JP2019049439A - Method of manufacturing measuring device - Google Patents

Abstract

[PROBLEMS] To manufacture a measuring device capable of simplifying the bonding operation of a sensor chip, making the thickness of the adhesive to the sensor chip uniform, and preventing damage to the sensor chip due to the non-uniform thickness of the adhesive. Provide a method. A method for manufacturing a measuring device for fixing sensor chips (12, 13) to an outer surface of a pipe (11) using an adhesive (51), wherein a first recess (41) is processed into the pipe (11), and the pipe (11), the sensor chip (12), The second recess 42 having a depth dimension that is the same as the preset adhesive film thickness between the sensor chip 12 and the width dimension of the sensor chips 12, 13 is defined as the first bottom surface of the first recess 41. 41a, the adhesive 51 is supplied into the second recess 42, the surface of the adhesive 51 filled in the second recess 42 is leveled so as to be flush with the first bottom surface 41a, and the sensor chip 12 , 13 is brought into contact with only the surface of the adhesive 51 filled in the second recess 42, and the adhesive 51 in contact with the sensor chips 12, 13 is cured. [Selection] Figure 7

Description

  The present invention relates to a method of manufacturing a measuring device provided with a sensor chip for measuring the flow rate of fluid flowing in piping.

  Conventionally, various types of measuring devices have been provided as measuring devices for measuring the flow rates of various fluids. Among them, the thermal type is beginning to be widely used because it is relatively easy to achieve cost reduction and power saving.

  In a thermal measurement device, a sensor chip (flow sensor) manufactured using semiconductor manufacturing process technology is used as a flow rate measuring means, and the principle that heater heat taken away by fluid changes depending on the flow rate There is one using. And as such a thermal type measuring device, it is indicated by patent documents 1-3, for example.

Japanese Patent Publication No. 2003-532099 JP, 2017-26428, A JP, 2017-26429, A

  Here, in the above-mentioned conventional measuring device, by fixing the sensor chip to the outer surface of the pipe, the flow rate of the fluid flowing in the pipe can be measured by the sensor chip. At this time, the sensor chip is attached to the outer surface of the pipe using an adhesive, and the adhesive is completely fixed by curing.

  For this reason, when the adhesive is cured in a state where the mounting surface (adhesive surface) of the sensor chip is in partial contact with the adhesive, a local load is applied to the mounting surface, and the sensor chip is There is a risk of damage. In particular, in the case where the mounting surface of the sensor chip is in the form of a thin film, the above-mentioned problems become significant.

  On the other hand, when applying an adhesive so that the thickness may become uniform, it is possible to use a masking tape. However, in the affixing operation, regardless of the tape length and the tape width, it is easy to be complicated, wrinkles are generated in the affixing masking tape, and it is difficult to accurately define the adhesive application region. Become.

  In addition, the thickness of the masking tape is limited, so there is a possibility that the thickness of the applied adhesive can not be made the desired thickness. For this reason, in the case of strict control of the adhesive thickness on the sensor chip, the use of the masking tape seems to be disqualified.

  Accordingly, the present invention solves the above-mentioned problems, and while simplifying the bonding operation of the sensor chip, the thickness of the adhesive to the sensor chip is made uniform, and the sensor chip is caused by the uneven thickness of the adhesive. It is an object of the present invention to provide a method of manufacturing a measuring device capable of preventing the damage of

  A method of manufacturing a measuring device according to the present invention is a method of manufacturing a measuring device in which a sensor is fixed to the outer surface of a tubular member using an adhesive, and a flat surface recessed from the outer surface is processed into a tubular member. And processing a recess having a depth dimension equal to a preset adhesion film thickness between the tubular member and the sensor and a width dimension wider than the width dimension of the sensor into a flat surface, and The adhesive was supplied, the surface of the adhesive filled in the recess was leveled so as to be flush with the flat surface, and the sensor was brought into contact with only the surface of the adhesive filled in the recess, and the sensor was in contact It cures the adhesive.

