WO2023148836A1

WO2023148836A1 - Semiconductor device

Info

Publication number: WO2023148836A1
Application number: PCT/JP2022/003930
Authority: WO
Inventors: 琳琳張; 孝之余語; 瑞紀伊集院
Original assignee: 日立Astemo株式会社
Priority date: 2022-02-02
Filing date: 2022-02-02
Publication date: 2023-08-10

Abstract

The present disclosure provides a semiconductor device with which it is possible to achieve greater reductions in material cost and processing cost than is possible with conventional technologies, and which is equipped with an intermediate member having good adhesion with a resin sealing portion. An aspect of the present disclosure is a semiconductor device comprising: a lead frame 208f; a semiconductor substrate 301 disposed on a die pad 208d of the lead frame 208f; and an intermediate member 208i disposed between the die pad 208d and the semiconductor substrate 301. The semiconductor device further comprises a resin sealing portion 208r that is integrally provided to seal the die pad 208d, the intermediate member 208i, and at least a part of the semiconductor substrate 301. The intermediate member 208i includes a metal plate 208m that has a linear coefficient of expansion equivalent to the linear coefficient of expansion of the semiconductor substrate 301, and a peeling preventing portion 208a that is provided on a surface of the metal plate 208m to prevent peeling of the resin sealing portion 208r.

Description

semiconductor equipment

The present disclosure relates to semiconductor devices.

Inventions related to sensor devices have been known for some time. For example, the sensor device described in Patent Document 1 below includes a sensor chip, support leads and external connection leads that are part of a lead frame, an intermediate member, and a sealing member (abstract, etc.). The sensor chip includes a substrate having a hollow portion, a detecting portion and a wiring portion connected to the detecting portion formed on the substrate, and a resistor forming the detecting portion is formed in a thin portion on the hollow portion.

A sensor chip is arranged on one surface of the support lead, with the lower surface where the hollow portion is opened as the opposite surface. The external connection lead is electrically connected to the wiring portion of the sensor chip. The intermediate member is arranged between the one surface of the support lead and the lower surface of the sensor chip, and is fixed to the one surface of the support lead via an adhesive containing a resin component while being in contact with and fixed to the lower surface of the sensor chip.

The sealing member is made of an insulating material and integrally arranged so as to cover the connecting portion between the wiring portion and the external connection lead while exposing the detecting portion and the thin portion. This conventional sensor device is characterized in that the linear expansion coefficient of the intermediate member is substantially equal to that of the substrate, and the intermediate member is made of a material having a Young's modulus larger than that of the adhesive.

According to this conventional sensor device, the displacement of the sensor chip is suppressed, and the electrical connection state between the sensor chip and the external connection lead is ensured. Moreover, the stress generated based on the difference in coefficient of linear expansion between the substrate constituting the sensor chip and the member adjacent to the substrate is reduced. In addition, deformation of the sensor chip is suppressed, and concentration of stress on the thin portion is suppressed (Patent Document 1, paragraphs 0009 to 0011).

JP 2009-036639 A

Patent Document 1 describes that a glass substrate containing silicon oxide as a main component is used as an intermediate member of a sensor device (claim 5, paragraphs 0019 and 0042). A glass substrate containing silicon oxide as a main component has good adhesion to a sealing member made of epoxy resin or the like, but it causes an increase in the material and processing costs of the sensor device.

The present disclosure provides a semiconductor device including an intermediate member that can reduce material costs and processing costs compared to conventional ones and has good adhesion to the resin sealing portion.

One aspect of the present disclosure is a semiconductor device including a lead frame, a semiconductor substrate arranged over a die pad of the lead frame, and an intermediate member arranged between the die pad and the semiconductor substrate. and a resin sealing portion integrally provided to seal the die pad, the intermediate member, and at least a portion of the semiconductor substrate, wherein the intermediate member has a coefficient of linear expansion and a coefficient of linear expansion of the semiconductor substrate. A semiconductor device comprising: a metal plate having an equivalent coefficient of linear expansion; and a peel prevention portion provided on the surface of the metal plate to prevent peeling of the resin sealing portion.

According to the above aspect of the present disclosure, it is possible to provide a semiconductor device including an intermediate member that can reduce material costs and processing costs compared to conventional ones and has good adhesion to the resin sealing portion. .

1 is a schematic cross-sectional view showing an embodiment of a semiconductor device according to the present disclosure; FIG. FIG. 2 is a rear view of the physical quantity detection device shown in FIG. 1 with a cover removed; FIG. 3 is a schematic cross-sectional view of the chip package taken along line III-III in FIG. 2; FIG. 4 is a schematic diagram showing a method for testing the shear strength of the interface between the resin-sealed portion and the intermediate member; FIG. 4 is a schematic diagram showing a method for testing the shear strength of the interface between the resin-sealed portion and the intermediate member; 4 is a graph showing the shear strength of the resin-sealed portion and the intermediate member after application of thermal shock; 6 is a graph showing the shear strength of the resin sealing portion and the intermediate member after maintaining the high temperature. 4 is a graph showing the shear strength of the resin sealing portion and the intermediate member after being maintained at high temperature and high humidity; 4 is a graph showing the shear strength of the resin-sealed portion and the intermediate member after application of thermal shock; 4 is a graph showing the shear strength of the resin sealing portion and the intermediate member after being maintained at high temperature and high humidity;

Hereinafter, embodiments of the semiconductor device according to the present disclosure will be described with reference to the drawings.

