JP6523034B2 - Semiconductor mounting structure - Google Patents

Description

  The present invention relates to a semiconductor mounting structure.

  Conventionally, a semiconductor pressure sensor (hereinafter, simply referred to as a pressure sensor) as a semiconductor mounting structure using MEMS (Micro Electro-Mechanical Systems) technology is used for portable devices and the like. As this type of pressure sensor, for example, a pressure sensor element, a semiconductor circuit chip (control element) receiving a signal from the pressure sensor element, a lead frame electrically connected to these, and a mold for covering the semiconductor circuit chip There exist some provided with resin (for example, refer patent documents 1-3).

Patent No. 3620185 JP, 2000-329632, A Patent No. 53511943

Such a semiconductor mounted structure achieves miniaturization by sealing the semiconductor circuit chip with a mold resin. However, a molded semiconductor circuit chip is susceptible to stress from the mold resin, and there is a possibility that the operation of the semiconductor circuit chip is adversely affected when the mold resin is deformed due to moisture absorption or temperature change.
The present invention has been made in view of the above problems, and an object of the present invention is to provide a semiconductor mounting structure capable of more accurate operation by reducing the load applied to a semiconductor circuit chip.

  The semiconductor mounting structure of the present invention is formed by curing a lead frame, a semiconductor circuit chip mounted on the first surface of the lead frame, and a liquid material supplied so as to cover the semiconductor circuit chip. The edge portion is formed on the first surface of the lead frame along the outline of the first surface when the semiconductor circuit chip is viewed in plan.

  In the semiconductor mounted structure, a distance between the edge portion and a side surface forming an outer shape of the semiconductor circuit chip may be larger than half of a thickness of the semiconductor circuit chip.

  In the semiconductor mounted structure, a distance between the edge portion and a side surface forming an outer shape of the semiconductor circuit chip may be larger than that of another portion at a corner of the outer shape of the semiconductor circuit chip.

  In the semiconductor mounting structure, a recessed groove along the outer shape of the semiconductor circuit chip is formed on the first surface of the lead frame, and the edge portion is at the boundary between the recessed groove and the first surface. It may be formed.

  In the semiconductor mounted structure, the plurality of recessed grooves may be intermittently formed on the first surface of the lead frame along the outer shape of the semiconductor circuit chip.

  In the semiconductor mounted structure, a distance between adjacent ones of the grooves formed intermittently may be 1/3 or less of a length of the grooves.

  In the semiconductor mounting structure, a mounting area for mounting the semiconductor circuit chip is formed at a position higher than the other area on the first surface of the lead frame, and the area between the mounting area and the other area is formed. A step may be formed along the outer shape of the semiconductor circuit chip, and the edge portion may be formed at the boundary between the step and the mounting area.

  The semiconductor mounting structure may include a base on which the lead frame, the semiconductor circuit chip, and the stress relieving layer are embedded, and a Young's modulus of the stress relieving layer may be lower than a Young's modulus of the base.

  In the semiconductor mounted structure, the Young's modulus of the stress relieving layer may be 1/10 or less of the Young's modulus of the base.

  In the semiconductor mounting structure, a pressure sensor chip is disposed on the second surface side opposite to the first surface of the lead frame such that at least a portion thereof overlaps with the semiconductor circuit chip in plan view, The semiconductor circuit chip may output a pressure detection signal in response to a sensor signal from the pressure sensor chip.

  In the semiconductor mounting structure, a pressure sensor chip is disposed on a second surface opposite to the first surface of the lead frame via a placement portion, and the placement portion is the first surface in a plan view. It may be located inside the field surrounded by the edge part of a face of a.

  In the semiconductor mounting structure, a pressure sensor chip is disposed on the second surface opposite to the first surface of the lead frame via the placement portion, and the Young's modulus of the material constituting the placement portion is And may be equal to or greater than the Young's modulus of the material constituting the lead frame.

According to the present invention, since the stress relieving layer covers the periphery of the semiconductor circuit chip, it is possible to relieve the stress generated in the members around the semiconductor circuit chip and to suppress the load applied to the semiconductor circuit chip.
Further, the supplied liquid stress relaxation layer before curing is prevented from spreading by wetting at the edge portion by surface tension. By curing this, the stress relieving layer is not formed in an unintended region, and the semiconductor circuit chip can be covered with certainty.

It is a top view of a pressure sensor of a 1st embodiment. It is a sectional side view of the pressure sensor of 1st Embodiment which follows the II-II line of FIG. FIG. 3 is a plan view of a lead frame and a semiconductor circuit chip used for the pressure sensor of the first embodiment, as viewed from a first surface of the lead frame. It is an enlarged view of the area | region A of FIG. It is a figure shown as a plane view which looked at a lead frame and a semiconductor circuit chip of the 1st modification which can be adopted to a 1st embodiment from a 1st field of a lead frame. It is an expanded sectional view which shows the peripheral part of the lead frame of a 1st modification, and the relationship of a stress relieving layer. It is a figure shown as a plane view which looked at a lead frame and a semiconductor circuit chip of the 2nd modification which can be adopted to a 1st embodiment from a 1st field of a lead frame. It is a figure shown as a plane view which looked at a lead frame and a semiconductor circuit chip of a 3rd modification which can be adopted to a 1st embodiment from a 1st field of a lead frame. It is a figure shown as a plane view which looked at a lead frame and a semiconductor circuit chip of a 4th modification which can be adopted to a 1st embodiment from the 1st field of a lead frame. It is a figure shown as a plane view which looked at a lead frame and a semiconductor circuit chip of a 5th modification which can be adopted to a 1st embodiment from a 1st field of a lead frame. It is an expanded sectional view showing a relation of a level difference of a level difference of a lead frame of a 6th modification which can be adopted to a 1st embodiment, and a stress relief layer. It is a top view of the pressure sensor of a 2nd embodiment. It is a sectional side view of the pressure sensor of 2nd Embodiment which follows the XIII-XIII line of FIG. It is a sectional side view of the pressure sensor of 3rd Embodiment. It is a sectional side view of the pressure sensor of a comparison form.

First Embodiment
Hereinafter, embodiments will be described with reference to the drawings.
In the drawings used in the following description, for the purpose of emphasizing the characteristic portions, the characteristic portions may be enlarged and shown for convenience, and the dimensional ratio of each component may be limited to the same as the actual Absent. Moreover, for the same purpose, there may be a case where parts which are not characteristic are omitted.

FIG. 1 is a plan view of a pressure sensor 100 as a semiconductor mounting structure according to the first embodiment. 2 is a cross-sectional view taken along line II-II in the pressure sensor 100 of FIG.
In each of the drawings, an XYZ coordinate system is shown. In the following description, each direction will be described based on each coordinate system as necessary.

  As shown in FIGS. 1 and 2, the pressure sensor (semiconductor mounting structure) 100 includes a lead frame 40, a pressure sensor chip 20, a protective agent 60, a semiconductor circuit chip 30, a stress relaxation layer 70, and a substrate. And 10.

The lead frame 40 has a plate shape. The semiconductor circuit chip 30 is mounted on the first surface 41 of the lead frame 40. The stress relief layer 70 is formed by supplying and curing a liquid material so as to cover the semiconductor circuit chip 30. The pressure sensor chip 20 is disposed on the second surface side of the lead frame 40. The pressure sensor chip 20 is covered by a protective agent 60.
Hereinafter, each part which comprises the pressure sensor 100 is demonstrated in detail.

