JP2021088158A - Recording element substrate, liquid discharge head and method for manufacturing them - Google Patents

Abstract

To provide a liquid discharge head which can seal an electric connection part between a recording element substrate and an electric wiring board with a sufficient amount of a sealing material, and can improve electric reliability.SOLUTION: In a recording element substrate 2 that has a discharge port for discharging a liquid and an energy generating element for imparting discharge energy to the liquid and has a connection terminal 213 to which a signal is input and is provided on one surface, a recess 215 is formed on the side face of the recording element substrate 2 corresponding to a formation position of the connection terminal 213. The recess 215 is formed on the side face of the recording element substrate 2 so as to be separated from the one surface of the recording element substrate 2 through a projection 216. On an edge 217 of the recess 215, an angle obtained by sandwiching the projection 216 between the side face of the recording element substrate 2 and a ceiling surface 218 that is a connection surface connected to the side face of the recording element substrate 2 in a surface constituting the recess 215 is less than 90°.SELECTED DRAWING: Figure 1

Description

The present invention relates to a liquid discharge head, and more particularly to a recording element substrate used for the liquid discharge head and a method for manufacturing the same, and a liquid discharge head including the recording element substrate and a method for manufacturing the same.

A liquid discharge head that discharges a liquid from a discharge port includes a recording element substrate in which an energy generating element that gives discharge energy to the liquid and a discharge port are formed, and an electric wiring board that supplies an electric signal to the recording element substrate. There is. The electrical wiring board and the recording element substrate are electrically connected by, for example, a plurality of flying-shaped leads, and the electrical connection portion between the electrical wiring board and the recording element substrate including the leads is sealed. It is sealed with a material to protect the coating. For reliable sealing, the sealing material is applied twice, from above and from below so as to sandwich the lead, but this is not efficient. Therefore, it has been proposed to form a recess on the side surface of the recording element substrate and apply a sealing material from above so as to extend beyond the lead to the edge of the recess and form a meniscus there. A general method for manufacturing a recording element substrate is disclosed in Patent Document 1, and patent document 2 discloses that a recess is formed on a side surface of the recording element substrate.

Japanese Unexamined Patent Publication No. 2006-281679 JP-A-2017-185677

When a sealing material is applied from above to seal an electrical connection portion using a recording element substrate having a recess formed on a side surface, the sealing material further forms a meniscus at the edge of the recess. Since the flow is stopped, the electrical connection is sealed with a sufficient amount of encapsulant. However, the meniscus may break and the encapsulant may flow further downwards, resulting in an inability to encapsulate the electrical connection with a sufficient amount of encapsulant, reducing electrical reliability.

An object of the present invention is to provide a recording element substrate and a liquid discharge head which can seal an electric connection portion between a recording element substrate and an electric wiring board with a sufficient amount of a sealing material and can improve electrical reliability. , And their manufacturing methods.

The recording element substrate of the present invention is a recording element substrate including a discharge port for discharging a liquid and an energy generating element for imparting discharge energy to the liquid, for driving the energy generating element on one surface of the recording element substrate. A connection terminal for inputting a signal is provided, a recess is formed on the side surface of the recording element substrate corresponding to the position where the connection terminal is formed, and the recess is formed on the side surface away from one surface and one surface. A convex portion is formed between the concave portion and the concave portion, and at the edge on the side close to one surface of the concave portion, a side surface and a connecting surface connected to the side surface of the surfaces constituting the concave portion sandwich the convex portion. Is less than 90 °.

The liquid discharge head of the present invention includes a recording element substrate based on the present invention, an electrical wiring board that is electrically connected to a connection terminal and supplies a signal to the recording element substrate, and includes a recording element substrate and an electrical wiring board. The electrical connection portion of the above is sealed with a sealing material.

The method for manufacturing a recording element substrate of the present invention uses a wafer of a silicon semiconductor having a size corresponding to a plurality of recording element substrates, and in a boundary region serving as a boundary between adjacent recording element substrates in the wafer, the wafer is formed. By forming a V-shaped groove on the first surface and dying at a position deviated from the apex of the groove in the boundary region, the individual recording element substrates are separated from the wafer and recesses are formed on the side surfaces of the recording element substrate. It is characterized by doing.

The method for manufacturing a liquid discharge head of the present invention includes a connection step of electrically connecting an electric wiring board and a recording element substrate, and a position of an edge from the position of one surface along the side surface of the recording element substrate after the connection step. It has a coating step of applying a liquid sealing material to the electrical connection portion in a direction of flowing toward.

According to the present invention, a recording element substrate and a liquid discharge head capable of improving electrical reliability by sealing an electrical connection portion between a recording element substrate and an electrical wiring board with a sufficient amount of a sealing material. , Their manufacturing methods and are provided.