FIG. 1 is a schematic cross-sectional view of an internal combustion engine control system 1 as one embodiment of a semiconductor device according to the present disclosure. The semiconductor device of this embodiment is, for example, a chip package 208 including a thermal flow sensor 300 that constitutes the physical quantity detection device 20 included in the internal combustion engine control system 1 (see FIGS. 2 and 3). In the following, the configuration of each part will be described in detail in the order of the internal combustion engine control system 1, the physical quantity detection device 20, and the chip package 208, which is the semiconductor device of the present embodiment.

In the internal combustion engine control system 1, for example, intake air is drawn from the air cleaner 21 based on the operation of the internal combustion engine 10 having the engine cylinder 11 and the engine piston 12. Intake air is led to the combustion chamber of the engine cylinder 11 through the main passage 22 , which is the intake body, the throttle body 23 , and the intake manifold 24 .

The physical quantity detection device 20 installed in the main passage 22 measures the physical quantity of the intake air. That is, the measured gas 2 of the physical quantity detection device 20 is, for example, intake air flowing through the main passage 22 . Further, based on the physical quantity of the intake air measured by the physical quantity detection device 20, fuel is supplied from the fuel injection valve 14 and introduced into the combustion chamber together with the intake air in the form of an air-fuel mixture.

In the example shown in FIG. 1, the fuel injection valve 14 is provided in the intake port of the internal combustion engine 10, the fuel injected into the intake port is mixed with the intake air, and the mixture of the fuel and the intake air is injected into the intake valve 15. to the combustion chamber via The air-fuel mixture led to the combustion chamber is explosively combusted by spark ignition of the ignition plug 13 to generate mechanical energy.

The physical quantity detection device 20 measures physical quantities such as the flow rate, temperature, humidity, and pressure of the intake air as the gas 2 to be measured that is taken in via the air cleaner 21 and flows through the main passage 22 . The physical quantity detection device 20 outputs an electrical signal corresponding to the physical quantity of the intake air. An output signal from the physical quantity detection device 20 is input to the control device 4 .

Also, the output of the throttle angle sensor 26 that measures the opening of the throttle valve 25 is input to the control device 4 . In addition, the output of the rotation angle sensor 17 is input to the control device 4 in order to measure the positions and states of the engine piston 12, the intake valve 15, and the exhaust valve 16 of the internal combustion engine 10, and the rotational speed of the internal combustion engine 10. . The output of the oxygen sensor 28 is input to the control device 4 in order to measure the state of the mixture ratio between the amount of fuel and the amount of air from the state of the exhaust gas 3 .

The control device 4 calculates the fuel injection amount and ignition timing based on the physical quantity of the intake air, which is the output of the physical quantity detection device 20, and the rotation speed of the internal combustion engine 10 measured based on the output of the rotation angle sensor 17. . Based on these calculation results, the amount of fuel supplied from the fuel injection valve 14 and the ignition timing by the spark plug 13 are controlled. Further, the fuel supply amount and ignition timing are further based on the temperature measured by the physical quantity detection device 20, the change state of the throttle angle, the change state of the engine rotation speed, the air-fuel ratio state measured by the oxygen sensor 28, and the like. , is finely controlled.

The control device 4 further controls the amount of air bypassing the throttle valve 25 in the idling state of the internal combustion engine 10 with the idle air control valve 27, thereby controlling the rotation speed of the internal combustion engine 10 in the idling state. The fuel supply amount and ignition timing, which are the main control variables of the internal combustion engine 10, are both calculated using the output of the physical quantity detection device 20 as a main parameter. Therefore, improving the accuracy of the physical quantity detection device 20, suppressing changes over time, and improving reliability are important for improving control accuracy and ensuring reliability of the vehicle.

Especially in recent years, the demand for fuel efficiency of vehicles is very high, and the demand for exhaust gas purification is also very high. In order to meet these demands, it is extremely important to improve the measurement accuracy of the physical quantity of the intake air as the measured gas 2 measured by the physical quantity detection device 20 . It is also important that the physical quantity detection device 20 maintains high reliability.

FIG. 2 is a rear view of the physical quantity detection device 20 shown in FIG. 1 with the cover removed. The physical quantity detection device 20 includes a housing 201 and a cover (not shown) attached to the housing 201 . The cover is made of, for example, a plate-like member made of a conductive material such as an aluminum alloy, or an injection-molded synthetic resin material.

The housing 201 is made of, for example, an injection-molded synthetic resin material. The housing 201 has a flange 201f, a connector 201c, and a measuring section 201m.

The flange 201f is fixed to the intake body, which is the main passage 22. The flange 201f has, for example, a substantially rectangular shape in a plan view with a predetermined plate thickness, and has through holes at the corners. The flange 201f is fixed to the main passage 22 by, for example, inserting a fixing screw through the through hole at the corner and screwing it into the screw hole of the main passage 22 .

The connector 201c protrudes from the flange 201f and is exposed outside from the intake body for electrical connection with external equipment. The connector 201c has, for example, four external terminals and a correction terminal provided therein. The external terminals are terminals for outputting physical quantities such as flow rate and temperature, which are measurement results of the physical quantity detection device 20, and power supply terminals for supplying DC power for operating the physical quantity detection device 20. The correction terminal is a terminal used to measure the manufactured physical quantity detection device 20, obtain a correction value for each physical quantity detection device 20, and store the correction value in the memory inside the physical quantity detection device 20. .