  According to the present invention, it is possible to simplify the bonding operation of the sensor chip, make the thickness of the adhesive with respect to the sensor chip uniform, and prevent the sensor chip from being damaged due to the uneven thickness of the adhesive.

It is a top view of the measuring device where the manufacturing method concerning Embodiment 1 of the present invention is applied. It is II-II arrow sectional drawing of FIG. It is a perspective view of a temperature sensor chip. It is IV-IV arrow sectional drawing of FIG. It is a perspective view of a heater chip. It is the VI-VI arrow sectional drawing of FIG. It is the figure which showed the procedure of the manufacturing method which concerns on Embodiment 1 of this invention. FIG. 7A is a view showing a process of processing a first recess and a second recess in a pipe. FIG. 7B is a view showing a step of supplying an adhesive into the second recess. FIG. 7C is a view showing a step of leveling the surface of the adhesive filled in the second recess. FIG. 7D is a view showing a process of adhering a sensor chip to the surface of a leveled adhesive and curing the adhesive.

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

Embodiment 1
As shown in FIG. 1, the measuring apparatus (for example, a thermal flow rate measuring apparatus) according to the present embodiment includes a pipe 11, a pair of sensor chips 12 and 13, a wire 14, a substrate 15 and the like. . The sensor chips 12 and 13 and the substrate 15 are adhesively fixed to the pipe 11 and electrically connected by the conductive wire 14.

  The pipe 11 is a circular tubular member that allows fluid (gas or liquid) to pass through its internal flow path. The material of the pipe 11 is, for example, glass, ceramic, plastic, stainless steel, or the like. In addition, the direction of the arrow described in FIG. 1 has shown the flow direction of the fluid.

  The pair of sensor chips 12 and 13 in the fluid flow direction is a thermal type flow sensor that measures the flow rate of the fluid flowing in the pipe 11, and is manufactured using semiconductor manufacturing process technology. Such thermal sensor chips 12 and 13 to be semiconductor chips are sequentially provided on the outer surface of the pipe 11 along the axial direction (fluid flow direction) of the pipe 11.

  At this time, the sensor chip 12 disposed on the upstream side in the fluid flow direction is a temperature sensor chip having a temperature measurement function that measures the temperature of the fluid flowing in the pipe 11. On the other hand, the sensor chip 13 disposed on the downstream side in the fluid flow direction has a temperature measurement function to measure the temperature of the fluid flowing in the pipe 11 and heat generation (heat supply to supply a predetermined amount of heat to the fluid flowing in the pipe 11) ) It is a heater chip having a function. Hereinafter, the sensor chip 12 will be referred to as a temperature sensor chip 12, and the sensor chip 13 will be referred to as a heater chip 13, and the present embodiment will be described.

  As shown in FIGS. 2 and 3, the temperature sensor chip 12 includes, for example, a base substrate 21, an insulating film 22, a temperature measuring unit 23, an electrical connection unit 24 and the like, and a structure separated from the substrate 15. It has become.

  Specifically, the surface of the base substrate 21 is covered with the insulating film 22. In addition, a temperature measuring unit 23 is provided at the center of the surface of the insulating film 22, and the electric connection unit 24 is electrically connected to the temperature measuring unit 23. The temperature measuring unit 23 measures the temperature of the fluid flowing in the pipe 11. The electrical connection portion 24 extends from the temperature measuring portion 23 toward the outside of the chip on the surface of the insulating film 22. The electrical connection portion 24 is electrically connected to the lead of the substrate 15 through the wire 14. Thus, the fluid temperature measurement signal output from the temperature measuring unit 23 is relayed from the electrical connection unit 24 to the substrate 15 via the wire 14, and then the flow rate measuring unit (not shown) from the substrate 15 outside the substrate Sent to

  On the other hand, as shown in FIGS. 4 and 5, the heater chip 13 includes, for example, a base substrate 31, an insulating film 32, a temperature measuring unit 33, and an electrical connection unit 34, and is separated from the substrate 15. It has a structure.

