KR100499119B1 - method for manufacturing of Monolithic nozzle assembly for ink-jet printhead using mono-crystalline silicon wafer - Google Patents

Abstract

The present invention describes a method of manufacturing a nozzle assembly for an integrated inkjet print head using a single crystal silicon wafer. The integrated microfluidic nozzle assembly for an inkjet printhead using a (100) plane single crystal silicon wafer according to the present invention simplifies the complicated structure of stacking using several wafers and plates. It is possible to reduce the number of wafers by making it integrated with no staggering, thereby enabling mass production, and by using batch automatic alignment process using anisotropic etching process using crystal surface of wafer and proper mask forming process using LOCOS process. . In other words, not only can the alignment error be reduced to a few microns or less by utilizing a general silicon photolithography process, but it is also not complicated, has excellent economic efficiency, and yields.

Description

Method for manufacturing a monolithic nozzle assembly for ink-jet printhead using mono-crystalline silicon wafer

The present invention relates to a method for manufacturing of a monolithic micro nozzle assembly for ink-zet print head using a mono-crystalline silicon wafer.

1A is a cross sectional view of a laminated ink jet recording head as described in EP 0 659 562 A2. As shown, the laminated inkjet recording head basically comprises a nozzle plate 101 on which a nozzle 100 is formed, three communicating hole forming boards 201a, 201b, and 201c, and a pressure generating chamber forming board 301. ) And the diaphragm 400 are sequentially laminated (laminated) structure. In the pressure generating chamber 300, the ink stored in the ink storage container 800 is temporarily stored in the storage chamber 600a after passing through the inlet 700, and then filled through the ink inlet 600c and the communication hole 600b. Ink provided from an external ink container flows into the ink storage container 800 through the filter 900. The piezoelectric vibrator 500 is attached to the diaphragm 400 to generate pressure in the ink filled in the pressure generating chamber 300 according to a voltage signal applied thereto. The pressurized ink is discharged through the nozzle 100 through the communicating holes 200a, 200b, and 200c. The laminated inkjet recording head of such a structure is manufactured by alignment bonding by separately producing each thin plate. That is, as shown in FIG. 1B, a very complicated process of processing and pasting each thin plate is selected. This requires a lot of know-how in the process and the economics and yields become very bad. In the process of sorting each other, the alignment error becomes large. In particular, the nozzle assembly portion, such as region "A" shown in FIG. 1A, solves the formation of the nozzle and the portion serving as a damper for the flow of fluid by lamination of thin plates of various sizes. As such, the conventional method of manufacturing nozzle assemblies that are directly related to the formation of fluid flow paths to fluid injection uses a method of fabricating and stacking each structure separately, so that the interface of the thin plate due to the unsmooth fluid flow due to alignment error. Distracts the flow of fluid.

Methods of forming such a nozzle assembly may vary as shown in FIGS. 2A to 2F and FIGS. 3 to 5. 2A to 2F and 3 to 5 are representative ones, all of which can be formed only by the nozzle part, and should be laminated when dampers are required. Of course, the lamination method also becomes a big problem, and there is a problem in economic efficiency and yield.

First, FIGS. 2A to 2F are nozzle forming methods described in US Pat. No. 3,921,916, which are subjected to selective partial doping as shown in FIGS. 2A to 2C, and then wet etching on opposite sides as shown in Fig. 2D. Only doped silicon has a selectivity to wet etching to form nozzle portions as shown in FIGS. 2E and 2F. This is a disadvantage in that the depth of the doping and the process is a rather complicated problem.

3 is a method of forming a nozzle by mechanical punching, the surface is not smooth, the yield may be used only in the method of lamination.

FIG. 4 shows a nozzle forming method described in “Sensors and Actuators A 65 (1998) 221-227”, in which a nozzle is formed by wet etching by time adjustment by performing double side alignment. In the original wet etching, the size of the nozzle is determined according to the etching depth and the size of the pattern, so there is a problem in uniformity, and in particular, there is a big disadvantage in that a process stop by time adjustment is required.

FIG. 5 is a nozzle forming method described in "G. Siewell et al., HP journal, vol 36, no. 5, pp 33-37 (1985)", except for the nozzle part with a photoresist pattern as shown in FIG. The remaining portion is subjected to nickel electroplating as shown in FIG. B) to remove the nozzle as shown in FIG. C). This is because the nozzle size is generally formed unevenly more than several micrometers, and the inclination angle control of the nozzle part is difficult and uneven.

6A, 6B, and 7A to 7D illustrate a method of fabricating a nozzle assembly by forming a damper structure and a nozzle structure and then stacking the silicon, respectively. The former forms the nozzle assembly as shown in FIG. 6B by attaching the bulk silicon 20 with the damper 21 as shown in FIG. 6A and the nozzle plate 30 with the nozzle 31 formed thereon. The latter forms the damper 41 structure in the bulk silicon 40 as shown in FIG. 7A, and then, as shown in FIG. 7B, the damper is provided in the bulk silicon 40 with the nozzle plate 50 at the same time. A wet mask 42 is deposited on the sidewalls of 41, and two wafers 40 and 50 are stacked, as shown in FIG. 7C, and a nozzle corresponding to damper 41, as shown in FIG. 7D. The nozzle 50 is formed by wet etching the plate 50.