The measuring portion 201m extends so as to protrude from the flange 201f toward the center of the main passage 22. The measuring portion 201m has a thin and long plate-like shape extending from the flange 201f toward the center of the main passage 22, and has a wide front surface and a rear surface, and a pair of narrow side surfaces, namely an upstream end surface 223 and a downstream end surface. 224. In addition, the X axis parallel to the central axis 22a of the main passage 22 and the short direction of the measuring portion 201m shown in FIG. 1, the Y axis parallel to the thickness direction of the measuring portion 201m, and the longitudinal direction of the measuring portion 201m. A three-dimensional Cartesian coordinate system consisting of a Z-axis is displayed in each figure.

With the physical quantity detection device 20 attached to the main passage 22, the measuring unit 201m protrudes from the inner wall of the main passage 22 toward the central axis 22a of the main passage 22, and has a front surface and a rear surface along the central axis 22a of the main passage 22. are arranged parallel to each other. The measurement portion 201m is arranged such that the upstream end surface 223 on one side in the width direction of the measurement portion 201m faces the upstream side of the main passage 22 between the upstream end surface 223 and the downstream end surface 224 having narrow widths. The downstream end surface 224 on the other hand direction side is arranged to face the downstream side of the main passage 22 .

The measurement part 201m has an upstream end surface 223 of the tip part 201t on the side opposite to the flange 201f provided at the base end part to take part of the gas 2 to be measured such as intake air into the secondary passage 234 in the measurement part 201m. An inlet 231 is provided openly. Moreover, the measurement part 201m has a first outlet 232 for returning the gas to be measured 2 taken into the sub-passage 234 in the measurement part 201m back to the main passage 22 on the downstream end face 224 opposite to the upstream end face 223 of the tip part 201t. and a second outlet 233 are provided.

In the physical quantity detection device 20, the entrance 231 of the sub-passage 234 is provided at the tip 201t of the measurement part 201m extending from the flange 201f toward the center of the main passage 22. Therefore, the physical quantity detection device 20 can take the gas not near the inner wall surface of the main passage 22 but near the central portion away from the inner wall surface into the sub-passage. As a result, the physical quantity detection device 20 can measure the flow rate of the gas in the portion distant from the inner wall surface of the main passage 22, and can suppress a decrease in accuracy due to the influence of heat or the like.

A sub-passage groove 250 for forming a sub-passage 234 and a circuit chamber 235 for accommodating the circuit board 207 are provided in the measurement section 201m. The circuit chamber 235 and the sub-passage groove 250 are provided in a concave shape on one surface of the plate-like measuring portion 201m in the thickness direction of the measuring portion 201m.

The circuit chamber 235 is arranged upstream in the main passage 22 in the flow direction of the gas to be measured 2 , and the sub passage 234 is arranged in the main passage 22 downstream of the circuit chamber 235 in the flow direction of the gas to be measured 2 . placed in position. The secondary passageway groove 250 forms the secondary passageway 234 with the cover. The sub-passage groove 250 has a first sub-passage groove 251 and a second sub-passage groove 252 branching in the middle of the first sub-passage groove 251 .

The first sub-passage groove 251 extends between an inlet 231 opening at an upstream end surface 223 of the measuring portion 201m and a first outlet 232 opening at a downstream end surface 224 of the measuring portion 201m. is formed to extend along the The first sub-passage groove 251 forms a first sub-passage 234 a extending from the inlet 231 along the central axis 22 a of the main passage 22 to the first outlet 232 with the cover. The first auxiliary passage 234 a takes in the measured gas 2 flowing in the main passage 22 from the inlet 231 and returns the taken-in measured gas 2 from the first outlet 232 to the main passage 22 . The first sub-passage 234 a has a branched portion between the inlet 231 and the first outlet 232 .

The second sub-passage groove 252 forms a second sub-passage 234b that branches from the first sub-passage 234a toward the flange 201f and reaches the second outlet 233 between the cover and the second sub-passage 234b. The second outlet 233 is open so as to face the downstream side in the flow direction of the gas 2 to be measured in the main passage 22 . The second outlet 233 has an opening area larger than that of the first outlet 232, and is formed closer to the proximal end in the longitudinal direction of the measuring section 201m than the first outlet 232 is. The second sub-passage 234b has, for example, a linear upstream portion 237, an arcuate or U-shaped curved portion 238, and a linear downstream portion 239, and reciprocates along the longitudinal direction of the measuring portion 201m. have a route to

More specifically, the second sub-passage groove 252 that forms the second sub-passage 234b branches, for example, from the first sub-passage groove 251 toward the flange 201f in the longitudinal direction of the measurement portion 201m. It extends in a direction substantially orthogonal to the central axis 22a. Further, the second sub-passage groove 252, for example, bends in a U-shape or arcuately toward the distal end portion 201t near the flange 201f of the measurement portion 201m and turns back to extend in the longitudinal direction of the measurement portion 201m, that is, the main passage 22. extends in a direction orthogonal to the central axis 22a of the . Furthermore, the second sub-passage groove 252 is connected to the second outlet 233 by bending in an arc shape toward the downstream end face 224 of the measuring portion 201m, for example.

