JP4617824B2 - 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. . The present invention flattens the lower layer of the heat generating element with a coating type insulating film, and makes the surface of the insulating film inorganic, thereby sufficiently preventing the generation of a step with the coating type insulating film, and the heating element. It is possible to prevent the deterioration of the material.

  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 has been made possible.

  In such a thermal type printer head, a heating element for heating ink is integrally formed on a semiconductor substrate together with a driving circuit by a logic integrated circuit for driving the heating element. As a result, in this type of printer head, the heat generating elements are arranged with high density and reliably driven.

  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, in order to obtain a printing result equivalent to 600 [DPI], for example, it is necessary to arrange the heating elements at intervals of 42.333 [μm]. It is extremely difficult to arrange individual driving elements. Thus, 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. 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 represents 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 heating element is formed while the step due to the wiring pattern is flattened by the SOG film 12 by repeating application of the SOG film and etching back a plurality of times. It is conceivable to remove the SOG film 12 for the production region 6.

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. If the wiring pattern is thus narrowed and the SOG film 12 is removed from the lower layer of the heating element 6 by repeatedly applying and etching back the SOG film, the step due to the wiring pattern cannot be sufficiently flattened. Accordingly, it is desired to sufficiently prevent the generation of a step by the SOG film and to prevent the heating element from deteriorating.
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. Applied to a liquid discharge head that ejects liquid droplets from a predetermined nozzle by driving, a coating type insulating film covering the entire surface of the substrate is disposed on the substrate side of the heating element, and wiring for driving the heating element The level difference due to the pattern is flattened, and a silicon oxide film obtained by mineralizing the coating type insulating film is formed on the surface of the coating type insulating film.

  According to a second aspect of the present invention, there is provided a heating element that heats the liquid held in the liquid chamber by applying the liquid discharging apparatus that supplies droplets ejected from the liquid discharging head to the object, and the heating element. And a semiconductor element that drives the heat generating element is integrally formed on the substrate, and a liquid droplet is ejected from a predetermined nozzle by driving the heat generating element by the semiconductor element. An insulating film is arranged to flatten the level difference due to the wiring pattern used to drive the heating element, and a silicon oxide film obtained by mineralizing the coating type insulating film is formed on the surface of the coating type insulating film. To.

  According to a third 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. Applying to the manufacturing method of the liquid discharge head that ejects more liquid droplets, arranging a coating type insulating film covering the whole surface of the substrate, flattening process and flattening the step by the lower wiring pattern A mineralization process for forming a silicon oxide film by mineralizing the surface of the mold insulating film, and a heating element creating process for creating a heating element on the upper layer of the coating type insulating film.

  According to the configuration of the first aspect, when applied to the liquid discharge head, a coating type insulating film covering the entire surface of the substrate is disposed on the substrate side of the heat generating element, and the step due to the wiring pattern for driving the heat generating element is flattened. By doing so, it is possible to prevent the occurrence of a step by the coating type insulating film, and it is possible to increase the adhesion between the resin layer and the nozzle sheet. According to the first aspect of the present invention, when a silicon oxide film obtained by mineralizing the coating type insulating film is formed on the surface of the coating type insulating film, the inorganic silicon is used when the heating element is driven. Oxidation of the organic component and solvent component in the coating type insulating film is suppressed by the oxide film. As a result, the generation of a step can be sufficiently prevented by the SOG film, and the deterioration of the heating element can be prevented.

  Thus, according to the configurations of claims 2 and 3, there are provided a liquid ejection apparatus and a liquid ejection head manufacturing method capable of preventing the generation of a step by the SOG film and preventing the heat generating element from deteriorating. be able to.

  According to the present invention, the generation of a step can be sufficiently prevented by the SOG 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 can be attached to the paper 23 and desired images can be 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 through the bonding terminals 36 after the head chips 34 having the liquid chamber partition 33 and the like 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 the ink liquid chamber and a partition of the ink flow path by a comb tooth shape so that this one side is open, and the flow path is provided along this one side. The head chip 34 is sequentially arranged on the nozzle sheet 35 in a zigzag manner with the flow path interposed therebetween, whereby the head assembly 30 forms a flow path by 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, and the ink thus guided to the liquid chambers can be heated by driving the heating element 37. ing.