It is a figure explaining the liquid discharge head. It is sectional drawing explaining the electric connection part between a recording element board and an electric wiring board. It is sectional drawing explaining the application of the sealing material to the electric connection part. It is sectional drawing of the main part of the liquid discharge head of one Embodiment of this invention. It is sectional drawing explaining the application of the sealing material to the electric connection part. It is sectional drawing which shows the manufacturing process of a recording element substrate. It is a figure explaining the dicing of a wafer. It is sectional drawing explaining the position of the edge of the recess. It is sectional drawing explaining the formation of the concave part by a processing tool.

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows the overall configuration of a liquid discharge head to which the present invention is applicable. 1 (a) is a bottom view of the liquid discharge head 10, and FIG. 1 (b) is a cross-sectional view taken along the line BB of FIG. 1 (a). The liquid discharge head 10 is mounted on a liquid discharge device such as an inkjet recording device in order to discharge a liquid such as a recording liquid or ink to a recording medium from a discharge port and record on the surface of the recording medium. The discharge port is formed on the recording element substrate 2 together with an energy generating element that applies discharge energy to the liquid. The recording element substrate 2 is formed by providing an energy generating element on the surface of a substrate such as a silicon semiconductor substrate and joining a discharge port forming member having a discharge port formed to the substrate. The liquid discharge head 10 shown in FIG. 1 enables color recording on a recording medium, and is a substantially rectangular shape in which a plurality of discharge ports for discharging black recording liquid (ink) are arranged in a row. The recording element substrate 2 of the above and a substantially square recording element substrate 2 for color recording are provided. In the recording element substrate 2 for color recording, three rows of discharge ports are formed by arranging the discharge ports for discharging the recording liquids of each color of cyan, magenta, and yellow in one row.

The recording element substrate 2 is supported on the surface of the base plate 1. An electric wiring board 3 is provided in order to supply a signal for driving the energy generating element from the main body of the liquid discharge device to the recording element board 2. The electrical wiring board 3 is attached to the surface of the base plate 1 via a support plate 4, and a plurality of connections formed at the end of the surface of the recording element substrate 2 opposite to the base plate 1. It is electrically connected to the recording element substrate 2 via a terminal. The support plate 4 has an opening corresponding to the recording element substrate 2 and is provided on the surface of the base plate 1, and the recording element substrate 2 is arranged so as to fit in the opening of the support plate 4. The electrical wiring board 3 is composed of a flexible wiring board, for example, a TAB (Tape Automated Bonding) tape. When the electrical wiring board 3 is a TAB tape, the TAB tape is provided with an opening corresponding to the recording element board 2, and the recording element board 2 is exposed at the position of this opening.

The electrical connection between the electrical wiring board 3 and the recording element substrate 2 may be performed by, for example, wire bonding, but it may be performed by joining the leads extending from the electrical wiring board 3 to the connection terminals of the recording element substrate 2. preferable. When a TAB tape is used as the electrical wiring board 3, the lead extending from the TAB tape is also called an inner lead or a flying lead. This inner lead is a portion of a TAB tape having a structure in which a conductor pattern is sandwiched between insulating films, in which only the conductor pattern protrudes without being sandwiched by the insulating film. The lead or bonding wire is a fine conductor and may be broken by being hit by a recording medium or being touched by hand when the liquid discharge head is attached to the liquid discharge device. Further, the distance between adjacent reeds is narrow, and if a liquid such as a recording liquid adheres to the reeds, an electrical short circuit may occur and the liquid discharge head may not operate normally. Therefore, the electrical connection portion between the electrical wiring board 3 and the recording element substrate 2, including the lead and bonding wire portions, is sealed with the sealing material 5 to protect the coating.

The side surface of the recording element substrate 2 is processed so as to be perpendicular to the surface of the base plate 1, but as will be described later, at least on the side surface of the recording element substrate 2 corresponding to the electrical connection portion, A recess is formed on the side close to the surface of the base plate 1. Then, after connecting the lead or the bonding wire to the connection terminal of the recording element substrate 2, a liquid sealing material 5 is applied to the electrical connection portion from above, that is, from the side opposite to the base plate 1 and cured. This completes the sealing of the electrical connection. Hereinafter, before explaining the liquid discharge head based on the present invention, the sealing in the case where the recording element substrate 2 having the recess formed on the side surface and the electrical wiring substrate 3 are electrically connected by a lead, using FIG. A general sealing method using the material 5 will be described. FIG. 2 shows an enlarged view of the vicinity of the electrical connection portion in the cross section taken along the line BB of FIG. 1 (a).