The gas 2 to be measured flowing through the main passage 22 shown in FIG. In addition, the gas to be measured 2 flowing in the first sub-passage 234a flows into the second sub-passage 234b from the branch portion of the first sub-passage 234a during the forward flow. The measured gas 2 branched from the first sub-passage 234 a and flowed into the second sub-passage 234 b passes through the second sub-passage 234 b and returns to the main passage 22 from the second outlet 233 .

The physical quantity detection device 20 includes, for example, a thermal flow sensor 300 arranged in the upstream portion 237 of the second sub-passage 234b as a detection element for detecting physical quantities. More specifically, in the upstream portion 237 of the second sub-passage 234b, the thermal flow sensor 300 is arranged between the first sub-passage 234a and the curved portion 238. As shown in FIG. Since the second sub-passage 234b has the curved shape as described above, it is possible to ensure a longer passage length. The influence on the sensor 300 can be reduced.

The circuit board 207 is accommodated in a circuit chamber 235 provided on one side in the short direction of the measuring section 201m. The circuit board 207, for example, extends along the longitudinal direction of the measuring section 201m, and extends along the lateral direction of the measuring section 201m at the end of the measuring section 201m on the flange 201f side, and is generally L-shaped. has the shape of

An intake air temperature sensor 203 , a pressure sensor 204 , a humidity sensor 206 , and a chip package 208 having a thermal flow sensor 300 are mounted on the surface of the circuit board 207 . That is, the physical quantity detection device 20 includes, for example, an intake air temperature sensor 203, a pressure sensor 204, a thermal flow sensor 300, and a humidity sensor as elements for detecting physical quantities such as temperature, pressure, flow rate, and humidity. 206.

The intake air temperature sensor 203 is arranged, for example, in the temperature detection passage and measures the temperature of the measured gas 2 flowing through the temperature detection passage. The temperature detection passage has an entrance, for example, near an entrance 231 that opens to the upstream end face 223 of the measurement section 201m, and has exits at both the front and rear covers 202 of the measurement section 201m.

The pressure sensor 204 measures the pressure of the gas 2 to be measured within the circuit chamber 235 , and the humidity sensor 206 measures the humidity of the gas 2 to be measured within the circuit chamber 235 . The circuit chamber 235 is defined between the housing 201 and the cover 202, communicates with the second sub-passage 234b through the pressure introduction passage, and the gas to be measured 2 flows from the second sub-passage 234b through the pressure introduction passage. influx.

FIG. 3 is a schematic cross-sectional view of the chip package 208 taken along line III-III in FIG. The chip package 208 has, for example, a lead frame 208f, a thermal flow sensor 300, an intermediate member 208i, a resin sealing portion 208r, and an electronic component 208e.

The lead frame 208f includes, for example, a die pad 208d sealed with a resin sealing portion 208r, outer leads 208o exposed from the resin sealing portion 208r, and inner leads (not shown) connecting these. The lead frame 208f is made of, for example, a metal plate having a coefficient of linear expansion similar to that of the semiconductor substrate 301 forming the thermal flow sensor 300. As shown in FIG.

The material of lead frame 208f is, for example, 42 alloy or copper. The coefficient of linear expansion of 42 alloy from 30° C. to 330° C. is about 4.5 [×10 ⁻⁶ /° C.] to about 6.5 [×10 ⁻⁶ /° C.]. The coefficient of linear expansion of copper from 20° C. to 300° C. is approximately 17.6 [×10 ⁻⁶ /° C.].

The thermal flow sensor 300 is a semiconductor element mounted on the lead frame 208f. Thermal flow sensor 300 includes, for example, semiconductor substrate 301 , cavity 302 , and diaphragm 310 . Semiconductor substrate 301 is placed, for example, on die pad 208d of lead frame 208f. The semiconductor substrate 301 is made of a semiconductor such as single crystal silicon (Si) and formed into a rectangular plate shape, and has a laminated portion formed by laminating an insulating film and a wiring film on the surface. The semiconductor substrate 301 is adhered, for example, via a die attach film (DAF) 208t to a peel preventing portion 208a formed on the surface of the intermediate member 208i.

The hollow portion 302 is formed in a concave shape on the back surface side of the semiconductor substrate 301 opposite to the stacked portion on the front surface by removing a portion of the semiconductor substrate 301 by wet etching, dry etching, or the like. Cavity 302 communicates with the outside of chip package 208 via, for example, ventilation passage 208v. The ventilation passage 208v is formed, for example, between a groove formed on the back surface of the die pad 208d on which the thermal flow rate sensor 300 is mounted and a resin sheet 208s such as polyimide adhered to the back surface. formed.

Diaphragm 310 is composed of a thin portion of semiconductor substrate 301 . More specifically, diaphragm 310 is part of a laminate formed on the surface of semiconductor substrate 301 and closes one end of cavity 302 . For example, the diaphragm 310 is formed by removing a part of the semiconductor substrate 301 by wet etching or dry etching from the back surface side of the semiconductor substrate 301 opposite to the front surface side of the semiconductor substrate 301 having the laminated portion, thereby forming a recessed cavity portion 302 . is provided by forming That is, by forming a cavity portion 302 from the back side of the semiconductor substrate 301 and exposing the laminated portion including the SiO ₂ layer, the SiN layer, the wiring layer, etc. on the front side of the semiconductor substrate 301 to the cavity portion 302 as a thin portion. , a diaphragm 310 is formed.