Since both methods require the use of wafers of thin nozzle plates 30 and 50, there is a big problem such as easy handling damage. 6A and 6B, alignment is essential when stacked. In the method of FIGS. 7A-7D, no alignment is required but two wafers are required and wafer handling problems still remain.

8A to 8C are views for explaining a wet etching method using a silicon crystal surface. 8A is a diagram showing a crystal plane of silicon. In many wet etching solutions such as TMAH, the (111) plane of silicon has a very low etching rate. This results in an etching aspect of the (100) silicon wafer due to the etch rate along the crystal plane as shown in FIG. 8B or 8C.

It is a figure explaining a dry etching process. As shown in the figure, when dry etching using plasma is performed, the thickness of the wall coating film c is thicker than that of the coating film a, which makes it hard to etch by the dry etching process.

And LOCOS (LOCal Oxidation of Silicon) refers to a method of partially oxidizing silicon. The silicon thermal oxide film is formed by growing an oxide film while silicon atoms meet oxygen atoms at a high temperature to produce silicon oxide SiO ₂ . Therefore, even if the silicon atoms are not exposed to the surface even at high temperatures, the thermal oxide film does not grow, so partial oxidation can be performed on this principle, which is called LOCOS. In a general manner, a thermodynamically stable film such as a nitride film can be coated on silicon and they can oxidize only the exposed portions of silicon by preventing the exposure of silicon atoms or preventing the ingress of oxygen. The nitride film can be patterned to create a continuation of the nitride film and the partial oxide film.

On the other hand, the outlet damper and the nozzle constituting the nozzle assembly directs the fluid to direct and inject the fluid flow. The nozzle is mainly used as the injection head and the valve structure of the application head, and the outlet damper not only improves the direction of the flow of the fluid, but also serves as an auxiliary device for the fluid injection by acting as a damper against external pressure.

A generally conceived method for forming a nozzle assembly with such a nozzle and outlet damper into a multi-layered structure (steps of tens of microns or more) in terms of a MEMS process using silicon is shown in FIGS. 10A-10K. Their method is fundamentally a problem in photolithography, so a method of using a special PR such as SU-8 (IBM; see US 4,882,245) has been attempted, but in many ways masking for solving the problem according to its practical use There can be no way. That is, FIGS. 10A and 10B are cross-sectional views of a substrate showing an assembly of a multi-stage structure, respectively, and FIGS. 10C and 10D are views showing a process for forming the multi-stage structure, respectively, and FIGS. 10E to 10K are each FIGS. It is a cross-sectional view showing the manufacturing process using a multilayer mask to obtain a structure step by step. That is, in order to obtain a structure as shown in FIG. 10A, first, a bulk silicon 80 as shown in FIG. 10E is provided, and a first mask 60 as shown in FIG. 10F is formed thereon. As shown in FIG. 10G, the second mask layer 70 is coated on the entire surface. Next, as shown in FIG. 10H, an opening 71a for damper formation is formed, and through this opening 71a, a damper 75 is formed as shown in FIG. 10I. Next, as shown in FIG. 10J, the second mask film existing on the upper surface of the bulk silicon 80 is removed and the upper surface portion of the bulk silicon 80 is etched to obtain a structure as shown in FIG. 10K. In order to fabricate the nozzle assembly having such a structure, there is a fatal problem in applying the photoresist. As shown in FIG. 10C, there is a nonuniformity of photoresist application due to centrifugal force during photoresist rotational application. As shown in FIG. 10D, bubbles 5 are formed when the photoresist is applied so that they burst when baking and the coating film is broken. In this case, as illustrated in FIGS. 10E to 10K, a general multilayer mask can be used to solve the problem. However, in order to obtain a conical structure as illustrated in FIG. 10B, the multilayer mask cannot be used. This is because the pattern of the 3rd pattern and the 1st pattern / 2nd pattern of Figure 10b is different when etching the structure, when obtaining the 3rd pattern 1st pattern and 2nd pattern should be etch protected when etching the 3rd pattern, 3rd when etching 1st pattern / 2nd pattern This is why the pattern must be etch protected. In this regard, the process using the multilayer mask of FIGS. 10E to 10K cannot solve this problem.

In addition, a fluid jet such as a nozzle requires hydrophilic (hydro-phobic) or hydrophobic (hydro-phobic) surface treatment, but there is a problem that it is almost impossible to control this boundary by conventional methods (mostly mechanical methods).