  Specifically, a cavity 31a is formed in the central portion of the base substrate 31 so as to penetrate the base substrate 31 in the thickness direction. On the other hand, the surface of the base substrate 31 is covered with an insulating film 32, and a thin film diaphragm 32a having heat insulation is provided at the center of the insulating film 32. That is, the diaphragm 32a covers the entire upper end opening of the cavity 31a from the outside.

  In addition, a temperature measuring unit 33 is provided at the center of the surface of the diaphragm 32 a, and the electric connection unit 34 is electrically connected to the temperature measuring unit 33. The temperature measuring unit 33 measures the temperature of the fluid flowing in the pipe 11 and heats the fluid flowing in the pipe 11 to a constant temperature. The electrical connection portion 34 extends from the temperature measuring portion 33 to the outside of the chip on the surface of the insulating film 32. The electrical connection portion 34 is electrically connected to the lead of the substrate 15 through the wire 14.

  As a result, the fluid temperature measurement signal output from the temperature measuring unit 33 is relayed to the substrate 15 from the electrical connection unit 34 via the wire 14, and then transmitted from the substrate 15 to the flow rate measuring unit outside the substrate. . On the other hand, the power for heating the fluid is relayed to the substrate 15 from a power supply device (not shown) outside the substrate, and is then sent to the temperature measurement unit 33 via the wire 14.

  Furthermore, as shown in FIG. 1 and FIG. 6, a rectangular tip protrusion 15 a is formed at the tip of the substrate 15. The tip end projecting portion 15 a protrudes in the radial direction of the pipe 11 from the center of the tip end of the substrate 15 toward the outside of the substrate. The chips 12 and 13 separated from the substrate 15 are respectively disposed on the left and right sides (both sides in the axial direction of the pipe 11) of the distal end protruding portion 15a.

  Thus, the tip end projecting portion 15 a is installed in the first recess 41 of the pipe 11 together with the chips 12 and 13 and is fixed to the first bottom surface 41 a of the first recess 41 by the adhesive 52. That is, the substrate 15 is adhered and fixed to the pipe 11 only at the tip projecting portion 15 a.

  Therefore, when the flow rate of the fluid flowing in the pipe 11 is measured, the temperature sensor chip 12 measures the temperature of the fluid flowing in the pipe 11. On the other hand, the heater chip 13 supplies heat to the fluid so that the temperature of the fluid flowing in the pipe 11 is higher than the temperature (measured temperature) of the fluid measured by the temperature sensor chip 12 Do.

  That is, the heat generation temperature set in the heater chip 13 changes in accordance with the measurement temperature measured by the temperature sensor chip 12, and the heater chip 13 corresponds to the temperature difference between the measurement temperature and the heat generation temperature. Heat is supplied to the fluid.

  It is conventionally known that the amount of electric power when the heater chip 13 supplies the heat quantity to the fluid has a correlation with the flow rate of the fluid flowing in the piping 11. Thus, the flow rate measuring unit can calculate (measure) the flow rate of the fluid flowing in the pipe 11 based on the amount of power.

  Here, the temperature sensor chip 12 and the heater chip 13 are fixed to the outer surface of the pipe 11 by an adhesive 51. Hereinafter, such a chip bonding structure will be described in detail.

  As shown in FIG. 1 to FIG. 6 and FIG. 7A, a first recess 41 is formed in the middle of the pipe 11 in the axial direction. The first recess 41 is recessed inward in the radial direction of the pipe 11, and the first bottom surface 41 a is a flat surface extending in the axial direction of the pipe 11.

  Furthermore, in the first bottom surface 41 a of the first recess 41, two second recesses 42 are formed corresponding to the chips 12 and 13. The second recess 42 is recessed inward in the radial direction of the pipe 11 and is a recess for accommodating the adhesive 51 used when bonding and fixing the chips 12 and 13. The second bottom surface 42 a of the second recess 42 is a flat surface extending in the axial direction of the pipe 11 and is parallel to the first bottom surface 41 a.