  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. In the nozzle sheet 35, openings 40 for working when wire bonding the head chips 34 to the bonding terminals 39 are formed in a staggered manner with the rows of nozzles 38 therebetween.

  FIG. 3 is a cross-sectional view showing a configuration in the vicinity including the nozzles of the head chip arranged in the head assembly. 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. In the head chip 34, a partition wall 33 is formed 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 flat to increase the adhesion between the partition wall 33 and the nozzle sheet 35.

  That is, as shown in FIG. 4A, the head chip 34 is formed with a silicon nitride film 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 is formed with a film thickness of 500 [nm] in a region where the silicon nitride film is removed by the thermal oxidation process, and element isolation for isolating the transistor by this thermal silicon oxide film is performed. 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 also 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 formed of a tungsten silicide film 45. In this embodiment, the gate length is 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. Accordingly, the driver transistor 47 is a MOS transistor having a breakdown voltage of up to about 18 [V], and serves to drive 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.

  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, 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 34 is a plug that connects the transistors 47 and 48 and the first wiring pattern 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. 50 is created.

  Next, the head chip 34 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 of 0.5 [at%]. The added aluminum is sequentially deposited with a film thickness of 500 nm. Subsequently, titanium having a film thickness of 5 nm, titanium nitride barrier metal having a film thickness of 100 nm, and titanium having a film thickness of 5 nm are sequentially deposited by sputtering, thereby forming a wiring pattern material layer. Is done. Subsequently, the formed wiring pattern material layer is selectively removed by a photolithography process and a dry etching process, and a first wiring pattern 51 is created. In the contact hole, the plug 50 can be omitted and the wiring pattern 51 can be directly buried.

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 almost buried by the O ₃ -TEOS film 53.

Subsequently, after the P-TEOS film 54 is formed with a film thickness of 200 [nm] by the CVD method, the SOG film 55 with a film thickness of 700 [nm] is applied 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 local 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 hydrogen. An organic SOG mainly composed of a silsesquioxane oxide polymer is applied, and CHF ₃ / CF ₄ / Ar gas is applied for etch back.

Accordingly, in this embodiment, after forming the P-TEOS film, the O ₃ -TEOS film is formed and etched back, and the SOG film is formed and etched back. Even when the pattern is narrowed, or even when the step generated by the wiring pattern is large, the generation of a step on the surface of the SOG film 55 can be reliably prevented. Further, such an SOG film 55 is formed by etching back after being formed with a film thickness sufficiently thicker than a step due to a lower wiring pattern, thereby sufficiently flattening the surface of the SOG film 55. can do.

When the SOG film 55 is formed in this way, the head chip 34 is subsequently subjected to a treatment for mineralizing the surface of the SOG film 55 as shown in FIG. The silicon substrate 41 is irradiated with oxygen plasma using a raw material gas. Specifically, on the surface of the SOG film 55, when the organic group of the coating type insulating material is an alkyl group by irradiation of oxygen plasma onto the silicon substrate 41, 4 (CH ₃ —Si (OH)) + 7 O ₂ → 4 Si (OH) +4 CO ₂ +6 When H ₂ O progresses and the organic group of the coating type insulating material is C ₂ H ₅ , 4 (C ₂ H ₅ —Si (OH) ) + 13O ₂ → 4 Si (OH) +8 CO ₂ + 10H ₂ O The chemical reaction represented by the reaction proceeds and the organic group is eliminated. At this time, as shown in FIG. 5B, silicon atoms on the surface of the SOG film are bonded to oxygen, and thereby a silicon oxide film 56 is generated on the surface of the SOG film 55. When the heat generating element 37 is driven, the head chip 34 encloses these organic components and solvent components in the SOG film 55 by the silicon oxide film 56 formed by mineralizing the SOG film 55 in this manner. Deterioration of the heating element 37 due to the detachment of is suppressed. As a result, in the head chip 34, the SOG film 55 can sufficiently prevent the occurrence of a step and can prevent the heating element 37 from deteriorating.

  In this embodiment, oxygen plasma is irradiated by a downflow type ashing apparatus having a plasma generation chamber above the wafer processing chamber so that the silicon substrate 41 is not excessively damaged by the collision of ions in the plasma. did.