The present invention was devised to improve the above problems, and in order to improve the existing high cost, low efficiency, complicated structure and manufacturing method, only one single crystal silicon wafer was fabricated using a silicon semiconductor process and a MEMS process (100). It is an object of the present invention to provide a method for manufacturing a nozzle assembly for an integrated micro inkjet head using a single-sided single crystal silicon wafer.

In order to achieve the above object, the manufacturing method by the batch automatic alignment process of the nozzle assembly for an integrated micro inkjet head using a single crystal silicon wafer according to the present invention, the ink flow path for distributing and supplying the ink flowing from the ink container to each head ; A channel through which a predetermined amount of ink is injected into each of the heads in the flow path; A pressure chamber of each head for temporarily storing the constant amount of ink drawn in from the channel and pressurizing the stored ink to be ejected; Dampers of the respective heads receiving ink from the pressure chamber and providing the ink to the nozzles; Nozzles of each of the heads each including a discharge port for discharging the ink stored in the damper and conical portions for inducing the ink stored in the damper to enter the discharge port at a higher pressure than the pressure in the damper. A manufacturing method, comprising: (a) depositing a first mask on a (100) plane single crystal silicon substrate; (b) locally etching the first mask to form the opening for channel formation, and then depositing a second mask; (c) etching the first mask and the second mask to form an opening for forming the pressure chamber; (d) depositing a third mask over the substrate and over the second mask exposed by the pressure chamber forming opening; (e) selectively etching the third mask using a photoresist mask to form openings for forming the damper and the flow path; (f) performing a first deep etching process for forming a damper on the silicon substrate through the opening for forming the damper; (g) etching the second mask and the first mask exposed by the opening of the third mask using the photoresist mask as it is to form the flow path formed in step (e) to form an opening for forming the flow path step; (h) performing a second deep etching on the silicon substrate through the damper and the opening for forming the flow path to complete the damper and simultaneously form a vertically downward etching portion of the flow path; (i) depositing a fourth sidewall protection mask on sidewalls of the damper and the vertical downward etching portion of the flow path; (j) etching the bottom surface of the damper and the channel vertical downward etching portion in the fourth mask for protecting the sidewall to form an opening for etching the nozzle cone portion and the inclined portion of the passage; (k) performing anisotropic wet etching along the crystal plane as TMAH (Tetra-Methyl Ammonium Hydroxide) through openings for forming the cone portion and the channel slope portion of the nozzle to form the cone portion of the nozzle and the slope portion of the flow path; (l) locally thermally oxidizing a silicon exposed surface of the cone portion of the nozzle and the inclined portion of the flow path to form a fifth mask; (m) locally removing the third mask (nitride film) to form an opening for forming a pressure chamber; (n) performing a third silicon dip etch to form the pressure chamber; (o) selectively removing the second mask to form an opening for forming the channel; (p) performing fourth deep etching on the silicon substrate using the channel forming opening; (q) selectively etching the second mask and the first mask formed on the back surface of the silicon substrate by dry etching using a photoresist mask to form a double-sided alignment opening for forming a nozzle outlet; (r) forming the nozzle outlet through a silicon substrate etching process using the double-sided alignment opening, and then removing the photoresist mask and depositing a hydrophobic coating film on the nozzle outlet; And (s) etching the film of the fifth mask of the nozzle cone to penetrate the outlet to allow ink flow.

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In the present invention, in step (a), any one of a thermal oxide film, an oxide film, and a nitride film is used as the first mask, but a metal film is used as the first mask, and the second, third, fourth, and fifth masks are used. It is preferable to deposit with any one of TEOS, PECVD nitride film, the metal film and another metal which can be deposited at a lower temperature than the metal film, and in step (b), the second mask may be any one of TEOS, oxide film, nitride film and metal. Deposition of a material, and in the step (c) the opening for forming the pressure chamber is formed in the size of 2800 * 260 μm, giving a radius of curvature of 100 μm to the corner of the opening for forming the pressure chamber, the step (d) In the third mask using any one of a nitride film, an oxide film, or a metal, in the step (e) the third mask is formed of a nitride film to form the opening by dry etching method, in the step (f) Prize The primary deep etching for damper formation is etched to a depth of about 150 μm using ICP RIE, the opening for forming the flow path in the step (g) is formed using a dry etching method, in the step (h) The etching depth of the second deep etching is 150 μm, in which case the etching depth of the damper is 300 μm, and in step (i), a thermal oxide film is deposited as the fourth mask for protecting the sidewalls, or other If an oxide film or a nitride film is used and a thermal oxide film cannot be locally formed as the sidewall protection fourth mask due to the property of the film deposited as the third mask in step (i), instead of step (i), and (i ') depositing a fourth mask for protecting the sidewalls over the entire surface thereof, wherein the opening of the nozzle cone and the inclined portion of the flow path in the (i) step is performed in (i'). deposition Preferably, the fourth mask is formed of the same material as the third mask, and is formed by selective etching according to a difference in thickness between the third mask and the fourth mask film, or in step (j), the nozzle circle The opening portion for etching the weight portion and the inclined portion of the flow path may be formed by selective etching according to the selectivity ratio between the thermal oxide film and the nitride material by forming the third mask as a nitride film and the fourth mask for protecting the side wall as a thermal oxide film. And in step (m), the third mask is formed of a nitride film, and the opening for forming the pressure chamber is removed by wet etching using a phosphoric acid as an etching solution. The third silicon dip etching for forming the pressure chamber is performed to a depth of about 85 μm using ICP RIE, and in step (o) The second mask is formed of TEOS, and the opening for forming the channel is removed only up to the depth of the second mask, and in step (p), the fourth deep etching is etched to a depth of 15 μm using an ICP RIE. In step (q), the double-sided alignment opening for forming the nozzle outlet is formed to have a diameter of 24 μm, or as a step (q ') instead of step (q), all masks on the upper and side surfaces of the silicon substrate are removed and the After forming a hydrophilic coating film on the exposed surface, by forming a double-sided alignment opening for forming a nozzle outlet by locally etching the second mask and the first mask formed on the back surface of the silicon substrate by a dry etching method using a photoresist mask It includes; and, in the step (r) using a Teflon-based film or an organic film by PECVD of C4F8 / SF6 / Ar mixed gas as the hydrophobic coating film Desirable, and the length of said discharge opening is determined by the wet-etching depth of the damper in the cone (k) step.