  At this time, the width dimension of the second recess 42 (the length dimension in the axial direction of the pipe 11), that is, the width dimension of the second bottom surface 42a is wider than the width dimensions of the chips 12 and 13. Further, the length dimension of the second recess 42 (the length dimension of the pipe 11 in the radial direction), that is, the length dimension of the second bottom surface 42 a is shorter than the dimension in the longitudinal direction of the chips 12 and 13.

  In the present embodiment, when bonding and fixing the chips 12 and 13, after the surface of the adhesive 51 filled in the second recess 42 is leveled to be flush with the first bottom surface 41a, the leveling is performed. The adhesive surfaces (surfaces of the insulating films 22 and 32) of the chips 12 and 13 are placed on and brought into contact with the surface of the adhesive 51 only. That is, with the adhesive surfaces of the chips 12 and 13, the longitudinal ends of the chips 12 and 13 protrude outward from the surface of the adhesive 51 in the longitudinal direction, and the adhesive surfaces of the chips 51 and 52 do not contact the first bottom surface 41 a. Bonded to the surface.

  As a result, the longitudinal ends of the bonding surfaces of the chips 12 and 13 are not in contact with the surface of the adhesive 51, and the electrical connection portion is a wire bonding position set at one longitudinal end of the bonding surfaces. 24, 34 are open. Therefore, even when the chips 12 and 13 are fixed to the pipe 11 with the adhesive 51, the bonding position of the wire 14 in the chips 12 and 13 can be secured. At the same time, interference between the wire 14 bonded to the chips 12 and 13 and the pipe 11 to which the chips 12 and 13 are fixed can be prevented.

  In addition, since it is not necessary to set the bonding position of the wire 14 by providing the electrical connection portions 24 and 34 at the other end in the longitudinal direction in the bonding surface of the chips 12 and 13, the other end in the longitudinal direction is The adhesive 51 may be adhered to the surface of the adhesive 51 without projecting the adhesive 51 outward in the longitudinal direction.

  Further, the depth dimension of the second recess 42, that is, the radial distance of the pipe 11 between the first bottom surface 41a and the second bottom surface 42a, is the thickness of the adhesive film when the chips 12 and 13 are adhered and fixed to the pipe 11. The dimensions of This adhesion film thickness is a predetermined standard that the chips 12 and 13 bonded to the adhesive 51 do not break with the curing of the adhesive 51 and the chips 12 and 13 do not peel off from the adhesive 51. It is more than the adhesion film thickness.

  That is, the second recess 42 is processed so that its depth dimension is the same as the adhesion film thickness set in advance, and the second bottom surface 42a is parallel to the first bottom surface 41a. Therefore, by filling the adhesive 51 in the second recess 42 processed in this manner, the thickness of the adhesive 51 becomes uniform in the same dimension as the adhesive film thickness.

  The adhesive 51 is a silicone-based thermally conductive adhesive containing a thermally conductive filler for the purpose of improving the thermal conductivity between the pipe 11 and the chips 12 and 13. Thus, the adhesive 51 can transfer the heat of the fluid flowing in the pipe 11 to the temperature sensor chip 12, and transfer the heat generated by the heater chip 13 to the fluid flowing in the pipe 11.

  Next, a method for bonding and fixing the chips 12 and 13 to the pipe 11 will be described in detail with reference to FIGS. 7A to 7D.

  First, as shown to FIG. 7A, the 1st recessed part 41 and the 2nd recessed part 42 are processed in the middle part of the axial direction of the piping 11. As shown in FIG. At this time, the first concave portion 41 and the second concave portion 42 are processed such that the first bottom surface 41 a and the second bottom surface 42 a are parallel to each other. Further, in the second recess 42, the depth dimension is processed to be the same as the adhesion film thickness set in advance, and the width dimension is processed to be wider than the width dimension of the chips 12 and 13. Ru.

  Next, as shown in FIG. 7B, the adhesive 51 is dropped and supplied into the second recess 42. In FIG. 7B, the case where the adhesive 51 is supplied to only one of the two second recesses 42 is illustrated.