Next, as shown in FIG. 6, the head chip 34 is formed with a P-TEOS film 57 having a film thickness of 200 [nm] by the CVD method. A second interlayer insulating film that insulates the pattern is formed by a laminated structure. In other words, the region where the heat generating element 37 is formed is 2 by the P-TEOS film 52, the O ₃ -TEOS film 53, the P-TEOS film 54, the SOG film 55, the silicon oxide film 56 and the P-TEOS film 57 from the silicon substrate 41 side. A second interlayer insulating film is formed, and the surface of the second interlayer insulating film is formed flat.

Next, as shown in FIG. 7, the head chip 34 forms a via hole by forming an opening in the second interlayer insulating film by a photoresist process and a dry etching process using CHF ₃ / CF ₄ / Ar gas. Is done.

  Subsequently, in the head chip 34, the natural oxide film is removed from the surface of the first wiring pattern 51 exposed by the via hole by argon (Ar) plasma treatment. Subsequently, a titanium nitride barrier metal having a thickness of 100 nm is deposited by sputtering, and then tungsten having a thickness of 500 nm is deposited by CVD, thereby completely filling the via hole. Further, in the head chip 34, the tungsten film and the titanium nitride film are removed from the portion excluding the contact hole by an etch back method, thereby creating a plug 58 for connecting the first and second wiring patterns.

  Subsequently, a second wiring pattern material layer is formed on the head chip 34 in the same manner as the first wiring pattern 51, and is selectively removed to form a second wiring pattern 59. In the via hole, it is also possible to directly fill the wiring pattern 59 without creating the plug 58.

Subsequently, the head chip 34 is formed with a third interlayer insulating film that insulates the second wiring pattern 59 from the subsequent third wiring pattern. That is, as described for the second interlayer insulating film, the P-TEOS film 60 is formed, the O ₃ -TEOS film 61 is formed and etched back, the P-TEOS film 62 is formed, and the SOG film 63 is formed. Film formation and etch back, formation of the silicon oxide film 64 by mineralization of the surface of the SOG film 63, and film formation of the P-TEOS film 65 are sequentially performed, and the interlayer insulation of the third layer whose surface is flattened thereby. A film is formed.

Next, as shown in FIG. 3, β-tantalum is deposited on the head chip 34 by sputtering so as to have a film thickness of 50 to 100 [nm], 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 has a resistor film selectively removed by a photolithography process and a dry etching process using BCl ₃ / Cl ₂ gas, and has a square shape or a folded shape in which one end is connected by a wiring pattern. , A heating element 37 having a resistance value of 40 to 100 [Ω] is formed.

Subsequently, a silicon nitride film 66 having a film thickness of 300 [nm] is formed on the head chip 34 by a CVD method. 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 37 to the wiring pattern. Further, a via hole is formed by forming an opening in the third interlayer insulating film by a dry etching process using CHF ₃ / CF ₄ / Ar gas.

  In the head chip 34, the natural oxide film is subsequently removed from the surface of the second wiring pattern 59 exposed by the via hole by argon plasma treatment. Subsequently, a titanium nitride barrier metal having a thickness of 100 nm is deposited by sputtering, and then tungsten having a thickness of 500 nm is deposited by CVD, thereby completely filling the via hole. Further, in the head chip 34, the tungsten film and the titanium nitride film except for the via holes are removed by an etch back method, thereby creating a plug 67 for connecting the second and third wiring patterns.

  Subsequently, in the same manner as the first-layer wiring pattern 51, a third-layer wiring pattern material layer is formed on the head chip 34, and is selectively removed to form a third-layer wiring pattern 68. At this time, the silicon nitride film 66 left on the heat generating element 37 functions as a protective layer for protecting the heat generating element 37 from chlorine radicals used for etching in the etching process when forming the wiring pattern. Further, in this etching process, the silicon nitride film 66 has a portion exposed to chlorine radicals reduced from a film thickness of 300 nm to a film thickness of 100 nm. In the via hole, it is also possible to directly bury the wiring pattern 68 without creating the plug 67.

