectional shapes and arranged successively for each liquid ejection opening having the same cross-sectional shape. The method according to any one of claims 3 to 6, And the opening area of the liquid discharge port having the chamfer-shaped groove in cross section is larger than the opening area of the liquid discharge port in the cross-sectional rectangle. A method for producing a silicon structure, wherein the silicon substrate is formed by a wet anisotropic etching and subsequent reactive ion etching on the silicon substrate.