  Then, as shown in FIG. 7C, the adhesive 51 supplied into the second recess 42 is filled in the second recess 42 using a spatula-shaped tool called a squeegee. At this time, the surface of the adhesive 51 filled in the second recess 42 is leveled so as to be flush with the first bottom surface 41 a.

  For example, the surface of the adhesive 51 filled in the second recess 42 by sliding the spatula-like tool over the first bottom surface 41 a so as to straddle the second recess 42 supplied with the adhesive 51. And the first bottom surface 41a can be made flush. That is, on the surface of the adhesive 51 filled in the second recess 42, the unevenness is eliminated, and the surface becomes flat.

  Then, as shown in FIG. 7D, the surface of the insulating film 22 in the temperature sensor chip 12 and the surface of the insulating film 32 in the heater chip 13 are bonded only to the surface of the adhesive 51 filled in the second recess 42. .

  Subsequently, in a state where the chips 12 and 13 are adhered to the pipe 11 by the adhesive 51, the adhesive 51 is heated to a predetermined temperature or higher to be cured. As a result, the chips 12 and 13 are adhesively fixed to the pipe 11 with a uniform adhesive film thickness.

  As mentioned above, according to the manufacturing method of the measuring apparatus which concerns on this invention, the width dimension wider than the uniform depth dimension and the width dimension of chip | tips 12 and 13 in the 1st bottom face 41a of the 1st recessed part 41 processed into piping 11 After processing the second recess 42 having the second surface 42, the surface of the adhesive 51 filled in the second recess 42 is leveled so as to be flush with the first bottom surface 41a, and the chip 12 is formed only on the surface of the adhesive 51. , 13 glue. As a result, the application region of the adhesive 51 can be defined with high precision without using a masking tape or the like, so that the bonding operation of the chips 12 and 13 can be simplified.

  Further, since the thickness of the adhesive 51 can be made uniform, it is possible to prevent the breakage of the chips 12 and 13 generated when the adhesive 51 which becomes uneven in thickness is cured. In particular, the diaphragm 32a of the heater chip 13 is adhered and fixed to the surface of the adhesive 51 filled in the second recess 42 regardless of the thin film shape, but the surface of the adhesive 51 is Since the surface is flat without unevenness, no local load is applied to the diaphragm 32a even if the adhesive 51 is cured. Thus, damage to the diaphragm 32a due to the uneven thickness of the adhesive 51 can be prevented.

  In the present invention, within the scope of the invention, modification of any component of the embodiment or omission of any component of the embodiment is possible. For example, in the above-described embodiment, as the flow sensor for measuring the flow rate of the fluid flowing in the pipe, the configuration in which the temperature sensor and the heater are separate flow sensors is mentioned, but in place of such a configuration It is also possible to adopt a configuration in which the temperature sensor and the heater are incorporated into one flow sensor.

11 Piping 12 Temperature sensor chip 13 Heater chip 14 Wire 15 Substrate 15a Tip projecting part 21, 31 Base substrate 22, 32 Insulation film 23, 33 Temperature measuring unit 24, 34 Electrical connection part 31a Cavity 32a Diaphragm 41 First concave part 41a 1st Bottom surface 42 second recess 42 a second bottom surface 51 adhesive 52 adhesive

Claims (2)

What is claimed is: 1. A method of manufacturing a measuring device, comprising: fixing a sensor to the outer surface of a tubular member using an adhesive;
Processing the flat surface recessed from the outer surface into the tubular member;
A recess having a depth dimension equal to a preset adhesion film thickness between the tubular member and the sensor and a width dimension wider than the width dimension of the sensor is processed on the flat surface;
Supplying the adhesive into the recess;
Leveling the surface of the adhesive filled in the recess to be flush with the flat surface,
Bringing the sensor into contact only with the surface of the adhesive filled in the recess;
A method of manufacturing a measuring device, comprising curing the adhesive in contact with the sensor. The method according to claim 1, wherein the flat surface and the bottom surface of the recess are processed to be parallel to each other.

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