In the head chip 34, a silicon nitride film 69 functioning as an ink protective layer and an insulating layer is subsequently formed with a film thickness of 200 to 400 [nm] by plasma CVD. Subsequently, after the anti-cavitation material layer is formed with a film thickness of 100 to 300 [nm], the anti-cavitation layer 70 is formed by patterning using BCl ₃ / Cl ₂ gas. In this embodiment, the anti-cavitation layer 70 made of β-tantalum is formed by a DC magnetron sputtering apparatus using tantalum as a target. Here, the anti-cavitation layer 70 protects the heating element 37 by absorbing physical damage (cavitation) when bubbles generated in the ink liquid chamber disappear due to the driving of the heating element 37, and drives the heating 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-curing dry film made of an organic resin is disposed by pressure bonding, the head chip 34 is removed by a photolithographic process at portions corresponding to the ink liquid chamber and the ink flow path, and then cured. A partition 33 of the liquid chamber 71, a partition of the ink flow path, and the like are created. The head chip 34 is formed by scribing a plurality of head chips formed on the silicon substrate 41 in this way.

(2) Operation of Embodiment 1 In the above configuration, in the line printer 21 (FIG. 1), the head cartridge 28 is driven by image data, text data, etc. used for printing, and the paper 23 to be recorded is predetermined. While being transported by the paper feed 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.

  Correspondingly, in 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 ink liquid chamber 71 via the ink flow path, and the heating element Ink droplets L are ejected from the nozzles 38 provided on the nozzle sheet 35 due to an increase in the pressure of the ink held in the ink liquid chamber 71 by driving 37. Thus, the line printer 21 can print a desired image or the like.

  In the head assembly 30 (FIG. 3), a heating element 37, a driver chip 47 for driving the heating element 37, and the like are integrally formed on a substrate, and a nozzle 38 for discharging ink droplets. The nozzle row and the opening 40 are formed by arranging a nozzle sheet 35 which is a sheet-like member formed by electroforming. In addition, the length of the nozzle row is set to be equal to or larger than the paper width to be recorded, whereby the head assembly 30 forms a full line type line head, which is faster than the case of using a serial head printer head. It is possible to print a desired image or the like.

In such a head assembly 30 (FIGS. 3 to 7), it is a part of the second and third interlayer insulating films provided on the substrate 41 side of the heat generating element 37, and is based on the wiring patterns 51 and 59. O ₃ -TEOS films 53 and 61 are formed in the portions related to the steps. Further, SOG films 55 and 63 covering the entire surface of the silicon substrate are disposed on the O ₃ -TEOS films 53 and 61, and local steps are flattened by these SOG films 55 and 63. Thereby, in the head assembly 30, the surface of the partition wall 33 is formed flat, and the adhesion between the partition wall 33 and the nozzle sheet 35 is increased even when the wiring pattern is multi-layered and the pitch is narrowed.

  In the head assembly 30, the organic component and the solvent component are desorbed from the SOG films 55 and 63 due to heat when the SOG films 55 and 63 are simply arranged, and there is a concern that the heating element 37 may be oxidized or carbonized due to these components. The In other words, in the line printer 21, the heating element 37 is oxidized or carbonized by the so-called empty space, and the resistance value rises and the ink droplet L cannot be ejected stably.

  Therefore, in this embodiment, silicon oxide films 56 and 64 obtained by mineralizing the SOG films 55 and 63 are formed on the surface of the coating type insulating film. Specifically, in the mineralization treatment, the surface of the SOG films 55 and 63 is irradiated with oxygen plasma, and organic components are removed from the surfaces of the SOG films 55 and 63 by a chemical reaction between the oxygen plasma and the surface of the SOG film. Release. At this time, silicon oxide films 56 and 64 are formed on the surfaces of the SOG films 55 and 63 by the combination of oxygen atoms and the like in the oxygen plasma and silicon atoms. As a result, in the head assembly 30, when the heating element 37 is driven, the silicon oxide films 56 and 64 thus mineralized function as a block layer that encloses excess organic components and solvent components in the SOG films 55 and 63. As a result, the head assembly 30 suppresses the deterioration of the heating element 37 due to the detachment of the organic component and the solvent component from the SOG films 55 and 63, sufficiently prevents the generation of a step by the SOG film, and generates heat. Deterioration of the element 37 can be prevented.

  Further, such SOG films 55 and 63 are formed by etching back after being formed with a film thickness sufficiently thicker than the step due to the lower wiring pattern, so that the surfaces of the SOG films 55 and 63 are formed. It can be sufficiently planarized.

(3) Effect of Example 1 According to the above configuration, the lower layer of the heating element is planarized by the SOG film, and the surface of the SOG film is made inorganic, thereby sufficiently preventing the generation of a step by the SOG film. In addition, deterioration of the heating element can be prevented.