First, as shown in FIG. 2A, the support plate 4 is joined to the surface of the base plate 1, and as shown in FIG. 2B, the recording element substrate 2 is housed in the opening of the support plate 4. , The recording element substrate 2 is joined to the base plate 1. At this time, a gap is formed between the support plate 4 and the recording element substrate 2 so that the liquid sealing material 5 can be injected. As described above, the recess 215 is formed on the recording element substrate 2. The recess 215 is formed by, for example, changing the shape of the beveling wheel generally used for processing the outer periphery of a semiconductor wafer into a convex shape and processing the side surface of the cut-out recording element substrate 2. Wheel. Alternatively, using stealth dicing technology, a modified layer in which cracks grow due to stress is formed at the edge of the substrate by a laser, and a recess 215 is formed so that the modified layer collapses when stress is applied to the substrate. May be good. The portion of the recording element substrate 2 above the concave portion 215 in the drawing is referred to as a convex portion 216. The surface of the side surface of the recording element substrate 2 that is connected to the edge 217 of the recess 215 and faces the inside of the recess 215 is called the ceiling surface 218 of the recess 215. The ceiling surface 218 is also a connecting surface connected to a side surface of the surfaces forming the recess 215. In the figure, the ceiling surface 218 of the recess 215 is perpendicular to the side surface of the recording element substrate 2, and is therefore parallel to the surface of the recording element substrate 2. As shown in FIG. 2B (and FIG. 4 described later), the surface on which the connection terminal 213 of the recording element substrate 2 is provided is the surface 2a of the recording element substrate 2, and the surface 2b connected to the surface 2a. Is the side surface of the recording element substrate.

Subsequently, as shown in FIG. 2C, the electrical wiring board 3 which is a TAB tape is joined to the support plate 4. In this case, the leads 301 extending from the electrical wiring board 3 are aligned so as to be located above the pad-shaped connection terminals formed on the recording element board 2. Then, as shown in FIG. 2D, the lead 301 and the connection terminal 213 are electrically joined to each lead (for each connection terminal) or to the plurality of leads 301 existing at the same time. Specifically, heat is applied to the recording element substrate 2 by heating the base plate 1, and in that state, an appropriate load is applied on the connection terminal 213 of the recording element substrate 2 with a single point capillary to suppress the lead 301. .. Then, ultrasonic vibration is applied to join the lead 301 and the connection terminal 213. Alternatively, a jig heated to a high temperature is brought into direct contact with the leads 301 and pressed against the connection terminal 213, and electrical joining of the plurality of leads 301 is performed at the same time by load control. As the lead 301, a copper foil having a thickness of 20 to 30 μm and thinly plated with nickel or gold is generally used.

Finally, a curable liquid encapsulant 5 is applied from above, and as shown in FIG. 2E, the electrical connection portion including the lead 301 is covered and protected by the encapsulant 5. The sealing material 5 encloses and covers the lead 301 with a sufficient thickness, and also covers the portion of the electrical wiring board 3 that is the root side of the lead 301 from both sides thereof, and connects the surface of the recording element substrate 2. The terminal 213 is also applied so as to cover it. When the sealing material 5 is cured at room temperature, it is applied and then left to be cured. When the heat-curing type sealing material 5 is used, the sealing material 5 is applied and then the thermosetting furnace is used. Is used to cure the sealing material 5. As the sealing material 5, for example, an epoxy resin or the like is used.

FIG. 3 shows in detail the coating process of the sealing material 5 shown in FIG. 2 (e). First, as shown in FIG. 3A, the coating needle 403 is positioned above the region including the lead 301 and the connection terminal 213, and the liquid sealing material 5 is discharged downward from the coating needle 403. As a result, the sealing material 5 is applied to the upper surfaces of the lead 301 and the connection terminal 213. When the sealing material 5 is further discharged from the coating needle 403, as shown in FIG. 3B, the sealing material 5 flows downward through the gap between the adjacent leads 301 and also covers the lower surface of the leads 301. Will be. The sealing material 5 is a highly viscous liquid, and when the sealing material 5 is discharged from the coating needle 403, it is necessary to apply pressure to the sealing material 5. The pressure-applied encapsulant 5 tends to flow in the direction of pressure, that is, downward, but does not easily flow in the direction orthogonal to the direction of pressure, that is, in the left-right direction shown in the drawing.

When the sealing material 5 is further discharged from the coating needle 403, the sealing material 5 flows downward along the side surface of the recording element substrate 2 in the convex portion 216, and the concave portion 215 formed on the side surface of the recording element substrate 2 Reach the position of edge 217. As described above, since the sealing material 5 does not easily flow in the left-right direction shown in the drawing, the force for forming the meniscus of the sealing material 5 becomes stronger at the position of the edge 217, and as shown in FIG. 3C, the recording element The downward flow of the sealing material 5 along the side surface of the substrate 2 is temporarily stopped at this position. At this point, the sealing material 5 does not flow along the ceiling surface 218 of the recess 215. When the outflow of the sealing material 5 from the coating needle 403 is continued, the sealing material 5 does not flow downward due to the meniscus. Therefore, as shown in FIG. 3D, the lead in the electrical wiring board 3 It flows to the root portion 302 of 301. The flow of the encapsulant to the root 302 to the leads 301 occurs simultaneously on both surfaces of the electrical wiring board 3. In this state, the covering of the electrical connection portion with the sealing material 5 is good.