<Substrate>
The substrate 10 is made of, for example, a resin such as an engineering plastic such as epoxy, PPS (polyphenylene sulfide resin), PBT (polybutylene terephthalate) or the like. The base 10 has the lead frame 40, the semiconductor circuit chip 30, the bonding wire 51 and the stress relieving layer 70 embedded in the resin of the base 10 to be integrated. As a result, the lead frame 40, the semiconductor circuit chip 30, the bonding wire 51, and the stress relieving layer 70 can be shielded from the outside air and moisture, and these can be protected.
The constituent resin of the base 10 is, for example, an epoxy resin, and its Young's modulus is, for example, 1 GPa to 50 GPa (preferably 10 GPa to 30 GPa).

The base 10 is a main body portion (semiconductor circuit chip side base body) 16 formed on the first surface 41 side (−Z side) of the lead frame 40 and an annular wall portion projecting annularly from the main body portion 16 to the + Z side. 12 and a collar 13 formed on the outer periphery of the annular wall 12.
The annular wall 12 and the collar 13 are integrally formed with the main body 16.
In addition, the main-body part 16 of the base | substrate 10 of this embodiment, the cyclic | annular wall part 12, and the collar part 13 are planar view circular. However, the shape in plan view is not limited to a circle, but may be an arbitrary shape such as a rectangle or another polygon.

  The annular wall portion 12 is formed in a cylindrical shape, and a housing portion 19 in which the pressure sensor chip 20 is housed is formed in the inner space thereof. The housing portion 19 is filled with a protective agent 60 that protects the pressure sensor chip 20.

A mounting portion 17 extending as a part of the base 10 is formed on a part of the bottom surface of the housing portion 19. The mounting portion 17 is formed on the second surface 42 side of the lead frame 40, and the pressure sensor chip 20 is installed.
A portion of the lead frame 40 (the sensor lead portion 44) is exposed on the bottom surface of the housing portion 19 where the mounting portion 17 is not formed. The pressure sensor chip 20 is electrically connected to the exposed lead frame 40 by a bonding wire 50.

  The placement unit 17 may be a member separate from the base 10. In that case, as a material which comprises the mounting part 17, the thing whose hardness is lower than the resin material which comprises the base | substrate 10, for example can be selected. As a result, the stress applied to the pressure sensor chip 20 due to moisture absorption or thermal expansion of the substrate 10 can be reduced, and the measurement accuracy of the pressure sensor 100 can be enhanced. Further, as the mounting portion 17 described above is formed thicker, the influence of this kind of stress can be alleviated, and the measurement accuracy can be further enhanced.

  The collar portion 13 is provided to protrude on the outer periphery of the base 10. The surface 13a formed on the + Z side of the ridge portion 13 is formed flat. When the pressure sensor 100 is mounted on a portable device, by pressing a gasket between the surface 13 a of the collar 13 and the lid of the portable device, waterproofing on the −Z side of the collar 13 is realized.

<Lead frame>
The lead frame 40 is a plate made of a conductor.
The semiconductor circuit chip 30 is disposed on the first surface 41 of the lead frame 40. Further, the pressure sensor chip 20 is disposed on the second surface 42 side opposite to the first surface 41 of the lead frame 40 via the mounting portion 17.

The lead frame 40 is preferably made of a material excellent in thermal conductivity. Thereby, overheating or overcooling of the pressure sensor chip 20 and the semiconductor circuit chip 30 can be prevented. Therefore, it is advantageous in stabilizing the operation of the pressure sensor chip 20 and the semiconductor circuit chip 30.
As such a material, the lead frame 40 is preferably formed of a metal such as copper (Cu) or iron (Fe).

FIG. 3 shows a plan view from the side of the first surface 41 (−Z side) of the lead frame 40. The lead frame 40 shown in FIG. 3 is shown in a state in which a portion bent at the inside of the pressure sensor 100 (a bent portion 45 a) is developed.
The lead frame 40 includes a pedestal 46 on which the semiconductor circuit chip 30 is mounted, four terminal terminals 45, and four sensor leads 44.
The number of terminal terminals 45 and sensor leads 44 is not limited to this.

The semiconductor circuit chip 30 is mounted on the pedestal portion 46, and a stress relaxation layer 70 covering the semiconductor circuit chip 30 is further formed.
In the pedestal portion 46, the first groove 41 is formed on the first surface 41 so as to draw a quadrilateral. Inside the recessed groove 43, a mounting area 46a for mounting the semiconductor circuit chip 30 is formed. The mounting area 46 a partitioned by the recessed groove 43 has a shape along the outer shape of the semiconductor circuit chip 30. That is, the recessed groove 43 is formed along the outer shape of the semiconductor circuit chip 30.
The recessed groove 43 suppresses the wetting and spreading of the stress relaxation layer 70 before hardening to the outside of the recessed groove 43.

FIG. 4 is an enlarged view of the region A of FIG. 2 and is a view showing the concave groove 43 and the state of the stress relaxation layer 70 in which the wetting and spreading is suppressed by the concave groove 43.
The recessed groove 43 of the present embodiment is formed in a V-shape or a U-shape, and has two slopes 43 b inclined in the depth direction. An edge portion 43a is formed at the edge between the slope 43b and the mounting area 46a. That is, the mounting area 46 a is partitioned by, in particular, the edge portion 43 a of the recessed groove 43.

  The liquid stress relaxation layer 70 before hardening is wetted by being supplied to the mounting area 46 a and covers the mounting area 46 a. Furthermore, when reaching the edge portion 43a which is the peripheral edge of the mounting area 46a, the wetting and spreading are stopped by surface tension, and it is possible to suppress the wetting and spreading of the stress relaxation layer 70 before hardening. By curing the uncured material in this state, the stress relaxation layer 70 can be formed only inside the mounting area 46 a.

The recessed groove 43 in the present embodiment is formed such that the edge portion 43 a formed on the mounting area 46 a side is at a distance W from the side surface 34 of the semiconductor circuit chip 30. The distance W is preferably larger than half of the thickness H of the semiconductor circuit chip 30, and more preferably larger than H.
The stress relieving layer 70 formed in the mounting area 46 a is formed in a dome shape whose outer surface 72 a is a curved convex surface by surface tension. That is, the stress relieving layer 70 is thinner in the vicinity of the edge portion 43a and gradually thickens toward the center. On the other hand, the semiconductor circuit chip 30 has a corner 35 that is perpendicular to the side surface 34 and the lower surface 31. Therefore, in the semiconductor circuit chip 30, the corner 35 between the side surface 34 and the lower surface 31 is easily exposed from the stress relieving layer 70.
By setting the distance W to be larger than 1/2 of the thickness H of the semiconductor circuit chip 30, the stress relieving layer 70 can reliably cover the whole of the semiconductor circuit chip 30 including the corner 35.

As an example, when the thickness H of the semiconductor circuit chip 30 is 300 μm, the distance W between the edge portion 43 a and the side surface 34 of the semiconductor circuit chip 30 is preferably 150 μm or more.
The stress relieving layer 70 may form an intervening portion 71 between the semiconductor circuit chip 30 and the lead frame 40 (see FIG. 4). When the thickness of the intervening portion 71 can not be ignored with respect to the thickness H of the semiconductor circuit chip 30, the distance W is larger than 1⁄2 of the sum of the thickness of the intervening portion 71 and the thickness H of the semiconductor circuit chip 30. It is preferable to do.

    The distance W between the edge portion 43a and the side surface 34 of the semiconductor circuit chip 30 does not have to be constant. For example, the recessed groove 43 may be formed in a meandering manner, and the distance W may be changed in a range where the distance W is larger than 1⁄2 of the thickness H of the semiconductor circuit chip 30.

