JPH07108287B2 - Disposable blood pressure transducer and manufacturing method thereof - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a pressure transducer for medical use, and more particularly to a disposable clinical open blood pressure transducer.

[Conventional technology]

Conventionally, this type of disposable clinical open blood pressure transducer (hereinafter referred to as a disposable blood pressure transducer) has a semiconductor pressure sensor having a diaphragm bonded to a first surface of an insulating substrate and a temperature compensation circuit on the same surface. Is formed, and on the side of the second surface of the insulating substrate, a first channel communicating with the hole of the insulating substrate formed at a position facing the diaphragm and a second channel communicating with the first channel are formed. It has a structure in which a housing having a flow path is bonded.

On the other hand, in the conventional method for manufacturing such a disposable blood pressure transducer, a step of adhering a semiconductor pressure sensor to a first surface of an insulating substrate, a step of forming a temperature compensation circuit on the same surface of the insulating substrate, and a housing with the insulating substrate The step of adhering to the second surface of the insulating substrate, the step of filling the first flow path of the housing communicating with the hole of the insulating substrate with silicon gel, and the resistance of the temperature compensation circuit formed on the first surface of the insulating substrate. And a step of adjusting.

An example of the disposable blood pressure transducer described above and the manufacturing method thereof is well known in US Pat. No. 4,576,181.

[Problems to be Solved by the Invention]

The above-mentioned conventional disposable blood pressure transducer has a drawback that the size of the insulating substrate becomes large because the surface bonded to the semiconductor pressure sensor and the surface forming the temperature compensation circuit are the same surface. That is, although a 96% alumina substrate for pressure film printing is usually used as the insulating substrate, a resistance pattern or a resistance pattern that configures a temperature compensation circuit in a plane on the same surface as the surface on which the die of the semiconductor pressure sensor is mounted is used. Since the conductor pattern is formed by the thick film printing method, the size of the insulating substrate cannot be reduced. The above-mentioned disposable blood pressure transducer is often used by being fixed to the arm of a patient, and even if it is desired to reduce its size, in reality, it cannot be sufficiently dealt with.

Further, the temperature compensation circuit in the conventional disposable blood pressure transducer is usually formed by the thick film printing method as described above, and by adjusting the thick film printing resistance by the laser trimming method, the offset voltage or the offset voltage temperature of the disposable blood pressure transducer is adjusted. The characteristics are adjusted and the pressure sensitivity is calibrated. However, conventional disposable blood pressure transducers
Since the surface on which the die of the semiconductor pressure sensor is bonded and the surface on which the temperature compensation circuit is formed are the same surface, sublimates and gaseous pulverized substances of the resistor are not generated when laser-trimming the thick film printing resistor. However, there is a drawback in that the die of the semiconductor pressure sensor is easily contaminated, which causes a decrease in yield and a decrease in reliability. That is, the die of the semiconductor pressure sensor is normally covered with the chip cover, but the chip cover is not completely sealed because the die cover side of the die is exposed to the atmosphere. Therefore, it is not possible to prevent the above-mentioned intrusion of resistance trimming sublimate or gaseous pulverized matter.
Furthermore, the surface of the die of a semiconductor pressure sensor is usually coated with a silicon-based gel-like potting material to protect the surface of the die, but a pulverized product of a thick film printing resistance material composed of components such as ruthenium oxide and glass. Is unavoidable, which causes deterioration of the semiconductor characteristics of the semiconductor pressure sensor, and cannot prevent a decrease in yield and a decrease in reliability.

In the conventional method for manufacturing a disposable blood pressure transducer described above, after the housing is bonded to the second surface of the insulating substrate, the resistance pattern of the temperature compensation circuit formed on the first surface of the insulating substrate is adjusted by laser trimming. is doing. Therefore, when performing laser trimming, a sample having a complicated shape with a housing attached must be fixed to the base of the laser trimming device. Further, in the laser trimming work, it is necessary to mount and remove the complicatedly-shaped materials with housings one by one.

Therefore, the conventional manufacturing method has the drawback that the workability is poor and it cannot be manufactured at low cost.

It is an object of the present invention to effectively utilize the element mounting surface of such an insulating substrate to reduce the size and to suppress the influence of trimming contamination as much as possible to improve the reliability and yield of the semiconductor pressure sensor, and at the same time, the workability is inexpensive and the disposable blood pressure is improved. It is to provide a transducer and a manufacturing method thereof.

