JP4617823B2 - Liquid discharge head, liquid discharge apparatus, and method of manufacturing liquid discharge head - Google Patents

Description

  The present invention relates to a liquid discharge head, a liquid discharge apparatus, and a method for manufacturing a liquid discharge head, and can be applied to, for example, a thermal inkjet printer in which a heating element and a transistor that drives the heating element are integrally formed on a substrate. . In the present invention, an interlayer insulating film is formed by a coating type insulating film, and a silicon insulating film is formed on a surface layer of the interlayer insulating film and an inner wall surface of a through hole provided in the interlayer insulating film. The insulating film sufficiently prevents the generation of a step and prevents the heating element from deteriorating.

  In recent years, in the field of image processing and the like, there is an increasing need for color hard copy. In response to this need, color copy systems such as a sublimation thermal transfer system, a melt thermal transfer system, an ink jet system, an electrophotographic system, and a heat development silver salt system have been proposed.

  Among these methods, the inkjet method is a method in which droplets of recording liquid (ink) are ejected from nozzles provided on a printer head, which is a liquid discharge head, and are attached to a recording target to form dots. A high-quality image can be output depending on the configuration. This ink jet method is classified into an electrostatic attraction method, a continuous vibration generation method (piezo method), and a thermal method according to the difference in the method of causing ink droplets to fly from the nozzles.

  Among these methods, the thermal method is a method in which bubbles are generated by local heating of the ink, and the ink is pushed out from the nozzles by the bubbles to fly to a printing target, and a color image can be printed with a simple configuration. it can.

  In such a thermal type printer head, a heating element for heating ink is integrally formed on a semiconductor substrate together with a drive circuit by a logic integrated circuit for driving the heating element. Are arranged at high density so that they can be driven reliably.

  That is, in this thermal printer, it is necessary to arrange the heating elements at a high density in order to obtain a high-quality printing result. Specifically, for example, in order to obtain a printing result corresponding to 600 [DPI], it is necessary to arrange the heating elements at intervals of 42.333 [μm]. However, it is extremely difficult to dispose individual driving elements on the heat generating elements disposed at such a high density. For this reason, in the printer head, a switching transistor or the like is created on a semiconductor substrate and connected to a corresponding heating element by integrated circuit technology, and furthermore, each switching transistor is driven by a drive circuit created on the semiconductor substrate. Thus, each heating element can be driven easily and reliably.

  That is, FIG. 12 is a cross-sectional view showing a configuration in the vicinity of a switching transistor and a heating element in this type of printer head. In this printer head 1, an element isolation region for insulating and isolating a MOS (Metal Oxide Semiconductor) type field effect transistor is formed on a silicon substrate 2, and then a MOS transistor 3 or the like is formed between the element isolation regions. Thus, the switching transistor for driving the heating element and the driving circuit for driving the switching transistor are constituted by the MOS transistor 3 by the semiconductor manufacturing process.

Subsequently, an interlayer insulating film or the like that insulates the MOS transistor 3 is laminated, and then an opening (contact hole) is formed in the interlayer insulating film, followed by the first-layer wiring pattern 4 and the first-layer wiring pattern 4. An interlayer insulating film 5 and a heating element 6 that insulate the wiring pattern of the layer are sequentially formed. Here, the heating element 6 is made of tantalum (Ta), tantalum nitride (TaN _x ), or tantalum aluminum (TaAl). In the printer head 1, an opening (via hole) is formed in the interlayer insulating film 5 to form a second-layer wiring pattern 7, and the heating element 6 is connected to the MOS transistor 3 by these two-layer wiring patterns 4 and 7. The Subsequently, an insulating protective layer 8 made of silicon nitride (Si ₃ N ₄ ) and a cavitation resistant layer 9 made of β-tantalum are sequentially formed on the heating element 6.

  Subsequently, in the printer head 1, a photosensitive resin material is applied to the entire surface of the substrate 2 on which the heat generating elements 6 and the like are formed in this way, and excess portions of the applied photosensitive resin are removed by the exposure development process. Thus, the resin layer 10 is formed. Further, a nozzle sheet 11 made of an alloy of nickel and cobalt (Ni—Co) is attached to the upper layer, thereby creating an ink liquid chamber, an ink flow path for guiding ink to the ink liquid chamber, and a nozzle. The printer head 1 applies a pulsed voltage to the heating element 6 by the MOS transistor 3 to drive the heating element 6, thereby ejecting ink droplets.

  In the printer head 1 configured as described above, it is not possible to avoid the occurrence of a step due to the wiring pattern 4 or the like on the surface of the insulating protective layer 8 simply by stacking the constituent members. A step also appears on the surface of the formed resin layer 10, and a gap is generated between the nozzle sheet attached to the resin layer 10 and the resin layer surface. When such a gap is generated in the printer head 1, the adhesion between the resin layer 10 and the nozzle sheet 11 may be deteriorated.

  Thus, in the conventional printer head 1, for example, the method disclosed in US Pat. No. 6,450,622 is applied to form the interlayer insulating film 5 with the SOG (Spin On Glass) film 12 so as to eliminate this kind of step. The nozzle sheet 11 is flattened and held sufficiently firmly. Here, the SOG film 12 is a coating type insulating material containing a silanol (Si—OH) bond with an alcohol component as a solvent and applied to the substrate surface with a sufficient thickness by a spin coating method. After the film is formed on the entire surface of the silicon substrate 2 so as to be buried, the film is etched back to a predetermined thickness by an etch back method.

  However, if the step is simply eliminated by the SOG film 12, the printer head 1 has a problem that the heating element 6 deteriorates due to the driving of the heating element 6. Specifically, when the heating element 6 is driven without holding ink in the ink liquid chamber (so-called empty), in the printer head 1, the resistance value of the heating element 6 increases remarkably, and the cavitation-resistant layer 9 It was confirmed that the surface turned black.