The depth D1 of the recessed groove 43 is preferably 10 μm or more. By setting the depth D1 to 10 μm or more, the wetting and spreading of the stress relaxation layer 70 before hardening can be reliably suppressed by the surface stress.
The depth D1 of the recessed groove 43 is preferably 2/3 or less, more preferably 1/2 or less of the thickness of the lead frame 40. Thereby, the strength of the lead frame 40 can be secured, and breakage in the assembly process can be prevented.

The recessed groove 43 can be formed by etching. Thereby, the sharp edge part 43a is formed, and the wetting and spreading of the stress relaxation layer 70 can be reliably suppressed by surface tension.
In addition, the method of forming the recessed groove 43 may be formed by photolithography or may be formed by machining.

The terminal 45 is electrically connected to the semiconductor circuit chip 30 by the bonding wire 51.
The terminal terminal 45 is a terminal used to exchange signals and power between the pressure sensor 100 and the outside, and is provided corresponding to, for example, a power supply terminal, a ground terminal, a signal input terminal, a signal output terminal, and the like.
The terminal 45 has a connecting portion 45 b to which the bonding wire 51 is connected, a groove 45 c and a bent portion 45 a.
The groove 45 c is a groove formed on the first surface 41 side. The groove 45c can be formed by etching or the like. The terminal 45 is bent by raising the bent portion 45a with respect to the connecting portion 45b, with the groove 45c as a valley. The terminal terminal 45 is formed so that the bent portion 45a rises, so that one surface of the bent portion 45a is exposed in a sufficient area on the peripheral surface of the base 10 or the like to secure a contact with the outside (not shown) ).

As shown in FIG. 2, the sensor lead portion 44 is electrically connected to the semiconductor circuit chip 30 by the bonding wire 51 on the first surface 41. In addition, the sensor lead portion 44 is electrically connected to the pressure sensor chip 20 by the bonding wire 50 on the second surface 42.
The sensor lead portion 44 is provided as a relay terminal for exchanging signals between the semiconductor circuit chip 30 and the pressure sensor chip 20.

  In FIG. 2, the removal portion 47 is indicated by broken lines around the sensor lead portion 44 and the pedestal portion 46. These removing portions 47 are provided by the base 10 for holding by the mold when the lead frame 40 is insert-molded. The removal portion 47 is cut and removed after the substrate 10 is formed.

<Pressure sensor chip>
The pressure sensor chip 20 includes, for example, a diaphragm, a sealed space as a reference pressure chamber, and a plurality of strains for measuring changes in strain resistance of the diaphragm due to pressure on one side of a semiconductor substrate made of silicon or the like. It is equipped with a gauge. The strain gauges are electrically connected to different sensor leads 44 via bonding wires 50, respectively.

In the pressure sensor chip 20, when the diaphragm portion receives pressure and bends, a stress corresponding to the strain amount of the diaphragm portion is generated in each strain gauge, and the resistance value of the strain gauge changes according to this stress, and this resistance value A sensor signal corresponding to the change is output.
The pressure sensor chip 20 is a pressure sensor chip using MEMS (Micro Electro-Mechanical Systems) technology.

The pressure sensor chip 20 is housed in the housing portion 19 and fixed on the mounting portion 17.
The pressure sensor chip 20 is provided on the second surface 42 side of the lead frame 40. In addition, the pressure sensor chip 20 may be disposed at a position where a partial area or the whole area is deviated from the lead frame 40 in a plan view.

  The pressure sensor chip 20 is disposed with the upper surface 21 opposite to the mounting portion 17 as a surface on which a circuit is formed. The circuit of the pressure sensor chip 20 is connected to the sensor lead portion 44 of the lead frame 40 via the bonding wire 50 connected to the upper surface 21.

<Protective agent>
The protective agent 60 is filled in the container 19 and covers the pressure sensor chip 20.
The protective agent 60 prevents the infiltration of water and outside air, and protects the pressure sensor chip 20 from these.
As the protective agent 60, for example, a silicone resin or a fluorine-based resin can be used. The protective agent 60 can be in liquid or gel form. The protective agent 60 preferably has a high viscosity.
As the protective agent 60, for example, it is desirable to use a soft gel agent having a hardness of about 0 (Shore A hardness; in accordance with JIS K 6253). Since the pressure applied from the measuring object can be transmitted to the pressure sensor chip 20 as it is, the accuracy of pressure detection by the pressure sensor chip 20 is not reduced.
The protective agent 60 can prevent water and outside air from entering and can prevent the pressure sensor chip 20 from being adversely affected.

  The protective agent 60 preferably has low light transmittance and blocks visible light and ultraviolet light. Thereby, deterioration of the pressure sensor chip 20 can be prevented. A pigment etc. may be contained in the protective agent 60, and light transmittance may be made low.

<Semiconductor circuit chip>
The semiconductor circuit chip 30 is, for example, an integrated circuit (IC).
The semiconductor circuit chip 30 has a rectangular shape in plan view, and has a rectangular bottom surface 33, side surfaces 34 respectively formed on the four peripheral portions, and a bottom surface 31 opposite to the bottom surface 33. Have.

  The semiconductor circuit chip 30 is disposed on the mounting area 46 a of the pedestal 46 on the first surface 41 of the lead frame 40. As described above, the mounting area 46 a is an area defined by the edge portion 43 a of the recessed groove 43. The semiconductor circuit chip 30 is disposed such that the side surface 34 thereof is at a constant distance W from the edge portion 43a.

  The semiconductor circuit chip 30 is at a position where at least a part thereof overlaps the pressure sensor chip 20 in a plan view. The pressure sensor 100 can be miniaturized by arranging the semiconductor circuit chip 30 and the pressure sensor chip 20 to overlap in a plan view as described above.

  When the sensor signal from the pressure sensor chip 20 is input, the semiconductor circuit chip 30 processes this and outputs it as a pressure detection signal. A sensor signal from the pressure sensor chip 20 is input to the semiconductor circuit chip 30 via the bonding wire 50, the sensor lead portion 44, and the bonding wire 51.

The semiconductor circuit chip 30 has a temperature sensor 32 for measuring an external temperature, an A / D converter (not shown) for A / D converting a signal from the temperature sensor 32 and outputting it as a temperature signal, and the temperature signal is input. And an arithmetic processing unit (not shown).
The arithmetic processing unit can correct the sensor signal from the pressure sensor chip 20 based on the temperature signal.
As the temperature sensor 32, a resistance type (bridge resistance type), a diode type, a thermocouple type, an infrared type, or the like can be adopted. By incorporating the temperature sensor 32, the semiconductor circuit chip 30 can correct the pressure detection signal according to the temperature in the system. Therefore, highly accurate pressure measurement can be performed.
It is desirable that the temperature sensor 32 be provided at a position close to the lower surface 31 inside the semiconductor circuit chip 30 to enhance the accuracy of the temperature measurement.

  The semiconductor circuit chip 30 is provided such that the bottom surface 33 is opposed to the first surface 41 side of the lead frame 40. The semiconductor circuit chip 30 is preferably arranged such that the entire area is accommodated in the pedestal portion 46 of the lead frame 40 in plan view.

  The semiconductor circuit chip 30 is disposed with the lower surface 31 opposite to the lead frame 40 as a surface on which a circuit is formed. The circuit of the semiconductor circuit chip 30 is connected to the sensor lead portion 44 and the terminal terminal 45 of the lead frame 40 via the bonding wire 51 connected to the lower surface 31.