[Means for Solving the Problems]

The disposable blood pressure transducer of the present invention has one end formed so that it can be connected to a catheter and a liquid is filled to form a first flow path and a conduit having a flow rate adjusting mechanism and a diaphragm on the first surface. An insulating substrate having a semiconductor pressure sensor attached thereto and having a temperature compensation circuit formed on a second surface near the conduit and having a hole formed at a position facing the diaphragm; and an insulating substrate fixed to the second surface of the insulating substrate, A molded body that forms a hole communicating with the hole of the insulating substrate and forms a second flow path that follows the first flow path of the conduit, and the molded body that is integrally formed with the conduit fits into the molded body. And a housing that covers the insulating substrate and the semiconductor pressure sensor, communicates the first flow path and the second flow path, and transmits them via the catheter and the conduit. Configured to pressure on the liquid which is to be transmitted to the semiconductor pressure sensor.

Further, in the method for manufacturing a disposable blood pressure transducer of the present invention, a conductor pattern and a solder pad are formed on a first surface by a thick film printing method, and a temperature including a thick film printing resistor is formed on a second surface opposite to the first surface. A compensating circuit is formed by a thick film printing method, and a semiconductor pressure sensor is mounted on the first surface of an insulating substrate having a through hole at the center so that a pressure chamber is formed by the through hole and the diaphragm space. A step of bonding and connecting the pads on the first surface of the semiconductor pressure sensor and the insulating substrate, and a molded body having a hole formed at the center thereof on the second surface of the insulating substrate, the molded body A step of adhering so that the centers of the hole and the through hole of the insulating substrate coincide with each other, the hole of the molded body, the through hole of the insulating substrate, and the da Filling the aflam space with silicon gel, adjusting the resistance value of the thick film printing resistor of the temperature compensation circuit formed on the second surface of the insulating substrate, and partially cutting the insulating film. And a step of fitting and adhering the molded body fixed to the insulating substrate to a conduit for forming a liquid flow path integrally provided with a housing for the substrate.

〔Example〕

Next, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 is a perspective view of a disposable blood pressure transducer showing an embodiment of the present invention.

As shown in FIG. 1, in this embodiment, a catheter (not shown) inserted into a blood vessel of a patient is connected to a conduit 1, and blood pressure pulsation is applied to the catheter and a drug solution such as physiological saline filled in the conduit 1. The blood pressure pulsation is known by transmitting it to the die of the semiconductor pressure sensor installed inside the housing 2 having the wing portion 2A for replacement and fixing.
The flash device 3 connected to the conduit 1 can increase the flow rate by pressing the button 4 by adjusting the flow rate of the chemical solution such as physiological saline. Housing 2 described above
The both ends of the plastic conduit 1 integrally formed with the above have a luer lock type connection mechanism so that a tube of a catheter or a tube of a drug solution can be easily connected. Here, a luer lock female screw 5 is attached to one end, and a luer lock male screw 6 is provided to the other end.
A three-way stopcock 7 is connected to the conduit 1 so that the flow path of the chemical solution can be changed. The electric wire 8 is a wiring that is electrically connected to a semiconductor pressure sensor or the like provided inside the housing 2.

FIG. 2 is an exploded view of the blood pressure transducer shown in FIG.

As shown in FIG. 2, such a blood pressure transducer is
A capillary 16 and a rubber tube 17 are attached to one end of a conduit 1 formed integrally with the housing 2, and a flash unit 3 including the rubber tube 17 and the like is attached via a hinge 18. The flash device 3 is fixed to one end of the conduit 1 by a side plate 19 having a luer lock type male screw 6. Further, the other end of the conduit 1 is attached with a luer lock type female screw 5 and a three-way stopcock 7 as described in FIG.

On the other hand, the molded body 13 fixed to the upper surface of the alumina substrate 9 having the hole 10 is fitted to the lower portion of the conduit 1 integrally formed with the housing 2. The molded body 13 also has a cylindrical hole 14 formed at a position corresponding to the hole 10 of the alumina substrate 9. Further, the alumina substrate 9 comes into contact with the conduit 1 via the cover paper 15 having a hole for avoiding the molded body 13.
The temperature compensation circuit formed on the upper surface of the alumina substrate 9 is omitted here. Further, a semiconductor pressure sensor 11 is fixedly attached to the lower surface of the alumina substrate 9 to cover it.
Protected by 12.

The alumina substrate 9 to which the semiconductor pressure sensor 11 and the molded body 13 are fixed is arranged in a sensor housing portion 20 having a bottom plate 21, and the sensor housing portion 20 is fitted in the housing 2.

