JP6537242B2 - Method of manufacturing liquid discharge head - Google Patents

Description

  The present invention relates to a method of manufacturing a liquid discharge head.

  As a liquid discharge head used for an ink jet printer or the like, there is a liquid discharge head having a chip having an energy generating element and a pad, a support member for supporting the chip, and an electric wiring substrate for transmitting an electrical signal to the chip (Patent Document 1, 2). When manufacturing such a liquid discharge head, first, the chip is bonded and fixed to the support member, and then the electric wiring substrate is bonded and fixed to the support member. Then, the electrical wiring substrate and the pads of the chip are electrically connected by the electrical connection member. Finally, the electrical connection member is sealed with a sealing material. As described above, the liquid discharge head is manufactured.

  A portion of the method of manufacturing such a liquid discharge head, particularly regarding the connection of the electric connection member, will be described in more detail by taking the case where the electric connection member is an inner lead as an example. The connection between the chip and the inner lead is made for each lead (one pad) by aligning the position of the electrical connection pad disposed on the chip with the inner lead provided on the electrical wiring substrate. Specifically, heat is applied to the chip by heating the support member, and in this state, an appropriate load is applied on the chip pad with a single point capillary to suppress the inner lead. Then ultrasonic vibration is applied to bond the inner lead and the pad. As the inner lead, generally used is a copper foil of 20 to 30 μm thinly plated with nickel or gold.

  In addition, the inner lead is required to be insulated and protected so as not to easily touch the ink. The insulation protection is performed by applying a curable liquid sealant (epoxy resin or the like) so as to include the inner lead, and curing the applied sealant in a heat curing furnace.

Japanese Patent Laid-Open No. 2002-19120 Japanese Patent Application Publication No. 2007-15263

  According to the study of the present inventors, it was found that there is the following problem when curing the sealing material for sealing the electrical connection member.

  In the heating process for curing the sealing material, the chip, the electric wiring substrate, and the support member constituting the liquid discharge head cause thermal expansion in accordance with their linear expansion coefficients. Moreover, it shrink | contracts after a heating process. Since the distance between the chip and the electric wiring board changes due to the expansion and contraction of each member due to the heat, stress is applied to the electric connection member connecting the chip and the electric wiring board. In particular, when the distance between the chip and the electrical wiring substrate is increased, a force in the breaking direction may be applied to the electrical connection member, and the electrical connection member may be peeled off from the pad. When the electrical connection member peels off from the pad, the electrical connection member can not transmit the electrical signal to the chip, so the function of the liquid discharge head is largely degraded. And especially when a support member is formed with resin, the influence by the thermal expansion and contraction of a support member is large.

  Therefore, an object of the present invention is to provide a method of manufacturing a liquid discharge head in which the distance between the chip and the electrical wiring substrate is changed by the heating process for curing the sealing material and the electrical connection member is prevented from being formed by the pad. The purpose is to

The above problems are solved by the present invention described below. That is, according to the present invention, a chip having a discharge port surface for discharging a liquid, an energy generating element for generating energy for discharging a liquid, and a pad electrically connected to the energy generating element; A sealing member for sealing the electric connection member, the electric wiring substrate having the formed support member, the electric connection member provided on the support member and electrically connected to the energy generating element through the pad; And the side opposite to the side on which the tip of the support member is provided has a counterbore shape, and the support member has a counterbore shape along the direction in which the electric connection member extends. In the cross section of the liquid discharge head passing through the pad and the electrical connection member, a direction in which the thin portion of the counterbore of the support member and the electrical connection member extend To overlap Oite, a connecting step of connecting the electrical connection member to the pad, and a sealing step of sealing the electrical connection member by the sealing material, a curing step of curing by heating the sealing material And, in the connecting step, heating means is provided at a portion where the thickness of the support member is thin, the support member is heated by the heating means, and the support member is expanded, the electric connection member is A method of manufacturing a liquid discharge head, characterized in that the pad is connected to the pad.

  According to the present invention, there is provided a method of manufacturing a liquid discharge head, in which the distance between the chip and the electric wiring substrate is changed by the heating step for curing the sealing material, and the electrical connection member is prevented from peeling off the pad. be able to.

FIG. 2 shows a liquid discharge head. FIG. 7 is a view showing the method of manufacturing the liquid discharge head. FIG. 6 is a view showing how the support member of the liquid discharge head is heated.