Hereinafter, referring to the drawings, a nozzle assembly for an integrated inkjet printhead using a single crystal silicon wafer according to the present invention and a manufacturing method thereof by a batch automatic alignment process will be described in detail.

Using a wet etching method using a crystal surface and a LOCOS (LOCal Oxidation of Silicon) process, an integrated nozzle assembly for an inkjet head can be manufactured as shown in FIG.

11 and 12 are cross-sectional and perspective views, respectively, of an integrated nozzle assembly for an ink jet head manufactured as an example. As shown, the integrated nozzle assembly for an inkjet head according to the present invention includes a nozzle 401, an ink damper 402, a pressure chamber 403, a channel 404, and a flow path 405 on a silicon substrate 400. do. Here, the flow path 405 is a main manifold for supplying ink to each nozzle from an ink container (not shown), and ink is distributed to each ink jet head nozzle through each channel 404 in this flow path 405. do. Ink passing through the channel 404 is stored in the pressure chamber 403 and the damper 402 and is ejected through the nozzle 401 by the pressure of a diaphragm (not shown) attached to the upper surface of the pressure chamber 403.

In the integrated nozzle assembly for the inkjet head of this structure, the cone of the nozzle 401, the ink damper 402, the pressure chamber 403, etc. must be hydrophilic surface treatment to be refilled ink The inner wall surface of the discharge port of the nozzle must be hydrophobic to break the ink drop during ink ejection. Silicon itself has a hydrophobic surface, but when left in air for a long time, a natural oxide film is formed to have a hydrophilic surface. Therefore, hydrophobic surface treatment rather than hydrophilic surface treatment is a major process for forming an inkjet head. Looking at the manufacturing process with reference to Figure 13a to Figure 13s as follows.

First, as shown in FIG. 13A, a first mask 501 is deposited on a (100) plane single crystal silicon substrate 400. The first mask 501 uses a material that can serve as a mask in wet or dry silicon etching. For example, materials such as thermal oxide film, oxide film, nitride film, and metal are used. In particular, the coating of a metal film allows direct transfer to eutectic bonding after completion of the process. In this case, the high temperature process affecting the metal is not accompanied. Instead of a high temperature film such as a thermal oxide film, a material capable of low temperature deposition such as TEOS and PECVD nitride film or other metals are deposited.

Next, as shown in FIG. 13B, the first mask 501 is etched to form the openings 511 to form a pattern for forming a channel, and then a second mask 502 is formed. Deposit. This second mask 502 also uses a material that can act as a mask during wet or dry silicon etching. For example, TEOS, oxide film, nitride film, metal and the like are used.

Next, as shown in FIG. 13C, the opening 512 is formed by etching the first mask 501 and the second mask 502 to form a pressure chamber. The opening 512 has a size of 2800 * 260 μm. In addition, a radius of curvature of 100 μm is provided at the corners to prevent vortex of the fluid.

Next, as shown in FIG. 13D, a third mask 503 is deposited. In forming the third mask 503, a material such as a nitride film, an oxide film, or a metal that can serve as a mask during wet or dry silicon etching is used.

Next, as shown in FIG. 13E, a third mask 503 is formed to form an ink damper and an manifold (main flow path) using a photoresist mask 521. ) Is etched to form openings 513 and 513 '. In this case, anisotropic etching is performed according to the angle of the wafer in the process of FIG. 13K, and this should be considered. For example, the openings 513 for damper formation are etched in a circular shape, and the openings 513 'for channel formation do not have to be angled, and fluid analysis is easy, and nitride film etching uses a dry etching method.