When this point is examined in detail, the heat generated by driving the heating element 6 propagates to the SOG film 12 directly below, and the SOG film component itself is decomposed by this heat, and the solvent remaining in the SOG film. It has been found that the resistance value increases remarkably due to oxidation of the heating element or carbonization of the heating element by desorption of the components. More specifically, it has been confirmed that such an increase in the resistance value is particularly remarkable when organic SOG is used as a coating type insulating material provided for the SOG film. Note here organic SOG _{film, R n Si (OH) 4} -n (R is an alkyl group CH _3, C ₂ H _5, an organic group such as alkoxy group C ₃ H _7, n is a natural number of 1 to 4) by As shown, it is a silicon compound containing an organic group in the molecule, has excellent flatness related to the relief of the level difference, and has a feature that cracks hardly occur even when applied with a thick film thickness.

  As a method for solving this problem, as shown in FIG. 13 in comparison with FIG. 12, the SOG film 12 is not formed in the region where the heating element 6 is formed by repeating application and etch back of the SOG film a plurality of times. It is possible to do so.

However, in recent years, this type of printer head has been required to have a higher density. For this reason, the MOS transistor 3 is miniaturized, and the wiring pattern tends to be multilayered and narrow pitched. Thus, if the wiring pattern is narrowed and the SOG film is repeatedly applied and etched back so that the SOG film 12 is not formed in the region where the heating element 6 is formed, the step due to the wiring pattern cannot be sufficiently flattened. Accordingly, it is desired to sufficiently prevent the step from being generated by the SOG film and to prevent the heating element from being deteriorated.
US Pat. No. 6,450,622

  The present invention has been made in consideration of the above points, and a liquid discharge head, a liquid discharge device, and a liquid discharge head capable of sufficiently preventing the occurrence of a step by a coating type insulating film and preventing deterioration of a heating element, and A method for manufacturing a liquid discharge head is proposed.

  In order to solve such a problem, in the invention of claim 1, a heating element for heating the liquid held in the liquid chamber and a semiconductor element for driving the heating element are integrally formed on the substrate, and the heating element of the semiconductor element is formed. When applied to a liquid discharge head that ejects liquid droplets from a predetermined nozzle by driving, an interlayer insulating film that insulates the upper wiring pattern from the lower layer is formed of a coating type insulating film on the substrate side of the heating element. The coating type insulating film is formed such that a silicon insulating film is formed on the surface layer, and a silicon insulating film is formed on the inner wall surface of the through hole that connects the upper wiring pattern to the corresponding portion of the lower layer.

  According to a third aspect of the present invention, a heating element that heats the liquid held in the liquid chamber by applying the liquid ejecting apparatus that supplies liquid droplets ejected from the liquid ejecting head to the object, and the heating element And a semiconductor element for driving the substrate are integrally formed on the substrate, and a liquid droplet is ejected from a predetermined nozzle by driving the heating element by the semiconductor element. An upper wiring pattern is formed on the substrate side of the heating element from the lower layer. The insulating interlayer is formed of a coating type insulating film, and the coating type insulating film has a silicon insulating film formed on the surface layer, and the inner wall surface of the through hole that connects the upper wiring pattern to the corresponding portion of the lower layer In addition, a silicon insulating film is formed.

  According to a fourth aspect of the present invention, a heating element for heating the liquid held in the liquid chamber and a semiconductor element for driving the heating element are integrally formed on the substrate, and the predetermined nozzle is driven by driving the heating element by the semiconductor element. Interlayer insulating film that is applied to a method of manufacturing a liquid discharge head that ejects liquid droplets more and covers the entire surface of the substrate with a coating type insulating film, and creates an interlayer insulating film that insulates the upper wiring pattern from the lower layer And a first silicon insulating film forming process for forming a silicon insulating film on the surface of the coating type insulating film, and a through hole for connecting the upper wiring pattern to the corresponding lower layer in the interlayer insulating film And a second silicon insulating film forming process for selectively forming a silicon insulating film on the inner wall surface of the through hole.

  According to the structure of claim 1, when applied to a liquid discharge head, an interlayer insulating film that insulates an upper wiring pattern from a lower layer is formed by a coating type insulating film on the substrate side of the heating element. The step due to the wiring pattern can be sufficiently flattened by the coating type insulating film. Further, according to the structure of claim 1, the coating type insulating film has a silicon insulating film formed on the surface layer, and the silicon insulating film is formed on the inner wall surface of the through hole connecting the upper wiring pattern to the corresponding portion of the lower layer. If formed, the volatile component of the coating-type insulating film can be contained in the coating-type insulating film by these silicon insulating films, thereby preventing deterioration of the heating element due to this volatile component. it can.

  Thus, according to the configurations of claims 3 and 4, a liquid ejection apparatus and a method for manufacturing a liquid ejection head that can prevent the occurrence of a step by the coating type insulating film and prevent deterioration of the heating element. Can be provided.

  According to the present invention, the occurrence of a step can be sufficiently prevented by the coating type insulating film, and the deterioration of the heating element can be prevented.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings as appropriate.

(1) Configuration of Embodiment 1 FIG. 1 is a perspective view showing a line printer according to the present invention. The line printer 21 is a full line type line printer, and a printer main body 22 is formed in a substantially rectangular shape. The line printer 21 can feed the paper 23 by mounting a paper tray 24 containing the paper 23 to be printed from a tray inlet / outlet formed on the front surface of the printer main body 22.

  In the line printer 21, when the paper tray 24 is attached to the printer main body 22 from the tray entrance and the printing is instructed by the user, the rotation of the paper feed roller provided in the printer main body 22 rotates the printer main body 22. The paper 23 is sent out from the paper tray 24 toward the back side, and the feeding direction of the paper 23 is switched to the front direction by a reverse roller provided on the back side of the printer main body 22. In the line printer 21, the sheet 23 in which the sheet feeding direction is switched to the front direction is conveyed so as to cross the sheet tray 24, and is discharged to the tray 25 from the discharge port disposed on the front side of the line printer 21. Is done.

