JP2018093212A - Semiconductor device and measurement apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a semiconductor device and a measurement apparatus capable of being miniaturized and of reducing wiring resistance.SOLUTION: A semiconductor device comprises: a lead frame; an oscillator mounted in a first region of the lead frame; an integrated circuit mounted in a second region different from the first region, of the lead frame; and a plurality of first bonding wires that connect between a first terminal of the oscillator and a second terminal of the integrated circuit. The lead frame is configured to include a plurality of third terminals formed around a mounting part including the first and second regions and connected with the second terminal by a plurality of second bonding wires. Apexes of the first bonding wires are lower than apexes of the second bonding wires, and the second bonding wires stride over the first bonding wires.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a semiconductor device and a measuring instrument.

  In recent years, in measuring devices such as a power meter that measures an integrated power amount, a demand for measuring the integrated power amount for each time zone is increasing. Along with this, there is a measuring instrument in which a semiconductor device including an oscillator and an integrated circuit is incorporated inside the measuring instrument so that power and time can be measured. Further, there is a piezoelectric oscillator in which an integrated circuit is mounted on the surface of a lead frame and a piezoelectric vibrator (oscillator) is mounted on the back surface of the lead frame (for example, Patent Document 1).

  In the invention of Patent Document 1, the semiconductor device can be reduced in size as compared with the case where the integrated circuit and the oscillator are mounted side by side on one side of the lead frame, but the integrated circuit and the oscillator are electrically connected. For this purpose, it is necessary to route the wiring to the back side of the lead frame, which may increase the wiring resistance.

JP 2007-234994 A

  An object of the present invention is to provide a semiconductor device and a measuring instrument that are reduced in size and reduced in wiring resistance in consideration of the above facts.

  The semiconductor device according to claim 1, a lead frame, an oscillator mounted in a first region of the lead frame, an integrated circuit mounted in a second region different from the first region of the lead frame, A plurality of first bonding wires that connect the first terminal of the oscillator and the second terminal of the integrated circuit, and the lead frame includes a first portion and a second region. A plurality of third terminals are formed around the second terminals and connected to the second terminals by a plurality of second bonding wires, and the apex of the first bonding wires is lower than the apex of the second bonding wires. The second bonding wire straddles the first bonding wire.

  Since the present invention is configured as described above, it is possible to provide a semiconductor device and a measuring instrument that are reduced in size and reduced in wiring resistance.

It is a perspective view of the integrating watt-hour meter provided with the semiconductor device concerning a 1st embodiment. It is the partially broken view which looked at the semiconductor device concerning a 1st embodiment from the back. FIG. 3 is a sectional view taken along line 3-3 in FIG. 2. FIG. 2 is an exploded perspective view showing the resonator according to the first embodiment. 1 is a block diagram for explaining an LSI of a semiconductor device according to a first embodiment. (A)-(e) is explanatory drawing which shows the procedure which arrange | positions an oscillator and LSI on a lead frame and wire-bonds in the manufacturing method which manufactures the semiconductor device which concerns on 1st Embodiment. (A)-(d) is explanatory drawing which shows the procedure which seals a lead frame, an oscillator, and LSI with resin in the manufacturing method which manufactures the semiconductor device which concerns on 1st Embodiment. It is a partially broken figure which shows the modification of the semiconductor device which concerns on 1st Embodiment. It is a flowchart which shows the flow of the 1st frequency correction process which concerns on 1st Embodiment. It is a flowchart which shows the flow of the 2nd frequency correction process which concerns on 1st Embodiment. It is a figure which shows the relationship between the temperature and frequency deviation in the semiconductor device which concerns on 1st Embodiment. It is a block diagram for demonstrating LSI of the semiconductor device which concerns on 2nd Embodiment. (A) is a figure which shows an example of the clock value of the oscillator of the semiconductor device which concerns on 2nd Embodiment, (b) is an example of the clock value of the reference signal oscillator of the semiconductor device which concerns on 2nd Embodiment. FIG. It is a flowchart which shows the flow of the 1st frequency correction process which concerns on 2nd Embodiment. It is a flowchart which shows the flow of the frequency error derivation process concerning 2nd Embodiment. It is a timing chart in the frequency error derivation processing concerning a 2nd embodiment, (a) is a figure showing the time of a count start, and (b) is a figure showing the time of a count stop. It is a flowchart which shows the flow of the 2nd frequency correction process which concerns on 2nd Embodiment. It is a block diagram for demonstrating another example of LSI of the semiconductor device which concerns on 2nd Embodiment. It is a block diagram for demonstrating another example of LSI of the semiconductor device which concerns on 2nd Embodiment. It is the partially broken figure which looked at the semiconductor device concerning a 3rd embodiment from the back. It is a 21-21 line sectional view of Drawing 20. It is the partially broken figure which looked at the semiconductor device concerning a 4th embodiment from the back. It is explanatory drawing for demonstrating the lead frame of the semiconductor device which concerns on 4th Embodiment. It is the partially broken figure which looked at the semiconductor device concerning a 5th embodiment from the back. It is the 14-14 sectional view taken on the line of FIG. (A)-(e) is explanatory drawing which shows the procedure which arrange | positions an oscillator and LSI on a lead frame and wire-bonds in the manufacturing method which manufactures the semiconductor device of 5th Embodiment. (A)-(d) is explanatory drawing which shows the procedure which seals a lead frame, an oscillator, and LSI with resin in the manufacturing method which manufactures the semiconductor device which concerns on 5th Embodiment. It is the partially broken figure which looked at the semiconductor device concerning a 6th embodiment from the back. FIG. 19 is a sectional view taken along line 18-18 in FIG. 28. It is a block diagram which shows an example of the state with which the semiconductor device incorporating the conventional time measuring function, and the resonator were connected. It is a block diagram which shows an example of the state with which the semiconductor device incorporating the conventional time measuring function, and the resonator were connected. It is a schematic sectional drawing which shows the conventional packaged general semiconductor device.

(First embodiment)
Hereinafter, a semiconductor device according to the present invention will be described in detail with reference to the accompanying drawings.

<Configuration>

  As shown in FIG. 1, an integrating watt-hour meter 10 including the semiconductor device of Embodiment 1 is attached to an upper surface of a fixed plate 102 fixed to an outer wall 100 such as a house. A transparent cover 14 covering the part 12 and a connection part 16 provided at the lower part of the main body part 12 are configured.

  A power supply side wiring 18 and a load side wiring 20 are connected from below the connecting portion 16 to supply current to the integrated watt-hour meter 10. The main body 12 is a rectangular box in a plan view, and the main body 12 includes a semiconductor device 24 to be described later and a measurement for measuring an integrated power amount according to a signal output from the semiconductor device 24. An electric energy measuring circuit 22 as means is mounted on a substrate (not shown). In FIG. 1, for convenience of explanation, the sizes of the electric energy measuring circuit 22 and the semiconductor device 24 are exaggerated.

  A horizontally long liquid crystal display 15 is provided in front of the main body 12. The liquid crystal display 15 displays the amount of power used per unit time measured by the power amount measuring circuit 22, the amount of accumulated power used for each time zone, and the like. Note that the integrated watt-hour meter 10 according to the present embodiment is an electronic watt-hour meter using the power amount measurement circuit 22 as a measuring unit, but is not limited thereto, and for example, the amount of power is obtained by rotating a disk. An inductive watt-hour meter to be measured may be used.

  Next, a detailed configuration of the semiconductor device 24 according to the present embodiment will be described. In the following description, the horizontal direction in the plan view of the semiconductor device 24 shown in FIG. 2 is the arrow X direction, the vertical direction is the arrow Y direction, and the height direction in the cross-sectional view of the semiconductor device 24 shown in FIG. This will be described as a direction. As shown in FIGS. 2 and 3, the outer shape of the semiconductor device 24 is a rectangular shape in plan view, and is mounted on the lead frame 26 serving as a skeleton and the surface (first surface) of the lead frame 26. The oscillator 28, an LSI 30 as an integrated circuit mounted on the back surface (second surface) of the lead frame 26, and a mold resin 32 serving as a sealing material are included.

  The lead frame 26 is a plate material formed by punching a flat plate made of a metal such as copper (Cu) or an alloy of iron (Fe) and nickel (Ni) with a press, and serves as a mounting portion provided in the center portion. The die pad 26A includes a suspension lead 26B that extends diagonally outward from the die pad 26A, and a plurality of leads (terminals) 38 provided between adjacent suspension leads 26B.

  The leads 38 are elongated members extending toward the center of the die pad 26A, and a plurality of leads 38 are formed around the die pad 26A at a predetermined interval. In the present embodiment, 16 leads 38 are formed between adjacent suspension leads 26B. The lead 38 includes an inner lead 38A located on the die pad 26A side and an outer lead 38B located on the outer peripheral end side of the semiconductor device 24. The inner lead 38A is located below the die pad 26A. Thus, it is pushed down by the press and extends parallel to the die pad 26A (see FIG. 3). The tip of the inner lead 38A closest to the die pad 26A is covered with the plating film 40. In the present embodiment, as an example, the plating film 40 is formed of silver (Ag). However, the present invention is not limited to this. For example, the plating film may be formed of a metal such as gold (Au).