Next, as shown in FIG. 13F, silicon deep etching for forming a damper (Outlet-Damper) 402 is performed. It is etched to the depth indicated by c-d in FIG. In practice, it is etched to a depth of about 150 μm using an ICP RIE.

Next, as shown in FIG. 13G, the second mask 502 and the first mask 501 are etched using the photoresist mask 521 as it is to form a manifold (main flow path). 513 ") to expose the silicon substrate region for the formation of the flow path. This flow path is used as the main flow path for ink distribution, and the larger size is better in the spec. The opening 513" is formed using a dry etching method. do.

Next, as shown in FIG. 13H, a deep etching is performed on the silicon substrate to form a manifold 405. Etching depth (d of FIG. 11) shall be about 150 micrometers. An etching depth (c in FIG. 11) of the damper (Outlet-Damper) 402 is formed to be 300 μm. In this case, when the etching rate is a problem, the same effect may be obtained by using a wafer (SOI or Bonded wafer) having an etch stop layer as shown in FIGS. 14A and 14B. However, there is a disadvantage in that the additional cost is high. In the case of forming a damper structure with a single wafer, the etching uniformity must be good to have uniformity in forming the nozzle, so that the above structure can be easily realized with a single wafer by obtaining etching uniformity using ICP RIE.

Next, as shown in FIG. 13I, a fourth mask 504 for protecting sidewalls is deposited. The sidewall protection fourth mask 504 serves as a mask for wet etching in the nozzle portion wet etching process as shown in FIG. 13K. As the fourth mask for protecting the sidewalls, a thermal oxide film is deposited, or other oxide film, nitride film or the like is used. When the thermal oxide film cannot be locally formed as the fourth mask 504 for sidewall protection due to the property of the film deposited as the third mask 503, as shown in FIG. 504 '). That is, in this case, when the LOCOS phenomenon in which the third mask 503 is deposited as the nitride film and the thermal oxide film is locally formed as the fourth mask 504 for sidewall protection does not occur, the oxide film or nitride film as the sidewall protective film on the entire surface thereof. It means to deposit. For example, a nitride film is coated with the third mask 503 and another oxide film or nitride film other than the thermal oxide film is deposited as the sidewall protection mask 504 '.

Next, as shown in FIG. 13J, the openings 514 are formed by etching the fourth masks 504 and 504 ′ of the bottom surface to the portion where the wet etching is to be performed in the nozzle part wet etching process of FIG. 13K. . This deep etching process uses dry etching equipment with excellent anisotropic etching. At this time, in the case of the fourth mask 504 of FIG. 13I, the opening 514 is formed by selective etching according to the selectivity between the different materials (oxide vs. nitride), and the fourth mask 504 ′ of FIG. In this case, the opening 514 is formed by selective etching according to the interlayer thickness difference, and is selectively wet etched during the nozzle part forming process of FIG. 13K. The embodiment follows a process as shown in FIG. 13I.

Next, as shown in FIG. 13K, wet etching using Tetra-Methyl Ammonium Hydroxide (TMAH) in the area opened in the previous process to form the conical portion 514 'of the nozzle and the inclined portion of the flow path. Is done. In this wet etching process, the cone shape of the nozzle is etched by anisotropic etching along the silicon crystal direction, and the flow path region is also etched obliquely. In particular, the wet etch depth of this damper cone portion determines the length of the nozzle outlet formed next.

Next, as shown in FIG. 13L, the silicon surface exposed by the above etching process is locally thermally oxidized to form a fifth mask 505 (using the LOCOS process). The fifth mask 505 serves to maintain the shape of the nozzle by acting as a mask during the process of FIG. 13N and the process of FIG. 13P. In these etching processes, the thermal oxide film resulting from the LOCOS phenomenon of the thermal oxide film with respect to the nitride film masks only the nozzle portion.

Next, as shown in FIG. 13M, the third mask 503 (nitride film) is locally removed to form an opening 515 for forming a pressure chamber. At this time, the nitride film on the entire surface of the wafer is removed by wet etching using etchant as phosphoric acid.

Next, as shown in FIG. 13N, a silicon deep etching for forming a pressure chamber 403 is performed. The etching depth is taken as the depth of b-a in FIG. That is, etching is performed to a depth of about 85 μm using ICP RIE.

Next, as shown in FIG. 13O, the second mask (TEOS) 502 is locally removed to form an opening 516 for channel formation. The opening 516 is removed only by the thickness of the second mask TEOS by dry etching.

Next, as shown in FIG. 13P, silicon deep etching (to depth a in FIG. 11) is performed to form a channel 404 using the openings 516. That is, it etches to the depth of about 15 micrometers using ICP RIE.