  The line printer 21 is provided with an upper lid 26 on the upper end surface, and the head cartridge 28 is disposed so as to be replaceable as indicated by an arrow A in the middle of the upper lid 26 and in the middle of conveying the paper in the front direction.

  Here, the head cartridge 28 is a full-line type printer head with four colors of yellow, magenta, cyan, and black, and ink tanks 29Y, 29M, 29C, and 29K for each color are provided on the upper side. The head cartridge 28 is provided on the head assembly 30 which is an assembly of printer heads related to the ink tanks 29Y, 29M, 29C and 29K, and on the paper 23 side of the head assembly 30, and is provided in the head assembly 30 when not in use. And a head cap 31 that closes the nozzle row and prevents the ink from drying. As a result, in the line printer 21, by driving the head assembly 30 provided in the head cartridge 28, ink droplets of each color are attached to the paper 23 and a desired image or the like is printed in color.

  FIG. 2 is an enlarged perspective view of the head assembly 30 as viewed from the paper 23 side, with a portion related to the ejection of the ink droplets L being enlarged. The head assembly 30 is formed by wiring the head chips 34 via the bonding terminals 36 after the head chips 34 that have formed the partition walls 33 of the ink liquid chambers are sequentially attached to the nozzle sheet 35.

  Here, the head chip 34 is formed with a plurality of heating elements 37, a drive circuit for driving the plurality of heating elements 37, a bonding terminal 36 for inputting a power source for driving the drive circuit, and the like. When viewed from the element 37 side, the whole is formed in a rectangular shape, and a plurality of heating elements 37 are provided at a predetermined pitch along one side of the long side of the rectangular shape.

  The head chip 34 is formed with a partition 33 of an ink liquid chamber and a partition of an ink flow path by a comb tooth shape so that the one side is open, and an ink flow path is provided along the one side. The head chip 34 is sequentially arranged on the nozzle sheet 35 in a zigzag manner with the ink flow path interposed therebetween. As a result, the head assembly 30 forms an ink flow path with the partition wall 33, the head chip 34, etc. The ink in the corresponding ink tanks 29Y, 29M, 29C, and 29K can be guided to the respective ink liquid chambers from the flow paths, and the ink thus guided to the liquid chambers can be heated by driving the heating element 37. It is made like that.

  On the other hand, the nozzle sheet 35 is a sheet-like member in which a row of nozzles 38 having paper widths corresponding to yellow, magenta, cyan, and black inks are arranged in parallel, and is made of nickel material containing cobalt by electroforming technology. It is formed. The nozzle sheet 35 is formed with openings 40 for working when wire bonding the head chips 34 to the bonding terminals 36 in a staggered manner with the rows of the nozzles 38 interposed therebetween.

  FIG. 3 is a cross-sectional view showing the head chip disposed in the head assembly together with the peripheral configuration. The head chip 34 is formed by scribing each chip after a plurality of chips are collectively formed on a semiconductor wafer made of a silicon substrate by a semiconductor manufacturing process. The head chip 34 is formed with a partition wall 33 on the surface on the side of the heat generating element 37 at the stage of the semiconductor wafer, and the surface of the partition wall 33 is formed to be flat to ensure adhesion between the partition wall 33 and the nozzle sheet 35. It is made to do.

  That is, as shown in FIG. 4A, the silicon nitride film is deposited on the head chip 34 after the silicon substrate 41 is cleaned. Subsequently, the silicon substrate 41 is processed by a photolithography process and a reactive ion etching process, whereby the silicon nitride film is removed from regions other than the predetermined region where the transistor is formed. As a result, the head chip 34 forms a silicon nitride film in a region on the silicon substrate 41 where a transistor is to be formed.

  Subsequently, in the head chip 34, a thermal silicon oxide film having a thickness of 500 nm is formed in a region where the silicon nitride film is removed by a thermal oxidation process, and an element isolation for isolating the transistor by this thermal silicon oxide film. A region (LOCOS: Local oxidation of silicon) 42 is formed. This element isolation region 42 is finally formed to a film thickness of 260 [nm] by subsequent processing.

  In the head chip 34, after the silicon substrate 41 is subsequently cleaned, a thermal oxide film for a gate is formed in the transistor formation region. Subsequently, the silicon substrate 41 is cleaned, and polysilicon with a film thickness of 70 nm and tungsten silicide with a film thickness of 70 nm are sequentially deposited by CVD (Chemical Vapor Deposition). Note that tungsten silicide can be formed by sputtering. In the head chip 34, after the gate region is further exposed by a lithography process, an excessive thermal oxide film, polysilicon film, and tungsten silicide film are removed by a dry etching method, whereby the gate oxide film 43, the polysilicon film are removed. 44, a gate electrode is formed by a polycide structure of a tungsten silicide film 45. In this embodiment, the gate electrode is formed with a gate length of 2 [μm] or less.

  Subsequently, the silicon substrate 41 is processed by an ion implantation process and a heat treatment process, whereby a low-concentration diffusion layer 46 is formed. Further, the silicon substrate 41 is processed by an ion implantation process and a heat treatment process for forming source and drain regions. As a result, MOS transistors 47, 48 and the like are formed. Here, the low-concentration diffusion layer 46 is an electric field relaxation layer that relaxes the electric field between the channel formation region under the gate and the drain to ensure a breakdown voltage between the source and the drain. The driver transistor 47 is a MOS transistor having a withstand voltage up to about 18 [V], and is used for driving the heating element 37. On the other hand, the switching transistor 48 is a transistor constituting a drive circuit that controls the driver transistor 47, and operates with a voltage of 5 [V].

  When the transistors 47 and 48 are formed in this way, the head chip 34 is made of an NSG (Non-doped Silicate Glass) film which is a silicon oxide film by a CVD method, and a silicon oxide film to which boron and phosphorus are added. A certain BPSG (Boron Phosphorus Silicate Glass) film is sequentially formed with a film thickness of 100 [nm] and 900 [nm], thereby forming a first interlayer insulating film 49 with a film thickness of 1000 [nm] as a whole. .