FIG. 3 is a sectional view of the blood pressure transducer taken along the line AA ′ in FIG.

As shown in FIG. 3, a method of manufacturing such a blood pressure transducer will be described here in the order of steps.

First, the temperature compensation circuit 23 is formed on one surface of the alumina substrate 9 by the thick film printing method. Next, the semiconductor pressure sensor 11 is formed on the other surface of the 96% alumina substrate 9 on which the temperature compensating circuit 23 is formed.
The die is adhered, electrically connected by a bonding wire 24, and potted by a silicon gel 25.
The cover 12 is adhered from above. Next, the molded body 13 in which the cylindrical hole 14 is formed is adhered to the upper surface of the alumina substrate 9 so that the hole 14 communicates with the hole 10 of the alumina substrate 9. Then, the holes 14 of the molded body 13 are filled with silicon gel. Since such a silicon gel has a low viscosity, gravity naturally causes the hole 10 of the alumina substrate 9 and the diaphragm below the hole 10.
It is also filled in 22 spaces.

Next, the temperature compensation circuit 23 formed on one surface of the alumina substrate 9
The resistance of is adjusted by the laser trimming method. After adjusting the resistance, the cover paper 15 is placed on the alumina substrate 9. After that, the molded body 13 is fitted into the conduit 1 integrally formed with the housing 2 and bonded. That is, so that a part of the conduit 1 of the housing 2 fits the molded body 13,
It is formed as a depression. In this way, the first flow path in the conduit 1 is communicated with the second flow path formed by the hole 14 of the molded body 13, the hole 10 of the alumina substrate 9 and the space of the diaphragm 22 therebelow. . That is, the diaphragm 22 of the semiconductor pressure sensor 11 passes from the first channel to the second channel.
The path becomes narrower as it approaches, so that even a slight change in liquid pressure can be sensitively transmitted.

Next, a capillary 16 used to properly control the flow rate of the liquid, a rubber tube 17 which is a component of the flash device 3 for increasing and adjusting the flow rate, and a hinge 18 and a button 4 shown in FIG. 2 are assembled. To glue. Thereafter, the side plate 19 shown in FIG. 2 and the three-way stopcock 7 are bonded. Further, the lead wire 26 is soldered to the pad of the alumina substrate 9,
The bottom plate 21 is adhered to the housing 2 while being led out to the outside as the electric wire 8.

FIG. 4 is a perspective view in which a part of the semiconductor pressure sensor shown in FIGS. 2 and 3 is cut away.

As shown in FIG. 4, the semiconductor pressure sensor 11 has a thin film diaphragm shown by a dotted line in the central portion of the silicon substrate 27.
22 and four diffusion resistors 28 are provided around the diaphragm 22. This diffused resistor 28 forms a Wheatstone bridge circuit with aluminum wiring 30, and the aluminum pad
29 connected respectively. When pressure is applied to this diaphragm 22, the value of the diffusion resistance 28 increases or decreases due to the piezoresistive effect, and the pressure can be determined by the output of the Wheatstone bridge circuit. The die of the semiconductor pressure sensor 11 thus formed (silicon substrate 2
7) is adhered to the alumina substrate 9 shown in FIG. 3 with a silicone rubber elastic adhesive. This is to avoid the influence of stress due to the thermal expansion of the silicon substrate 27 and the alumina substrate 9. A concave portion is formed on the back surface side of the semiconductor pressure sensor 11, and the pressure of the chemical liquid filled in the conduit 1 is transmitted through the concave portion and the hole 10. However,
As described above, in order to prevent the chemical solution from directly contacting the diaphragm 22, the hole 14 of the molded body 13 is filled with a silicon gel substance (not shown).

The aluminum pad 29 of the semiconductor pressure sensor 11 is connected to the alumina substrate 9 by the bonding wire 24 shown in FIG.
Bonding connection is made to the stitch land to make an electrical connection. The circuit forming surface (upper) side of the semiconductor pressure sensor 11 has a silicon gel material 24 shown in FIG. 3 for protecting the bonding wire 24 and the circuit forming surface.
Be potted in. Furthermore, this semiconductor pressure sensor 11
Is covered with an opaque cover 12 to prevent the influence of light on the semiconductor pressure sensor 11.

FIG. 5 is a blood pressure transducer and a fourth blood pressure transducer shown in FIG.
It is a circuit diagram of the semiconductor pressure sensor shown in the figure.

