JP3131374B2 - Semiconductor pressure sensor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a semiconductor pressure sensor, and more particularly to a differential pressure type semiconductor pressure sensor.

[0002]

2. Description of the Related Art As shown in FIG. 7, a conventional differential pressure type semiconductor pressure sensor has a terminal pin 53 projecting from the lower surface of a case 52 and a pressure introducing pipe from the lower surface and the upper surface of the case 52. 55 and 56 project in the up-down direction. This type of semiconductor pressure sensor is a case 5
Pressure is applied to the pressure-receiving diaphragm of the sensor chip mounted in 2 from the pressure introduction pipes 55 and 56, respectively.
A change in the resistance value due to the distortion of the gauge resistance formed in the pressure receiving diaphragm is taken out from the terminal pin 53 to an external circuit as an electric signal.

[0003]

In the above-mentioned semiconductor pressure sensor, since the pressure introducing pipes 55 and 56 project in the vertical direction of the case 52, the height of the sensor body becomes large. There is a problem that it is difficult to reduce the thickness, and furthermore, if a pressure introducing tube is inserted into the pressure introducing pipes 55 and 56, the size of the entire sensor becomes large. When the semiconductor pressure sensor is mounted on a wiring board or the like, a hole must be formed in the wiring board to prevent the pressure introduction pipe 55 from hitting the wiring board. In such a case, there is a problem that the cost of drilling becomes very high. Further, the necessity of the perforation processing also hinders double-sided mounting.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a differential pressure type semiconductor pressure sensor which is thinner than conventional ones.

[0005]

According to a first aspect of the present invention, there is provided a sensor chip in which a gauge resistor is formed on a pressure receiving diaphragm formed by providing a recess in a semiconductor single crystal substrate. A case in which the sensor chip is housed and has a space above the diaphragm, wherein the case has a first insertion port provided with a first pressure introduction hole communicating with the recess, and a second communication port communicating with the space; are those and each receptacle has a second insertion opening pressure introducing hole is provided in is characterized by comprising provided on a side surface of the case at lower than the sensor chip, the spigot Is the case below the sensor chip
Since it is provided on the side of the can thin the sensor body than the semiconductor pressure sensor of a conventional differential pressure type, can be lowered mounting height from the wiring board when mounting Rutotomoni, surface mounting
Easy to use, enabling downsizing of the pressure sensor as a whole
And the surface of the sensor body is easily mounted in a reflow furnace
As a result, manufacturing costs can be reduced.

[0006]

[0007]

According to a second aspect of the present invention, there is provided the circuit board according to the first aspect of the present invention, wherein the sensor chip is mounted and installed in the case and has a recess and an opening communicating with the first pressure introducing hole. Since the temperature compensation IC and the peripheral circuit are mounted on the circuit board, the temperature difference between the sensor chip and the temperature compensation IC is small and the temperature compensation is easy because the temperature difference is hardly affected by the ambient temperature. The detection sensitivity is improved.

According to a third aspect of the present invention, in the first aspect of the present invention, the sensor main body is a rod-shaped body, and the sensor main body itself is inserted into a pressure introducing cylinder for sending pressure to each pressure introducing hole. Therefore, the sensor itself can be used as a joint. According to a fourth aspect of the present invention, in the first aspect of the invention, electric wiring is performed by a three-dimensional molded circuit wiring in which a conductor pattern is formed on a synthetic resin molded product, and external input / output terminals are formed on the back surface of the body. It is not necessary, and material costs and bending costs can be reduced as compared with the case where a lead frame is used, so that manufacturing costs can be reduced. Further, since the mounting area and mounting height on the wiring board can be reduced, the size of the pressure sensor as a whole can be reduced.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments. (Embodiment 1) FIG. 1 is a sectional view of a semiconductor pressure sensor according to the present embodiment. In this semiconductor pressure sensor, a sensor chip 1 having a pressure receiving diaphragm 10a is bonded to a body 2 which is formed simultaneously with a lead frame 4 and has an open upper surface, with an adhesive such as a silicone resin. And a pressure reference chamber 20 is formed in the space above the sensor chip 1. Here, a case is formed by the body 2 and the cap 3.