Subsequently, after the photolithography process, a contact hole is formed on the silicon semiconductor diffusion layer (source / drain) by a reactive ion etching method using C ₄ F ₈ / CO / O ₂ / Ar-based gas. Here, the contact hole is formed with an aspect ratio of 1 having a circular cross section having a diameter of 0.7 [μm].

  In the head chip 34, the natural oxide film is removed from the surface of the silicon semiconductor diffusion layer exposed by the contact hole by subsequent cleaning with dilute hydrofluoric acid. Further, by sputtering, titanium with a film thickness of 30 [nm], titanium nitride barrier metal with a film thickness of 70 [nm], titanium with a film thickness of 30 [nm], and silicon with a film thickness of 480 [nm] are added by 1 [at%]. A titanium nitride oxide antireflection film having a thickness of 25 nm is sequentially deposited. As a result, the first layer wiring pattern material is deposited on the head chip 34, and the contact holes are completely filled with the wiring pattern material.

In the head chip 34, subsequently, the formed wiring pattern material is selectively removed by a photolithography process and a dry etching process using BCl ₃ / Cl ₂ gas, and a first wiring pattern 51 is created. .

Next, as shown in FIG. 4B, the head chip 34 is formed by a silicon oxide film (hereinafter referred to as a P-TEOS film) by a CVD method using TEOS (tetraethoxysilane: Si (OC ₂ H ₅ ) ₄ ) as a source gas. A TEOS film (hereinafter referred to as O ₃ -TEOS film) oxidized by O ₃ by atmospheric pressure plasma CVD using TEOS and O ₃ as source gases. 53) is formed with a film thickness of 500 nm. Subsequently, after the resist is applied to the entire surface of the substrate 41, the head chip 34 is processed by the etch-back method using CHF ₃ and CF ₄ as source gases, and thereby the level difference caused by the wiring pattern 51 is processed. Such a portion is roughly buried by the O ₃ -TEOS film 53.

Subsequently, after the P-TEOS film 54 is formed with a film thickness of 200 [nm] again by the CVD method, the SOG film 55 is formed with a film thickness of 700 [nm] by applying a coating type insulating material to the entire surface of the substrate. ] Is formed. Subsequently, the SOG film 55 is etched by an etch-back method using CHF ₃ and CF ₄ as source gases until the film thickness is reduced to 100 [nm], whereby the SOG film 55 covering the entire surface of the silicon substrate 41 is formed. . In the head chip 34, the step remaining by the O ₃ -TEOS film 53 is flattened by the SOG film 55 formed in this way.

In this embodiment, the coating type insulating material includes organic SOG mainly composed of silica glass, organic SOG mainly composed of alkylsiloxane polymer, organic SOG mainly composed of alkylsilsesquioxane polymer, or Organic SOG mainly composed of hydrogenated silsesquioxane polymer is applied, and CHF ₃ / CF ₄ / Ar gas is used for etch back.

  When the SOG film 55 is formed in this manner, the head chip 34 is subsequently irradiated with oxygen plasma using oxygen as a source gas by an ashing device on the silicon substrate 41, and SOG is caused by a chemical reaction caused by this oxygen plasma irradiation. Organic groups are detached from the surface of the film 55. At this time, as shown in FIG. 5A, silicon atoms on the surface are bonded to oxygen, and thereby a silicon oxide film 56 obtained by mineralizing the SOG film 55 is formed on the surface of the SOG film 55. Note that in such plasma irradiation, a mixed gas containing oxygen may be used.

  Next, a P-TEOS film 57 having a film thickness of 200 nm is formed on the head chip 34 by a CVD method, whereby two layers for insulating the first wiring pattern 51 from the second wiring pattern. An interlayer insulating film for the eyes is formed by a laminated structure.

Thus, the head chip 34 includes the P-TEOS film 52, the O ₃ -TEOS film 53, the P-TEOS film 54, the SOG film 55, and the SOG film 55 from the silicon substrate 41 side, including the region where the heat generating element 37 is formed. A second interlayer insulating film is formed by the inorganicized silicon oxide film 56 and the P-TEOS film 57. As a result, the head chip 34 has the SOG film 55 applied to the second interlayer insulating film so that the interlayer insulating film can be used regardless of whether the wiring pattern 51 is narrowed or the wiring pattern 51 is thick. It is possible to sufficiently prevent the occurrence of a level difference on the surface. Further, such an SOG film 55 is formed by etching back after being formed with a film thickness sufficiently thicker than the step formed by the lower wiring pattern 51, thereby sufficiently flattening the surface of the SOG film 55. can do.

Next, as shown in FIG. 5B, the head chip 34 is formed by a photoresist process and a dry etching process using CHF ₃ / CF ₄ / Ar gas. A via hole 58 which is a through hole connecting the pattern is formed in the second interlayer insulating film.

Subsequently, as shown in FIG. 6A, the head chip 34 has a silicon nitride (Si ₃ N ₄ ) film thickness of 100 [nm] by plasma CVD using SiH ₄ gas, NH ₃ gas, and N ₂ O gas. As a result, a silicon nitride film 59 is formed on the side wall of the via hole 58 and on the bottom surface of the via hole 58. The plasma CVD is performed with a plasma power of 300 to 500 [W] and a film forming temperature of 350 to 400 degrees.

Subsequently, as shown in FIG. 6B, the entire surface is etched back by dry etching using mixed plasma containing CHF ₃ and CF ₄ as main components, and a silicon nitride film 59 formed on the surface layer of the interlayer insulating film is formed. While removing, the silicon nitride film 59 is removed from the bottom surface of the via hole 58. As a result, in the head chip 34, the surface of the lower wiring pattern is exposed at the bottom surface of the via hole 58, and the silicon nitride film 59 having a film thickness of 70 to 90 [nm] is left only on the sidewall of the via hole 58. Since titanium fluoride is difficult to volatilize, the titanium nitride oxide antireflection film provided on the surface layer of the lower wiring pattern functions as an etching stopper layer against the fluorine-based plasma in this etchback process. This prevents excessive etching of the wiring pattern. By these processes, in this embodiment, as shown in FIG. 7A, the silicon insulating film 59 is selectively formed on the inner wall surface of the through hole connecting the upper wiring pattern to the corresponding portion of the lower layer. It is made to do. Note that the silicon insulating film formed on the side wall of the via hole 58 in this way may be formed of a silicon oxynitride film or a silicon oxide film instead of the silicon nitride film 59. When a silicon oxide film is applied, silicon oxide is deposited by plasma CVD using SiH ₄ gas and N ₂ O gas, and then etched back to selectively form a silicon insulating film on the side wall. be able to.