The thickness of the diaphragm 310 is, for example, 2 [μm] or more and 10 [μm] or less, more specifically, for example, about 4 [μm]. The thickness of the semiconductor substrate 301 is, for example, 300 [μm] or more and 1 [mm] or less, more specifically, for example, about 400 [μm]. That is, the thickness of diaphragm 310 is, for example, about 1/100 of the thickness of semiconductor substrate 301 . The surface side of the diaphragm 310 on the side opposite to the cavity 302 serves as a flow rate detection section having a pair of temperature detection elements (not shown) and a heating resistor provided between the pair of temperature detection elements. .

The thermal flow sensor 300 and the lead frame 208f, the electronic component 208e and the lead frame 208f, and the thermal flow sensor 300 and the electronic component 208e are connected by bonding wires, for example. The electronic component 208e is, for example, an LSI including a control circuit that operates the thermal flow sensor 300, and is adhered to the peel prevention portion 208a of the intermediate member 208i via the DAF 208t. Note that the electronic component 208 e may be arranged outside the chip package 208 , such as being mounted on the circuit board 207 .

The intermediate member 208 i is arranged between the die pad 208 d of the lead frame 208 f and the semiconductor substrate 301 of the thermal flow sensor 300 . The intermediate member 208i includes a metal plate 208m having a coefficient of linear expansion equivalent to that of the semiconductor substrate 301, a peeling prevention portion 208a provided on the surface of the metal plate 208m to prevent the resin sealing portion 208r from peeling, have

Here, the fact that the coefficient of linear expansion of the metal plate 208m and the coefficient of linear expansion of the semiconductor substrate 301 are equal means that, for example, the number of digits of the coefficient of linear expansion of the metal plate 208m and the number of digits of the coefficient of linear expansion of the semiconductor substrate 301 are equal to each other. is equal. For example, if the coefficient of linear expansion of the metal plate 208m is greater than 1/10 and less than 10 times the coefficient of linear expansion of the semiconductor substrate 301, the coefficient of linear expansion of the metal plate 208m and the coefficient of linear expansion of the semiconductor substrate 301 are are equivalent.

In this embodiment, the material of the semiconductor substrate 301 is, for example, silicon, and the coefficient of linear expansion of the semiconductor substrate 301 is, for example, about 4.15 [×10 ⁻⁶ /° C.] at temperatures from 10° C. to 50° C. . The material of the metal plate 208m is, for example, 42 alloy, and the linear expansion coefficient of the metal plate 208m is, for example, about 4.5 [×10 ^-6 /°C] at temperatures from 30°C to 330°C. to about 6.5 [×10 ⁻⁶ /° C.]. The material of the metal plate 208m is not particularly limited as long as the coefficient of linear expansion is the same as the coefficient of linear expansion of the material of the semiconductor substrate 301 .

At least a portion of the peeling prevention portion 208a is exposed outside the region where the semiconductor substrate 301 is bonded on the surface of the metal plate 208m, and is covered with the resin sealing portion 208r. The detachment preventing portion 208a is, for example, a resin coating layer formed on the surface of the metal plate 208m or a metal layer formed on the surface of the metal plate 208m. When the detachment preventing portion 208a is a resin coating layer, the material of the resin coating layer is, for example, acrylic resin, polyimide, or epoxy resin. The resin coating layer is formed by spraying and drying these resins on the surface of the metal plate 208m.

When the delamination preventing portion 208a is a metal layer, the material of the metal layer is, for example, nickel, copper, or silver. The metal layer is, for example, a plated layer formed on the surface of the metal plate 208m by plating, or a sputtered layer formed on the surface of the metal plate 208m by sputtering. A plated layer and a sputtered layer can be distinguished, for example, by surface observation using an electron microscope.

When the delamination preventing portion 208a is a metal layer, the metal layer may be, for example, a roughened plating layer formed by roughening the surface of the metal plate 208m with nickel, copper, or silver. The roughened plating layer has, for example, a plurality of pinpoint-shaped minute projections on the surface, and the surface roughness is increased compared to the relatively flat surface of the metal plate 208m.

When the peeling prevention portion 208a is a metal layer, the surface roughness is greater than that of the metal plate 208m in any of the plating layer, the sputtering layer, and the roughening plating layer. That is, the value (S-ratio) obtained by dividing the surface area of the defined region of the surface of the metal layer as the peel preventing portion 208a by the area of the defined region is the surface area of the defined region of the surface of the metal plate 208m divided by the area of the defined region. greater than the divided value (S-ratio).

The resin sealing portion 208r is provided integrally and seals the die pad 208d of the chip package 208, the intermediate member 208i, and at least a portion of the semiconductor substrate 301. More specifically, the resin sealing portion 208r covers, for example, most of the die pad 208d, the entire intermediate member 208i, and a portion of the semiconductor substrate 301 excluding the flow rate detection portion. The resin sealing portion 208r is formed, for example, by insert molding in which the lead frame 208f on which the thermal flow sensor 300 and the electronic component 208e are mounted is arranged in a mold and a resin material is molded. For example, an epoxy resin can be used as the resin material of the resin sealing portion 208r.