  The outer lead 38B is exposed from the mold resin 32 and bent downward, and the tip is parallel to the inner lead 38A. That is, it is a gull wing lead. The outer lead 38B is covered with a solder plating film. As a material of the solder plating film, tin (Sn), an alloy of tin (Sn) and lead (Pb), an alloy of tin (Sn) and copper (Cu), or the like is used.

  The die pad 26A at the center of the lead frame 26 is a flat plate-like member formed in a rectangular shape in plan view, and two openings penetrating in the thickness direction of the die pad 26A are on the right side of the center of the die pad 26A. 26C is formed. The opening 26C is formed in a horizontally long rectangular shape, and is provided so as to face an external electrode 34 of an oscillator 28 described later (see FIG. 4).

  An area between the two openings 26C is an oscillator mounting beam 42 as an oscillator mounting area extending in the left-right direction. The oscillator mounting beam 42 on the surface of the lead frame 26 has an adhesive ( An oscillator 28 is mounted via a not shown) (see FIG. 4). In other words, the openings 26 </ b> C are provided on both sides of the oscillator mounting beam 42. The oscillator 28 is a rectangular electronic component whose longitudinal direction is the longitudinal direction. In this embodiment, the oscillator 28 is externally attached to a general-purpose semiconductor device 24 having a frequency of 32.768 kHz mounted on a general electronic device. A possible oscillator 28 is used.

As shown in FIG. 4, the oscillator 28 includes a vibrating piece 44, a package main body 46 that houses the vibrating piece 44, and a lid 48, and has a rectangular shape in plan view. . The resonator element 44 is a crystal resonator element in which an excitation electrode 44A is formed on the surface of a tuning-fork type crystal element made of artificial quartz. When a current is passed through the excitation electrode 44A, the resonator element 44 oscillates due to the piezoelectric effect. . Here, the vibrating piece 44 is not limited to a tuning fork type, and an AT-cut crystal piece may be used. In addition to quartz, a resonator element formed of lithium tantalate (LiTaO ₃ ) or lithium niobate (LiNbO ₃ ) may be used. Further, a MEMS vibrating piece made of silicon may be used.

  The package body 46 is a box having an open top, and a pedestal 47 to which the vibration piece 44 is fixed is formed at the bottom on one end side in the longitudinal direction. The base of the vibrating piece 44 is fixed to the pedestal 47 so that the vibrating piece 44 can vibrate, and the package body 46 and the lid 48 are joined in a vacuum state, whereby the vibrating piece 44 is hermetically sealed. In addition, external electrodes 34 as terminals electrically connected to the excitation electrode 44A of the resonator element 44 are formed on both ends of the lower surface of the package body 46 at a predetermined distance L1. Further, the width L2 of the oscillator mounting beam 42 is formed to be narrower than the distance between the external electrodes 34.

  The external electrode 34 is formed to have the same width as the width of the package body 46. As shown in FIG. 2, the size of the external electrode 34 is set to an electrode pad 50 formed on an LSI 30 to be described later, and an oscillator electrode. It is larger than the pad 54. Further, the opening 26C of the die pad 26A is formed larger than the external electrode 34.

  As shown in FIGS. 2 and 3, an LSI 30 as an integrated circuit or a semiconductor chip is mounted on the back surface of the lead frame 26 at the center of the die pad 26A via an adhesive (not shown). The LSI 30 is a rectangular and thin electronic component, and the right end of the LSI 30 covers about half of the opening 26C. For this reason, the oscillator 28 and the LSI 30 are arranged so as to overlap when projected in a plan view. Further, when the lead frame 26 is viewed from the LSI 30 side, the external electrode 34 of the oscillator 28 is exposed from the opening 26C.

  A plurality of electrode pads 50 electrically connected to the wiring inside the LSI 30 are provided at the outer peripheral end of the lower surface along each side of the rectangular LSI 30. The electrode pads 50 are made of metal such as aluminum (Al) or copper (Cu), and 16 electrode pads 50 are provided on each side of the LSI 30. The number of electrode pads 50 may be the same on each side, or may be different, for example, by reducing or increasing the number of sides on which an oscillator electrode pad 54 described later is provided. Each electrode pad 50 is connected to the inner lead 38 </ b> A by a bonding wire 52. In the present embodiment, 16 electrode pads 50 are provided on each side of the LSI 30 so as to match the number of leads 38. However, the number of electrode pads 50 is not limited to this, and more than the number of leads 38 is provided. It may be used for other purposes.

  In addition to the electrode pad 50, an oscillator electrode pad 54 is provided on the outer peripheral end of the LSI 30 on the oscillator 28 side. Two oscillator electrode pads 54 are provided in the center of the LSI 30 in the vertical direction, and are located between the electrode pads 50. That is, a region (first region) in which the oscillator electrode pad 54 is arranged is formed in the central portion, and each of the remaining three regions from the central portion to the end of the side where the resonator electrode pad 54 is provided. An electrode pad 50 arrangement region (second region) is formed on the side. The oscillator electrode pad 54 is connected to the external electrode 34 of the oscillator 28 by a bonding wire 52 through the opening 26C. The bonding wire is a linear conductive member made of a metal such as gold (Au) or copper (Cu).

  The two oscillator electrode pads 54 provided at the center in the vertical direction of the LSI 30 are provided apart from the electrode pads 50 provided on the same side. In other words, the distance between the oscillator electrode pad 54 and the electrode pad 50 adjacent to the oscillator electrode pad 54 is longer than the distance between the electrode pads 50.

  The distance between the electrode pad for the oscillator 54 and the adjacent electrode pad 50 is made equal to the distance between the electrode pads 50, and the electrode pad 50 adjacent to the oscillator electrode pad 54 is not wire-bonded. The distance between the wire-bonded electrode pad 50 and the oscillator electrode pad 54 may be longer than the distance between the wire-bonded electrode pads 50. In other words, on the electrode pad 50 of the LSI 30, the bonding wire 52 and the electrode that connect the oscillator electrode pad 54 and the external electrode 34 rather than the distance between the bonding wire 52 that connects the electrode pad 50 and the inner lead 38 </ b> A. The distance between the pad 50 and the bonding wire 52 that connects the inner lead 38A is longer.

  Here, the bonding wire 52 connecting the oscillator electrode pad 54 and the external electrode 34 and the bonding wire 52 connecting the electrode pad 50 and the inner lead 38A cross three-dimensionally, and FIG. As shown, the bonding wire 52 connecting the electrode pad 50 and the inner lead 38A is formed so as to straddle the bonding wire 52 connecting the oscillator electrode pad 54 and the external electrode 34. Yes. That is, in order to prevent a short circuit of the bonding wire 52, the apex of the bonding wire 52 connecting the oscillator electrode pad 54 and the external electrode 34 is the bonding connecting the electrode pad 50 and the inner lead 38A. It is formed so as to be lower than the apex of the wire 52.

  Note that the height of the apex of the bonding wire 52 connecting the oscillator electrode pad 54 and the external electrode 34 is lower than the apex of the bonding wire 52 connecting all the electrode pads 50 and the inner leads 38A. Alternatively, the height may be lower than the height of the apex of the bonding wire 52 that connects the electrode pad 50 between the oscillator electrode pad 54 and the external electrode 34 and the inner lead 38A. .

  Further, the LSI 30 and the rectangular parallelepiped oscillator 28 are arranged in parallel so that the center CP of the cuboid-shaped oscillator 28 substantially coincides with the X axis. That is, the deviation width of the center CP of the oscillator 28 from the X axis in the Y axis direction is smaller than the width in the Y axis direction of the central portion. In such an arrangement state, the oscillator electrode pad 54 provided near the center of any one side of the LSI 30 and the external electrodes 34 arranged at both ends in the longitudinal direction of the oscillator 28 are connected by the bonding wires 52. doing. At the same time, the electrode pads 50 arranged so as to sandwich the oscillator electrode pad 54 and the electrode pads 50 and the inner leads 38A arranged in parallel in the Y-axis direction are connected by a bonding wire 52.

  Furthermore, since the oscillator electrode pad 54 is provided apart from the electrode pad 50, the bonding wire 52 that connects the electrode pad 50 and the inner lead 38A connects the oscillator electrode pad 54 and the external electrode 34. The portion of the bonding wire 52 that is lower than the oscillator 28 passes through. In other words, it is possible to avoid crossing the vicinity of the apex of the bonding wire 52 that connects the oscillator electrode pad 54 and the external electrode 34, and to efficiently make a three-dimensional intersection. Furthermore, since the height of the apex of the bonding wire 52 that connects the electrode pad 50 and the inner lead 38A can be kept low, the height of the package can be reduced.

  Further, the connecting position of the bonding wire 52 on the external electrode 34 of the oscillator 28 is shifted from the center position of the oscillator 28 to the inner lead 38A side in the X-axis direction. By connecting in this way, it can reduce that the bonding wire 52 contacts the edge part of LSI30. On the other hand, in the X-axis direction, the center of the oscillator 28 is shifted from the center of the external electrode 34. By connecting in this way, it is possible to reduce the number of times of intersection between the electrode pad 50 and the bonding wire 52 that connects the inner lead 38A.