  Subsequently, as shown in FIG. 8, the natural oxide film is removed from the surface of the first wiring pattern 51 exposed by the via hole 58 in the head chip 34 by argon plasma processing. Subsequently, by sputtering, titanium with a thickness of 200 [nm], aluminum with 1 [at%] of silicon with a thickness of 600 [nm], and a titanium nitride oxide antireflection film with a thickness of 25 [nm] are sequentially formed. The first wiring pattern material is deposited by these films, and the via hole 58 is completely filled with the wiring pattern material. Subsequently, in the head chip 34, the second-layer wiring pattern material is selectively removed in the same manner as the first-layer wiring pattern 51, and the second-layer wiring pattern 64 is created.

The head chip 34 is formed with a third interlayer insulating film that insulates the second wiring pattern 64 and the subsequent third wiring pattern. Specifically, the head chip 34 is formed with a P-TEOS film 65, an O ₃ -TEOS film 66 and an etch back, a P-TEOS film 67, as with the second interlayer insulating film. Application and etch-back of the SOG film 68, formation of the silicon oxide film 69 by mineralization of the surface of the SOG film 68, and film formation of the P-TEOS film 70 are sequentially performed. An interlayer insulating film for the eyes is formed.

Subsequently, the head chip 34 forms a through hole in the third interlayer insulating film by a dry etching process using CHF ₃ / CF ₄ / Ar gas, and connects the upper wiring pattern to the lower wiring pattern 64. A via hole 72 is created for this purpose. Further, silicon nitride is deposited with a film thickness of 100 nm by plasma CVD using SiH ₄ gas, NH ₃ gas, and N ₂ O gas. As a result, the sidewall of the via hole 72 is formed on the third interlayer insulating film. A silicon nitride film 73 is formed on the bottom surface of the via hole 72. The plasma CVD is performed with a plasma power of 300 to 500 [W] and a film forming temperature of 350 to 400 degrees.

Subsequently, as in the case of the second interlayer insulating film, the entire surface of the head chip 34 is etched back by the mixed plasma containing CHF ₃ and CF ₄ as main components, and from the surface layer of the interlayer insulating film and the bottom surface of the via hole 72. The silicon nitride film is removed, and a silicon nitride film 73 having a thickness of 70 to 90 [nm] is selectively formed only on the sidewall of the via hole 72 by this series of processes.

  Subsequently, after the natural oxide film is removed from the surface of the second wiring pattern 64 exposed by the via hole 58 by argon plasma treatment, the head chip 34 is formed by a sputtering method to a thickness of 50 to 100 nm. -Tantalum is deposited, thereby forming a resistor film that forms the heating element. The sputtering conditions were set to a wafer heating temperature of 200 to 400 degrees, a DC applied power of 2 to 4 [kW], and an argon gas flow rate of 25 to 40 [sccm].

  Subsequently, the head chip 34 deposits aluminum or aluminum added with 0.5 [at%] with a film thickness of 400 [nm] by a sputtering apparatus used for the formation of the resistor film. The via hole 72 is embedded by a laminated structure of tantalum and aluminum constituting the resistor film, and a third wiring pattern layer is formed.

Subsequently, the head chip 34 selectively removes the laminated film of tantalum and aluminum by a photolithography process and a dry etching process using BCl ₃ / Cl ₂ gas, thereby forming a third wiring pattern 76. To do. Subsequently, the aluminum film is selectively removed from the portion of the heating element 37 where the resistor film is formed by wet etching using a mixed solution of nitric acid-acetic acid-phosphoric acid, and one end thereof is connected by the wiring pattern 76. The heating element 37 having a resistance value of 100 [Ω] is formed by the folded shape. The heating element 37 may be formed in a square shape.

Next, as shown in FIG. 3, the head chip 34 is formed with a silicon nitride film 77 functioning as an ink protective layer and an insulating layer with a film thickness of 200 to 400 [nm] by plasma CVD. Further, after a cavitation-resistant material layer is formed with a film thickness of 100 to 300 [nm], a cavitation-resistant layer 78 is formed by patterning using BCl ₃ / Cl ₂ gas. In this embodiment, the anti-cavitation layer 78 made of β-tantalum is formed by a DC magnetron sputtering apparatus using tantalum as a target. Here, the anti-cavitation layer 78 protects the heat generating element 37 by absorbing physical damage (cavitation) when bubbles generated in the ink liquid chamber disappear due to the driving of the heat generating element 37, and drives the heat generating element 37. This is a protective layer that protects the heating element 37 from the chemical action of the ink that has been heated to a high temperature.

  Subsequently, after an exposure curable dry film made of an organic resin is disposed by pressure bonding, the head chip 34 is cured by removing portions corresponding to the ink liquid chamber and the ink flow path by a photolithography process. A partition wall 33 of the chamber 79, a partition wall of the ink flow path, and the like are created. The head chip 34 is formed by scribing individually after a plurality of chips are formed on the silicon substrate 41 in this way.

(2) Operation of Embodiment 1 In the configuration described above, the line printer 21 (FIG. 1) feeds a sheet 23 to be recorded to a predetermined sheet by driving the head cartridge 28 with image data, text data, etc. for printing. While being transported by the mechanism, ink droplets are ejected from a head assembly 30 provided in the head cartridge 28, and the ink droplets adhere to the paper 23 being transported to print an image, text, or the like.