  FIG. 1A shows a perspective view of the liquid discharge head of the present invention. The liquid discharge head includes a chip 1, an electric wiring substrate 2, a support member 3 for supporting the chip 1, and a sealing material 4. A view of the liquid discharge head as viewed from above is shown in FIG. Further, FIG. 1C is a cross-sectional view of the liquid discharge head at A-A ′ of FIG. FIGS. 1B and 1C are enlarged views of the area where the sealing material 4 of the liquid discharge head is formed. The chip 1 is formed with a discharge port 8 for discharging a liquid. Further, below the discharge port, there is an energy generating element (not shown) that generates energy for discharging the liquid. The energy generating element can be electrically connected to the pad 7 by wiring or the like. The chip 1 has an energy generating element and a pad. In FIG. 1, the electrical connection member 6 extends from the electrical wiring board 2, and the electrical wiring board 2 is an inner lead. The electrical connection member 6 is in contact (contact) with the pad 7. Thus, the energy generating element is electrically connected to the electrical wiring board 2 through the pad 7. The electrical connection member 6 is a flying lead, and is sealed between the electrical wiring substrate 2 and the pad 7 by the sealing material 4. A region under the sealing material 4 between the chip 1 and the support member 3 is sealed by a chip horizontal sealing material 5. The electrical connection member 6 is formed on the support member. Electricity is sent from the electrical wiring board 2 to the energy generating element of the chip 1 through the electrical connection member 6. The energy generating element is formed of a heat generating resistor or a piezoelectric body, and the liquid in the flow path is discharged from the discharge port 8 by driving the energy generating element. The discharged liquid lands on a recording medium such as paper, and characters and images are recorded on the recording medium.

  Next, a method of manufacturing a liquid discharge head according to the present invention will be described.

  First, as shown in FIG. 2A, the chip 1 and the support member 3 are prepared. The chip 1 has a substrate formed of silicon and, in some cases, a flow path member formed of a resin on the substrate. Here, only the substrate is illustrated. The support member 3 is formed of resin. Examples of the resin forming the support member 3 include modified polyphenylene ether. The chip 1 is formed on the support member 3 and is fixed on the support member by an adhesive or the like.

  Next, as shown in FIG. 2 (b), a connecting step is performed to connect the electrical connection member 6 to the pad of the chip 1. Here, an example is shown in which an inner lead is used as the electrical connection member 6 and the single point bonding method which is one of the TAB mounting techniques is performed. Single point bonding is a method in which the pad 7 and the electrical connection member 6 to be electrically connected are joined together using heat and ultrasonic waves. The electrical connection member 6 may be, for example, a wire of wire bonding. Here, in the present invention, when connecting the electrical connection member 6 to the pad, the support member is heated to expand the support member. When the support member 3 expands, the distance between the chip 1 and the electrical wiring board 2 increases. With the support member expanded in this manner, the electrical connection member 6 is connected to the pad. The heating of the support member may be performed while connecting the electrical connection member 6 to the pad, or the support member 3 is heated first, the heating is stopped, and the support member 3 is expanded by the residual heat. In the stored state, the electrical connection member 6 may be connected to the pad. In the present invention, at least when the electrical connection member 6 is connected to the pad, the support member 3 may be expanded.

  After connecting the pads no heating takes place. Thus, the temperature of the support member 3 is reduced. When the temperature of the support member 3 decreases, the support member 3 contracts as shown in FIG. 2 (c). Therefore, the distance between the chip 1 and the electrical wiring board 2 becomes narrow. At this time, the electrical connection member 6 has slack more than the state of FIG. 2 (b). For example, in FIG. 2 (b), the electrical connection member 6 has a linear shape, whereas in FIG. 2 (c), the central portion has a curved slack. This is because both sides of the electrical connection member 6 are fixed by the electrical wiring substrate and the pad, and the support member contracts in that state.

  Next, a sealing step of sealing the electrical connection member 6 with the sealing material 4 is performed. The sealing step is performed by applying the sealing material 4 to the electrical connection member 6 using a needle or the like. Examples of the sealing material 4 include a thermosetting sealing material.

  Subsequently, a curing step of heating and curing the sealing material 4 is performed. The supporting member 3 is also heated together with the sealing material 4 by the curing process. Thus, as shown in FIG. 2 (d), the support member 3 expands.

  Here, conventionally, the support member 3 hardly expands in the state of FIG. 2 (b). That is, since the electrical connection member 6 is connected to the pad in a state where the support member 3 is not expanded, the electrical connection member 6 has no slack. This tendency is particularly noticeable when the electrical connection member 6 is an inner lead. When the support member 3 expands in the curing step, the electrical connection member 6 having no slack may be pulled by the expansion of the support member 3 in the curing step, and may be separated from the pad.