The resin sealing portion 208r has a concave groove in which the thermal flow sensor 300 is arranged on the surface facing the circuit board 207. This concave groove has a constricted shape in which the width gradually narrows from both ends toward the center in the flow direction of the gas to be measured 2 flowing in the upstream portion 237 of the second sub-passage 234b, and the width is narrowest at the center. A thermal flow sensor 300 is arranged. Due to the constricted shape of the groove, the measured gas 2 flowing through the second sub-passage 234b is rectified, and the influence of noise on the thermal flow sensor 300 can be reduced.

The thermal flow sensor 300 measures, for example, the flow rate of the measured gas 2 flowing through the channel between the groove of the chip package 208 and the circuit board 207 . More specifically, the gas to be measured 2 flows through, for example, a flow path between the groove of the chip package 208 and the circuit board 207 and a flow path between the second sub-passage groove 252 of the housing 201 and the circuit board 207. and the channel between the chip package 208 and the cover. Then, the flow rate, which is one of the physical quantities of the gas 2 to be measured flowing through the flow path between the groove of the chip package 208 and the circuit board 207, is detected by the flow rate detector provided in the diaphragm 310 of the thermal flow sensor 300. detected.

The operation of the semiconductor device of this embodiment will be described below.

The semiconductor device of the present embodiment is used in a physical quantity detection device 20 for detecting the physical quantity of the gas 2 to be measured, which is intake air flowing through a main passage 22 such as an intake body of the internal combustion engine control system 1, for example. be done. Therefore, the semiconductor device of the present embodiment is required to have durability against thermal shock caused by repeated high and low temperatures and long-term exposure to high temperature or high temperature and humidity.

In the conventional sensor device described in Patent Document 1, the coefficient of linear expansion of the intermediate member arranged between one surface of the support lead and the lower surface of the sensor chip is approximately equal to that of the substrate of the sensor chip. With such a configuration, the stress generated due to the difference in coefficient of linear expansion between the substrate constituting the sensor chip and the member adjacent to the substrate is reduced. We are hiring. Therefore, in this conventional sensor device, the material cost and processing cost of the intermediate member are factors that increase the cost of the sensor device.

In contrast, as shown in FIG. 3, the semiconductor device of the present embodiment includes a lead frame 208f, a semiconductor substrate 301 arranged on the die pad 208d of the lead frame 208f, and the die pad 208d and the semiconductor substrate 301. and an intermediate member 208i disposed therebetween. The semiconductor device of this embodiment further includes a resin sealing portion 208r that is integrally provided and seals the die pad 208d, the intermediate member 208i, and at least a portion of the semiconductor substrate 301. FIG. The intermediate member 208i includes a metal plate 208m having a coefficient of linear expansion equivalent to that of the semiconductor substrate 301, a peeling prevention portion 208a provided on the surface of the metal plate 208m to prevent the resin sealing portion 208r from peeling, have.

As described above, in the semiconductor device of this embodiment, the intermediate member 208i interposed between the semiconductor substrate 301 and the die pad 208d of the lead frame 208f is replaced by the metal plate 208m having a coefficient of linear expansion similar to that of the semiconductor substrate 301. Configured by As a result, the material cost and processing cost of the intermediate member 208i can be reduced as compared with the case where a glass substrate containing silicon oxide as the main component is used as the intermediate member 208i. An increase in stress can be suppressed.

On the other hand, the shear strength between the surface of the metal plate 208m constituting the intermediate member 208i and the resin sealing portion 208r tends to be lower than the shear strength between the surface of the glass substrate and the resin sealing portion 208r. be. Therefore, if the semiconductor device is subjected to a thermal shock or exposed to a high temperature or high temperature and humidity environment for a long time, peeling may occur at the bonding interface between the surface of the metal plate 208m and the resin sealing portion 208r. There is

On the other hand, in the semiconductor device of the present embodiment, as described above, the intermediate member 208i has the detachment preventing portion 208a provided on the surface of the metal plate 208m to prevent detachment of the resin sealing portion 208r. . That is, the shear strength between the peel prevention portion 208a and the resin sealing portion 208r is higher than the shear strength between the metal plate 208m and the resin sealing portion 208r. As a result, the semiconductor device of this embodiment prevents the resin sealing portion 208r from peeling off from the intermediate member 208i even when subjected to thermal shock or exposed to a high temperature or high temperature and high humidity environment for a long time. can do.

Further, in the semiconductor device of this embodiment, the material of the semiconductor substrate 301 is silicon, and the material of the metal plate 208m is 42 alloy. With such a configuration, in the semiconductor device of the present embodiment, the coefficient of linear expansion of the metal plate 208m can be equal to that of the semiconductor substrate 301, that is, the difference can be within one digit. Thermal stress acting on 301 can be reduced.

Further, in the semiconductor device of the present embodiment, at least part of the separation prevention portion 208a is exposed outside the region where the semiconductor substrate 301 is adhered on the surface of the metal plate 208m as shown in FIG. It is covered with the stopping portion 208r. With such a configuration, the separation preventing portion 208a exposed outside the region where the semiconductor substrate 301 is bonded on the surface of the metal plate 208m and the resin sealing portion 208r are firmly coupled, and the resin sealing portion 208r is an intermediate member. Separation from 208i can be more reliably prevented.