  The oscillator 28, the LSI 30, and the lead frame 26 are sealed with a mold resin 32, and the outer shape of the semiconductor device 24 is formed. The mold resin 32 is filled so as not to provide a gap therein, and the height of the mold resin 32 is twice or more the height of the inner lead 38. In other words, the distance H1 from the surface of the mold resin 32 on the oscillator 28 mounting side to the center of the inner lead 38 is longer than the distance H2 from the surface of the mold resin 32 on the LSI 30 mounting side to the center of the inner lead 38. The distance H3 from the surface of the mold resin 32 on the LSI 30 mounting side to the center of the die pad 26 is longer than the distance H2 from the surface of the mold resin 32 on the LSI 30 mounting side to the inner lead 38. In the present embodiment, a thermosetting epoxy resin containing a silica-based filler is used as the mold resin 32. However, the present invention is not limited to this. For example, a thermoplastic resin may be used.

  Next, the internal configuration of the LSI 30 will be described. As shown in FIG. 5, the LSI 30 includes an oscillation circuit 51, a frequency dividing circuit 53, a time measuring circuit 56, a temperature sensor 58, a control unit 60, and a register unit 70. The oscillation circuit 51 is connected to the oscillator 28 and causes the oscillator 28 to oscillate. The frequency divider 53 divides the signal output from the oscillator 28 (in this embodiment, a frequency of 32.768 kHz) to obtain a predetermined clock (for example, 1 Hz). The time measuring circuit 56 measures time based on the signal divided by the frequency dividing circuit 53 and transmits the time to the control unit 60. The temperature sensor 58 measures the temperature of the LSI 30 and transmits it to the control unit 60. Note that the temperature of the oscillator 28 that is disposed on the same lead frame in the vicinity of the LSI 30 and is electrically connected to the LSI 30 can be regarded as the same as the temperature of the LSI 30. That is, the temperature sensor 58 can accurately measure the temperature of the oscillator 28 disposed around the LSI 30. Based on the time measured by the time measuring circuit 56, the controller 60 causes the liquid crystal display 15 to display the accumulated power amount per unit time measured by the power amount measuring circuit 22 (see FIG. 1). Further, as will be described later, the control unit 60 also functions as a correction unit that corrects the oscillation frequency of the oscillator 28. The register unit 70 includes a plurality of registers for storing various data used when correcting the oscillation frequency of the oscillator 28. The plurality of registers will be described in detail in the description of oscillation frequency correction described later. In addition to this, the LSI 30 incorporates an arithmetic circuit for performing arithmetic operations and an internal power supply.

<Manufacturing procedure>
Hereinafter, a manufacturing procedure of the semiconductor device 24 will be described.
First, as shown in FIG. 6A, the lead frame 26 is mounted on the mounting table 2 of the bonding apparatus 1 so that the leads 38 are positioned below. The mounting table 2 is provided with a recess 3 for receiving the oscillator 28 when the lead frame 26 is turned upside down with the oscillator 28 fixed to the first surface. The oscillator 28 is encapsulated and transported in a package 29 on the tape with the external electrode 34 facing downward. Note that the opening 26C is formed in advance in the lead frame 26 by pressing or the like.

  Next, as shown in FIG. 6 (b), the package 29 is opened, the oscillator 28 is taken out by the picker 4, and the oscillator is placed on the first surface of the die pad 26A, that is, the upper surface in FIG. 6 (b). The oscillator 28 is arranged so that the 28 external terminals 34 overlap the opening 26C, and fixed to the die pad 26A with an adhesive. When the oscillator 28 is sealed in the package 29 with the external electrode 34 facing upward, the picker 4 having a rotating mechanism is used, and the oscillator 28 is taken out by the picker 4 and then rotated. It is preferable to place the oscillator 28 upside down by the mechanism and place the external terminal 34 downward on the first surface of the die pad 26A.

  When the oscillator 28 is fixed to the first surface of the die pad 26A, the lead frame 26 is turned upside down and placed on the mounting table 2 as shown in FIG. 6C. As a result, the lead frame is placed on the mounting table 2 with the first surface facing downward. At this time, the oscillator 28 is accommodated in the recessed portion 3 of the mounting table 2.

  When the lead frame 26 is turned upside down and placed on the mounting table 2, as shown in FIG. 6D, a portion adjacent to the opening 26C on the second surface opposite to the first surface of the die pad 26A. The LSI 30 is fixed to the board. In FIG. 6D, the second surface is an upper surface of the die pad 26A.

  Finally, as shown in FIG. 6E, the electrode pad 50 of the LSI 30 and the lead 38 are connected by the bonding wire 52, and the oscillator electrode pad 54 of the LSI 30 and the external electrode 34 of the oscillator 28 are bonded. The semiconductor device 24 is formed by connecting with wires 52. At this time, the height of the apex of the bonding wire 52 that connects the oscillator electrode pad 54 of the LSI 30 and the external electrode 34 of the oscillator 28 is equal to the height of the bonding wire 52 that connects the electrode pad 50 of the LSI 30 and the lead 38. Connect so that it is lower than the height of the vertex. In addition, after connecting the oscillator electrode pad 54 of the LSI 30 and the external electrode 34 of the oscillator 28 with a bonding wire, the electrode pad 50 and the lead 38 of the LSI 30 are connected so as to jump over the bonding wire 52. Connection is made with a bonding wire 52. Further, the bonding wire 52 that connects the oscillator electrode pad 54 of the LSI 30 and the external electrode 34 of the oscillator 28 and the bonding wire 52 that connects the electrode pad 50 and the lead 38 are three-dimensionally crossed. . At that time, the bonding wire 52 for connecting the electrode pad 50 of the LSI 30 and the lead 38 at a position shifted from the apex of the bonding wire 52 for connecting the oscillator electrode pad 54 of the LSI 30 and the external electrode 34 of the oscillator 28. Make connections so that they intersect.

  The oscillator 28 and the LSI 30 are fixed to the lead frame 26 (die pad 26A) by the procedure shown in FIGS. 6A to 6E, and the LSI 30 and the oscillator 28 are connected, whereby the LSI 30 is connected to the die pad 26A. Although the oscillator 28 is fixed to the second surface opposite to the first surface to which the oscillator 28 is fixed, the connection between the LSI 30 and the oscillator 28 is also between the LSI 30 and the lead 38 of the lead frame. As with the connection, it can be performed from the second surface of the die pad 26A, which is efficient. Since the oscillator 28 and the LSI 30 are directly connected by the bonding wire 32 without the lead frame 26, the oscillator 28 and the LSI 30 are connected via the lead frame 26, or the bonding wire is lead. The wiring resistance can be reduced as compared with the case of being connected to the back side of the frame 26.

Next, a procedure for sealing the semiconductor device 24 with the mold resin 32 will be described.
First, as shown in FIG. 7A, the first surface of the lead frame 26 (die pad 26A), that is, the surface on which the oscillator 28 is fixed becomes the upper surface of the semiconductor device 24, and the lead frame 26 (die pad). 26A) is fixed inside the cavity 6 of the mold 5 so that the second surface, that is, the surface to which the LSI 30 is fixed becomes the lower surface. Here, since the oscillator 28 is thicker than the LSI 30, the semiconductor device 24 includes the cavity 6 so that the lead frame 26 (die pad 26 </ b> A) is positioned below the center of the mold 5 in the height direction of the cavity 6. Arranged inside. Further, the outer lead 38 </ b> B protrudes outside the mold 5 in a state where the semiconductor device 24 is fixed inside the cavity 6.

  When the semiconductor device 24 is fixed inside the cavity 6, the mold resin 32 is injected from the injection port 7 provided along the lower surface of the lead frame 26 as indicated by an arrow a in FIG. Here, as described above, the lead frame 26 (die pad 26A) is fixed so as to be positioned below the center in the height direction of the cavity 6 in the mold 5; Injection is performed along the lead frame 26 (die pad 26A). Here, since the injected mold resin 32 has a characteristic of flowing into a wider space, it flows above the lead frame 26 from, for example, a gap between the rear end of the lead frame 26 and the die pad 26A. However, since the path is blocked by the oscillator 28, the flow flows around the lead frame 26 as indicated by an arrow b in FIG. 7C.

  Thereafter, as indicated by an arrow c in FIG. 7D, the mold resin 32 also flows into the upper surface side of the lead frame 26. When the lower surface side of the lead frame 26 is filled with the mold resin 32, the upper surface side of the lead frame 26 is also filled with the mold resin 32.

  When both sides of the lead frame 26 are filled with the mold resin 32, the mold 5 is heated to cure the mold resin 32.

  In the semiconductor device 24, the oscillator 28 is fixed to the upper surface of the lead frame 26 (die pad 26A) and the LSI 30 is fixed to the lower surface. Therefore, when the semiconductor device 24 is sealed with the mold resin 32, the lead frame 26 is It is necessary to arrange the mold 5 below the center in the height direction of the cavity 6. As described above, when there is a wide space above the lead frame 26, the mold resin 32 tends to flow into the upper side of the lead frame 26.

  Therefore, it is considered that the pressure by the mold resin 32 injected into the cavity 6 from the injection port 7 is not uniformly applied to both surfaces of the lead frame 26 but is more strongly applied to the upper surface of the lead frame 26.