  On the other hand, in the present invention, the support member 3 made of resin is expanded in the state of FIG. 2 (b), and the electrical connection member 6 is connected to the pad in that state. Even if it is expanded again after being contracted, the electrical connection member 6 has room for slack. As a result, even if the support member 3 expands in the curing step, the electrical connection member 6 can be prevented from peeling off from the pad.

  As described above, the liquid discharge head of the present invention is manufactured.

  In the present invention, the support member is heated when the support member is expanded in the connection step of the electrical connection member, but the heating temperature of the support member at that time is to the support member when the sealing material is heated and cured. It is preferable to make it higher than the heating temperature. With such a temperature relationship, the support member can be sufficiently expanded in advance, and the electrical connection member is less likely to be peeled off by heating when curing the sealing material.

  In the heating performed to expand the support member in the connection step of the electrical connection member, the heating temperature of the support member is preferably 100 ° C. or higher, and more preferably 120 ° C. or higher. By raising the heating temperature, the support member can be favorably expanded so that the electrical connection member is not easily peeled off in the curing step. Further, in the case where the electric connection member is also heated together with the support member, the connection (metal connection) between the electric connection member and the pad can be performed more firmly.

  The heating temperature of the support member to expand the support member in the connecting step is preferably 150 ° C. or less, more preferably 130 ° C. or less. If the heating temperature is too high, the pad may be damaged. Furthermore, the heating temperature of the heating performed to expand the support member in the connection step is preferably 15 ° C. or more higher than the temperature applied to the support member when heating and curing the sealing material, and is 25 ° C. or more It is more preferable to do. When the temperature is raised to a certain extent, the electrical connection member after the curing step tends to be slack. Therefore, the reliability (the difficulty in peeling off) of the electrical connection member as the liquid discharge head is improved. Also, even if it is higher, the difference is preferably 50 ° C. or less, more preferably 40 ° C. or less. If it is too high, the electrical connection member after the curing step may be too piled up and may protrude above the electrical wiring substrate. The upper side is the direction opposite to the side where the support member of the chip is located. The lower side is the side on which the chip support member is located. If a part of the electrical connection member protrudes above the electrical wiring substrate, it may interfere with the needle when applying the sealing material, or it may be difficult to achieve good sealing. In addition, metal fatigue may occur at a bent portion of the electrical connection member, and the electrical connection member may be broken starting from that portion. Therefore, after the curing step, the electrical connection member is preferably formed to be located below the electrical wiring board. In the case where the electrical connection member has a mountain shape, it is preferable that the top of the mountain shape is formed below the electrical wiring substrate. In addition, it is preferable that the electrical connection member be formed below the electrical wiring board similarly after the connection process.

  As a method of heating a support member, as shown, for example in FIG. 3, the method of heating the support member 3 by the heating means 9 from the downward direction is mentioned. Also, in order to suppress the warping (especially in the vertical direction) of the support member 3 due to thermal expansion, the support member 3 is provided with a counterbored shape 10 on the back surface side (the side opposite to the side on which the chip 1 is provided). It is preferable to use a thin structure. And it is preferable to arrange a heating means in the part which has a counterbore shape and the thickness of the supporting member 3 is thin. It is preferable to heat the support member 3 using this heating means.

  Hereinafter, the present invention will be more specifically described by way of examples.

Example 1
First, as shown in FIG. 2A, the chip 1 and the support member 3 were prepared. The chip 1 is formed of a substrate formed of silicon and a flow path member formed of an epoxy resin, and has an energy generating element. The energy generating element is formed of TaSiN, and is connected to a pad formed of gold and a wire of aluminum. The chip 1 is fixed on the support member 3 with an adhesive. The supporting member 3 was formed using a modified polyphenylene ether as a resin and containing 40% by mass of a filler. The linear expansion coefficient of the support member 3 was 70 ppm.

  Next, as shown in FIG. 2B, the electrical connection member 6 was connected to the pad of the chip 1. At this time, the support member 3 was heated to 125 ° C. The electrical connection member 6 used was a copper foil having a thickness of 25 μm and plated with nickel and gold. The support member 3 was heated at 125 ° C., and the electrical connection member 6 was connected to the pad by a single point bonding method. For heating the support member 3, a heating means as shown in FIG. 3 was used. The back surface of the support member 3 was formed into a counterbore shape, and heating was performed by the heating means from the portion where the thickness of the counterbore shape is reduced. In the bonded state, ultrasonic waves were applied for 0.3 msec.