In the state shown in FIG. 3D, the sealing material 5 is suppressed from flowing downward and flowing into the recess 215 by the meniscus formed at the position of the edge 217 of the recess 215. However, the meniscus may break, and in that case, as shown in FIG. 3 (e), a small amount of the sealing material 5 enters the inside of the recess 215 along the ceiling surface 218 of the recess 215. If the amount of the sealing material that enters the inside of the recess 215 is as shown in FIG. 3 (e), it can be said that the coating of the electrical connection portion by the sealing material 5 is still good. However, as shown in FIG. 3 (f), when the amount of the sealing material 5 that enters the recess 215 increases, the sealing material 5 is supplied to the position that becomes the root portion 302 of the lead 301 in the electrical wiring board 3. The amount is reduced, and the coating at the root portion 302 becomes insufficient. In particular, when the sealing material 5 reaches the wall 219 in the vertical direction shown in the drawing at the innermost part of the recess 215, the sealing material 5 flows downward along the wall 219, and the electrical wiring board 3 It becomes difficult to secure the coating amount of the sealing material 5 at the root portion 302 of the lead 301 in the above. In such a case, the root portion 302 cannot be stably protected, and the coating protection of the lead 301 itself by the sealing material 5 becomes insufficient.

In recent years, a liquid discharge device typified by an inkjet recording device has been required to have a long life, and the liquid discharge head 10 is also required to have high durability. In order to make the liquid discharge head 10 have high durability, the sealing material 5 for covering the electrical connection portion between the recording element substrate 2 and the electrical wiring substrate 3 is made of a material having higher electrical reliability. Is required to be used. More specifically, it is required to select a material having a high volume resistivity and use it as the sealing material 5. Then, it is necessary to cover the lead 301 and the connection terminal 213 from the root portion 302 of the lead 301 in the electric wiring board 3 by using such a sealing material 5. Therefore, in the liquid discharge head 10 of the present embodiment, even when a sealing material 5 made of a material having a particularly high volume resistivity is used, the sealing material 5 can sufficiently protect the coating of the electrical connection portion. The shape of the recess 215 formed on the side surface of the recording element substrate 2 is devised. The material used for the sealing material 5 ^{is preferably one having a volume resistivity of 1 × 10 14} Ω · cm or more when cured as the sealing material 5. Hereinafter, the liquid discharge head 10 according to the embodiment of the present invention will be described.

FIG. 4 is a diagram showing a cross-sectional configuration of a main part of the liquid discharge head 10 according to the embodiment of the present invention, and is a diagram corresponding to FIG. 2 (e) showing a general sealing method. Also in the liquid discharge head 10 of the present embodiment, the connection terminal 213 is provided on one surface of the recording element substrate 2, and the recording element substrate 2 is provided at a position corresponding to the electrical connection portion between the recording element substrate 2 and the electrical wiring substrate 3. A recess 215 is formed on the side surface of the above. The recess 215 is formed on the side surface of the recording element substrate 2 on the side closer to the base plate 1, that is, away from one surface of the recording element substrate 2, and is formed between one surface of the recording element substrate 2 and the recess 215. The space is the convex portion 216. In FIG. 4, a conductor pattern 311 which is an extension portion of the lead 301 in the electric wiring board 3 and insulating films 312 and 313 sandwiching the conductor pattern 311 are also drawn. In the liquid discharge head 10 of the present embodiment, the sealing material 5 that has flowed along the side surface of the recording element substrate 2 in the region of the convex portion 216 is formed by making the shape of the concave portion 215 different from that shown in FIG. It is difficult to enter the recess 215. Specifically, at the position of the edge 217 of the recess 215 in the recording element substrate 2, the angle formed by the side surface of the recording element substrate 2 that sandwiches the convex portion 216 and the ceiling surface of the recess 215 is an acute angle, that is, less than 90 °. I am trying to be. As a result, as will be described below, the sealing material 5 that flows along the side surface of the recording element substrate 2 and forms the meniscus at the edge 217 is less likely to enter the recess 215. Since the sealing material 5 is less likely to enter the recess 215, the root portion 302 of the lead 301 in the electric wiring board 3 is surely covered by the sealing material 5, and the electricity generated by the sealing material 5 is increased. The coating protection of the connection portion can be sufficiently performed. In the present embodiment, in the coating step of the liquid sealing material 5, the sealing material 5 is sealed at least until the sealing material 5 reaches the edge 217 along the side surface of the recording element substrate 2 and forms a meniscus at the position of the edge 217. Apply material 5.

FIG. 5 shows in detail the step of applying the sealing material 5 to the electrical connection portion of the liquid discharge head 10 shown in FIG. Similar to the case shown in FIG. 2, as shown in FIG. 5A, the coating needle 403 is positioned above the region including the lead 301 and the connection terminal 213, and the liquid sealing material 5 is lowered from the coating needle 403. To leak to. As a result, the sealing material 5 is applied to the upper surfaces of the lead 301 and the connection terminal 213. Further, by letting the sealing material 5 flow out, the sealing material 5 flows downward through the gap between the leads 301 as shown in FIG. 5 (b), and subsequently as shown in FIG. 5 (c). , A meniscus is formed at the position of the edge 217 of the recess 215. At this point, the downward flow of the sealing material 5 is temporarily stopped. When the outflow of the sealing material 5 from the coating needle 403 is continued, the sealing material 5 does not flow downward due to the meniscus. Therefore, as shown in FIG. 5 (d), the lead in the electrical wiring board 3 It flows to the root portion 302 of 301. In this state, as in the case shown in FIG. 2D, the covering of the electrical connection portion with the sealing material 5 is good.