The semiconductor circuit chip 30 and the pressure sensor chip 20 are disposed on the lead frame 40 so as to overlap with each other on the opposite side in plan view. Thus, the wiring length can be shortened and the influence of noise can be reduced.
In addition, since the semiconductor circuit chip 30 and the pressure sensor chip 20 are disposed close to each other via the lead frame 40, the temperature difference between the two can be reduced. As a result, accurate temperature measurement can be performed in the temperature sensor 32 of the semiconductor circuit chip 30, and the pressure detection value can be corrected with high accuracy to improve the detection accuracy.

<Stress relaxation layer>
The stress relieving layer 70 covers the bottom surface 33, the four side surfaces 34, and the lower surface 31 of the semiconductor circuit chip 30. The stress relieving layer 70 is formed by supplying and curing in the uncured state.
The stress relaxation layer 70 has a Young's modulus lower than that of the material of the substrate 10 and the material of the lead frame 40, and functions to relieve the stress applied to the semiconductor circuit chip 30.

  The stress relieving layer 70 has an intervening portion 71 provided on the bottom surface 33 side of the semiconductor circuit chip 30 and a covering portion 72 provided on the side surface 34 and the lower surface 31 side of the semiconductor circuit chip 30. In the stress relieving layer 70 of the present embodiment, the intervening portion 71 and the covering portion 72 are formed in separate steps.

  The intervening portion 71 covers the entire area of the bottom surface 33 of the semiconductor circuit chip 30. In addition, the interposing portion 71 is formed between the bottom surface 33 and the first surface 41 of the lead frame 40. Therefore, the bottom surface 33 of the semiconductor circuit chip 30 is separated from the lead frame 40.

  By providing the intervening portion 71, the semiconductor circuit chip 30 can be prevented from being stressed due to the difference in the thermal expansion coefficient of the base 10, the lead frame 40, and the semiconductor circuit chip 30, and the moisture absorption of the base 10.

  The intervening portion 71 preferably has a constant thickness. The thickness of the intervening portion 71 can be, for example, 5 to 100 μm (preferably 10 to 50 μm). By setting the thickness of the intervening portion 71 to 5 μm or more, a high stress relaxation effect can be obtained. Moreover, the thickness dimension of the whole can be suppressed by thickness being 100 micrometers or less.

The intervening portion 71 can be formed on the bottom surface 33 before the semiconductor circuit chip 30 is mounted on the lead frame 40.
In this case, the intervening portion 71 is formed by supplying an uncured (liquid) material to the bottom surface 33 of the semiconductor circuit chip 30 before mounting by a dispenser or the like, curing it by heating or the like, and thereafter forming the lead frame 40 It can be formed by mounting.

The intervening portion 71 may be formed by supplying an uncured material to the first surface 41 of the pedestal portion 46 of the lead frame 40 and curing the same before mounting the semiconductor circuit chip 30.
In this case, first, the first surface 41 of the lead frame 40 is directed upward (in FIG. 2, the state of being vertically reversed). Next, an uncured (liquid) material is supplied from above to the mounting area 46 a (inside the recessed groove 43) of the pedestal portion 46 by a dispenser or the like. Next, the semiconductor circuit chip 30 is mounted on the uncured material supplied, and the uncured material is cured by heating or the like to form the intervening portion 71.
Alternatively, an uncured material may be supplied to the mounting area 46a, and curing may be repeated to form the thickly coated intervening portion 71.

  In addition, the intervening portion 71 may be formed by attaching a sheet made of a low Young's modulus material to the semiconductor circuit chip 30 or the first surface 41 of the pedestal portion 46 of the base frame 40.

The covering portion 72 is formed in a dome shape so as to cover the whole of the semiconductor circuit chip 30.
The covering portion 72 covers the entire area of the four side surfaces 34 and the lower surface 31 of the semiconductor circuit chip 30 and is fixed. Further, the covering portion 72 covers and fixes the peripheral region on which the semiconductor circuit chip 30 is mounted in the pedestal portion 46 of the lead frame 40.

By providing the covering portion 72, the semiconductor circuit chip 30 can be prevented from being stressed due to the difference in the thermal expansion coefficient of the base 10, the lead frame 40, and the semiconductor circuit chip 30, and the moisture absorption of the base 10.
In addition, after the semiconductor circuit chip 30 is mounted on the lead frame 40, the substrate 10 is made to insert resin by making the resin wrap around these. Therefore, when the resin material constituting the base 10 is cured, stress may remain and a load may be applied to the semiconductor circuit chip 30. By providing the covering portion 72, the stress from the base 10 can be relaxed, and the load applied to the semiconductor circuit chip 30 can be reduced.
Furthermore, by providing the covering portion 72, even if the base 10 is deformed by an external force, moisture absorption or the like, it is possible to suppress application of stress resulting from this to the semiconductor circuit chip 30.
Thereby, the measurement function of the semiconductor circuit chip 30 can be maintained normally.

The outer surface 72a of the covering portion 72 forms a curved convex surface. That is, the covering portion 72 is thickest at its central portion, and becomes thinner toward the periphery. By forming the outer surface 72a of the covering portion 72 as a curved convex surface, stress concentration hardly occurs. Thus, even when the base 10 is deformed by external force, moisture absorption, thermal stress or the like, the effect of suppressing the influence of the base 10 on the semiconductor circuit chip 30 can be enhanced.
Further, by forming the outer surface 72a of the covering portion 72 as a curved convex surface, when forming the base 10 by insert molding, the resin material constituting the base 10 flows smoothly in the mold, and voids etc. are formed in the base 10. It is possible to suppress the formation of defects.

The covering portion 72 is formed after the semiconductor circuit chip 30 is mounted on the lead frame 40 and electrically connected by the bonding wire 51.
An example of a method of forming the covering portion 72 will be described. First, an uncured (liquid) material is supplied from above the semiconductor circuit chip 30 by a dispenser or the like in a state in which the first surface 41 of the lead frame 40 is directed upward (in FIG. 2, upside down). The supplied uncured material forms a dome shape by surface tension and covers the semiconductor circuit chip 30. Also, the uncured material wets and spreads so as to cover the mounting area 46a. When the uncured material reaches the recessed groove 43, its surface tension suppresses the wetting and spreading, and does not spread outside the recessed groove 43.
In this state, the covering portion 72 is formed by curing the uncured material by heating or the like.
The covering portion 72 thus formed is integrated with the intervening portion 71 to form a stress relieving layer 70 covering the entire surface (bottom surface 33, side surface 34, lower surface 31) of the semiconductor circuit chip 30.

  As a material of which the stress relieving layer 70 is made, a thermosetting resin, an ultraviolet curable resin, or the like can be used. Specifically, the stress relaxation layer 70 is made of, for example, a silicone resin, an epoxy resin, a urethane resin, a polyimide resin, or the like. In addition, two or more of these materials may be used in combination. Among these, silicone resins are most preferable because they hardly absorb moisture, and their physical properties do not change easily even in high temperature and high humidity environments.

The Young's modulus of the stress relaxation layer 70 is preferably, for example, 1 MPa to 500 MPa (preferably 1 MPa to 100 MPa).
The Young's modulus of the stress relaxation layer 70 is preferably 1/10 or less (preferably 1/100 or less) of the Young's modulus of the constituent material of the substrate 10. In addition, Young's modulus can be measured by the method of JISK7161 and JISK7244.

  The stress relaxation layer 70 is preferably made of a resin material having low thixotropy (thixotropy). The resin material to which the thixotropic agent is added exhibits high thixotropic properties, and therefore, it is preferable to use the stress relaxation layer 70 to which the thixotropic agent is not added. As a resin material of the stress relaxation layer 70, a water-soluble polymer (cellulose or polycarboxylic acid) or inorganic particles (silica, clay mineral such as layered silicate) is added in place of the thixotropic agent to obtain characteristics. It is possible to use what has been viewed.