As shown in FIG. 5, such a blood pressure transducer circuit
32 is constructed by connecting a resistive element R _A to R _D to the constructed sensor circuit 31 by the resistance element R ₁ to R _4. These resistive elements
Pressure sensitivity is adjusted by adjusting the resistance values of R _A and R _B , and offset voltage and offset voltage temperature characteristics are reduced by adjusting the resistance value of resistance elements R _C and R _D. Is measuring. The resistance elements R _{1 to} R ₄ constituting the sensor circuit 31 represent the diffused resistors 28 in FIG. 4, and the terminals close to the sensor circuit 31 represent the aluminum pads 29 in FIG. 4.

FIGS. 6 (a) and 6 (b) are a thick film printing pattern diagram on the semiconductor pressure sensor mounting surface and a thick film printing pattern diagram on the molded body mounting surface of the alumina substrate shown in FIG. 2 or 3, respectively.

As shown in FIGS. 6A and 6B, solder pads 33, through holes 34, conductor patterns 35, the stitch lands 36 described above, and the like are formed on the alumina substrate 9 by a thick film printing method. Incidentally, 10 is the above-mentioned substrate hole. The semiconductor pressure sensor 11 described with reference to FIG. 4 is mounted on the upper surface of the alumina substrate 9 so that the diaphragm 22 and the substrate hole 10 face each other. Then, from aluminum pad 29 to stitch land 36
Bonding wire 24 is connected to. This electrical connection is connected to the conductor pattern 35 or the like on the opposite surface through the through hole 34.

〔The invention's effect〕

As described above, in the disposable blood pressure transducer of the present invention, the semiconductor pressure sensor having the diaphragm is bonded to the first surface of the insulating substrate and the temperature compensating circuit is formed on the second surface, while the disposable blood pressure transducer is formed on the portion facing the diaphragm. By adopting a configuration in which the pressure of the chemical liquid filled in the conduit is transmitted to the diaphragm through the hole of the insulating substrate, there is an effect that the size can be reduced and highly accurate measurement can be realized.

First, the temperature compensating circuit forming surface and the semiconductor pressure sensor mounting surface are made into a two-layer structure by making the insulating substrate the front and back sides,
The area of the insulating substrate can be effectively used, and the area of the insulating substrate can be reduced. Therefore, the size of the disposable blood pressure transducer body can be reduced. Specifically, the size of the insulating substrate can be reduced by about 30%. In particular, since such a disposable blood pressure transducer may be worn on the arm of a patient, a disposable blood pressure transducer that is smaller and easier to wear can be realized. Next, the temperature compensation circuit is formed on the insulating substrate by thick film printing and the resistance is adjusted by laser trimming.The temperature compensation circuit is formed on the opposite side of the surface of the insulating substrate to which the semiconductor pressure sensor is bonded. Has been done. Therefore, during laser trimming, the semiconductor pressure sensor is positioned below the stage of the laser trimming device, so that the semiconductor pressure sensor is not contaminated by the sublimated substance or the gaseous pulverized substance of the resistor generated by the laser trimming. Therefore, the reliability as a transducer and the yield can be improved.

Furthermore, since the surface on which the temperature compensation circuit is formed is close to the conduit filled with the chemical solution such as physiological saline, the temperature of the resistor forming the temperature compensation circuit is close to the temperature of the chemical solution. Therefore,
The temperature compensation function can be easily performed accurately, and more accurate blood pressure measurement can be realized.

In addition, the method for manufacturing a disposable blood pressure transducer of the present invention, a molded body having a hole communicating with the hole of the insulating substrate is bonded to the second surface of the insulating substrate, and after filling the hole of the molded body with silicone gel, the temperature is changed. By adjusting the resistance value of the compensation circuit, and then fitting and adhering the housing to the molded body, it is necessary to fix a large structure such as the housing to the laser trimming device when adjusting the resistance value of the temperature compensation circuit. Disappears. That is, laser trimming can be performed easily like resistance adjustment of a normal HIC circuit board, production efficiency can be improved, and an inexpensive disposable blood pressure transducer can be supplied.