In the state shown in FIG. 5D, the sealing material 5 is suppressed from flowing downward and flowing into the recess 215 by the meniscus formed at the position of the edge 217 of the recess 215. The meniscus may also break in the liquid discharge head 10 of the present embodiment, but since the angle between the side surface of the recording element substrate 2 and the ceiling surface 218 of the concave portion 215 at the edge 217 sandwiching the convex portion 216 is an acute angle, FIG. The meniscus is less likely to break than the one shown. Further, in the present embodiment, since the ceiling surface 218 is inclined in the climbing direction from the edge 217 in the direction away from the base plate 1, the sealing material 5 is difficult to flow along the ceiling surface 218 even if the meniscus breaks. ing. As a result, the amount of the sealing material 5 that enters the recess 215 when the meniscus breaks is smaller than that shown in FIG. 2, and the sealing material to the root portion 302 of the lead 301 in the electrical wiring board 3 is correspondingly smaller. The supply of 5 increases. The root portion 302 is covered and protected by a sufficient amount of the sealing material 5. In the present embodiment, the sealing material 5 reliably covers and protects the electrical connection portion, and the liquid discharge head 10 having high electrical reliability can be obtained.

The sealing material 5 needs to flow out of the coating needle 403, pass through the gap between the leads 301, and further flow in the direction of the electrical wiring board 3 while forming a meniscus. The encapsulant 5 that must undergo such flow is a material having relatively high fluidity, for example, a material having a viscosity of 70 Pa · s or less in an uncured state and a thixo ratio of 1.5 or less. Is preferably used.

Next, a method of manufacturing the recording element substrate 2 used in the liquid discharge head 10 of the present embodiment will be described with reference to FIG. For the production of the recording element substrate 2, it is preferable to use a silicon semiconductor wafer 201 having a crystal plane orientation of <100>, similar to that described in Patent Document 1. In the manufacture of the recording element substrate 2, it is common that a plurality of recording element substrates 2 are collectively formed by using one wafer 201, and then individual recording element substrates 2 are cut out from the wafer 201. .. The cross section shown in FIG. 6 shows a region of one recording element substrate 2 and its vicinity in the wafer 201. As shown in FIG. 6A, a surface layer 202 formed of silicon oxide or silicon nitride is laminated on one surface of the wafer 201, here, the upper surface in the drawing. The surface layer 202 also functions as a stop layer when performing anisotropic etching, which will be described later.

On the surface of the surface layer 202, a plurality of energy generating elements 203 for imparting energy for discharge to the liquid are arranged at desired positions. The energy generating element 203 is composed of, for example, an electric heat conversion element or a piezoelectric element. When the energy generating element 203 is an electric heat conversion element, the liquid is foamed by heating the liquid in the vicinity of this element, and the liquid is discharged from the discharge port. In this case, the surface layer 202 may also function as a heat storage tank. When a piezoelectric element is used as the energy generating element 203, discharge energy is given to the liquid by the mechanical vibration of this element, and the liquid is discharged from the discharge port. The energy generating element 203 is provided with an electrode (not shown) into which a signal for operating the element is input. When a signal is supplied to the recording element substrate 2 via the connection terminal 213, a signal is supplied to each electrode via a drive circuit (not shown) provided on the recording element substrate 2 to drive the energy generating element 203. To. Although not shown in FIG. 6, the connection terminal 213 is also formed on one surface of the wafer 201 at the same time as or before the formation of the energy generating element 203. The energy generating element 203 may be provided with various functional layers such as a protective layer for the purpose of improving its durability. The surface layer 203 can also be used as a protective layer.

Next, as shown in FIG. 6B, a coating layer 214 serving as a mask when the liquid supply path 204 or the like is formed by silicon anisotropic etching is formed on the other surface of the wafer 201. The liquid supply path 204 is a flow path that penetrates the recording element substrate 2 in order to supply the liquid to the position of the energy generating element 203. A silicon oxide film, a silicon nitride film, or the like is preferably used for the coating layer 214. The coating layer 214 can be installed on one surface of the wafer 201 as needed, and the above-mentioned protective layer or the like may also be used as the coating layer 214. The coating layer 214 is formed with a film thickness of, for example, several tens of μm by using a film forming apparatus such as a CVD (chemical vapor deposition) apparatus. Subsequently, as shown in FIG. 6C, a region that is a boundary between the region where the liquid supply path 204 should be formed and the adjacent recording element substrate 2 and includes a position where the recess 215 is formed. And removes the coating layer 214. As a result, the coating layer 214 is formed with an opening 210 corresponding to the recess 215 and an opening 211 corresponding to the liquid supply path 204. Since the opening 210 also corresponds to the boundary region between the recording element substrates 2 and the boundary region is preferably narrow in consideration of the utilization efficiency of the wafer 201, the opening 211 is generally formed larger than the opening 210. .. To remove the coating layer 214, dry etching with _{CF 4 gas using a normal photoresist as a mask is used.} Here, by using a double-sided mask aligner or the like, the position of the opening 211 corresponding to the liquid supply path 204 is accurately determined based on the position of the energy generating element 203 formed on one surface of the wafer 201.