  However, the oscillator 28 is used to adjust the flow path of the mold resin 32, and the mold resin 32 is first introduced into the lower portion of the lead frame 26, thereby supporting the lead frame 26 by the mold resin 32 injected into the cavity 6. Can be expected. Accordingly, the lead frame 26 is prevented from being displaced in the vertical direction inside the cavity 6 during the injection of the mold resin 32.

<Action>

  Next, the operation of the semiconductor device 24 and the integrated watt-hour meter 10 according to the present embodiment will be described. In the semiconductor device 24 according to the present embodiment, the oscillator 28 and the LSI 30 are sealed and integrated with the mold resin 32, and the LSI 30 includes the oscillation circuit 51, the frequency dividing circuit 53, and the timing circuit 56. Therefore, the time can be measured only by mounting the semiconductor device 24 on the substrate inside the integrating watt-hour meter 10 shown in FIG. That is, it is not necessary to separately mount the oscillator 28, the frequency dividing circuit 53, and the like on the substrate. This eliminates the need for adjustment of the connection between the oscillator 28 and the semiconductor device 24.

  Further, since the temperature sensor 58 is built in the LSI 30, the temperature around the oscillator 28 can be accurately measured. Thereby, even if the signal (frequency) output from the oscillator 28 fluctuates due to a temperature change, the frequency can be corrected with high accuracy. Therefore, it is possible to make the frequency highly accurate even with an inexpensive oscillator without using an expensive highly accurate oscillator.

  Further, as shown in FIG. 2, the external electrode 34 of the oscillator 28 and the oscillator electrode pad 54 of the LSI 30 are directly connected through the opening 26 </ b> C by the bonding wire 52. Therefore, wiring can be performed at the shortest distance without using the lead frame 26, and wiring resistance can be reduced. Further, since the lengths of the two bonding wires 52 connecting the external electrode 34 and the oscillator electrode pad 54 are uniform, the tension applied to the bonding wire 52 can be equalized, and the bonding wire 52 is broken or bent. Can prevent contact. Further, since the wiring can be performed without going through the lead frame 26, it is difficult to be affected by noise, so that a signal can be smoothly transmitted from the oscillator 28 to the LSI 30. Further, although noise is likely to occur between the bonding wires 52 formed in parallel, the bonding wire 52 connecting the oscillator electrode pad 54 and the external electrode 34 is connected to the other bonding wires 52. Thus, the three-dimensional crossing can reduce interference between the bonding wire 52 connecting the oscillator electrode pad 54 and the external electrode 34 and the other bonding wire 52, and in particular, oscillation from the other bonding wire 52. The influence of noise on the child 28 can be reduced. Furthermore, since the external electrode 34 is larger than the oscillator electrode pad 54, wire bonding can be easily performed.

  In addition, the oscillator 28 and the LSI 30 are mounted on the front and back surfaces of the lead frame 26 and are arranged so as to overlap when projected in a plan view. Therefore, the oscillator 28 and the LSI 30 are connected to the lead frame 26. The vertical and horizontal sizes of the semiconductor device 24 can be reduced compared to the case where the semiconductor devices 24 are mounted side by side.

  Further, since the LSI 30 is located at the center of the die pad 26A, the length of the bonding wire 52 that connects the electrode pad 50 and the inner lead 38 can be made constant. As a result, wire bonding work is facilitated and yield can be improved.

  In the present embodiment, all the inner leads 38A are connected to the electrode pads 50 of the LSI 30. However, the present invention is not limited to this, and an arbitrary inner lead 38A can be connected with the bonding wires 52 as in the modification shown in FIG. The die pad 26A may be grounded by connecting to the die pad 26A and connecting the outer lead 38B to the ground. In this case, the die pad 26A can be prevented from being charged. Further, since the LSI 30 and the oscillator 28 are arranged on both sides of the lead frame so as to sandwich the lead frame, noise from the LSI 30 to the oscillator 28 can be shielded by the die pad 26A.

  In this modification, an oscillation circuit 51 is disposed in the vicinity of the oscillator electrode pad 54, and a digital circuit unit 55 is disposed so as to surround the oscillation circuit 51. The digital circuit unit 55 is a circuit unit that processes a digital signal, and is less likely to generate noise than other elements. For this reason, the influence of the noise which the oscillation circuit 51 receives from the other element (especially analog circuit part) incorporated in LSI30 can be reduced. An example of the digital circuit unit 55 is a CPU.

<Correction of oscillation frequency>

  Next, frequency correction processing for correcting an error depending on the temperature of the oscillation frequency of the oscillator 28 in the semiconductor device 24 according to the present embodiment will be described.

  For example, when the temperature of the LSI 30 in the semiconductor device 24 is set to room temperature (here, 25 ° C.) at the time of shipment, the semiconductor device 24 is set to a reference temperature (hereinafter, also referred to as “low temperature”) lower than the room temperature. The temperature is measured by the temperature sensor 58 in each state when the temperature is set to a reference temperature higher than normal temperature (hereinafter also referred to as “high temperature”). Then, for example, after shipping, the semiconductor device 24 uses the temperature obtained by this measurement as trimming data and corrects the frequency error of the oscillator 28 in consideration of a measurement error caused by manufacturing variations of the temperature sensor 58.

  The register unit 70 (see FIG. 5) described above stores a temperature measurement value register 71 that stores data indicating the temperature measured by the temperature sensor 58, and indicates the temperature measured by the temperature sensor 58 when the ambient temperature is low. A low temperature register 72 for storing data, a normal temperature register 73 for storing data indicating the temperature measured by the temperature sensor 58 when the ambient temperature is normal temperature, and a temperature measured by the temperature sensor 58 when the ambient temperature is high And a frequency correction register 75 for storing a correction value of the oscillation frequency of the oscillator 28 derived from the data indicating these temperatures. Each register is connected to the control unit 60 via the data bus 76, and the control unit 60 reads and writes each register via the data bus 76.

  In order to correct the frequency error of the oscillator 28, the semiconductor device 24 measures the temperature by the temperature sensor 58 in each state when the temperature of the semiconductor device 24 is low, normal, and high. Then, a first frequency correction process is performed in which the temperature obtained by the measurement is stored as trimming data in the low temperature register 72, the normal temperature register 73, and the high temperature register 74, respectively.

  For example, at the time of a shipping test, the tester first places the semiconductor device 24 inside a thermostatic chamber in which the temperature in the bath is set to room temperature. Then, the user causes the semiconductor device 24 to execute the first frequency correction process by inputting, for example, a measurement operation signal for starting temperature measurement by the temperature sensor 58 to the semiconductor device 24. At this time, for example, the user connects the device that outputs the measurement operation signal to the lead 38 of the semiconductor device 24 to input the measurement operation signal to the semiconductor device 24. In addition, the measurement operation signal includes information indicating whether the temperature set in the thermostatic chamber is normal temperature, high temperature, or low temperature.

  FIG. 9 is a flowchart showing the flow of the first frequency correction process in the semiconductor device 24 according to the present embodiment. The program that executes the first frequency correction processing is a program that is executed at the timing when the measurement operation signal is input, and is stored in advance in a storage unit that the control unit 60 has. Note that the execution timing is not limited to this.

  In step S101, the control unit 60 determines whether or not a predetermined time (for example, several hours) has elapsed since the measurement operation signal was input. Note that the predetermined time is preferably a time required for the internal temperature of the semiconductor device 24 (the temperature of the LSI 30) to coincide with the temperature of the thermostatic chamber.

  When it is determined in step S101 that the predetermined time has elapsed, in step S103, the control unit 60 acquires a measurement value obtained by the temperature sensor 58. Note that the measurement value obtained by the temperature sensor 58 is stored in the temperature measurement value storage register 71. Moreover, when acquiring a measured value with the temperature sensor 58, it measures every predetermined time (for example, 1 minute) progress, and uses the value which averaged the several measured value obtained by multiple times of measurement as a measured value. You may get it.

  In step S105, the control unit 60 stores the acquired measurement value in the normal temperature register 73 when the temperature set in the thermostatic bath is normal temperature (here, 25 ° C.) and is set in the thermostatic bath. When the temperature is high, the temperature is stored in the high temperature register 74, and when the temperature set in the thermostat is low, the temperature is stored in the low temperature register 72, and the first frequency correction process is terminated. Note that the first frequency correction process may be performed in advance in the wafer state.

  The tester arranges the semiconductor device 24 inside the thermostatic chamber in which the temperature in the bath is set to a high temperature, in addition to the state in which the semiconductor device 24 is arranged in the thermostatic bath in which the temperature in the bath is set to room temperature. In each of the above state and the state in which the semiconductor device 24 is disposed inside the thermostatic chamber in which the temperature in the bath is set to a low temperature, the semiconductor device 24 is caused to perform the processes of steps S101 to S105. Thereby, the measured values by the temperature sensor 58 are stored in the normal temperature register 73, the high temperature register 74, and the low temperature register 72, respectively.

  The semiconductor device 24 according to the present embodiment is shipped after the above-described processing is performed, and a second frequency correction process described later is performed at a predetermined timing after the shipment.