  Corresponding to this, the head assembly 30 of the head cartridge 28 (FIGS. 1 and 2), the ink in the ink tanks 29Y, 29M, 29C, and 29K is guided to the respective ink liquid chambers via the ink flow paths, and the heating elements 37 are formed. Ink droplets L are ejected from the nozzles 38 provided on the nozzle sheet 35 by the increase in the pressure of the ink held in the ink chamber by the driving of. Thus, the line printer 21 can print a desired image or the like.

  This head assembly 30 (FIG. 3) is formed by sequentially arranging a head chip 34 on a nozzle sheet 35 via a partition wall 33. The head chip 34 includes a semiconductor element 47 and a heating element 37 in three layers of wiring patterns 51. , 64, 76 to form a connection. As a result, if the constituent members are simply laminated on the substrate, a step due to the lower wiring patterns 51 and 64 is generated on the surface of the partition wall 33 and the adhesion between the partition wall 33 and the nozzle sheet 35 deteriorates.

For this reason, in the head chip 34, the O ₃ -TEOS films 53 and 66 are formed in the second interlayer insulating film between the wiring patterns 51 and 64 and the third interlayer insulating film between the wiring patterns 64 and 76. The steps due to the lower wiring patterns 51 and 64 are substantially flattened by the etch back. The SOG film 55,68 covering the entire surface of the silicon substrate 41 is formed on the O ₃ -TEOS film 53,66, O ₃ also remains stepped flat by -TEOS film 53,66 This SOG film 55,68 The surface of the interlayer insulating film is planarized. As a result, in the head assembly 30, the surface of the partition wall 33 on the head chip 34 is formed flat, and the partition wall 33 can be securely adhered to the nozzle sheet 35 even when the wiring pattern is multilayered or narrowed.

  However, by adopting such SOG films 55 and 68, the head chip 34 detaches organic components and solvent components from the SOG films 55 and 68 by driving the heating element 37, unless any measures are taken. The heating element 37 is oxidized and carbonized.

  Therefore, in the head chip 34, in the second interlayer insulating film, a silicon oxide film 56 obtained by mineralizing the SOG film 55 is formed on the surface of the SOG film 55, and further on the surface of the silicon oxide film 56. A silicon insulating film is formed by the P-TEOS film 57. In the third interlayer insulating film, a silicon insulating film 69 made of an inorganicized SOG film 68 and a P-TEOS film 70 are formed on the surface of the SOG film 68. As a result, the head chip 34 can contain the volatile components of the SOG films 55 and 68 in the SOG films 55 and 68 by the silicon insulating films 56, 57, 68 and 70 formed on these interlayer insulating films, respectively.

  However, in these interlayer insulating films, via holes 58 and 72, which are through holes that connect the upper wiring pattern to corresponding portions in the lower layer, are formed, so that SOG is formed via the inner wall surfaces of the via holes 58 and 72. Volatile components in the films 55 and 68 may be desorbed, and the heat generating element 37 may be deteriorated.

  Therefore, in this embodiment, the silicon insulating films 59 and 73 are formed again on the inner wall surfaces of the via holes 58 and 72, thereby preventing the exposure of the SOG films 55 and 68 on the inner wall surfaces. As a result, in the head chip 34, the volatile components of the SOG films 55 and 68, which are coating type insulating films, are also encapsulated in the coating type insulating film by the silicon insulating films 59 and 73 on the inner wall surfaces of the via holes 58 and 72. Accordingly, deterioration of the heat generating element 37 due to the volatile component can be prevented.

  Actually, when the volatile components from the head chip 34 thus prepared were analyzed using thermal desorption gas analysis, the volatile components were almost completely desorbed from the SOG films 55 and 68. It was confirmed that it could be removed. Thus, in this embodiment, the application type insulating film can sufficiently prevent the generation of a step and can prevent the heat generating element from deteriorating.

(3) Effect of Example 1 According to the above configuration, the interlayer insulating film is formed by the coating type insulating film, and the surface layer of the interlayer insulating film, the inner wall surface of the through hole provided in the interlayer insulating film is formed. By forming the silicon insulating film, it is possible to sufficiently prevent the occurrence of a step by the coating type insulating film and to prevent the heating element from deteriorating.

  FIG. 9 is a cross-sectional view showing a head chip applied to the printer according to the second embodiment of the present invention in comparison with FIG. In the head chip 84 according to this embodiment, the upper wiring pattern is connected to the lower layer by a plug using tungsten. That is, as shown in FIG. 10, in the same manner as described above with respect to the first embodiment, the head chip 84 is formed by forming the transistors 47 and 48 on the silicon substrate 41 and then forming the silicon oxide film NSG ( BPSG (Boron Phosphorus Silicate Glass) film, which is a non-doped silicate glass (Si) film to which boron and phosphorus are added, is successively formed with a film thickness of 100 [nm] and 900 [nm]. A first interlayer insulating film 85 having a thickness of 1000 nm is formed.

Subsequently, after the photolithography process, a contact hole is formed on the silicon semiconductor diffusion layer (source / drain) by a reactive ion etching method using C ₄ F ₈ / CO / O ₂ / Ar-based gas.

  In the head chip 84, the natural oxide film is removed from the surface of the silicon semiconductor diffusion layer exposed by the contact hole by subsequent cleaning using dilute hydrofluoric acid. Further, titanium having a film thickness of 50 nm and titanium nitride barrier metal having a film thickness of 100 nm are sequentially deposited by sputtering, and then tungsten having a film thickness of 500 nm is deposited by CVD. The hole is completely filled. Subsequently, the head chip 84 is formed by removing the tungsten film, the titanium nitride film, and the titanium film from portions other than the contact holes by an etch back method, thereby connecting the transistors 47 and 48 and the wiring pattern of the first layer. 86 is created.