Next, as shown in FIG. 13Q, the second mask 502 and the first mask 501 formed on the substrate back-side are locally etched by the photoresist mask PR to discharge the nozzles. The double-sided alignment openings 517 for forming the grooves are formed by dry etching. The size of the outlet of the nozzle is determined by the size of this opening 517. That is, in this opening step, the second mask (TEOS) and the first mask (thermal oxide film) are continuously etched by the dry etching method with the opening for forming the nozzle outlet having a diameter of 24 µm. In addition, unlike the above, as shown in FIG. 13qa, after removing all the mask material and applying a hydrophilic coating for ink refill, the second mask and the first mask formed on the back-side of the substrate are removed. A double-sided alignment opening 517 'for locally etching to form a nozzle outlet is formed by dry etching using a photoresist mask PR. That is, a thermal oxide film is deposited with a hydrophilic coating film, and an opening having a diameter corresponding to the nozzle outlet diameter of 24 mu m in diameter is formed. It is a very uniform and accurate spec. For the size using the semiconductor process.

Next, as shown in FIG. 13R, the nozzle outlet 401a is formed by etching the silicon using the opening 517. After removing the PR mask, the hydrophobic coating layer 506 is deposited after washing. When the ink is ejected, the nozzle 401a of the nozzle should have no wetting of the ink, and a hydrophobic surface treatment capable of breaking the ink drop is required. In fact, the silicon etching depth is etched to about 24 μm so that it is only blocked by the film of the fifth mask 505 on the nozzle outlet side. As the hydrophobic coating film 506, an organic film by PECVD of a Teflon-based and C4F8 / SF6 / Ar mixed gas is used. The process shown in FIG. 13ra consists of the same process as the process of FIG. 13r as a continuation of the process shown in FIG. In this FIG. 13r and FIG. 13ra process, the boundary of the hydrophobic coating can be clearly controlled and can be manufactured in a batch process.

Next, as shown in FIG. 13S, the discharge port 401a is penetrated so that ink flows by etching the film of the fifth mask 505 of the nozzle cone portion 401b using a wet or dry etching method. At this time, the hydrophobic coating film 506 should be maintained, the hydrophilic coating for the flow path can be replaced with a natural oxide film. In fact, when etching from the nozzle side when removing the fifth mask 505 film, it is not necessary to consider the hydrophilic coating film, but when etching in the opposite direction, the hydrophilic coating film is also removed, which is a natural oxide film formed by simple hydrophilic treatment. No problem with hydrophilic treatment The process shown in FIG. 13sa is the same as the process shown in FIG. 13s with the extension of the process shown in FIG. 13ra.

The processes shown in FIGS. 13A to 13S or 13A to 13SA described above are performed in a continuous process on a wafer on which a damper, a nozzle, a channel, an ink flow path, and an ink chamber are formed using a (100) plane silicon wafer. The proposed method of fabrication shows that the specification of the structure is accurate to several microns or less and that the two objects can be automatically aligned. The use of multiple masks of several microns or less to form multi-layered structures thus solves the problem of photolithography processes that must overcome tens of hundreds of microns of steps with only a few microns of surface steps and more accurate Not only can the structure be formed, but the process can be simplified. However, if a general multiple mask is used, a simple multiple mask method cannot be applied to a process requiring structure etching with different etching patterns (such as anisotropic etching depending on the crystal direction) as the nozzle introduced in this proposal. As shown in FIGS. 13A to 13S (or FIG. 13sa), the LOCal Oxidation of Silicon (LOCOS) phenomenon is capable of etching a structure including a nozzle shape by patterning to protect complex structures having different etching patterns by several hundred microns. It can be the only masking method.

As described above, the nozzle assembly for an integrated inkjet printhead using a single crystal silicon wafer according to the present invention uses a single (100) plane silicon single crystal wafer by simplifying a complicated structure laminated using several wafers and plates. Therefore, it is possible to reduce the number of wafers by fabricating them in one-piece without any staggering and by mass batch production by using an anisotropic etching process using the crystal surface of the wafer and an appropriate mask forming process using the LOCOS process. In other words, not only can the alignment error be reduced to a few microns or less by utilizing a general silicon photolithography process, but it is also not complicated, has excellent economic efficiency, and yields. In particular, the two-sided alignment can be etched on the backside of the wafer (substrate) to drill the nozzle size down to sub-microns and to clearly distinguish the boundaries of the surface treatment. In addition, the use of silicon semiconductor processing technology enables not only mass production, but also integration of core nozzles and the effect of hydrophilic / hydrophobic surface treatment.