  As an example, the resin material of the stress relaxation layer 70 is, in a rotational viscometer described in JIS K 7117, a ratio of viscosity at 2 rpm to viscosity at 20 rpm per minute (viscosity at 2 rpm / viscosity at 20 rpm) A resin material having a thixotropy index of 1.7, which is required as the above, can be adopted as the stress relaxation layer 70.

  By using a material with low thixotropy as the stress relieving layer 70, when the material of the stress relieving layer 70 before curing is supplied by a dispenser or the like, this material can wet and spread on the coated surface. Therefore, the height J (see FIG. 2) of the stress relaxation layer 70 does not become too large. On the other hand, when a material with high thixotropy is used, the height J of the stress relieving layer 70 becomes large, and a thin portion may be formed on the substrate 10 covering the stress relieving layer 70.

  On the other hand, when a material with low thixotropy is used, there is a possibility that the uncured material may wet and spread to an unintended region to form the stress relaxation layer 70. In the pressure sensor 100 of the present embodiment, the mounting area 46 a is partitioned by the recessed groove 43 in order to hold the area where the stress relaxation layer 70 is formed in the mounting area 46 a of the lead frame 40. By forming the recessed groove 43, it is possible to suppress the uncured stress relaxation layer 70 from spreading outside the mounting area 46a.

<Comparison form>
The pressure sensor 700 which is not equipped with the ditch | groove 43 in the lead frame 740 as a comparison form in FIG. 15 is shown. In addition, about the component similar to 1st Embodiment, the same code | symbol is attached | subjected and the description is abbreviate | omitted.
The stress relieving layer 770 of the pressure sensor 700 is formed on the entire surface of the pedestal 746 on the first surface 741 of the lead frame 740. This is because supplying the uncured stress relaxation layer 770 to the pedestal 746 spreads the pedestal 746 in its entirety. As a result, the thin portion 710a is formed on the base 710 near the portion where the pedestal portion 746 of the lead frame 740 is exposed to the outside, etc., and there is a possibility that desired strength can not be obtained. Furthermore, the interface between the stress relieving layer 770 and the base 710 may be exposed to the outer peripheral surface of the pressure sensor 700, and a crack may be generated from the exposed interface.
Also, as the stress relieving layer 770 wets and spreads, it becomes necessary to supply a large amount of uncured stress relieving layer 770 in order to completely cover the semiconductor circuit chip 30. As a result, the supply time of the stress relaxation layer 770 becomes longer, and the production cost is increased.

  The pressure sensor 100 according to the first embodiment solves the above-described problem in the pressure sensor 700 of the comparative embodiment by forming the recessed groove 43 in the lead frame 40 and partitioning the mounting area 46 a.

<Manufacturing method>
An example of a method of manufacturing the pressure sensor 100 will be described.
The stress relief layer 70 in the uncured state is supplied to the bottom surface 33 of the semiconductor circuit chip 30 or the mounting area 46 a of the lead frame 40 and cured to form the intervening portion 71 of the stress relief layer 70.
Next, the semiconductor circuit chip 30 is placed on the lead frame 40, and the semiconductor circuit chip 30 and the lead frame 40 are connected by the bonding wires 51.
Then, the stress relief layer 70 in the uncured state is supplied and cured so as to cover the semiconductor circuit chip 30 to form the covering portion 72 of the efficacy relief layer.
Next, the semi-assembled product formed in the previous steps is placed in a mold, and the substrate 10 is formed by resin molding.
Then, the pressure sensor chip 20 is placed on the mounting portion 17 of the base 10, and the pressure sensor chip 20 and the sensor lead portion 44 are connected by the bonding wire 50.
Then, the protective agent 60 is filled in the housing portion 19 to cover the pressure sensor chip 20.
Through the above steps, the pressure sensor 100 can be formed.

  In the pressure sensor 100 of the present embodiment, the stress relieving layer 70 covers the periphery of the semiconductor circuit chip 30. Therefore, it is possible to relieve the stress generated in the components (the base 10 and the lead frame 40) around the semiconductor circuit chip 30, and to suppress the load applied to the semiconductor circuit chip 30. By this, it can be avoided that an output error of, for example, the temperature sensor 32 of the semiconductor circuit chip 30 becomes large.

  The substrate 10 is in a state of being subjected to stress generated at the time of curing of the resin and thermal stress generated by the temperature difference between the curing temperature and the room temperature. In this state, if temperature stress or humidity stress is applied due to the external environment, the base 10 or the like is easily deformed. In addition, the lead frame 40 may be deformed as the base 10 or the like is deformed. In particular, in a high temperature and high humidity environment, such a deformation is likely to occur because the substrate 10 easily absorbs moisture.

In the pressure sensor 100, since the semiconductor circuit chip 30 is in contact with the stress relieving layer 70 made of a low Young's modulus material, the pressure caused by the deformation of the base 10 and the lead frame 40 can be suppressed from reaching the semiconductor circuit chip 30.
Therefore, even if temperature stress or humidity stress is applied to the base 10 etc. due to a change in the external environment, the measurement function of the temperature sensor 32 of the semiconductor circuit chip 30 is normally maintained, and the output of the temperature sensor 32 has an error. It can be suppressed to occur.

  In the present embodiment, the stress relieving layer 70 includes the intervening portion 71 formed between the semiconductor circuit chip 30 and the lead frame 40, and the covering portion 72 covering the side surface 34 and the lower surface 31 of the semiconductor circuit chip 30. Have. However, even if the stress relaxation layer 70 has a configuration in which either the intervening portion 71 or the covering portion 72 is provided, certain effects can be achieved.

First Modified Example
Next, a lead frame 140 of a first modified example that can be adopted in the above-described first embodiment will be described based on FIG. 5 and FIG. In addition, the description is abbreviate | omitted about the component same as 1st Embodiment.

FIG. 5 is a plan view from the first surface 141 side (−Z side) of the lead frame 140. FIG. 5 corresponds to FIG. 3 showing the lead frame 40 of the first embodiment.
The lead frame 140 includes a pedestal 146 on which the semiconductor circuit chip 130 is mounted, four terminal terminals 145, and four sensor leads 144.

The semiconductor circuit chip 130 is mounted on the pedestal portion 146, and a stress relaxation layer 170 covering the semiconductor circuit chip 130 is further formed.
In the pedestal portion 146, a rectangular mounting area 146a partitioned by the recessed groove 143 and the peripheral portion 146b of the pedestal portion 146 is formed. The mounting area 146 a has a shape along the outer shape of the semiconductor circuit chip 130.
The recessed groove 143 and the peripheral portion 146 b suppress the wetting and spreading of the stress relieving layer 170 before hardening to the outside of the mounting region 146 a.

  The principle of suppressing the wetting and spreading of the stress relaxation layer 170 before curing is the same as that of the first embodiment described above. The principle of suppressing the wetting and spreading of the stress relieving layer 170 before hardening will be described based on FIG.

FIG. 6 shows an enlarged cross-sectional view of the peripheral portion 146 b of the pedestal 146 and the stress relieving layer 170 whose wetting and spreading are suppressed by the peripheral portion 146 b.
The peripheral portion 146 b is formed substantially at right angles to the mounting area 146 a formed on the first surface 141 of the pedestal 146. Therefore, an edge 146 d is formed at the boundary between the peripheral edge 146 b and the mounting area 146 a.
The mounting area 146a is surrounded by an edge portion 146d by the peripheral portion 146b of the pedestal portion 146 and an edge portion (corresponding to the edge portion 43a in FIG. 4) by the recessed groove 143.