  Specifically, in this mineralization treatment, the surface of the SOG film is irradiated with oxygen plasma to sufficiently prevent the step from being generated by the coating type insulating film and to prevent the heating element from deteriorating. it can.

  FIG. 8 is a cross-sectional view showing a configuration in the vicinity including the nozzles of the head chip arranged in the head assembly of the printer according to the embodiment of the present invention. In this head chip, in addition to mineralization of the surface of the SOG film, the organic component and the solvent component in the SOG film are made difficult to desorb by a prior treatment. In this embodiment, except for the configuration related to the prior processing, the same configuration as that of the first embodiment is given, and the corresponding reference numerals are given, and the duplicate description is omitted.

  That is, as shown in FIG. 9A, the head chip 74 includes transistors 47 and 48 on the silicon substrate 41, a first interlayer insulating film 49, a first wiring pattern 51, and a second interlayer insulating film. Are sequentially formed. In the head chip 74, the SOG film 55 is disposed in the second interlayer insulating film to flatten the surface of the interlayer insulating film, and the surface of the SOG film 55 is made of silicon oxide obtained by mineralizing the SOG film 55. A film 56 is formed.

Subsequently, the head chip 74 is formed with a via hole by forming an opening in the second interlayer insulating film by a photoresist process and a dry etching process using CHF ₃ / CF ₄ / Ar gas. Here, in this embodiment, in addition to the via hole 75 for the plug 58, a plurality of degassing via holes 76 for removing the organic component and the solvent component in the SOG film are formed, and thereby the silicon oxide film 56 is formed. A recess that penetrates and exposes the SOG film 55 is formed. In this embodiment, the plurality of via holes 76 are arranged around the formation region of the heating element 37 so that the organic component and the solvent component can be easily removed from the SOG film in the generation region of the heating element 37.

  The head chip 74 is subsequently subjected to a heat treatment at the same temperature as when the heat generating element 37 is driven, whereby volatile components are removed from the interlayer insulating film via the via holes 75 and 76. At this time, moisture and organic components in the SOG film 55 are released from the recesses in the SOG film 55, whereby the head chip 74 removes moisture and organic components related to the deterioration of the heating element 37 at the stage of producing the head chip 74. Desorb from 55. In this example, the heat treatment was performed in an inert gas atmosphere, in a nitrogen gas atmosphere, or in a vacuum at 300 to 400 degrees for 10 minutes to 60 minutes by a heat treatment apparatus.

Subsequently, as shown in FIG. 9B, a silicon nitride film is formed by plasma CVD using SiH ₄ gas, NH ₃ gas, and N ₂ O gas, and then CHF ₃ and CF ₄ as main components. Etching is performed until the lower wiring pattern surface is exposed on the bottom surfaces of the via holes 75 and 76 by the dry etching method using the mixed plasma as described above, whereby silicon is formed only on the sidewall surface of the second interlayer insulating film by the via holes 75 and 76. A nitride film 77 is formed. In the head chip 74, a silicon nitride film 77 is also formed on the surface of the concave portion of the SOG film 55, and when the heating element 37 is driven, the silicon nitride film 77 and the silicon oxide film 56 remain in the SOG film 55. It functions as a block layer that contains the solvent component. Thereby, in the head chip 74, deterioration of the heating element 37 due to the detachment of the organic component and the solvent component through the via holes 75 and 76 is suppressed. Further, when such a silicon nitride film 77 is not formed at all, the SOG film 55 is directly exposed to the atmosphere during transportation to the subsequent process and absorbs moisture from the atmosphere. The silicon nitride film 77 prevents the SOG film 55 from coming into contact with the atmosphere, whereby the SOG film 55 is held in a degassed state.

  In this way, in the block layer formed on the side wall of the second interlayer insulating film, a silicon oxynitride film or a silicon oxide film may be used instead of the silicon nitride film 77, and further, a tantalum film. It is also possible to use a metal film having a microcrystalline grain structure such as.

  When the silicon nitride film 77 is thus formed, the head chip 74 is subsequently formed with a plug 58 as shown in FIG. 10, and the same material as the plug 58 is formed in the degassing via hole 76. A dummy plug 78 is formed by being embedded.

  Further, the head chip 74 is formed with a second-layer wiring pattern 59 and a third-layer interlayer insulating film in order, and the third-layer interlayer insulating film is also flattened by the SOG film 63. A silicon oxide film 64 is formed. In addition, a dummy plug 78 that closes the via hole 76 by the third interlayer insulating film is sandwiched between and insulated from the second interlayer insulating film.