The sensor chip 1 includes a single crystal semiconductor substrate 10
Is formed on the main surface of the pressure receiving diaphragm 10a formed by providing a recess 10b, and a gauge resistor (not shown) whose resistance value changes in accordance with strain is formed. The material of the case is, for example, PPS (polyphenylene sulfide), ABS (acrylonitrile butadiene styrene), PES (polyether sulfone), L
An electrode pad (not shown) on the surface of the sensor chip 1 and the lead frame 4 are electrically connected to each other by a wire W made of a fine gold wire or a thin aluminum wire (a synthetic resin such as CP (liquid crystal plastic)). Wire bonding). That is, the sensor chip 1 is connected to the lead frame 4 via the wire W, and the lead piece 4 ′ of the lead frame 4 protruding from the side surface of the body 2 (see FIG. 2).
Is connected to an external circuit. The lead piece 4 'is bent downward in the thickness direction of the body, and its tip is bent in an L-shape. The lead piece 4' is mounted on a wiring board on which a circuit pattern is formed, and is connected to an external circuit. The cap 3 is joined to the body 2 after the wire bonding process.

On the side surface of the body 2, first and second insertion ports 1 formed integrally with the body 2 and projecting in the lateral direction are provided.
5 and 16 are provided. A first pressure introducing hole 5 communicating between the recess 10b and the inside and outside of the case is provided in a portion extending from the first insertion port 15 to the recess 10b, and a first pressure introduction hole 5 is provided between the second insertion port 16 and the upper side of the diaphragm 10a. Pressure reference chamber 20
A second pressure introducing hole 6 for communicating the pressure reference chamber 20 with the inside and outside of the case is provided at a portion straddling. The present semiconductor pressure sensor is used by fitting a pressure introducing tube (not shown) into each of the insertion ports 15 and 16.

In the present semiconductor pressure sensor, the primary pressure transmitted from the first pressure introducing hole 5 of the first insertion port 15 to the lower surface of the diaphragm 10a of the sensor chip 1 (that is, the concave portion 10b); The diaphragm 1 enters the pressure reference chamber 20 through the second pressure introduction hole 6 of the second insertion port 16 and enters the diaphragm 1.
The pressure difference from the secondary pressure transmitted to the upper surface side of Oa causes distortion in the diaphragm 10a and changes the resistance value of the gauge resistance. By taking it out as a voltage output, the pressure can be measured.

The lead piece 4 'is connected to a circuit pattern of a wiring board (not shown) by soldering or the like, but can be joined by a reflow furnace together with mounting of components constituting a peripheral circuit. Thus, in the differential pressure type semiconductor pressure sensor of the present embodiment, the sensor body (including each of the insertion ports 15 and 16) can be made thinner than the conventional differential pressure type semiconductor pressure sensor. Surface mounting becomes possible.

In the semiconductor pressure sensor of the present invention,
Each pressure introduction hole 5, 6 is provided even if water is generated by condensation
Water can be easily drained from each of the
Can be.(Reference example)  FIG.As a reference exampleShows a cross-sectional view of a semiconductor pressure sensor.
You. The basic configuration and operation of this semiconductor pressure sensor
Approximately the same as in Embodiment 1 except that the reference pressure
A second pressure introducing hole 6 communicating with the force chamber 20 is provided.
2 plug 16 into cap 3, not body 2.
Is formed so as to protrude upward. others
Therefore, in this semiconductor pressure sensor, the cap 3
Flat plate with no vent 16 and partly vented
By joining the cap into the body 2, the gauge
Can be used as a pressure sensor for pressure. The vent
The cap without the second insertion port 16 to the body 2
If the reference pressure chamber 20 is made substantially vacuum, the absolute pressure is sensed.
can do.

As in the first embodiment, the differential pressure type semiconductor pressure sensor of the present reference example can be made thinner than the conventional differential pressure type semiconductor pressure sensor, and can be surface-mounted on a wiring board. It becomes possible. Also, in the present semiconductor pressure sensor, similarly to Embodiment 1, even if water is generated in the package due to dew condensation, water can be easily drained from the insertion ports 15 and 16 provided with the pressure introduction holes 5 and 6. Can be.