  The stress relieving layer 170 before curing is wet spread by being supplied to the mounting area 146a and covers the mounting area 146a. Further, when reaching the edge portion which is the peripheral edge of the mounting area 146a, the surface tension stops the wetting and spreading. This can suppress the stress relieving layer 170 from being formed outside the mounting region 146a.

  The peripheral portion 146 b of the pedestal 146 is formed such that the edge 146 d is at a distance W from the side surface 134 of the semiconductor circuit chip 130. Preferably, the distance W is greater than 1⁄2 of the thickness H of the semiconductor circuit chip 130. By making the distance W larger than half of the thickness H of the semiconductor circuit chip 130, the stress relieving layer 170 can reliably cover the semiconductor circuit chip 130.

Second Modified Example
Next, a lead frame 240 of a second modified example that can be adopted in the above-described first embodiment will be described based on FIG. 7. FIG. 7 corresponds to FIG. 3 showing the lead frame 40 of the first embodiment, and the description of the same components is omitted.

FIG. 7 is a plan view from the first surface 241 side (−Z side) of the lead frame 240.
The lead frame 240 includes a pedestal 146 on which the semiconductor circuit chip 230 is mounted, four terminal terminals 245, and four sensor leads 244.

A semiconductor circuit chip 230 is mounted on the pedestal 246, and a stress relief layer 270 covering the semiconductor circuit chip 230 is formed.
In the pedestal portion 246, a rectangular mounting area 246a is formed, which is divided by the plurality of concave grooves 243 intermittently formed and the peripheral portion 246b of the pedestal portion 246. The mounting area 246 a has a shape along the outer shape of the semiconductor circuit chip 230.
The recessed groove 243 and the peripheral portion 246 b suppress the wetting and spreading of the stress relieving layer 270 before hardening outside the mounting area 246 a.

The lead frame 240 of the second modification is different from the lead frame 140 (see FIG. 6) of the first modification in that a plurality of concave grooves 243 are formed intermittently.
An inter-groove portion 243 a between adjacent concave grooves 243 is a flat surface continuous with the first surface 241. Therefore, in the lead frame 240, the recessed groove 243 and the inter-groove portion 243a are formed in order along the side surface 234 of the semiconductor circuit chip 230.

  Thus, the strength of the lead frame 140 can be enhanced by forming the intermittent concave grooves 243 and forming the inter-groove portions 243 a between the adjacent concave grooves 243. Therefore, the lead frame 140 can be easily handled in the assembly process, and the simplicity of the assembly process can be increased.

In the lead frame 240 of the second modification, the liquid stress relaxation layer 270 in a liquid state before hardening is spread by the edge portion (corresponding to the edge portion 43a in FIG. 4) formed at the boundary between the recessed groove 243 and the mounting region 246a. Can be suppressed. In addition, although the inter-groove portion 243 a is a flat surface, the stress relaxation layer 270 before hardening is not spread by wetting from the inter-groove portion 243 a due to surface tension generated in the recessed groove 243.
The distance between adjacent concave grooves 243 (that is, the length of the inter-groove portion 243 a) is preferably 1/3 or less of the length of the concave groove 243. Within this range, the wetting and spreading from the inter-groove portion 243 a can be sufficiently suppressed by the surface tension generated by the recessed groove 243.

Third Modified Example
Next, a lead frame 340 of a third modification that can be employed in the first embodiment described above will be described based on FIG. FIG. 8 corresponds to FIG. 3 showing the lead frame 40 of the first embodiment, and the description of the same components is omitted.

FIG. 8 is a plan view from the first surface 341 side (−Z side) of the lead frame 340.
The lead frame 340 includes a pedestal 346 on which the semiconductor circuit chip 330 is mounted, four terminal terminals 345, and four sensor leads 344.

The semiconductor circuit chip 330 is mounted on the pedestal portion 346, and a stress relief layer 370 covering the semiconductor circuit chip 330 is further formed.
In the pedestal portion 346, a rectangular mounting area 346a surrounded by the peripheral edge portion 346b of the pedestal portion 346 and the recessed groove 343 is formed. The mounting area 346 a has a shape along the side surface 334 of the outer shape of the semiconductor circuit chip 330.

  The peripheral portion 346b is formed substantially at right angles to the mounting area 346a formed on the first surface 341 of the pedestal portion 346. Therefore, the edge between the peripheral portion 346b and the mounting area 346a is an edge portion. (Corresponding to the edge portion 146 d in FIG. 6) is formed. Further, an edge portion (corresponding to the edge portion 43 a in FIG. 4) is formed between the mounting area 346 a and one of the terminal terminals 345 by the recessed groove 343. These edge portions suppress the spreading of the stress relaxation layer 370 before hardening. Thus, formation of the stress relaxation layer 370 outside the mounting area 346a can be suppressed.

Fourth Modified Example
Next, a lead frame 440 of a fourth modified example that can be adopted in the first embodiment described above will be described based on FIG. FIG. 9 corresponds to FIG. 3 showing the lead frame 40 of the first embodiment, and the description of the same components is omitted.

FIG. 9 is a plan view from the first surface 441 side (−Z side) of the lead frame 440.
The lead frame 440 includes a pedestal 446 on which the semiconductor circuit chip 430 is mounted, four terminal terminals 445, and four sensor leads 444.

The semiconductor circuit chip 430 is mounted on the pedestal 446, and a stress relief layer 470 covering the semiconductor circuit chip 430 is further formed.
In the pedestal portion 446, a mounting region 446a surrounded by the recessed groove 443 and the peripheral portion 446b of the pedestal portion 446 is formed.

The stress relieving layer 470 is formed in a dome shape. Further, since the semiconductor circuit chip 430 is formed in a rectangular shape, it is most easily exposed from the stress relieving layer 470 at the corner portion 436 of the outer shape.
In the lead frame 440 of the fourth modification, the mounting region 446 a formed in the pedestal 446 is formed wider in the vicinity of the corner 436 of the outer shape of the semiconductor circuit chip 430 than the other portions.
The recessed groove 443 is formed at a distance W from the side surface 434 of the semiconductor circuit chip 430 except in the vicinity of the corner portion 436 of the semiconductor circuit chip 430. In the vicinity of the corner portion 436 of the semiconductor circuit chip 430, the recessed portion 443 or the peripheral portion 446b of the pedestal portion 446 is formed at a distance CW from the side surface 434 of the semiconductor circuit chip 430. The distance CW in the vicinity of the corner portion 436 is formed larger than the distance W of the portion other than the corner portion 436. The distance CW is preferably 1.4 times or more the distance W.
Thus, the stress relieving layer 470 can be widely spread to the outside of the semiconductor circuit chip 430 in the vicinity of the corner portion 436 of the semiconductor circuit chip 430, and exposure of the corner portion 436 can be suppressed.

Fifth Modified Example
Next, a lead frame 540 of a fifth modified example that can be adopted in the first embodiment described above will be described based on FIG. FIG. 10 corresponds to FIG. 3 showing the lead frame 40 of the first embodiment, and the description of the same components is omitted.

FIG. 10 is a plan view from the first surface 541 side (−Z side) of the lead frame 540.
The lead frame 540 includes a pedestal 546 on which the semiconductor circuit chip 530 is mounted, four terminal terminals 545, and four sensor leads 544.