 1A and 1B are cross-sectional views and exploded perspective views showing the structure of a nozzle assembly for a conventional inkjet head, respectively;

2a to 2f are views showing a lamination method of another conventional nozzle assembly (U.S. 3,921,916),

3 to 5 are views for explaining various methods of forming a conventional micro nozzle assembly, respectively;

6A and 6B are views for explaining a method of forming a nozzle by attaching a nozzle in a conventional method of forming a silicon nozzle assembly;

7A to 7D are views for explaining a method of forming a nozzle after attaching a nozzle plate in a conventional method of forming a silicon nozzle assembly;

8A to 8C illustrate anisotropic wet etching results of a single crystal silicon substrate using a crystal plane;

9 illustrates a dry etching process;

10A through 10K are sectional views illustrating a method of etching a silicon nozzle assembly having a stepped structure by photolithography;

11 is a cross-sectional view of a nozzle assembly for an integrated inkjet head using a (100) plane single crystal silicon wafer according to the present invention;

12 is a schematic perspective view of the nozzle assembly for the integrated inkjet head of FIG. 11;

13A to 13S (s') are cross-sectional views illustrating a manufacturing method by an automatic alignment process of the nozzle assembly for an integrated inkjet head using the single crystal silicon wafer of FIGS.

14A and 14B are diagrams for explaining a method of forming a damper using a wafer bonded with an SOI wafer and an etch stop layer, respectively.

<Description of the symbols for the main parts of the drawings>

10. 1st mask 11.opening

12. Damper 13, 13 '. Side wall protection mask

14. Opening 15. Nozzle cone

16. Opening 17. Nozzle Outlet

400. Silicon substrate 401. Nozzle

402. Ink Damper 403. Pressure Chamber

404. Channel 405. Euro

501. 1st mask 502. 2nd mask

503. 3rd mask 504, 504 '. Protective fourth mask

505. Fifth Mask 506. Hydrophobic Coating Film

511. Openings 512. Openings

513, 513 ', 513 ". Opening 514. Opening

516. Openings 517, 517 '. Opening

521. Photoresist Mask

Claims (26)