  Next, the head chip 84 is formed by sputtering using titanium with a film thickness of 20 [nm], titanium nitride barrier metal with a film thickness of 20 [nm], titanium with a film thickness of 5 [nm], and copper with a film thickness of 500 [nm]. 0.5 [at%] added aluminum, titanium with a film thickness of 5 [nm], titanium nitride barrier metal with a film thickness of 100 [nm], and titanium with a film thickness of 5 [nm] are sequentially deposited. A material layer is deposited. Subsequently, the wiring pattern material layer is selectively removed by a photolithography process and a dry etching process, and a first wiring pattern 87 is created.

Subsequently, in the same manner as described above with respect to the first embodiment, the head chip 84 is made of silicon obtained by inorganicizing the surfaces of the P-TEOS film 52, the O ₃ -TEOS film 53, the P-TEOS film 54, the SOG film 55, and the SOG film 55. An oxide film 56 and a P-TEOS film 57 are formed to form a second interlayer insulating film. Accordingly, also in this embodiment 2, the SOG film 55 is applied to the second interlayer insulating film, On the surface of the second interlayer insulating film, the occurrence of a step is sufficiently prevented. Further, the volatile components are prevented from desorbing from the surface layer of the SOG film 55.

  Subsequently, in the head chip 84, a via hole 58 is formed in the same manner as described above for the first embodiment, and a silicon nitride film 59 is selectively formed on the inner wall surface of the via hole 58. As a result, in this embodiment, the volatile components are also prevented from being desorbed from the inner wall surface of the SOG film 55 by the via hole 58, thereby preventing the heating element from being deteriorated by the SOG film 55.

  Subsequently, as shown in FIG. 11, the natural oxide film of the head chip 84 is removed from the surface of the first wiring pattern 51 exposed by the via hole 58 by argon plasma processing. Subsequently, a titanium nitride barrier metal film having a film thickness of 100 nm is formed by sputtering, and then a tungsten film having a film thickness of 500 nm is formed by CVD, thereby completely filling the via hole 58. It is. Subsequently, the tungsten film and the titanium nitride film are sequentially removed from the surface of the interlayer insulating film by etch back, whereby tungsten is buried only inside the via hole 58.

  Thus, the silicon nitride film 59 selectively formed on the inner wall surface of the via hole 58 also blocks the released gas from the SOG film in the CVD process when burying tungsten in this way, and thereby this released gas. This also prevents the growth inhibition of tungsten in the via hole 58. As a result, in this embodiment, filling defects due to tungsten are prevented.

  Subsequently, the head chip 84 is formed by sputtering using titanium with a film thickness of 20 [nm], titanium nitride barrier metal with a film thickness of 20 [nm], titanium with a film thickness of 5 [nm], and copper with a film thickness of 500 [nm]. 0.5 [at%] added aluminum, titanium with a film thickness of 5 [nm], titanium nitride barrier metal with a film thickness of 100 [nm], and titanium with a film thickness of 5 [nm] are sequentially deposited, thereby forming two layers A wiring pattern material layer for the eyes is formed. In the head chip 84, the wiring pattern material layer is selectively removed by a photolithography process and a dry etching process, and a second wiring pattern 64 is created.

In the head chip 84, the P-TEOS film 65, the O ₃ -TEOS film 66 and the etch back, the P-TEOS film 67, and the SOG film 68 are formed in the same manner as in the first embodiment. Film formation and etch back, formation of the silicon oxide film 69 by mineralization of the surface of the SOG film 68, and film formation of the P-TEOS film 70 are sequentially performed. An insulating film is formed.

Subsequently, β-tantalum is deposited on the head chip 84 with a film thickness of 50 to 100 [nm] by a sputtering method, whereby a resistor film is formed on the silicon substrate 41. The sputtering conditions were set to a wafer heating temperature of 200 to 400 degrees, a DC applied power of 2 to 4 [kW], and an argon gas flow rate of 25 to 40 [sccm]. Subsequently, the head chip 34 is about 100 [Ω] in a folded shape in which the resistor film is selectively removed by a photolithography process and a dry etching process using BCl ₃ / Cl ₂ gas, and one end is connected by a wiring pattern. A heating element 90 having a resistance value of is formed. Note that the heating element 90 may be formed in a square shape. Subsequently, a silicon nitride film having a film thickness of 300 nm is formed on the head chip 84 by the CVD method, and the insulating protective layer 91 of the heating element 90 is formed.

  Further, in the head chip 84, a via hole 72 is formed in the third interlayer insulating film in the same manner as in the first embodiment, and a silicon nitride film 73 is selectively formed on the inner wall surface of the via hole 72.

  As a result, in this embodiment, the third interlayer insulating film is also confined in the SOG film 68 in the same manner as described above with respect to the first embodiment, and the deterioration of the heating element 90 is prevented. Further, similarly to the case of the via hole 58, the growth inhibition of tungsten when the tungsten is buried in the via hole 72 is also prevented, and the filling failure due to tungsten is prevented.

  Then, after the tungsten film and the titanium nitride film are sequentially formed in the same manner as the via hole 58, the head chip 84 is sequentially removed from the surface of the interlayer insulating film by etch back, As a result, tungsten is buried only inside the via hole 72.

Subsequently, the silicon nitride film at a predetermined position is removed by a photoresist process and a dry etching process using CHF ₃ / CF ₄ / Ar gas, thereby exposing a portion connecting the heating element 90 to the wiring pattern.

  Subsequently, in the head chip 84, a third-layer wiring pattern 92 is created in the same manner as the second-layer wiring pattern 64. The silicon nitride film 91 left on the surface layer of the heating element 90 functions as a protective layer for the dry etching process when forming the wiring pattern. As a result, the silicon nitride film 91 is exposed to chlorine radicals and has a thickness of 300 nm. ] To 100 [nm].

  Subsequently, as shown in FIG. 9, the head chip 84 is formed with the cavitation-resistant layer 78 after the silicon nitride film 77 that functions as an ink protective layer and an insulating layer is formed in the same manner as described above for the first embodiment. Is done. Subsequently, the partition wall 33 of the ink liquid chamber 79, the partition wall of the ink flow path, and the like are created and individually scribed.