A semiconductor circuit chip 530 is mounted on the pedestal portion 546, and a stress relaxation layer 570 covering the semiconductor circuit chip 530 is further formed.
In the pedestal portion 546, a mounting region 546a surrounded by the recessed groove 543 and the peripheral portions 546b and 546c of the pedestal portion 546 is formed.

In the lead frame 540 of the fifth modification, the mounting area 546 a formed in the pedestal 546 is formed wider in the vicinity of the corner 536 of the outer shape of the semiconductor circuit chip 530 than the other parts.
A peripheral portion 546 c of the pedestal 546 is formed at a distance W from the semiconductor circuit chip 530 except near the corner 536 of the semiconductor circuit chip 530. Further, in the vicinity of the corner portion 536 of the semiconductor circuit chip 530, the peripheral portion 546b of the pedestal portion 546 is formed at a distance CW from the semiconductor circuit chip 530. The distance CW in the vicinity of the corner portion 536 is formed larger than the distance W of the portion other than the corner portion 536.
As a result, the stress relieving layer 570 can be widely spread to the outside of the semiconductor circuit chip 530 in the vicinity of the corner portion 536 of the semiconductor circuit chip 530, and exposure of the corner portion 536 can be suppressed.

<Sixth Modified Example>
In the above-described first embodiment (and its modification), the lead frame 40 is formed with an edge portion 43 a surrounding the semiconductor circuit chip 30.
The edge portion 43a of the first embodiment is formed as a boundary between the recessed groove 43 and the mounting area 46a. The edge 146 d of the first modification is formed as a boundary between the peripheral edge 146 b of the pedestal 146 and the mounting area 146 a. In the first embodiment and its modified example, in these edge portions, the surface tension is generated in the stress relaxation layer before curing.
However, the configuration for forming the edge portion is not limited to these, and the edge portion may be formed by a step formed at the periphery of the mounting region.
A lead frame having such an edge portion will be described based on FIG. 11 as a lead frame 640 of the sixth modification.

FIG. 11 is an enlarged cross-sectional view of the step 643 of the pedestal 646 of the lead frame 640 and the stress relaxation layer 670 whose wetting and spreading are suppressed by the step 643.
In the pedestal portion 646 of the first surface 641 of the lead frame 640, a mounting area 646a for mounting the semiconductor circuit chip 630 is formed at a position higher than the other area (non-mounting area 641a). A step 643 having a height D2 is formed along the outer shape of the semiconductor circuit chip 630 between the mounting area 646a and the non-mounting area 641a.

The step 643 is formed substantially at right angles to the mounting area 646a. Therefore, an edge portion 646 d is formed at the boundary between the step 643 and the mounting area 646 a.
The stress relaxation layer 670 before hardening is spread to the mounting area 646a by being supplied to the mounting area 646a and covers the mounting area 646a. Furthermore, when reaching the edge portion 646d which is the periphery of the mounting area 646a, the surface tension stops the wetting and spreading.

  The step 643 is formed such that the edge portion 646 d is at a distance W from the side surface 634 of the semiconductor circuit chip 630. Preferably, the distance W is greater than 1⁄2 of the thickness H of the semiconductor circuit chip 630. By making the distance W larger than half of the thickness H of the semiconductor circuit chip 630, the stress relieving layer 670 can reliably cover the semiconductor circuit chip 630.

  Such a step difference 643 can be provided, for example, in place of the recessed groove 43 (see FIG. 3) of the first embodiment. This can suppress the formation of the stress relieving layer 670 outside the mounting area 646a.

  The height D2 of the step 643 is preferably 10 μm or more. By setting the depth D2 to 10 μm or more, the wetting and spreading of the stress relaxation layer 670 before hardening can be reliably suppressed by the surface stress.

  The step 643 can form the first surface 641 of the lead frame 640 by mechanical processing such as pressing or cutting. Alternatively, the deposit may be stacked on the first surface 641 of the lead frame 640 with a uniform thickness to form a deposited layer having a height D 2 with respect to the first surface 641. In this case, the surface of the adhesion layer is configured as a mounting area 646a.

Second Embodiment
Next, a pressure sensor (semiconductor mounting structure) 800 according to a second embodiment will be described.
FIG. 12 is a plan view of the pressure sensor 800. FIG. FIG. 13 is a cross-sectional view taken along line XIII-XIII of the pressure sensor 800 of FIG. 12.
The pressure sensor 800 mainly differs in the configuration of the mounting portion 817 from the pressure sensor 100 of the first embodiment. In addition, the description is abbreviate | omitted about the component same as 1st Embodiment.

  As shown in FIGS. 12 and 13, the pressure sensor 800 includes the lead frame 40, the base 810, the pressure sensor chip 20, the protective agent 60, and the semiconductor circuit chip as in the pressure sensor 100 according to the first embodiment. 30 and a stress relaxation layer 70.

  In the lead frame 40 of the present embodiment, the recessed groove 43 is formed to draw a quadrilateral on the first surface 41 as in the first embodiment. The semiconductor circuit chip 30 is mounted in the area inside the recessed groove 43 in the first surface 41.

  The substrate 810 is made of a resin material as in the first embodiment. The base 810 has a cylindrical annular wall 12 that opens on the upper side (+ Z side), and in the internal space of the annular wall 12, a housing 19 in which the pressure sensor chip 20 is housed is formed. On a part of the bottom surface of the housing portion 19, a mounting portion 817 extending as a part of the base 810 is formed.

  The mounting portion 817 is formed on the second surface 42 side of the lead frame 40, and the pressure sensor chip 20 is mounted. The pressure sensor chip 20 is fixed to the mounting portion 817 by, for example, an adhesive 20 a. As shown in FIG. 12, the placement unit 817 has a rectangular shape. Bridge portions 817a radially extend from the four corners 817b of the mounting portion 817, respectively. The placement unit 817 is connected to the inner circumferential surface of the annular wall 12 via the bridge 817 a.

  The placement portion 817 is located inside the area surrounded by the recessed groove 43 of the lead frame 40 in plan view. The lead frame 40 may be deformed due to a swelling stress or the like due to moisture absorption of the base 810. The lead frame 40 is easily deformed starting from the locally thinned concave groove 43. The placement portion 817 is less likely to be affected by the deformation of the lead frame 40 by being disposed inside the recessed groove 43. The bridge portion 817a is disposed to overlap the recessed groove 43 in a plan view, but is formed to be sufficiently thin so as not to be affected by the deformation of the lead frame 40.

  According to the pressure sensor 800 of the present embodiment, the pressure sensor chip 20 is affected by the deformation of the lead frame 40 starting from the recessed groove because the mounting portion 817 is positioned inside the recessed groove 43 in plan view. It can be suppressed. That is, deformation of the mounting portion 817 together with the lead frame 40 is suppressed, and stress can not be applied to the pressure sensor chip 20 mounted on the mounting portion 817 due to the deformation of the lead frame 40, and accurate pressure measurement is possible. It becomes. In addition to the pressure sensor chip 20, stress is less likely to be applied to the semiconductor circuit chip 30.

Third Embodiment
Next, a pressure sensor (semiconductor mounting structure) 900 according to a third embodiment will be described.
FIG. 14 is a plan view of the pressure sensor 900. FIG.
The pressure sensor 900 mainly differs from the pressure sensor 100 of the first embodiment in the configuration of the mounting portion 917. In addition, the description is abbreviate | omitted about the component same as 1st Embodiment.

  Similar to the pressure sensor 100 of the first embodiment, the pressure sensor 900 has a lead frame 40 having a recessed groove 43 formed in the first surface 41, a base 910 made of a resin material, a pressure sensor chip 20, and protection. An agent 60, a semiconductor circuit chip 30, a stress relieving layer 70, and a mounting portion 917 are provided. In the present embodiment, the base 910 and the placement unit 917 are separate bodies.