Embodiment 2 FIG. 4 is a sectional view of a semiconductor pressure sensor according to the present embodiment. The basic configuration and operation of the present semiconductor pressure sensor are substantially the same as those of the first embodiment. The feature of the semiconductor pressure sensor is that the sensor chip 1 is not directly joined to the body 2 but the sensor chip 1 is The circuit board 30 is mounted on a circuit board 30 having an opening 31 communicating with the first pressure introducing hole 5, and the circuit board 30 is bonded to the body 2 formed at the same time as the lead frame 4 with a resin such as epoxy without leakage. That is to be. As a material of the circuit board 30,
There are resins, ceramics, glass, and the like. In the pressure sensor of the present embodiment, Pyrex glass (heat-resistant glass) having a thermal expansion coefficient substantially equal to that of silicon is used as the circuit board 30, so that the sensor chip 1 has a well-known structure. Direct bonding can be performed by anodic bonding (electrostatic bonding) or the like, and a highly accurate pressure sensor can be realized due to temperature characteristics. Further, when the sensor chip 1 is mounted on the circuit board 30, a temperature compensation IC chip (not shown) and a peripheral circuit (not shown) such as an electronic component are simultaneously mounted to constitute an IC built-in pressure sensor. are doing. Also, since a plurality of chips are mounted on the flat circuit board 30 instead of the box-shaped body 2 and the circuit board 30 is housed in the body 2, the workability of die bonding is improved.

In the differential pressure type semiconductor pressure sensor according to the present embodiment, the temperature compensation IC chip and the peripheral circuit are mounted on the circuit board 30. Since the temperature difference is small and the influence of the ambient temperature is small, the temperature compensation becomes easy and the detection sensitivity is improved. Also in the present semiconductor pressure sensor, similarly to the first embodiment, even if water is generated in the case due to dew condensation, water can be easily drained from the insertion ports 15 and 16 provided with the pressure introduction holes 5 and 6. Can be.

(Embodiment 3 ) FIG. 5 is a sectional view of a semiconductor pressure sensor according to the present embodiment. The basic configuration and basic operation of the present semiconductor pressure sensor are substantially the same as those of the first embodiment, and the feature thereof is that the sensor main body itself is a rod-shaped body and the sensor main body itself is connected to the pressure introducing tubes 41 and 42. It can be inserted and used like a joint. For this reason, the sensor body enters the pressure introducing tubes 41 and 42, so that the mounting area can be significantly reduced. Also, it is only necessary to make an electrical connection with the wiring board on which the sensor body is mounted. For example, by lengthening or bending the external leads, there is no restriction on the mounting location, so that the degree of freedom in mounting is improved. Extremely high.

(Embodiment 4 ) FIG. 6A shows a back view of a semiconductor pressure sensor of this embodiment, and FIG. 6B shows a side view. The basic configuration and operation of the present semiconductor pressure sensor are substantially the same as those of the first embodiment,
The feature is that the sensor chip 1 is mounted on a three-dimensionally formed circuit board having a plated wiring pattern, and is electrically connected to the outside by a wiring plating pattern 34 formed on the back side of the body 2. For this reason, the mounting height on the wiring board can be reduced as compared with the connection using the lead frame 4 described in the first embodiment. Further, since the lead frame 4 does not protrude to the side, the mounting area can be reduced as compared with the connection by the lead frame 4. Thus, the size of the entire pressure sensor can be reduced. Further, since a lead frame is not required, costs such as material costs and bending costs can be reduced.

The wiring plating pattern 34 is formed by roughening the substrate surface, electroless copper plating → patterning by resist coating and exposure → electrolytic plating (copper, nickel, gold) →
It is performed in the procedure of substrate cleaning (resist removal). Also in the present semiconductor pressure sensor, similarly to the first embodiment, even if water is generated in the case due to dew condensation, water can be easily drained from the insertion ports 15 and 16 provided with the pressure introduction holes 5 and 6. Can be.

In each embodiment, the sensor chip 1
Has been described, the sensor chip 1 is joined to a glass pedestal having an opening communicating with the recess 10b and the first pressure introducing hole 5, and this glass pedestal is joined to the body 2. Of course it is good.