Next, as shown in FIG. 6D, the wafer 201 is immersed in a silicon anisotropic etching solution typified by a strong alkaline solution to form a liquid supply path 204. The surface of the wafer 201 is protected as needed. Since the coating layer 214 is provided with the opening 210, the position serving as the boundary with the adjacent recording element substrate 2 is also etched, but since the opening 210 is narrower than the opening 211, the wafer 201 has a through hole at this position. A groove 212 having a V-shaped cross section is formed without being formed. Anisotropic etching of silicon utilizes the difference in solubility between crystal orientations with respect to a strongly alkaline etching solution, and etching is stopped on the <111> plane, which shows almost no solubility. Therefore, the shape of the liquid supply path 204 differs depending on the crystal plane orientation of the wafer 201 used. When the surface orientation of the wafer 201 is <100>, the inclination angle of the side surface of the liquid supply path 204 with respect to the surface of the wafer 201 is 54.7 °, and when the surface orientation is <110>, the inclination angle is 90. It becomes °. When forming the recess 215 having the shape shown in FIG. 4, a wafer 201 having a plane orientation of <100> is used.

Next, the step of forming the discharge port forming member 221 provided with the discharge port 207 on one surface of the wafer 201 is started. At the time of performing the silicon anisotropic etching, one surface of the wafer 201 including the position of the liquid supply path 204 is covered with the surface layer 202. A layer that can be dissolved and removed in a later step is formed on the surface layer 202 by spin coating or roll coating, and this layer is patterned to form a flow path pattern 205 as shown in FIG. 6 (e). To do. After that, as shown in FIG. 6 (f), the resin layer 206 is formed on the entire surface of the surface layer 202 including the flow path pattern 205. Since the resin layer 206 is a structural material of the liquid discharge head 10 as a discharge port forming member 221, it has high mechanical strength, heat resistance, adhesion to the wafer 201 and the surface layer 202, and resistance to the liquid for discharge. Properties such as not altering the quality of this liquid are required. As the resin for forming the resin layer 206, a resin that is polymerized and cured by applying light or heat energy and strongly adheres to the wafer 201 and the surface layer 202 is preferably used.

_{After curing the resin layer 206, plasma dry etching using CF 4} gas or the like is performed from the other surface of the wafer 201 to form a surface layer 202 that blocks the liquid supply path 204 as shown in FIG. 6 (g). Remove and penetrate the liquid supply path 204. The surface layer 202 at the position corresponding to the liquid supply path 204 may be removed after the discharge port 207 is formed in the next step, but it is preferably performed before the flow path pattern 205 is removed. Next, as shown in FIG. 6H, the discharge port 207 is formed in the resin layer 206, and the resin layer 206 in the boundary region with the adjacent recording element substrate 2 is removed. When the resin layer 206 made of a photosensitive material is used for forming the discharge port 207 and removing the resin layer 206 in the boundary region, patterning by a photolithography technique may be used. By forming the discharge port 207 and removing the resin layer 206 in the boundary region, the discharge port forming member 221 is completed. The connection terminal 213 is formed on one surface of the wafer 201 so as to be exposed when the resin layer 206 in the boundary region is removed. By immersing the wafer 201 in an appropriate solvent as shown in FIG. 6 (i), the flow path pattern 205 remaining in the discharge port forming member 221 is dissolved and removed.

Through the above steps, the wafer 201 in which a plurality of recording element substrates 2 are connected is obtained. In the wafer 201, the discharge port forming member 221 is provided separately for each recording element substrate 2. Therefore, next, the wafer 201 is cut and separated into individual recording element substrates 2. FIG. 7 is a diagram illustrating separation into individual recording element substrates 2. First, as shown in FIGS. 7A and 7B, the other surface side of the wafer 201 is attached to the dicing tape 401 so that the wafer 201 does not fall apart during cutting. The dicing tape 401 is generally one in which an adhesive layer made of an acrylic material having adhesiveness is formed on a polypropylene base material, and the wafer 201 is held and fixed via the adhesive layer made of an acrylic material. Will be done. Reference numeral 208 indicates a cutting line when cutting the wafer 201.