  For example, after shipping, the user causes the semiconductor device 24 to execute a second frequency correction process by inputting, for example, a derivation operation signal for starting the derivation of the frequency correction value to the semiconductor device 24. At this time, the user inputs the derivation operation signal by connecting a device that outputs the derivation operation signal to the lead 38 of the semiconductor device 24, for example. Alternatively, the semiconductor device 24 may execute the second frequency correction process at regular intervals.

  FIG. 10 is a flowchart showing the flow of the second frequency correction process in the semiconductor device 24 according to the present embodiment. The program that executes the second frequency correction processing is a program that is executed at the timing when the derivation operation signal is input after the semiconductor device 24 is shipped, and is stored in advance in a storage unit that the control unit 60 has.

  In step S <b> 201, the control unit 60 acquires measurement values stored in the normal temperature register 73, the high temperature register 74, and the low temperature register 72, respectively.

  In step S <b> 203, the control unit 60 derives a correction value (hereinafter also referred to as “frequency correction value”) of the oscillation frequency of the oscillator 28 using the measurement value acquired in step S <b> 201.

FIG. 11 is a diagram showing a relationship between temperature and frequency deviation in the semiconductor device according to the present embodiment. FIG. 11 shows not a frequency error obtained in an actual temperature environment but a theoretical value obtained by calculation using a quadratic function. The quadratic function is expressed by the following equation (1). In the following formula (1), f is a frequency deviation, a is a secondary temperature coefficient, T is a measured temperature, T ₀ is a vertex temperature, and b is a vertex error. The secondary temperature coefficient a is a constant determined in advance according to the individual difference of the oscillator 28 and is stored in advance in a storage unit included in the control unit 60.

... (1)

  In the first embodiment, the frequency deviation f is unknown, but the known secondary temperature coefficient a, the measured value at room temperature stored in the room temperature register 73, and the measurement at high temperature stored in the high temperature register 74. The vertex error b can be derived from the value and the measured value at the low temperature stored in the low temperature register 72. Then, the control unit 60 sets the value of the vertex error b as the frequency correction value so that the frequency deviation becomes the smallest at the temperature T0 at normal temperature.

  In the derivation of the frequency correction value, for example, in a measurement environment at −10 ° C., when the value measured by the temperature sensor 58 is −8 ° C., correction corresponding to + 2 ° C. is necessary. . The product at the shipping stage reads out three-point measurement values of normal temperature, high temperature and low temperature stored in each register through the data bus 76, and derives the temperature in the actual environment using the read data as trimming data. . If the measured value by the temperature sensor 58 is a value that is not stored in each register, the temperature in the actual environment may be derived using the values of the two adjacent registers.

  In step S <b> 205, the control unit 60 stores data indicating the frequency correction value derived in step S <b> 203 in the frequency correction register 75. In the semiconductor device 24, the frequency dividing circuit 53 generates a clock signal from the signal input from the oscillation circuit using the frequency correction value stored in the frequency correction register 75, and thereby the oscillation frequency of the oscillator 28. Is corrected.

  As described above, according to the semiconductor device 24 according to the first embodiment, at the time of shipment, the measurement value obtained by the temperature sensor 58 under the three-point environmental temperature of the semiconductor device 24 is prepared as trimming data. By deriving the frequency correction value based on the original, it is possible to obtain the frequency correction value based on highly accurate temperature information without depending on the manufacturing variation of the temperature sensor 58 for each individual semiconductor device 24.

  In the conventional packaged semiconductor device, as shown in FIG. 32, when the semiconductor device is driven, the ambient temperature Ta (° C.), the package surface temperature Tc (° C.), and the chip surface temperature Tj (° C.) of the semiconductor device. Are different. For example, the chip surface temperature Tj is expressed by the following equation (2), where θja is the package thermal resistance (between junction and atmosphere) and P is the power consumption (maximum or average) of the chip.

... (2)

  However, in the semiconductor device 24 according to this embodiment, since the temperature sensor 58 and the oscillator 28 are sealed together, the ambient temperature of the temperature sensor 58 and the ambient temperature of the oscillator 28 are the same. The temperature of the oscillator 28 can be measured with high accuracy by the temperature sensor 58 included in the LSI 30, and therefore the accuracy of frequency correction is prevented from being lowered due to the temperature difference between the oscillator 28 and the temperature sensor 58.

(Second Embodiment)

  Next, a semiconductor device 24 according to a second embodiment of the present invention will be described. In addition, about the structure same as 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted.

  As shown in FIG. 12, in the semiconductor device 24 according to the second embodiment, a clock signal (hereinafter also referred to as “reference clock signal”) that is used as a reference when correcting the oscillation frequency of the oscillator 28 with respect to the LSI 30A. .) Is connected to a clock generator provided with a reference signal oscillator 80. In addition to the configuration of the LSI 30 of the semiconductor device 24 according to the first embodiment, the LSI 30A of the semiconductor device 24 according to the second embodiment transmits the measurement counter 81, the reference counter 82, and the clock signal from the oscillation circuit 57 to the outside. An output terminal 83 for outputting is further provided.

  As shown in FIGS. 13A and 13B, the reference signal oscillator 80 is an oscillator such as a crystal resonator having an oscillation frequency higher than that of the oscillator 28. In the second embodiment, the oscillation frequency of the oscillator 28 is 32.768 KHz, and the oscillation frequency of the reference signal oscillator 80 is 10 MHz.

  The measurement counter 81 is connected to the oscillation circuit 51, and receives a clock signal (hereinafter also referred to as “measurement clock signal”) from the oscillator 28 from the oscillation circuit 51 based on the control of the control unit 60. It is a counter that counts the number of clocks of the clock signal. The reference counter 82 is connected to a clock generator provided with a reference signal oscillator 80, and receives a clock signal from the reference signal oscillator 80 based on the control of the control unit 60 and calculates the number of clocks of the clock signal. Count. As shown in FIGS. 13A and 13B, the reference counter 82 and the measurement counter 81 count the number of clocks within the same time at substantially the same time while synchronizing with each other. The measurement counter 81 and the reference counter 82 may be operated in synchronization with each other based on the operation signal, or a synchronization counter may be used.

  In the second embodiment, in the register unit 70, data indicating the temperature measured by the temperature sensor 58 is stored in the temperature measurement value register 71, and the ambient temperature is lower than room temperature (25 ° C.) in the low temperature register 72. The temperature measured by the temperature sensor 58 when the reference temperature is set and data indicating the frequency error at that temperature are stored. The room temperature register 73 is measured by the temperature sensor 58 when the ambient temperature is the room temperature (25 ° C.). Data indicating the measured temperature and the frequency error at that temperature are stored, and when the ambient temperature is set to a reference temperature higher than room temperature (25 ° C.) in the high temperature register 74, the temperature measured by the temperature sensor 58 and the temperature Data indicating the frequency error is stored, and the frequency correction register 75 is derived from the data indicating the frequency error described above. That data indicating the frequency correction value is stored.

<Correction of oscillation frequency>

  For example, at the time of a shipping test, a user first places the semiconductor device 24 inside a thermostatic chamber in which the temperature in the bath is set to room temperature (here, 25 ° C.). Then, the user causes the semiconductor device 24 to execute the first frequency correction process by inputting, for example, a measurement operation signal for starting temperature measurement by the temperature sensor 58 to the semiconductor device 24. At this time, for example, the user connects the device that outputs the measurement operation signal to the lead 38 of the semiconductor device 24 to input the measurement operation signal to the semiconductor device 24. The measurement operation signal includes information indicating whether the temperature set in the thermostatic chamber is normal temperature, high temperature, or low temperature.

  FIG. 14 is a flowchart showing the flow of the first frequency correction process in the semiconductor device 24 according to the present embodiment. The program that executes the first frequency correction processing is a program that is executed at the timing when the measurement operation signal is input when the semiconductor device 24 is shipped, and is stored in advance in storage means included in the control unit 60.

  In step S301, the control unit 60 determines whether or not a predetermined time (for example, several hours) has elapsed since the measurement operation signal was input. The predetermined time may be a time required for the internal temperature of the semiconductor device 24 (the temperature of the LSI 30) to coincide with the temperature of the thermostatic chamber.

  When it is determined in step S301 that the predetermined time has elapsed, in step S303, the control unit 60 acquires a measurement value obtained by the temperature sensor 58. Note that the measurement value obtained by the temperature sensor 58 is stored in the temperature measurement value storage register 71. The temperature sensor 58 has been confirmed by testing to have a measurement accuracy equal to or higher than a predetermined reference value, and it is guaranteed that the temperature sensor 58 can perform temperature measurement with high accuracy. Or you may make it correct | amend using the measured value by the temperature sensor 58. FIG.

  In step S305, the control unit 60 performs a frequency error derivation process for deriving an error in the oscillation frequency of the oscillator 28. FIG. 15 is a flowchart showing a flow of frequency error derivation processing according to the present embodiment. FIGS. 16A and 16B are timing charts in the frequency error derivation process according to the present embodiment. FIG. 16A is a diagram illustrating a count start time, and FIG. 16B is a diagram illustrating a count stop time.

  In step S <b> 401, the control unit 60 outputs a correction operation signal to the measurement counter 81. The measurement counter 81 to which the correction operation signal is input starts the operation in step S403, starts counting the clock value of the clock signal by the oscillator 28, and outputs a start signal to the reference counter 82.