delete delete delete An ink flow path for distributing and supplying ink flowing from the ink bottle to each head; A channel through which a predetermined amount of ink is injected into each of the heads in the flow path; A pressure chamber of each head for temporarily storing the constant amount of ink drawn in from the channel and pressurizing the stored ink to be ejected; Dampers of the respective heads receiving ink from the pressure chamber and providing the ink to the nozzles; Nozzles of each of the heads each including a discharge port for discharging the ink stored in the damper and conical portions for inducing the ink stored in the damper to enter the discharge port at a higher pressure than the pressure in the damper. In the production method, (a) depositing a first mask on the (100) plane single crystal silicon substrate; (b) locally etching the first mask to form the opening for channel formation, and then depositing a second mask; (c) etching the first mask and the second mask to form an opening for forming the pressure chamber; (d) depositing a third mask over the substrate and over the second mask exposed by the pressure chamber forming opening; (e) selectively etching the third mask using a photoresist mask to form openings for forming the damper and the flow path; (f) performing a first deep etching process for forming a damper on the silicon substrate through the opening for forming the damper; (g) etching the second mask and the first mask exposed by the opening of the third mask using the photoresist mask as it is to form the flow path formed in step (e) to form an opening for forming the flow path step; (h) performing a second deep etching on the silicon substrate through the damper and the opening for forming the flow path to complete the damper and simultaneously form a vertically downward etching portion of the flow path; (i) depositing a fourth sidewall protection mask on sidewalls of the damper and the vertical downward etching portion of the flow path; (j) etching the bottom surface of the damper and the channel vertical downward etching portion in the fourth mask for protecting the sidewall to form the nozzle cone portion and the inclined portion etching opening portion of the passage; (k) performing anisotropic wet etching along the crystal plane as TMAH (Tetra-Methyl Ammonium Hydroxide) through openings for forming the cone portion and the channel slope portion of the nozzle to form the cone portion of the nozzle and the slope portion of the flow path; (l) locally thermally oxidizing a silicon exposed surface of the cone portion of the nozzle and the inclined portion of the flow path to form a fifth mask; (m) locally removing the third mask to form an opening for forming a pressure chamber; (n) performing a third silicon dip etch to form the pressure chamber; (o) selectively removing the second mask to form an opening for forming the channel; (p) performing fourth deep etching on the silicon substrate using the channel forming opening; (q) selectively etching the second mask and the first mask formed on the back surface of the silicon substrate by dry etching using a photoresist mask to form a double-sided alignment opening for forming a nozzle outlet; (r) forming the nozzle outlet through a silicon substrate etching process using the double-sided alignment opening, and then removing the photoresist mask and depositing a hydrophobic coating film on the nozzle outlet; And (s) etching the film of the fifth mask of the nozzle cone to penetrate the outlet to allow ink flow; The manufacturing method of the nozzle assembly for integrated inkjet printheads by the batch automatic sorting process characterized by including. The method of claim 4, wherein The method of manufacturing a nozzle assembly for an integrated inkjet printhead by a batch automatic alignment process, wherein any one of a thermal oxide film, an oxide film, and a nitride film is used as the first mask in the step (a). The method of claim 4, wherein In the step (a), a metal film is used as the first mask, and any one of TEOS, PECVD nitride film, the metal film and other metals can be deposited at a lower temperature than the metal film with the second, third, fourth and fifth masks. Method for producing a nozzle assembly for an integrated inkjet printhead by a batch automatic alignment process, characterized in that the deposition. The method of claim 4, wherein The method of claim 1, wherein the second mask is deposited using any one of TEOS, oxide film, nitride film, and metal. The method of claim 4, wherein In the step (c), the pressure chamber forming opening is formed in a size of 2800 * 260 μm, and the corner of the pressure chamber forming opening has a curvature radius of 100 μm. Method of manufacturing a nozzle assembly for a print head. The method of claim 4, wherein The manufacturing method of the nozzle assembly for an integrated inkjet print head by a batch automatic alignment process, wherein any one of a nitride film, an oxide film, and a metal is used as the third mask in the step (d). The method of claim 4, wherein In the step (e), the third mask is formed of a nitride film and the opening is formed by a dry etching method characterized in that the manufacturing method of the nozzle assembly for an integrated inkjet print head by a batch automatic alignment process. The method of claim 4, wherein The first deep etching for forming the damper in the step (f) is a method of manufacturing a nozzle assembly for an integrated inkjet printhead by a batch automatic alignment process, characterized in that etching to a depth of about 150 μm using an ICP RIE. The method of claim 4, wherein In the step (g) The method of claim 1, wherein the opening for forming the flow path is formed using a dry etching method. The method of claim 4, wherein In the step (h), the etching depth of the second deep etching is 150 µm, and in this case, the etching depth of the damper is 300 µm. How to make. The method of claim 4, wherein In the step (i), as the fourth mask for protecting the side wall, a thermal oxide film is deposited or another oxide film or nitride film is used. The method of claim 4, wherein If the thermal oxide film cannot be locally formed as the fourth mask for protecting the sidewall due to the property of the film deposited as the third mask in the step (i), instead of the step (i), the step (i ') And depositing a fourth mask for protecting the sidewalls over the entire surface thereof. The method of claim 15, In the step (j), the openings for etching the inclined portion of the nozzle cone and the flow path are formed in the fourth mask, which is deposited in the step (i '), of the same material as that of the third mask. A method of manufacturing a nozzle assembly for an integrated inkjet printhead by a batch automatic alignment process, characterized in that it is formed by selective etching according to the difference in thickness between the fourth mask films. The method of claim 4, wherein In the step (j), the openings for etching the inclined portion of the nozzle cone and the flow path may include the third mask formed of a nitride film, and the sidewall protecting fourth mask formed of a thermal oxide film, thereby forming a heterogeneous material between the thermal oxide film and the nitride film. A method of manufacturing a nozzle assembly for an integrated inkjet printhead by a batch automatic alignment process, characterized in that it is formed by selective etching at a selectivity. The method of claim 4, wherein In the step (m), the third mask is formed of a nitride film, and the opening for forming the pressure chamber is removed using a wet etching method to remove the nitride film on the entire surface of the silicon substrate using phosphoric acid as an etching solution. Method of manufacturing a nozzle assembly for an integrated inkjet print head The method of claim 4, wherein In the step (n), the third silicon dip etching for forming the pressure chamber is performed at a depth of about 85 μm using an ICP RIE. How to make. The method of claim 4, wherein In the step (o), the second mask is formed of TEOS, and the channel forming opening is removed only up to the depth of the second mask. Way. The method of claim 4, wherein In the step (p), the fourth deep etching is performed using an ICP RIE to etch to a depth of 15 μm. The method of claim 4, wherein And the double-sided alignment opening for forming the nozzle outlet in the step (q) is formed with a diameter of 24 μm. The method of claim 4, wherein Instead of the step (q), as a step (q '), all masks on the upper and side surfaces of the silicon substrate are peeled off and a hydrophilic coating film is formed on the exposed surface, and then the second mask and the first mask formed on the back surface of the silicon substrate are removed. Locally etching to form a double-sided alignment opening for forming a nozzle outlet by dry etching using a photoresist mask; The manufacturing method of the nozzle assembly for integrated inkjet printheads by the batch automatic sorting process characterized by including. The method of claim 23, A method of fabricating a nozzle assembly for an integrated inkjet printhead by a batch automatic alignment process, wherein a thermal oxide film is deposited with the hydrophilic coating film in the step (q '), and the diameter of the double-sided alignment opening is formed to be 24 μm. The method according to any one of claims 4, 22, 23 and 24, In the step (r), as the hydrophobic coating film, a Teflon-based film or an organic film by PECVD of a C ₄ F ₈ / SF ₆ / Ar mixed gas. Method of manufacturing a nozzle assembly for a head. The method of claim 4, wherein The length of the nozzle outlet is determined in the step (k) by the wet etching depth of the damper cone portion, characterized in that the manufacturing method of the nozzle assembly for an integrated inkjet printhead by a batch automatic alignment process.