  Next, as shown in FIG. 11, the head chip 74 is formed with a heat generating element 37 and a silicon nitride film 66 in sequence, and then a plug via hole 79 and a degassing via hole 80 related to the SOG film 63 are formed and heat-treated. Then, a silicon nitride film 81 is formed on the side wall of the interlayer insulating film by the via holes 79 and 80. Note that the silicon nitride film 66 covering the heat generating element 37 functions as a protective layer for protecting the heat generating element 37 from degassing from the SOG film 63 in the heat treatment step for the SOG film 63.

Subsequently, as shown in FIG. 8, the head chip 74 is formed by a photoresist process and a dry etching process using CHF ₃ / CF ₄ / Ar gas after the dummy plug 82 is formed at the time of creating the plug 67. A predetermined portion of the silicon nitride film 66 is removed from the surface of the substrate, thereby exposing a portion connecting the heating element 37 to the wiring pattern. Subsequently, a third-layer wiring pattern 68, an insulating protective layer 69, an anti-cavitation layer 70, and a partition wall 33 are sequentially formed. The head chip 74 is created by scribing a plurality of head chips created on the silicon substrate 41 in this way.

  According to the configuration shown in FIG. 8, in addition to the planarization process and the mineralization process, a process of forming a recess that penetrates the silicon oxide film by the mineralization process and exposes a part of the coating type insulating film; By providing the heat treatment for removing the volatile component of the coating type insulating film from the recess, the SOG film can sufficiently prevent the generation of a step and further prevent the heating element from deteriorating.

  In addition, by forming a silicon oxide film on the surface of the insulating film in the recess, the desorption of the organic component and the solvent component through the sidewall of the recess is suppressed, and further deterioration of the heating element is further prevented. Can do.

  In the above-described embodiment, the case where the coating type insulating film is mineralized by plasma irradiation using oxygen as a source gas has been described. However, the present invention is not limited to this, and a mixed gas containing oxygen is used as the source gas. You may do it.

  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. 2 is a cross-sectional view showing a portion related to ejection of ink droplets in the head assembly of FIG. 1. 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 part which concerns on discharge of the ink droplet of the head assembly 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. FIG. 10 is a cross-sectional view showing a continuation of FIG. 9. It is sectional drawing which shows the continuation of FIG. It is sectional drawing which shows the structure of the head chip in the conventional printer head. It is sectional drawing which shows the structure of the head chip different from FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Printer head, 2, 41 ... Substrate, 3, 47, 48 ... Transistor, 4, 7, 51, 59, 68 ... Wiring pattern, 5 ... Interlayer insulating film, 6, 37 ... Heating element 12, 55, 63 ... SOG film, 21 ... Line printer, 30 ... Head assembly, 34, 74 ... Head chip, 56, 64 ... Silicon oxide film

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
A coating type insulating film covering the entire surface of the substrate is disposed on the substrate side of the heating element, and a step due to a wiring pattern for driving the heating element is flattened,
The coating type insulating film is formed of a silicon compound containing an organic group,
On the surface of the coating type insulating film,
A liquid discharge head characterized in that a silicon oxide film in which the surface of the coating type insulating film is made inorganic is formed. 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. A coating type insulating film covering the entire surface of the substrate is disposed on the substrate side of the heat generating element, and a step due to a wiring pattern connecting the heat generating element and the semiconductor element is flattened,
The coating type insulating film is formed of a silicon compound containing an organic group,
On the surface of the coating type insulating film,
A liquid discharge apparatus, wherein a silicon oxide film in which the surface of the coating type insulating film is mineralized is formed. 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
Have covered the entire surface of the substrate, by arranging the insulating film of the coating type formed by a silicon compound containing an organic group, and planarization process to planarize the step due to the lower layer of the wiring pattern,
Mineralization treatment for forming a silicon oxide film by mineralizing the surface of the coating type insulating film;
A manufacturing method of a heat generating element for forming the heat generating element on an upper layer of the coating type insulating film. The mineralization treatment is
The method of manufacturing a liquid discharge head according to claim 3, wherein the surface of the coating type insulating film is irradiated with oxygen or a plasma of a mixed gas containing oxygen.

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