  According to this embodiment, even when the upper wiring pattern is connected to the lower layer by a tungsten plug, the same effect as that of the first embodiment can be obtained.

In the above-described embodiment, the case where the coating type insulating film is formed of the SOG film has been described. However, the present invention is not limited to this, and instead of the SOG film, for example, a low-level composition mainly composed of polyaryl ether or the like. Various coating type insulating films such as dielectric constant material films can be widely applied. Note that in the case where a low dielectric constant material film is applied to the coating type insulating film, the inorganic treatment by etching back and plasma irradiation can be omitted. In forming the via hole, the surface insulating film is etched by dry etching using CHF ₃ / CF ₄ / Ar gas until the surface of the coating type insulating film is exposed at the via hole, and then NH ₃ , N Etching the exposed insulating film by dry etching using a gas system containing ₂ / H ₂ gas as a main component until the lower wiring pattern is exposed again by a dry etching process using CHF ₃ / CF ₄ / Ar gas Will be etched.

  In the above-described embodiment, a case has been described in which the present invention is applied to a full-line type printer head for color printing to create four nozzle arrays. However, the present invention is not limited to this, for example, monochrome printing. For example, when the present invention is applied to a full-line type printer head for producing a single nozzle array, the present invention can be widely applied to the production of nozzle arrays with various numbers.

  In the above-described embodiments, the case where the present invention is applied to a full-line type printer head has been described. However, the present invention is not limited to this. For example, the present invention is applied to a so-called serial type printer head that moves the printer head in a specific direction. The present invention can also be widely applied when applied.

  In the above-described embodiments, the case where the present invention is applied to a printer head to eject ink droplets has been described. However, the present invention is not limited to this, and instead of ink droplets, the droplets are liquids of various dyes. Droplets, liquid discharge heads that are droplets for forming a protective layer, etc., microdispensers where the droplets are reagents, various measuring devices, various test devices, and various types of droplets that are agents that protect members from etching The present invention can be widely applied to pattern drawing apparatuses and the like.

  The present invention relates to a liquid discharge head, a liquid discharge apparatus, and a method for manufacturing a liquid discharge head, and can be applied to, for example, a thermal inkjet printer in which a heating element and a transistor that drives the heating element are integrally formed on a substrate. .

1 is a perspective view illustrating a line printer according to a first embodiment of the invention. FIG. 2 is an enlarged perspective view showing a portion related to ejection of ink droplets in the head assembly of FIG. 1. FIG. 3 is a cross-sectional view showing a portion related to ejection of ink droplets in the head assembly of FIG. 2. It is sectional drawing with which it uses for description of the creation process of the head chip of FIG. It is sectional drawing which shows the continuation of FIG. It is sectional drawing which shows the continuation of FIG. It is sectional drawing which shows the continuation of FIG. It is sectional drawing which shows the continuation of FIG. It is sectional drawing which shows the head chip applied to the line printer which concerns on Example 2 of this invention. It is sectional drawing with which it uses for description of the creation process of the head chip of FIG. It is sectional drawing which shows the continuation of FIG. It is sectional drawing which shows the structure of the conventional printer head. It is sectional drawing which shows the structure of the printer head different from FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Printer head, 2, 41 ... Substrate, 3, 47, 48 ... Transistor, 4, 7, 51, 64, 76, 92 ... Wiring pattern, 5 ... Interlayer insulating film, 6, 37, 90 ... Heating element, 12, 55, 68 ... SOG film, 21 ... Line printer, 30 ... Head assembly, 34, 84 ... Head chip, 56, 59, 69, 73 ... Silicon insulation film, 58, 72 …… Beer Hall

Claims (4)

A heating element that heats the liquid held in the liquid chamber and a semiconductor element that drives the heating element are integrally formed on a substrate, and the liquid droplet is discharged from a predetermined nozzle by driving the heating element by the semiconductor element. In the liquid discharge head that pops out
On the substrate side of the heating element,
An interlayer insulating film that insulates the upper wiring pattern from the lower layer is formed of a coating type insulating film,
The coating type insulating film is
Formed by silicon compounds containing organic groups,
A silicon insulating film is formed on the surface layer,
A liquid ejection head, wherein a silicon insulating film is formed on an inner wall surface of a through hole that connects the upper wiring pattern to a corresponding portion of a lower layer. The silicon insulating film on the inner wall surface is
The liquid discharge head according to claim 1, wherein the liquid discharge head is a silicon nitride film, a silicon oxynitride film, or a silicon oxide film. In a liquid ejection device that supplies liquid droplets ejected from a liquid ejection head to an object,
The liquid discharge head is
A heating element that heats the liquid held in the liquid chamber and a semiconductor element that drives the heating element are integrally formed on a substrate, and the liquid droplet is discharged from a predetermined nozzle by driving the heating element by the semiconductor element. Pop out
On the substrate side of the heating element,
An interlayer insulating film that insulates the upper wiring pattern from the lower layer is formed of a coating type insulating film,
The coating type insulating film is
Formed by silicon compounds containing organic groups,
A silicon insulating film is formed on the surface layer,
A liquid ejection apparatus, wherein a silicon insulating film is formed on an inner wall surface of a through hole that connects the upper wiring pattern to a corresponding portion of a lower layer. A heating element that heats the liquid held in the liquid chamber and a semiconductor element that drives the heating element are integrally formed on a substrate, and the liquid droplet is discharged from a predetermined nozzle by driving the heating element by the semiconductor element. In the manufacturing method of the liquid discharge head that causes the
An interlayer insulating film creating process for creating an interlayer insulating film that covers the entire surface of the substrate with a coating type insulating film formed of a silicon compound containing an organic group and insulates the upper wiring pattern from the lower layer;
A first silicon insulating film forming process for forming a silicon insulating film on a surface layer of the coating type insulating film;
In the interlayer insulating film, a through hole creating process for creating a through hole for connecting an upper wiring pattern to a corresponding portion of the lower layer, and
And a second silicon insulating film forming process for selectively forming a silicon insulating film on the inner wall surface of the through-hole.

Images