  The reference counter 83 that has received the start signal starts counting the clock value of the clock signal by the reference signal oscillator 80 in step S405. That is, as shown in FIG. 16A, when the correction operation signal is turned on, the measurement counter 81 starts counting, and the reference counter 82 also starts counting in synchronization with the measurement counter 81.

  In step S407, the measurement counter 81 determines whether or not the count value of the measurement counter is equal to or greater than a predetermined value (32.768 corresponding to 1 second in the present embodiment). If it is not greater than or equal to the predetermined value in step S407, the measurement counter 81 continues counting.

  If it is determined in step S407 that the value is equal to or larger than the predetermined value, in step S409, the measurement counter 81 stops counting and outputs a stop signal to the reference counter 82.

  The reference counter 82 that has received the stop signal stops counting in step S411. That is, as shown in FIG. 16B, when the correction operation signal is turned off, the measurement counter 81 stops counting, and the reference counter 82 also stops counting in synchronization with the measurement counter 81.

  In step S413, the control unit 60 acquires the count value of the reference counter 82.

  In step S415, the control unit 60 derives an error in the oscillation frequency of the oscillator 28 from the count value of the reference counter 82 acquired in step S413. That is, the control unit 60 can generate the reference signal oscillation that can count the count values (that is, 32,768) obtained in the same time in the measurement clock signal by the oscillator 28 with higher accuracy than the oscillator 28. By comparing with the count value of the reference clock signal by the child 80, the error of the oscillation frequency of the oscillator 28 is derived.

  For example, since the oscillation frequency of the reference signal oscillator 80 is 10 MHz, if the count value of the reference counter 82 is “10000000 (decimal number)”, it can be estimated that the oscillator 28 can accurately measure 1 second. The oscillation frequency error need not be corrected by 0, and the oscillation frequency error (frequency correction value) is 0. On the other hand, for example, if the count value of the reference counter 82 is “10000002 (decimal number)”, it can be estimated that the oscillation frequency of the oscillator 28 is delayed by 0.2 ppm, and the oscillation frequency of the oscillator 28 is determined as an error. Therefore, it is necessary to make correction so as to be faster by 0.2 ppm, and an error of the oscillation frequency (frequency correction value) is set to +0.2 ppm. For example, if the value of the reference counter 82 is “9999999 (decimal number)”, the oscillation frequency of the oscillator 28 is increased by 1.0 ppm. That is, it is necessary to delay by 1.0 ppm, and the oscillation frequency error (frequency correction value) is set to -1.0 ppm.

  In step S417, the control unit 60 stops outputting the correction operation signal to the measurement counter 81, and ends the frequency error derivation processing program. The measurement counter 81 and the reference counter 82 stop operating when the correction operation signal input stops.

  In step S307, the control unit 60 stores the temperature measurement value acquired in step S303 and the frequency error derived in step S415 in the room temperature register 73 when the temperature set in the thermostat is room temperature. When the temperature set in the constant temperature bath is high, the first frequency correction processing program is stored in the high temperature register 74, and when the temperature set in the constant temperature bath is low, the temperature is stored in the low temperature register 72. Exit.

  In addition to the state in which the semiconductor device 24 is disposed inside the thermostatic chamber in which the temperature in the bath is set to room temperature, the user places the semiconductor device 24 in the thermostatic bath in which the temperature in the bath is set to a high reference temperature. In the state in which the semiconductor device 24 is disposed, and in the state in which the semiconductor device 24 is disposed in the thermostatic chamber in which the temperature in the bath is set to a low reference temperature, the semiconductor device 24 is caused to perform the processes of steps S301 to S309. As a result, the temperature measurement value by the temperature sensor 58 and the error of the oscillation frequency of the oscillator 28 are stored in the room temperature register 73, the high temperature register 74, and the low temperature register 72, respectively.

  The semiconductor device 24 according to the present embodiment is shipped after the above-described processing is performed, and the oscillation frequency of the oscillator 28 indicates the frequency correction value stored in the frequency correction register 75 at a predetermined timing after shipment. Correction is performed based on the above-described equation (1) using the data. Note that the secondary temperature coefficient a and the apex error b in the second embodiment are determined by the frequency error derived at each temperature. Note that the frequency error may be obtained by linear approximation from the difference between the oscillation frequency error values stored in the higher temperature register and the lower temperature register. Then, when the system is reset, periodically, in response to the input of a predetermined signal via the lead 38, or when the oscillation frequency of the oscillator 28 is corrected using the above equation (1), the second described later. Frequency correction processing is performed.

  The user causes the semiconductor device 24 to execute the second frequency correction process by inputting, for example, a derivation operation signal for starting the derivation of the frequency correction value to the semiconductor device 24. At this time, the user inputs the derived operation signal, for example, by connecting a device that outputs the measurement operation signal to the lead 38 of the semiconductor device 24.

  FIG. 17 is a flowchart showing the flow of the second frequency correction process in the semiconductor device 24 according to the present embodiment. The program that executes the second frequency correction process is a program that is executed at the timing when the measurement operation signal is input, and is stored in advance in storage means included in the control unit 60.

  In step S503, the control unit 60 measures the current environmental temperature with the temperature sensor 58, and acquires the measured value. Note that the measurement value obtained by the temperature sensor 58 is stored in the temperature measurement value storage register 71.

  In step S505, the control unit 60 determines whether or not the temperature acquired in step S503 is different from the temperature measured in the thermostat (for example, the temperature acquired in step S303). If this determination is not necessary, the process may proceed to step S505 without performing the process of step S505 after performing the process of step S503.

  If it is determined in step S505 that the temperatures are not different, the control unit 60 determines that there is no need to change the frequency correction value, and ends the second frequency correction process.

  If it is determined in step S505 that the temperatures are different, the control unit 60 derives a frequency error by performing the same process as in step S305 described above in step S507. In step S507, the control unit 60 derives the secondary temperature coefficient a and the apex error b by substituting the data stored in each register of the register unit 70 into the above-described equation (1).

  In step S <b> 511, the control unit 60 stores the frequency correction value in the frequency correction register 75. At this time, if it is determined in step S505 that the temperatures are not different, a frequency correction value is derived and stored using the temperature and frequency error stored in the low temperature register 72, the normal temperature register 73, and the high temperature register 74. To do. On the other hand, if it is determined in step S505 that the temperatures are different, a frequency correction value is derived and stored using the frequency error derived in step S507.

  In the semiconductor device 24, the frequency divider 53 corrects the signal input from the oscillator based on the frequency correction value stored in the frequency correction register 75, thereby correcting the oscillation frequency of the oscillator 28. Do.

  As described above, according to the semiconductor device 24 according to the second embodiment, by measuring the frequency error at the actual temperature, even if the frequency deviation varies depending on the temperature due to the manufacturing variation of the oscillator 28, the time measurement is always stable. Can be engraved.

  Further, according to the semiconductor device 24 according to the second embodiment, by incorporating a time correction circuit inside the LSI 30A of the semiconductor device 24, time measurement can be performed with high accuracy even when the frequency accuracy of the clock signal supplied from the outside is low. It can be performed.

  In addition, according to the semiconductor device 24 according to the second embodiment, even if the number of terminals is limited by replacing an empty terminal due to the built-in oscillator 28 with another function (for example, serial communication or addition of I2C). High functionality can be realized.

  In the present embodiment, the error of the oscillation frequency of the oscillator 28 is derived using the reference signal oscillator 80, the measurement counter 81, and the reference counter 82, but the method of deriving the error is not limited to this, and the oscillation circuit 51 By comparing the time of a predetermined time (in this embodiment, 1 second (32, 768 CLK)) in the clock signal output from the oscout terminal output from the time with the predetermined time accurately measured by another method The oscillator 28 may measure how long the predetermined time is actually measured.

  In addition, after correcting the oscillation frequency error of the oscillator 28 in the semiconductor device 24 according to the second embodiment, the measurement error of the temperature sensor 58 in the semiconductor device 24 according to the first embodiment is corrected as necessary. You may perform the correction | amendment which considered.

  18 and 19 are block diagrams showing another example of the electrical configuration of the LSI 30A of the semiconductor device 24 according to this embodiment.

  As shown in FIG. 18, the semiconductor device 24 includes an output terminal 84, and an error (frequency correction value) in the oscillation frequency of the oscillator 28 derived by the control unit 60 is output to the outside of the semiconductor device 24. It may be output via. As a result, it is possible to carry out periodic calibration for finding characteristic deterioration of the reference clock generator.

  Further, as shown in FIG. 19, the LSI 30 </ b> A of the semiconductor device 24 may be connected to the measurement counter 81 with a high-accuracy clock generator 85 that serves as a calibration reference. In this case, in step S413 described above, the control unit 60 acquires the count value of the measurement counter 81 and the count value of the reference counter 82, and compares the count value of the measurement counter 81 with the count value of the reference counter 82. . For example, when the frequency of the clock signal of the measurement counter 81 is 10 MHz and the frequency of the clock generator 85 connected to the reference counter 82 is 10 MHz, the clock generator having the reference signal oscillator 80 and the clock connected to the reference counter 82 are used. If the generator 84 generates a clock signal having the same frequency, the count value of the measurement counter 81 and the count value of the reference counter 82 become the same value, but the characteristics of the reference signal oscillator 80 change. If so, a difference occurs between the count value of the measurement counter 81 and the count value of the reference counter 82. When there is a difference between the count value of the measurement counter 81 and the count value of the reference counter 82, the control unit 60 determines whether the difference is within a predetermined allowable error range, and determines the determination result. 8 to the output terminal 84. As a result, it is possible to carry out periodic calibration for finding characteristic deterioration of the clock generator provided with the reference signal oscillator 80.