Subsequently, as shown in FIG. 7 (c), the wafer 201 fixed to the dicing tape 401 is moved along the cutting line while rotating the dicing blade 402 having a thickness of 50 μm to 100 μm of the dicing device. As a result, the individual recording element substrates 2 are separated from the wafer 201. At this time, the position of the cutting center of the dicing blade 402 is shifted from the center of the groove 212 having a V-shaped cross section formed on the wafer 201, and cutting is performed so that the apex of the groove 212 is left uncut. The cross-sectional shape of the wafer 201 after cutting is shown in FIG. 7 (d). The recording element substrate 2 obtained by cutting in this way has a recess 215 formed on the side surface thereof, and the side surface of the recording element substrate 2 and the ceiling surface 218 of the recess 215 are convex at the position of the edge 217 of the recess 215. The angle formed by sandwiching the portion 216 is less than 90 °. By using a silicon substrate having a surface orientation of <100> as the wafer 201, the angle formed by the side surface of the recording element substrate 2 and the ceiling surface 218 of the recess 215 is 54.7 °. Finally, the individual recording element substrate 2 is picked up from the dicing tape 401 attached to the wafer 201 before dicing. According to the manufacturing method shown in FIGS. 6 and 7, the groove 212 can be formed at the same time in the manufacturing process of the liquid supply path 204. Therefore, the process is different from the conventional manufacturing method of the recording element substrate shown in Patent Document 1 and the like. The liquid discharge head 10 based on the present invention can be manufactured without addition.

In the manufacturing process of the recording element substrate 2 described above, the wafer 201 is anisotropically etched to form the discharge port forming member 221 and then the surface layer 202 which is a stop layer at the position of the liquid supply path 204. Is being removed. However, the manufacturing process is not limited to this, and the wafer 201 may be anisotropically etched after the discharge port forming member 221 is formed, and then the surface layer 202 may be removed. That is, the wafer 201 may be anisotropically etched after the coating layer 214, which is a mask layer, is formed on the other surface of the wafer 201, and then the discharge port forming member 221 is formed. However, in this case, since the discharge port forming member 221 or the like often does not have resistance to the etching solution for anisotropic etching, one surface of the wafer 201 on which the discharge port forming member 221 is formed is removed from the etching solution. It is necessary to protect it appropriately.

Next, the position of the edge 217 of the recess 215 on the recording element substrate 2 in the present embodiment will be described. FIG. 8 is a diagram illustrating the position of the edge 217 with respect to the thickness direction of the recording element substrate 2. FIG. 8A is a cross-sectional view of a main part of the liquid discharge head 10 including the recess 215, but the edge 217 is located at a position farther from the base plate 1 as compared with the one shown in FIG. .. FIG. 8B is an explanatory diagram for explaining the position of the edge 217. As shown in FIG. 8B, where L is the thickness of the recording element substrate 2 and a is the distance from the surface of the recording element substrate 2 far from the base plate 1 to the edge 217, a / L is 1. It is preferably less than / 2. In other words, the edge 217 is located closer to the surface of the recording element substrate 2 on which the connection terminal 213 is provided than half the thickness of the recording element substrate 2 in the thickness direction of the recording element substrate 2. Is preferable. The recess 215 having such a shape can be formed by changing the shape of the coating layer 214 used as a mask when performing anisotropic etching of the wafer 201 and the cutting position by the dicing blade 402 during dicing.

The coating of the sealing material 5 when the recording element substrate 2 in which the recess 215 is formed so that the a / L is less than 1/2 as shown in FIG. 8B is used will be described. In such a recording element substrate 2, the liquid encapsulant 5 flows downward through the gap between the leads 301, but the encapsulant 5 is recessed as compared with the recording element substrate 2 shown in FIG. It reaches the edge 217 of 215 early and forms a meniscus early at that position. Therefore, when the recording element substrate 2 shown in FIG. 8 is used, the coating shape required for the electrical connection portion can be achieved early by the sealing material 5 by using a smaller amount of the sealing material 5. Therefore, it becomes possible to provide the liquid discharge head 10 having high electrical reliability.

In the recording element substrate 2 described above, the recess 215 is formed by anisotropic etching of silicon and dicing of the wafer 201, but the recess 215 can also be formed by general machining. When general machining is used, it is not necessary to form a groove 212 having a V-shaped cross section in the wafer 201. Therefore, at all stages of mechanical machining for forming the recess 215, for example, Patent Document 1 is described. The manufacturing method of the recording element substrate 2 described above can be used. The mechanical processing for forming the concave portion 215 is performed on the recording element substrate 2 in a state where the concave portion is not formed on the side surface after being cut out from the wafer 201 by the dicer device. Specifically, as shown in FIG. 9, the shape of a processing jig such as a beveling wheel generally used for processing the outer peripheral portion of a silicon wafer is changed, and the side surface of the recording element substrate 2 cut out is formed. Perform processing.

In the one shown in FIG. 9A, a machining tool 404 whose tip is machined into a cone shape is used, and the recess 215 is formed by rotating the machining tool 404 while applying it perpendicularly to the surface of the recording element substrate 2. Is forming. As shown in the figure, at the position of the end portion of the recording element substrate 2, the portion remaining after cutting by the machining tool 404 is the convex portion 216. In the one shown in FIG. 9B, a machining tool 404 whose tip is machined into a cone shape is used, and the recess 215 is rotated by applying the machining tool 404 to the surface of the recording element substrate 2 from an oblique direction. Is forming. In the one shown in FIG. 9C, an elongated columnar machining tool 404 is used, and the recess 215 is formed by rotating the machining tool 404 while applying it to the surface of the recording element substrate 2 from an oblique direction. ing. In the one shown in FIG. 9D, a machining tool 404 having an elongated columnar shape and a concave tip is used, and the machining tool 404 is rotated while being applied to the surface of the recording element substrate 2 from an oblique direction. As a result, the recess 215 is formed. As described above, in the present invention, the recess 215 having a desired shape can be formed only by changing the shape of the cutting tool in the machining tool or by changing the cutting angle using a general machining jig.