[Brief description of drawings]

FIG. 1 is a perspective view of a disposable blood pressure transducer showing an embodiment of the present invention, FIG. 2 is an exploded assembly view of the blood pressure transducer shown in FIG. 1, and FIG. 3 is a sectional view taken along the line AA 'in FIG. 4 is a partially cutaway perspective view of the semiconductor pressure sensor shown in FIGS. 2 and 3, and FIG. 5 is a circuit diagram of the blood pressure transducer shown in FIG. 1 and the semiconductor pressure sensor shown in FIG. FIGS. 6 (a) and 6 (b) are a thick film printing pattern diagram on the semiconductor pressure sensor mounting surface and a thick film printing pattern diagram on the molded body mounting surface of the alumina substrate shown in FIG. 2 or 3, respectively. 1 ... conduit, 2 ... housing, 2A ... wings, 3 ...
… Flash device, 4 …… button, 5 …… Lure lock female screw, 6 …… Lure lock male screw, 7 …… Three-way stopcock,
8 ... Electric wire, 9 ... Alumina substrate, 10 ... Hole, 11 ... Semiconductor pressure sensor, 12 ... Cover, 13 ... Molded body, 14 ...
Board hole, 15 …… Cover paper, 16 …… Capillary, 17 …… Rubber tube, 18 …… Hinge, 19 …… Side plate, 20 …… Sensor housing, 21 …… Bottom plate, 22 …… Diaphragm, 23 …… Temperature compensation circuit, 24 …… bonding wire, 25 …… silicon gel, 26 …… lead wire, 27 …… silicon substrate, 28 …… diffusion resistance, 29 …… aluminum pad, 30 …… aluminum wiring, 31 ……
Sensor circuit, 32 ... Transducer circuit, 33 ... Solder pad, 34 ... Through hole, 35 ... Conductor pattern, 36 ...
… Stitch land, 37 …… Thick film printing resistor.

Claims (7)

[Claims] 1. A semiconductor pressure having a conduit formed at one end thereof for connecting to a catheter and filled with a liquid to form a first flow path and having a flow rate adjusting mechanism, and a diaphragm on a first surface. An insulating substrate on which a sensor is fixed and a temperature compensating circuit is formed on a second surface near the conduit and a hole is formed at a position facing the diaphragm; and the insulating substrate fixed on the second surface of the insulating substrate. A molded body that forms a hole communicating with the hole and forms a second flow path that follows the first flow path of the conduit, and the molded body that is integrally formed with the conduit and that fits the molded body A substrate covering the semiconductor pressure sensor, the first flow path and the second flow path communicating with each other, and the pressure applied to the liquid transmitted through the catheter and the conduit is applied to the semiconductor. By transmitting the force sensor, disposable blood pressure transducer and measuring blood pressure. 2. A disposable blood pressure transducer, wherein one surface of the semiconductor pressure sensor fixed to the insulating substrate according to claim 1 is potted with silicon gel. 3. A disposable blood pressure transducer, characterized in that the semiconductor pressure sensor fixed to the insulating substrate according to claim 1 is covered with a cover. 4. A disposable blood pressure transducer, wherein the insulating substrate according to claim 1 is an alumina substrate. 5. The disposable blood pressure transducer according to claim 1, wherein a hole in the insulating substrate formed at a position facing the diaphragm, a space reaching the diaphragm facing the hole, and a second flow formed by a hole in the molded body. A disposable blood pressure transducer characterized in that the tract is filled with silicone gel. 6. A disposable blood pressure transducer, wherein the temperature compensation circuit formed on one surface of the insulating substrate according to claim 1 is formed by a thick film printed resistor. 7. A conductor pattern and a solder pad are formed on a first surface by a thick film printing method, and a temperature compensation circuit including a thick film printing resistor is formed on the second surface opposite to the first surface by a thick film printing method. Forming and mounting the semiconductor pressure sensor on the first surface of the insulating substrate having a through hole at the center so as to form a pressure chamber with the through hole and the diaphragm space, and the semiconductor pressure sensor and Bonding and connecting the pads on the first surface of the insulating substrate,
A step of adhering a molded body having a hole formed in the center to the second surface of the insulating substrate so that the center of the hole of the molded body and the center of the through hole of the insulating substrate are aligned; Filling the holes of the insulating substrate, the through holes of the insulating substrate and the diaphragm space of the semiconductor pressure sensor with silicon gel, and the thick film printing of the temperature compensation circuit formed on the second surface of the insulating substrate. The step of adjusting the resistance value of the resistor, and the molded body fixed to the insulating substrate is fitted into a conduit for forming a liquid flow path, which is partially cut away and integrally formed with a housing for the insulating substrate. A method for manufacturing a disposable blood pressure transducer, comprising the steps of bonding and adhering.