In addition, in the semiconductor device of the present embodiment, the separation preventing portion 208a is, for example, a resin coating layer formed on the surface of the metal plate 208m. With such a configuration, the molecules are bonded together by a chemical reaction between the detachment preventing portion 208a and the resin sealing portion 208r, and the resin sealing portion 208r is strongly bonded to the detachment preventing portion 208a. Bonding by such a chemical reaction becomes stronger when, for example, the resin coating layer is made of acrylic resin and the resin sealing portion 208r is made of epoxy resin. In addition, the surface of the metal plate 208m and the detachment preventing portion 208a, which is a resin coating layer, serve as a bond between the surface of the metal plate 208m and the resin sealing portion 208r when the metal plate 208m is insert-molded into the resin sealing portion 208r. They are more tightly bound in comparison. Therefore, it is possible to more reliably prevent the resin sealing portion 208r from peeling off from the intermediate member 208i.

In addition, in the semiconductor device of the present embodiment, the separation preventing portion 208a is, for example, a metal layer formed on the surface of the metal plate 208m. With such a configuration, the surface roughness of the separation preventing portion 208a can be made rougher than the surface roughness of the metal plate 208m. As a result, the resin sealing portion 208r that covers the separation preventing portion 208a is more strongly bonded to the surface of the separation preventing portion 208a due to the anchor effect, compared to the case where the resin sealing portion 208r covers the surface of the metal plate 208m. Therefore, it is possible to more reliably prevent the resin sealing portion 208r from peeling off from the intermediate member 208i.

Further, in the semiconductor device of the present embodiment, when the separation preventing portion 208a is a metal layer, the value (S-ratio) obtained by dividing the surface area in the defined region of the surface of the metal layer by the area of the defined region is the metal plate Greater than the surface area of a defined region of a 208 m surface divided by the area of that defined region (S-ratio). With such a configuration, the surface roughness of the detachment preventing portion 208a is made rougher than that of the metal plate 208m, and the resin sealing portion 208r can be more strongly bonded to the surface of the detachment preventing portion 208a by the anchor effect. can. Therefore, it is possible to more reliably prevent the resin sealing portion 208r from peeling off from the intermediate member 208i.

Also, the semiconductor device of this embodiment is a chip package 208 having a thermal flow sensor 300 . With such a configuration, the semiconductor device of the present embodiment provides the reliability and durability of the thermal flow sensor 300 in the physical quantity detection device 20 used in an environment where thermal shock acts or in a high temperature or high temperature and high humidity environment. can be improved and costs can be reduced.

Although the embodiment of the semiconductor device according to the present disclosure has been described in detail above with reference to the drawings, the specific configuration is not limited to this embodiment, and design changes, etc. within the scope of the present disclosure are possible. are intended to be included in this disclosure.

For example, in the above embodiments, the semiconductor device according to the present disclosure is a chip package including a thermal flow sensor, but the semiconductor device according to the present disclosure is not limited to this example. The semiconductor device according to the present disclosure includes a lead frame, a semiconductor substrate, an intermediate member disposed therebetween, and is applicable to all semiconductor devices including a resin sealing portion that seals them. .

[Shear strength test]
Hereinafter, with reference to FIGS. 4 to 11, a description will be given of a shear strength test for proving the effect of preventing peeling of the resin sealing portion by the peeling prevention portion provided on the surface of the intermediate member of the semiconductor device described in the above-described embodiments. do. FIG. 4 is a perspective view showing the dimensions of the test piece. 5 is a schematic side view showing a shear strength test using the test piece of FIG. 4. FIG.

First, test pieces TP of Comparative Example 1, Example 1, and Example 2 were produced. In the test piece TP of Comparative Example 1, a plurality of truncated cone-shaped resins imitating the resin sealing portion of the semiconductor device described in the above-described embodiment was used without forming the separation prevention portion on the surface of the 42 alloy metal plate. Part R was molded. The diameter of the upper surface, the diameter of the lower surface, and the height of the resin portion R were set to 4 mm, 5 mm, and 3 mm, respectively, and the pitch between the resin portions R was set to 15 mm.

In the test piece TP of Example 1, the surface of the 42 alloy metal plate was subjected to nickel roughening plating to form a peel-preventing portion of the metal layer with an S-ratio of 1.25, and the above-mentioned comparative example was formed thereon. A plurality of resin parts R were molded in the same manner as in 1. In the test piece TP of Example 2, nickel roughening plating was applied to the surface of the metal plate of 42 alloy to form a peel-preventing portion of the metal layer with an S-ratio of 2, and the above-mentioned Comparative Example 1 and A plurality of resin parts R were formed in the same manner.

After that, the test pieces of Comparative Example 1, Example 1, and Example 2 were subjected to a thermal shock test to apply thermal shock, a high temperature test to maintain high temperature, and a high temperature and high humidity test to maintain high temperature and high humidity. In the thermal shock test, the temperature of the environment in which the specimen TP was placed was maintained at −40° C. for 30 minutes, followed by a thermal cycle in which the temperature of the environment in which the specimen TP was placed was maintained at 140° C. for 30 minutes. , repeated over a given test time. In the high temperature test, the temperature of the environment in which the specimen TP was placed was maintained at 140°C for the prescribed test time. In the high temperature humidity test, the temperature and humidity of the environment in which the specimen TP was placed was maintained at 85°C and 85% RH for the prescribed test time.