According to the above-described embodiment, when the electrical connection portion is sealed by the sealing material 5, the desired coating amount including the root portion 302 of the lead 301 can be secured as a whole in the electrical wiring board 3, and the liquid is discharged. The electrical reliability of the head 10 is improved. Further, in the above-described embodiment, the encapsulant 5 can be collectively applied only from above, and the process and equipment cost can be reduced as compared with the case where the encapsulant 5 is applied from two directions, and the electrical reliability can be reduced. The liquid discharge head 10 can be manufactured at low cost while ensuring the above.

2 Recording element board 3 Electrical wiring board 5 Encapsulant 10 Liquid discharge head 13 Connection terminal 215 Recess 216 Convex 217 Edge 218 Ceiling surface 301 Lead

Claims (16)

In a recording element substrate including a discharge port for discharging a liquid and an energy generating element for imparting discharge energy to the liquid.
A connection terminal for inputting a signal for driving the energy generating element is provided on one surface of the recording element substrate.
A recess is formed on the side surface of the recording element substrate corresponding to the position where the connection terminal is formed.
The concave portion is formed on the side surface away from the one surface, and a convex portion is formed between the one surface and the concave portion.
At the edge of the concave portion on the side close to the one surface, the angle between the side surface and the connecting surface connected to the side surface of the surfaces constituting the concave portion is less than 90 °. A recording element substrate characterized by this. The recording element substrate according to claim 1, wherein the edge is located closer to one of the surfaces than half the thickness of the recording element substrate along the thickness direction of the recording element substrate. .. The recording element substrate according to claim 1 or 2, wherein the recording element substrate is made of a silicon semiconductor substrate having a crystal plane orientation of <100>. The energy generating element is formed on one of the surfaces.
The recording element substrate according to claim 3, further comprising a liquid supply path formed through the other surface of the recording element substrate and the one surface. The recording element substrate according to any one of claims 1 to 4, wherein the recess is provided so as to reach the other surface of the recording element substrate. In the liquid discharge head
The recording element substrate according to any one of claims 1 to 4,
An electrical wiring board that is electrically connected to the connection terminal and supplies the signal to the recording element substrate.
A liquid discharge head, wherein the electrical connection portion between the recording element substrate and the electrical wiring substrate is sealed with a sealing material. The lead extending from the electrical wiring board toward the connection terminal and connecting to the connection terminal, the connection terminal, and the root portion of the lead in the electrical wiring board are covered and protected by the sealing material. The liquid discharge head according to claim 6. The liquid discharge head according to claim 6 or 7, wherein the convex portion is covered with the sealing material from the one surface to the position of the edge on the side surface of the recording element substrate. The liquid discharge head according to any one of claims 6 to 8, wherein the volume resistivity of the sealing material is 1 × 10 ^{14 Ω · cm or more.} In the method for manufacturing a recording element substrate according to claim 3 or 4.
Using silicon semiconductor wafers of a size corresponding to the plurality of recording element substrates,
A groove having a V-shaped cross section is formed on the first surface of the wafer in a boundary region serving as a boundary between adjacent recording element substrates in the wafer.
By dicing at a position deviated from the apex of the groove in the boundary region, the individual recording element substrate is separated from the wafer and the recess is formed on the side surface of the recording element substrate. A method for manufacturing a recording element substrate. The method for manufacturing a recording element substrate according to claim 10, wherein anisotropic etching of silicon is used for forming the groove. The method for manufacturing a recording element substrate according to claim 11, wherein at the same time as forming the groove, a through hole for a liquid supply path penetrating the recording element substrate is formed in the wafer. In the method for manufacturing a liquid discharge head according to claim 6 or 7.
A connection process for electrically connecting the electrical wiring board and the recording element substrate, and
After the connection step, the liquid encapsulant is applied to the electrical connection portion in a direction of flowing from the position of the one surface to the position of the edge along the side surface of the recording element substrate. The coating process and
A method for manufacturing a liquid discharge head. The method for manufacturing a liquid discharge head according to claim 13, further comprising a step of curing the sealing material. 13. The coating step is characterized in that the encapsulant is applied at least until the encapsulant reaches the edge along the side surface and forms a meniscus at the position of the edge. 14. The method for manufacturing a liquid discharge head according to 14. The production of the liquid discharge head according to any one of claims 13 to 15, wherein the liquid encapsulant has a viscosity of 70 Pa · s or less and a thixo ratio of 1.5 or less. Method.

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