[0023]

[Effect of the Invention] The invention of claim 1, since the insertion port is provided on the side surface of the lower Deke over scan than cell Nsachippu, can thin the sensor body than the semiconductor pressure sensor of a conventional differential pressure type , together with the cut with even lower mounting height from the wiring board when mounting enables downsizing of the entire pressure <br/> sensor because the surface mount is facilitated, also, sensor
Since the main body can be easily surface-mounted in a reflow oven,
There is an effect that the strike can be reduced .

[0024]

[0025]

According to a second aspect of the present invention, there is provided the circuit board according to the first aspect of the present invention, wherein the circuit board is mounted in the case and has a recess and an opening communicating with the first pressure introducing hole. Since the temperature compensation IC and the peripheral circuit are mounted on the circuit board, the temperature difference between the sensor chip and the temperature compensation IC is small and the temperature compensation is easy because the temperature difference is hardly affected by the ambient temperature. This has the effect of improving the detection sensitivity.

According to a third aspect of the present invention, in the first aspect of the present invention, the sensor main body is a rod-shaped body, and the sensor main body itself is inserted into a pressure introducing cylinder for sending pressure to each pressure introducing hole. Therefore, there is an effect that the sensor body itself can be used as a joint. According to a fourth aspect of the present invention, in the first aspect of the invention, electric wiring is performed by a three-dimensional molded circuit wiring in which a conductor pattern is formed on a synthetic resin molded product, and external input / output terminals are formed on the back surface of the body. It is not necessary, and there is an effect that the material cost and the bending cost can be reduced as compared with the case where a lead frame is used, and the manufacturing cost can be reduced. Further, since the mounting area and the mounting height on the wiring board can be reduced, the size of the pressure sensor as a whole can be reduced.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a first embodiment.

FIG. 2A is a rear view showing the first embodiment. (B) is a side view of the same.

FIG. 3 is a schematic sectional view showing a reference example .

FIG. 4 is a schematic sectional view showing a second embodiment.

FIG. 5 is a schematic sectional view showing a third embodiment.

FIG. 6A is a rear view showing the fourth embodiment. (B) is a side view of the same.

FIG. 7 is an external side view showing a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Sensor chip 2 Body 3 Cap 4 Lead frame 5 First pressure introducing hole 6 Second pressure introducing hole 10 Single crystal semiconductor substrate 10a Pressure receiving diaphragm 10b Concave part 15 First insertion port 16 Second insertion port 20 Reference pressure Chamber W wire

Continuation of the front page (56) References JP-A-4-130238 (JP, A) JP-A-8-228661 (JP, A) JP-A-5-188082 (JP, A) JP-A 64-61641 (JP) , A) Fully open sho 63-145141 (JP, U) Fully open sho 63-63735 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G01L 13/00-13/06 G01L 9/04

Claims (4)

(57) [Claims] 1. A sensor chip in which a gauge resistor is formed in a pressure-receiving diaphragm formed by providing a recess in a semiconductor single crystal substrate, a case in which the sensor chip is housed and has a space above the diaphragm, The case has a first insertion port provided with a first pressure introduction hole communicating with the recess, and a second insertion port provided with a second pressure introduction hole communicating with the space, and A semiconductor pressure sensor, wherein an insertion port is provided on a side surface of the case below the sensor chip. 2. A sensor chip is mounted and installed in the case.
And an opening communicating with the recess and the first pressure introducing hole is provided.
Having a formed circuit board, the circuit board having a temperature compensation
2. The semiconductor pressure sensor according to claim 1, wherein an IC and a peripheral circuit are mounted . 3. A sensor according to claim 1 , wherein said sensor body is a rod.
Introduces pressure into the body itself, sending pressure into each pressure introduction hole
2. The semiconductor pressure sensor according to claim 1, wherein the semiconductor pressure sensor is inserted into a cylinder . 4. A conductor pattern is formed on a synthetic resin molded product.
Electrical wiring with the three-dimensional molded circuit wiring
An external input / output terminal is formed on the surface.
2. The semiconductor pressure sensor according to 1 .