After that, as shown in FIG. 5, a metal plate was placed at a height of 100 μm by a jig of an external force loading device with respect to the resin portion R on the test pieces of Comparative Example 1, Example 1, and Example 2 that had undergone each test. An external force F parallel to the surface of was applied to peel off the resin portion R. Then, using the following formula (1), the shear strength between the surface of the metal plate or the peel-preventing portion and the resin portion R was calculated for each test piece that had undergone each test.

Shear strength [MPa] = external force F [N] at the time of peeling / bonding area [mm ² ] (1)

FIG. 6 is a graph showing the shear strength ISS [MPa] of the test pieces TP of Comparative Example 1, Example 1, and Example 2 that have undergone a thermal shock test. In addition, each graph shows the results of the thermal shock test when the test time is from 0 [h] to 2000 [h]. As shown in FIG. 6, the shear strength ISS in Examples 1 and 2 in which the anti-peeling portion is formed by roughening nickel plating is higher than the shear strength ISS in Comparative Example 1 in which the anti-peeling portion is not formed. Especially when the test time is 1000 [h] or more, the shear strength ISS of Examples 1 and 2 is improved to about twice the shear strength ISS of Comparative Example 1, and the S-ratio is higher than that of Example 1. The shear strength ISS is improved in Example 2, which has a higher value.

FIG. 7 is a graph showing the shear strength ISS [MPa] of the test pieces TP of Comparative Example 1, Example 1, and Example 2 that have undergone a high temperature test. FIG. 8 is a graph showing the shear strength ISS [MPa] of the test pieces TP of Comparative Example 1, Example 1, and Example 2 that underwent a high-temperature, high-humidity test. The test pieces TP of Examples 1 and 2 that have undergone the high temperature test and the high temperature and high humidity test also show the same tendency as the test pieces TP that have undergone the thermal shock test.

Next, test pieces TP of Comparative Example 2 and Example 3 were produced. In the test piece TP of Comparative Example 2, as in the test piece TP of Comparative Example 1, a plurality of resin portions R were formed without forming an anti-separation portion on the surface of the 42 alloy metal plate. In the test piece TP of Example 3, the surface of a 42-alloy metal plate is nickel-plated to form a peel-preventing portion for the metal layer, and a plurality of resin portions R are formed thereon in the same manner as in Comparative Example 2 described above. bottom. After that, the test pieces of Comparative Example 2 and Example 3 were subjected to the thermal shock test and the high temperature and high humidity test described above.

FIG. 9 is a graph showing the shear strength ISS [MPa] of the test pieces TP of Comparative Example 2 and Example 3 that have undergone the thermal shock test. FIG. 10 is a graph showing the shear strength ISS [MPa] of the test pieces TP of Comparative Example 2 and Example 3 that have undergone the high temperature and high humidity test. As shown in FIG. 9, no significant difference was observed between the shear strengths ISS of the test pieces TP of Comparative Example 2 and Example 3 in the test pieces TP that had undergone the thermal shock test.

However, as shown in FIG. 10, in the test piece TP that has undergone the high-temperature and high-humidity test, the shear strength ISS of the test piece TP of Example 3 is lower than that of the test piece TP of Comparative Example 2 at a test time of 1000 [h] or more. The shear strength is higher than ISS. Therefore, even if a metal layer is formed on the surface of the metal plate as a detachment prevention portion by a normal plating process other than roughening plating, detachment of the resin portion in a high-temperature and high-humidity environment can be prevented.

208 chip package (semiconductor device)
208a peeling prevention part (resin coating layer, metal layer)
208d die pad

208f lead frame

208m metal plate 208i intermediate member 208r resin sealing portion 300 thermal flow sensor 301 semiconductor substrate

Claims

A semiconductor device comprising a lead frame, a semiconductor substrate arranged on a die pad of the lead frame, and an intermediate member arranged between the die pad and the semiconductor substrate,
further comprising a resin sealing portion integrally provided to seal the die pad, the intermediate member, and at least a portion of the semiconductor substrate;
The intermediate member includes a metal plate having a coefficient of linear expansion equal to that of the semiconductor substrate, and a peeling prevention portion provided on the surface of the metal plate to prevent the resin sealing portion from peeling off. A semiconductor device characterized by:
The material of the semiconductor substrate is silicon,
2. The semiconductor device according to claim 1, wherein the material of said metal plate is 42 alloy.
2. At least a part of said separation preventing part is exposed outside a region of said surface of said metal plate to which said semiconductor substrate is adhered, and is covered with said resin sealing part. The semiconductor device according to .
3. The semiconductor device according to claim 1, wherein the separation preventing portion is a resin coating layer formed on the surface of the metal plate.
3. The semiconductor device according to claim 1, wherein the peeling preventing portion is a metal layer formed on the surface of the metal plate.
A value obtained by dividing the surface area of the defined region of the surface of the metal layer by the area of the defined region is larger than the value obtained by dividing the surface area of the defined region of the surface of the metal plate by the area of the defined region. 6. The semiconductor device according to claim 5.
The semiconductor device according to claim 1, wherein the semiconductor device is a chip package equipped with a thermal flow sensor.