  Next, the support member 3 was cooled to 25 ° C. and contracted as shown in FIG. Next, the region between the chip 1 and the support member 3 was sealed with a chip lateral sealing material (not shown) having a viscosity of 10 Pa · s having an epoxy resin. Subsequently, a sealing material having a viscosity of 200 Pa · s having a thermosetting epoxy resin was applied by a dispenser, and the electrical connection member 6 was sealed with the sealing material 4. The inner diameter of the dispensing needle was 1 mm, and the dispensing pressure was 0.3 MPa. Moreover, the distance from the electrical connection member 6 to the dispensing needle was 0.3 mm.

  Next, in order to cure the chip side sealing material and the sealing material 4, they were placed in a heat curing furnace. Then, heating was performed at 100 ° C., and the sealing material 4 was heated and cured to manufacture a liquid discharge head.

  The connection state between the electrical connection member and the pad of the manufactured liquid discharge head was observed with a microscope. As a result, the electrical connection member was well connected to the pad, and peeling was not confirmed.

Comparative Example 1
In Example 1, the support member 3 was heated at 125 ° C., but in Comparative Example 1, this heating was not performed. However, only the contact portion between the electrical connection member and the pad, not the support member 3, was heated at 125 ° C. A liquid discharge head was manufactured in the same manner as Example 1 except for the above.

  When the connection state between the electrical connection member of the manufactured liquid discharge head and the pad was observed with a microscope, it was confirmed that the electrical connection member was peeled off from the pad.

Claims (11)

A discharge port surface for discharging a liquid, an energy generating element for generating energy for discharging a liquid, a chip having a pad electrically connected to the energy generating element, and a support member for supporting the chip and formed of resin And an electrical wiring substrate provided on the support member and having an electrical connection member electrically connected to the energy generating element through the pad, and a sealing material for sealing the electrical connection member. A method of manufacturing a liquid discharge head, comprising
The side opposite to the side on which the tip of the support member is provided has a counterbore shape,
In the cross section of the liquid discharge head passing through the pad and the electrical connection member along the direction in which the electrical connection member extends, the portion of the support member having a thin counterbore thickness and the electrical connection member Connecting the electrical connection member to the pad so as to overlap in the extending direction ;
A sealing step of sealing the electrical connection member with the sealing material;
And curing the sealing material by heating and curing.
In the connection step, a heating means is provided at a portion where the thickness of the support member is thin, and the electric connection member is connected to the pad in a state where the support member is heated by the heating means to expand the support member. A method of manufacturing a liquid discharge head characterized by   The heating temperature of the support member at the time of heating the said support member and expanding the said support member is higher than the heating temperature which heats the said support member, when heating and hardening the said sealing material. Method of manufacturing liquid discharge head.   The method for manufacturing a liquid discharge head according to claim 1, wherein the electrical connection member is an inner lead.   The method for manufacturing a liquid discharge head according to any one of claims 1 to 3, wherein the heating unit is provided in a portion where the thickness of the support member is thin before the connection step to heat the support member.   The method for manufacturing a liquid discharge head according to any one of claims 1 to 4, wherein the heating temperature of the support member at the time of heating the support member to expand the support member is 100 ° C or more and 150 ° C or less. .   The method for manufacturing a liquid discharge head according to any one of claims 1 to 4, wherein the heating temperature of the support member when heating the support member to expand the support member is 100 ° C or more and 130 ° C or less. .   The heating temperature of the support member at the time of expanding the support member by heating the support member is higher by at least 15 ° C. than the heating temperature at which the support member is heated when the sealing material is heated and cured. 7. A method of manufacturing a liquid discharge head according to any one of items 1 to 6.   The heating temperature of the support member at the time of expanding the support member by heating the support member is higher than the heating temperature at which the support member is heated when the sealing material is heated and cured, and the difference is 50 The method for manufacturing a liquid discharge head according to any one of claims 1 to 7, wherein the temperature is not higher than ° C.   The heating temperature of the support member at the time of expanding the support member by heating the support member is higher than the heating temperature at which the support member is heated when the sealing material is heated and cured, and the difference is 40 The method for manufacturing a liquid discharge head according to any one of claims 1 to 7, wherein the temperature is not higher than ° C.   The method for manufacturing a liquid discharge head according to any one of claims 1 to 9, wherein after the connection step, the electric connection member is formed to be located below the electric wiring substrate.   The method for manufacturing a liquid discharge head according to any one of claims 1 to 10, wherein the electrical connection member is formed to be located below the electrical wiring substrate after the curing step.

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