  Further, as shown in FIG. 19, even when the LSI 30A of the semiconductor device 24 includes the clock generator 85, the clock signal output from the oscillation circuit 51 and the clock generator 85 are included in the LSI 30A. A selector 86 that selectively inputs one of the output clock signals and outputs it to the measurement counter 81 may be connected. The semiconductor device 24 shown in FIG. 19 can function in the same manner as the semiconductor device 24 shown in FIG. 18 by connecting the selector 86.

(Third embodiment)

  Next, a semiconductor device 200 according to a third embodiment of the present invention will be described. In addition, about the structure same as 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted. As shown in FIGS. 9 and 10, an oscillator 28 is mounted on an oscillator mounting beam 206 on the surface of a lead frame 202 constituting the semiconductor device 200 according to the present embodiment via an adhesive. The LSI 30 is mounted on the die pad 202A on the back surface of the lead frame 202 via an adhesive.

  Here, the LSI 30 is mounted shifted to the left side from the center of the die pad 202A so as not to overlap the opening 202C formed in the die pad 202A. For this reason, the entire surface of the LSI 30 is bonded to the die pad 202A.

  The oscillator 28 is fixed to the first surface of the die pad 202A, the LSI 30 is fixed to the second surface opposite to the first surface, the oscillator electrode pad 54 of the LSI 30 of the LIS 30 and the external electrode 34 of the oscillator 28. The procedure of connecting the electrode pad 50 of the LSI 30 and the inner lead 38A with the bonding wire 52 to make the semiconductor device 200 is as shown in FIGS. 6A to 6E, as in the semiconductor device 24 of the first embodiment. It is. The procedure for sealing the semiconductor device 200 with the mold resin 32 is also as shown in FIGS.

  In the semiconductor device 200 according to the present embodiment, the adhesive strength of the LSI 30 can be improved as compared with the semiconductor device 24 according to the first embodiment. Further, since the entire surface of the external electrode 34 of the oscillator 28 is exposed, the oscillator electrode pad 54 and the external electrode 34 can be easily connected by the bonding wire 52.

(Fourth embodiment)

  Next, a semiconductor device 300 according to a fourth embodiment of the present invention will be described. In addition, about the structure same as 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted. As shown in FIGS. 22 and 23, the lead frame 302 constituting the semiconductor device 300 according to the present embodiment includes a circular die pad 302A and an outer frame portion 302B provided on the outer peripheral side of the die pad 302A as support beams. The shape spans between 302C and the resonator mounting beam 302D.

  The die pad 302A is located at the center of the lead frame 302 and is smaller than the LSI 30 mounted on the back surface of the die pad 302A. The support beam 302C extends to the top and bottom and the left side of the die pad 302A, and the oscillator mounting beam 302D extends to the right side of the die pad 302A. The oscillator mounting beam 302D is formed wider than the support beam 302C, and the width of the oscillator mounting beam 302D is formed to be narrower than the distance between the external electrodes 34 of the oscillator 28. An oscillator 28 is mounted via an adhesive.

  The oscillator 28 is fixed to the first surface of the die pad 302A, the LSI 30 is fixed to the second surface opposite to the first surface, the oscillator electrode pad 54 of the LSI 30 of the LIS 30 and the external electrode 34 of the oscillator 28. The procedure for forming the semiconductor device 300 by connecting the electrode pads 50 of the LSI 30 and the leads 38 with the bonding wires 52 is as shown in FIGS. 6A to 6E, as in the semiconductor device 24 of the first embodiment. is there. The procedure for sealing the semiconductor device 300 with the mold resin 32 is also as shown in FIGS.

  In the semiconductor device 300 according to the present embodiment, since the die pad 302A is formed as small as possible and the outside of the die pad 302A is punched out, the material cost for the lead frame 302 is reduced compared to the semiconductor device 24 according to the first embodiment. can do.

  Further, since the die pad 302A is made smaller, the contact area between the mold resin 32 and the LSI 30 becomes larger than in the first embodiment. Here, since the adhesive force between the LSI 30 and the mold resin 32 is greater than the adhesive force between the LSI 30 and the die pad 302A, the LSI 30 is less likely to be peeled off as much as the contact area between the mold resin 32 and the LSI 30 is increased. In particular, when the semiconductor device 300 is mounted on the substrate by reflow or the like, since the semiconductor device 300 is heated, there is a possibility that the adhesion between the die pad 302A and the mold resin 32 may be reduced, but the die pad 302A is reduced, By increasing the contact area between the mold resin 32 and the LSI 30, it is possible to ensure adhesion even during heating.

  Further, the support beam 302C and the oscillator mounting beam 302D are arranged in a cross shape (lattice shape) inside the outer frame portion 302B, and the oscillator 28 is mounted so as to intersect the oscillator mounting beam 302D perpendicularly. Therefore, it is possible to suppress short circuit due to contact between the support beam 302C and the external electrode 34 of the oscillator 28. Alternatively, the support beam 302C that supports the die pad 302A may be removed, and the outer frame portion 302B and the die pad 302A may be connected to each other by only the oscillator mounting beam 302D.

(Fifth embodiment)

  Next, a semiconductor device 400 according to a fifth embodiment of the present invention is described. In addition, about the structure same as 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted. As shown in FIGS. 24 and 25, a step portion 404 is provided in the die pad 402A located at the center of the lead frame 402 according to the present embodiment. The stepped portion 404 extends in the vertical direction of the die pad 402A and is inclined upward from left to right as shown in FIG. For this reason, the die pad 402A is divided into a first mounting surface 402B located below and a second mounting surface 402C located above, with the stepped portion 404 as a boundary.

  The first mounting surface 402B and the second mounting surface 402C are continuously provided on the back surface of the lead frame 402, and are formed in parallel with the inner lead 408A. The LSI 30 is mounted on the first mounting surface 402B via an adhesive, and the electrode pad 50 provided on the lower surface of the LSI 30 and the inner lead 408A are electrically connected by a bonding wire 412.

  The oscillator 28 is mounted on the second mounting surface 402C via an adhesive. Here, the second mounting surface 402C is positioned above the first mounting surface 402B by the difference in thickness between the integrated circuit 30 and the oscillator 28, and the lower surface of the LSI 30 and the lower surface of the oscillator 28 have the same height. It has become.

  As shown in FIG. 25, the bonding wire 412 connecting the electrode pad 50 and the inner lead 408A is formed so as to straddle the bonding wire 412 connecting the oscillator electrode pad 54 and the external electrode 34. Has been. That is, in order to prevent the bonding wire 412 from being short-circuited, the apex of the bonding wire 412 connecting the oscillator electrode pad 54 and the external electrode 34 is the bonding connecting the electrode pad 50 and the inner lead 408A. It is formed to be lower than the apex of the wire 412.

<Manufacturing procedure>

  Hereinafter, a manufacturing procedure of the semiconductor device 400 will be described.

  First, as shown in FIG. 26A, the lead frame 402 is mounted on the mounting table 2 of the bonding apparatus 1 so that the inner lead 408A is positioned above and the die pad 402A is positioned below. The mounting table 2 is provided with a step 8 for holding the portion of the die pad 402A where the second mounting surface 402C is formed. In this state, both the first mounting surface 402B and the second mounting surface 402C face upward. The oscillator 28 is encapsulated and transported in a package 29 on the tape with the external electrode 34 facing upward. Note that a stepped portion 404 is formed in advance in the lead frame 402 by pressing or the like.

  Next, as shown in FIG. 26 (b), the package 29 is opened, the oscillator 28 is taken out by the picker 4, and the external electrode 34 of the oscillator 28 faces upward as shown in FIG. 26 (c). The oscillator 28 is disposed on the first mounting surface 402B of the die pad 402A, and is fixed to the first mounting surface 402B with an adhesive. When the oscillator 28 is enclosed in the package 29 with the external electrode 34 facing downward, the picker 4 having a rotating mechanism is used, and after the oscillator 28 is taken out by the picker 4, it is rotated. It is preferable to place the oscillator 28 upside down by the mechanism and place the external electrode 34 upward on the first surface of the die pad 26A.

  When the oscillator 28 is fixed to the first mounting surface 402B, as shown in FIG. 26D, the LSI 30 is placed on the second mounting surface 402C of the die pad 402A with the electrode pad 50 and the oscillator electrode pad 54 facing upward. Fix with adhesive so that it faces. Since the second mounting surface 402C is formed so as not to overlap the first mounting surface 402B in plan view, the LSI 30 is also fixed so as not to overlap the oscillator 28 in plan view. The LSI 30 and the oscillator 28 are fixed to the same side surface of the die pad 402A.