  The base 910 has a cylindrical annular wall 12 opened to the upper side (+ Z side), and in the internal space of the annular wall 12, a housing 19 in which the pressure sensor chip 20 is housed is formed. A mounting portion 917 is mounted on the second surface 42 of the lead frame 40 on the bottom surface of the housing portion 19. The placement unit 917 is fixed to the lead frame 40 by an adhesive 917 a.

The placement unit 917 has, for example, a rectangular shape. The Young's modulus of the material forming the mounting portion 917 is equal to or greater than the Young's modulus of the material forming the lead frame 40. The mounting portion 917 can be made of, for example, a Cu alloy, Si, an Fe alloy, or alumina. In particular, it is preferable to use alumina having a high Young's modulus.
As described above, the lead frame 40 may be deformed due to the swelling stress or the like due to the moisture absorption of the base 910. By setting the Young's modulus of the material forming the mounting portion 917 to the above-described configuration, the mounting portion 917 exerts an effect of reinforcing the lead frame 40, and deformation of the lead frame 40 can be suppressed.
The reinforcing effect of the mounting portion 917 changes in accordance with the ratio of the thickness of the mounting portion 917 to the thickness of the lead frame 40. For example, the thickness of the mounting portion 917 is preferably 0.5 times or more and 3 times or less the thickness of the lead frame 40. Within this range, deformation of the lead frame 40 can be effectively suppressed.

  The placement portion 917 is located inside the area surrounded by the concave groove 43 of the lead frame 40 in a plan view. Since the lead frame 40 is easily deformed starting from the locally thin recessed groove 43, the placement portion 917 is hardly influenced by the deformation of the lead frame 40 by being disposed inside the recessed groove 43.

  According to the pressure sensor 900 of the present embodiment, the deformation of the lead frame 40 is suppressed by the mounting portion 917 being made of a material having a high Young's modulus. On the other hand, the placement portion 917 is less likely to be affected by the deformation of the lead frame 40 starting from the recessed groove 43 by being disposed inside the area surrounded by the recessed groove 43 in plan view. By these actions, the pressure chip mounted on the mounting portion 917 is less likely to be affected by the deformation of the lead frame 40, and the pressure sensor 900 can perform accurate pressure measurement. In addition to the pressure sensor chip 20, stress is less likely to be applied to the semiconductor circuit chip 30.

  In the second and third embodiments, the means for suppressing the deformation starting from the recessed groove 43 when the recessed groove 43 is provided in the lead frame 40 has been described. On the other hand, even when the step 643 is provided in the lead frame as shown in the sixth modification (FIG. 11) described above, deformation starting from the step 643 is likely to occur in the lead frame. The solutions in the second and third embodiments are effective in such a case.

  Although various embodiments of the present invention have been described above, each configuration and each combination thereof in each embodiment is an example, and addition, omission, replacement of a configuration, and the like without departing from the spirit of the present invention And other modifications are possible. Further, the present invention is not limited by the embodiments.

10, 810, 910 ... base body, 20 ... pressure sensor chip, 17, 817, 917 ... mounting portion, 30, 130, 230, 330, 430, 530, 630 ... semiconductor circuit chip, 34, 134, 234, 334, 434, 634 ... side surfaces 40, 140, 240, 340, 440, 540, 640 ... lead frames 41, 141, 241, 341, 441, 541, 641 ... first surface, 42 ... second surface, 43 , 143, 243, 343, 443, 543 ... recessed grooves 43a, 146 d, 646 d ... edge portions 44, 144, 244, 344, 444, 544 ... sensor lead portions 45, 145, 245, 345, 445, 545 ... terminal terminals 46, 146, 246, 346, 446, 546, 646 ... pedestal portions 46a, 146a, 246a, 346 446a 546a 646a mounting region 50 51 bonding wire 60 protective agent 70 170 270 370 470 570 670 stress relieving layer 71 intervening portion 72 covering portion 100, 800, 900 ... pressure sensor (semiconductor mounting structure), 146b, 246b, 346b, 446b, 546b, 546c ... peripheral part, 243a ... inter-groove part, 436, 536 ... corner part 641a ... non-mounting area, 643 ... step, CW, W ... distance, D1, D2 ... height, H ... thickness, J ... height

Claims (11)

Lead frame,
A semiconductor circuit chip mounted on the first surface of the lead frame;
And a stress relief layer formed by curing a liquid material supplied so as to cover the semiconductor circuit chip,
An edge portion is formed on the first surface of the lead frame along the outer shape of the first surface when the semiconductor circuit chip is viewed in plan .
A pressure sensor chip is disposed on a second surface opposite to the first surface of the lead frame via a mounting portion,
The semiconductor mounting structure , wherein the placement portion is located inside a region surrounded by the edge portion of the first surface in a plan view .   Lead frame,
  A semiconductor circuit chip mounted on the first surface of the lead frame;
  And a stress relief layer formed by curing a liquid material supplied so as to cover the semiconductor circuit chip,
  An edge portion is formed on the first surface of the lead frame along the outer shape of the first surface when the semiconductor circuit chip is viewed in plan.
  A pressure sensor chip is disposed on a second surface opposite to the first surface of the lead frame via a mounting portion,
  The semiconductor mounting structure, wherein the Young's modulus of the material forming the mounting portion is equal to or greater than the Young's modulus of the material forming the lead frame. The distance of the edge portion and the side surface constituting the outer shape of the semiconductor circuit chip, the semiconductor mounting structure according to larger than 1/2 claim 1 or 2 in the thickness of the semiconductor circuit chip. The semiconductor mounting structure according to any one of claims 1 to 3 , wherein a distance between the edge portion and a side surface forming an outer shape of the semiconductor circuit chip is larger at a corner portion of the outer shape of the semiconductor circuit chip than other portions. body. A recessed groove along the outer shape of the semiconductor circuit chip is formed on the first surface of the lead frame,
The semiconductor mounting structure according to any one of claims 1 to 4 , wherein the edge portion is formed at a boundary between the recessed groove and the first surface. The semiconductor mounting structure according to claim 5 , wherein a plurality of the recessed grooves are intermittently formed on the first surface of the lead frame along the outer shape of the semiconductor circuit chip. 7. The semiconductor mounting structure according to claim 6 , wherein a distance between adjacent ones of the concave grooves formed intermittently is 1/3 or less of a length of the concave grooves. A mounting area for mounting the semiconductor circuit chip is formed at a position higher than the other area on the first surface of the lead frame, and the outer area of the semiconductor circuit chip is formed between the mounting area and the other area. Steps are formed,
The said edge part is a semiconductor mounting structure as described in any one of Claims 1-4 currently formed in the boundary of the said level | step difference and the said mounting area | region. The lead frame, the semiconductor circuit chip, and a base for embedding the stress relieving layer,
The semiconductor mounting structure according to any one of claims 1 to 8 , wherein a Young's modulus of the stress relaxation layer is lower than a Young's modulus of the substrate. 10. The semiconductor mounting structure according to claim 9 , wherein a Young's modulus of the stress relaxation layer is 1/10 or less of a Young's modulus of the substrate. The pressure sensor chip is disposed on the second surface side opposite to the first surface of the lead frame so that at least a portion thereof overlaps with the semiconductor circuit chip in plan view,
The semiconductor mounting structure according to any one of claims 1 to 10 , wherein the semiconductor circuit chip receives a sensor signal from the pressure sensor chip and outputs a pressure detection signal.

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