  When the LSI 30 is fixed to the second mounting surface 402C, as shown in FIG. 26E, the electrode pads 50 of the LSI 30 and the inner leads 408A of the lead frame 402 are connected by bonding wires 412 and the oscillator electrodes of the LSI 30 are connected. The pad 54 and the external electrode 34 of the oscillator 28 are connected by a bonding wire 412.

  Next, a procedure for sealing the semiconductor device 400 with the mold resin 32 will be described.

  As shown in FIG. 27A, the semiconductor device 400 is fixed inside the cavity 6 of the mold 5 while being inverted upside down from the state shown in FIG. At this time, the side on which the LSI 30 is mounted in the semiconductor device 400 is located closer to the injection port 7 for injecting the mold resin 32 in the mold 5 than the side on which the oscillator 28 is mounted, and the LSI 30 in the die pad 402A is located. It is preferable to arrange the semiconductor device 400 so that the mounted side portion is located in the vicinity of the center of the cavity 6 in the height direction. Further, the semiconductor device 400 is arranged such that the outer lead 408B protrudes outside the mold 5.

  When the semiconductor device 400 is fixed inside the cavity 6, the mold resin 32 is injected into the cavity 6 from the injection port 7 as indicated by an arrow a in FIG.

  As shown in FIG. 27 (c), the mold resin 32 injected from the injection port 7 is evenly distributed above and below the lead frame 402 in the portion where the LSI 30 is fixed in the lead frame 402 (die pad 402A). Flow into.

  However, the lead frame 402 (die pad 402A) has a step 404 formed in the thickness direction, and the portion of the die pad 402A where the oscillator 28 is fixed is different from the portion where the LSI 30 is fixed with the step 404 as a boundary. 27 (a) to 27 (d) are bent upward.

  Therefore, as indicated by an arrow c in FIG. 27D, the flow velocity below the die pad 402A is lower than the flow velocity above the die pad 402A in the portion where the oscillator 28 of the die pad 402A is fixed. Accordingly, in the portion of the die pad 402A, the mold resin is preferentially filled downward, so that the lead frame 402 (die pad 402A) is supported from below by the injected mold resin 32.

  When both sides of the lead frame 402 are filled with the mold resin 32, the mold 5 is heated to cure the mold resin 32.

  In the semiconductor device 400 according to the present embodiment, since the oscillator 28 and the LSI 30 are mounted on the back surface of the lead frame 402, it is not necessary to invert the lead frame 402 when mounting the oscillator 28 and the LSI 30. . Thereby, the production efficiency of the semiconductor device 400 can be improved as compared with the first embodiment.

  If the surface on which the bonding wire 412 is formed is defined as the upper surface, the second mounting surface 402C is located below the first mounting surface 402B. Therefore, the electrode pad 50 and the inner lead of the LSI 30 straddle the oscillator 28. When connecting 408A to the bonding wire 412, the oscillator 28 does not interfere with the bonding wire 412.

  In the present embodiment, the first mounting surface 402B and the second mounting surface 402C are provided on the back surface of the lead frame 402. However, the present invention is not limited to this, and may be provided on the surface of the lead frame 402. Even in this case, by forming the second mounting surface 402C below the first mounting surface 402B with the surface on which the bonding wire 412 is formed as the upper surface, the oscillator 28 can be prevented from obstructing the bonding wire 412. .

  In the present embodiment, the second mounting surface 402C is provided above the first mounting surface 402B by the difference in thickness between the LSI 30 and the oscillator 28. However, the present invention is not limited to this, and the bonding wire 412 is not limited thereto. As long as there is a level difference that does not interfere with the above, the lower surface of the oscillator 28 may protrude downward from the lower surface of the LSI 30.

(Sixth embodiment)

  Next, a semiconductor device 500 according to a sixth embodiment of the present invention will be described. In addition, about the structure same as 1st Embodiment, the same code | symbol is attached | subjected and description is abbreviate | omitted. As shown in FIGS. 28 and 29, a step 504 is formed in the die pad 502A located at the center of the lead frame 502 according to the present embodiment, as in the fifth embodiment. As shown in FIG. 29, the stepped portion 504 is inclined upward from left to right, and the die pad 502A has a first mounting surface 502B positioned below and the upper side of the stepped portion 504 as a boundary. The second mounting surface 502C is divided.

  Both the first mounting surface 502B and the second mounting surface 502C are continuously provided on the back surface of the lead frame 502, and are parallel to the inner lead 508A. Further, the LSI 30 is mounted on the first mounting surface 502B via an adhesive, and the oscillator 28 is mounted on the second mounting surface 502C via an adhesive. Here, as shown in FIG. 28, the LSI 30 is located at the center of the lead frame 502, and the right end of the LSI 30 covers a part of the oscillator 28. That is, the oscillator 28 and the LSI 30 are arranged so as to overlap when projected in a plan view.

  The oscillator 28 is fixed to the first mounting surface 502B of the die pad 502A, the LSI 30 is fixed to the second mounting surface 502C, the oscillator electrode pad 54 of the LSI 30 of the LIS 30, the external electrode 34 of the oscillator 28, and the electrode pad 50 of the LSI 30. The procedure of connecting the lead 38 and the lead 38 with the bonding wire 512 to form the semiconductor device 500 is as shown in FIGS. 26A to 26E, as in the semiconductor device 400 of the fourth embodiment. The procedure for sealing the semiconductor device 500 with the mold resin 32 is also as shown in FIGS.

  In the semiconductor device 500 according to the present embodiment, since the LSI 30 is mounted at the center of the lead frame 502, the distance between the electrode pad 50 of the LSI 30 and the inner lead 508A can be made constant on each side of the LSI 30. Thereby, wire bonding can be performed easily. Other operations are the same as in the fifth embodiment.

  The first to sixth embodiments of the present invention have been described above, but the present invention is not limited to such embodiments, and the first to sixth embodiments may be used in combination. Needless to say, the present invention can be implemented in various forms without departing from the scope of the invention. For example, an oscillator including an oscillation circuit 51 may be used as the oscillator 28. Further, the opening 26C in FIG. 2 may be a slit-shaped hole.

DESCRIPTION OF SYMBOLS 1 Bonding apparatus 2 Mounting stand 5 Mold 6 Cavity 10 Integrated electric energy meter 22 Electric energy measuring circuit (measuring means)
24 Semiconductor Device 26 Lead Frame 26C Opening 28 Oscillator 30 LSI (Integrated Circuit)
34 External electrode (Oscillator terminal)
50 Electrode pads (terminals of integrated circuits)
51 Oscillator 52 Bonding Wire 54 Electrode Pad for Oscillator (Integrated Circuit Terminal)
55 Digital circuit part 58 Temperature sensor 60 Control part (correction means)
70 register unit 80 reference signal oscillator 81 measurement counter 82 reference counter 85 clock generation circuit 86 selector 200 semiconductor device 202 lead frame 202C opening 300 semiconductor device 302 lead frame 400 semiconductor device 402 lead frame 402B first mounting surface 402C second mounting Surface 412 Bonding wire 500 Semiconductor device 502 Lead frame 502B First mounting surface 502C Second mounting surface 512 Bonding wire

Claims (11)

A lead frame;
An oscillator mounted in the first region of the lead frame;
An integrated circuit mounted in a second region different from the first region of the lead frame;
A plurality of first bonding wires connecting the first terminal of the oscillator and the second terminal of the integrated circuit;
Have
The lead frame is formed around a mounting portion including the first region and the second region, and includes a plurality of third terminals connected to the second terminal by a plurality of second bonding wires. ,
A semiconductor device in which a top of the first bonding wire is lower than a top of the second bonding wire, and the second bonding wire straddles the first bonding wire.   The angle formed by the adjacent first bonding wires is larger than the angle formed by the adjacent second bonding wires, and the first bonding wire and the second bonding wire intersect each other. Semiconductor device.   3. The semiconductor device according to claim 1, wherein an angle formed between the first bonding wires is an obtuse angle, and an angle formed between the second bonding wires is an acute angle. The lead frame further comprises an opening facing the first terminal,
The semiconductor device according to claim 1, wherein the first terminal and the second terminal are connected by the first bonding wire through the opening.   The semiconductor device according to claim 4, wherein an opening area of the opening is larger than the first terminal, and the first terminal is larger than the second terminal.   The semiconductor device according to claim 1, wherein the oscillator and the integrated circuit are sealed with resin.   The semiconductor device according to claim 1, wherein the mounting portion is smaller than the integrated circuit. The lead frame, the oscillator, and the integrated circuit are sealed with resin,
The distance from the surface of the resin on the first surface side of the lead frame to the third terminal is from the surface of the resin on the second surface side opposite to the first surface side of the lead frame. The semiconductor device according to claim 7, wherein the semiconductor device is longer than a distance to the third terminal.   The distance from the resin surface on the first surface side of the lead frame to the mounting portion is longer than the distance from the resin surface on the second surface side of the lead frame to the mounting portion. The semiconductor device according to claim 8, characterized in that:   The semiconductor device according to claim 1, wherein the integrated circuit further includes an oscillation circuit that oscillates the oscillator and a correction unit that corrects a frequency generated by the oscillation circuit. A semiconductor device according to any one of claims 1 to 10,
Measuring means for measuring an integrated amount according to a signal output from the semiconductor device;
Measuring instrument.