JP2019125796A - Method of manufacturing semiconductor device - Google Patents

Abstract

To provide a method of manufacturing a semiconductor device capable of encapsulating a lead frame on which an oscillator and an integrated circuit are arranged with a resin, without generating voids in the resin, and of effectively preventing the lead frame from being displaced in a vertical direction during the resin encapsulation.SOLUTION: A method of manufacturing a semiconductor device includes the following steps of: providing an oscillator on an upper surface of a die pad; providing an integrated circuit on a lower surface of the die pad; arranging the die pad, the oscillator and the integrated circuit in a mold that has a first portion provided between a lower surface of a lead separated from the die pad and the mold via an opening; and injecting a resin into the mold from the opening.SELECTED DRAWING: Figure 7

Description

  The present invention relates to a method of manufacturing a semiconductor device.

  BACKGROUND In recent years, in measuring instruments such as electric power meters that measure integrated power, the demand for measuring integrated power by time zone has been increasing. Along with this, there is a measuring device which can measure power and time by incorporating a semiconductor device provided with an oscillator and an integrated circuit inside the measuring device.

  As an oscillator used for such a measuring device, a vibrator and an IC chip for oscillating the vibrator are arranged in a plane direction on one side of a wiring board and the one side of the wiring board There is an oscillator which is sealed with resin (Patent Document 1).

  In addition, there is a piezoelectric device in which an IC is mounted on a wiring substrate and a piezoelectric vibration element is mounted on the IC in a superimposed manner, and connection pads of the IC and external terminals of the piezoelectric vibration element are connected by solder balls (Patent Document 2) )

  Furthermore, there is a piezoelectric oscillator in which an integrated circuit provided with a piezoelectric vibrator on one side of a lead frame and an oscillation circuit for driving the piezoelectric vibrator on the other side is mounted (Patent Document 3).

JP, 2009-213061, A JP 2008-219348 A Unexamined-Japanese-Patent No. 2007-234994

  The oscillators, the piezoelectric devices, and the piezoelectric oscillators in Patent Documents 1 to 3 integrate the vibration element and the transmission circuit. However, in these oscillators, the piezoelectric devices, and the piezoelectric oscillators, a microcontroller and an oscillator that perform timekeeping The number of parts is 2 points, and it is necessary to adjust these parts.

  Further, in the oscillator of Patent Document 1, there is a problem that the mounting area tends to be large since the vibrator and the IC chip are arranged in a plane direction on one surface of one wiring substrate. .

  On the other hand, in the inventions of Patent Documents 2 and 3, although the semiconductor device can be miniaturized as compared with the case where the integrated circuit and the oscillator are mounted side by side on one side of the lead frame, the integrated circuit and the oscillator are electrically In order to make a connection, it is necessary to lead the wiring to the back side of the lead frame, which may increase the wiring resistance.

  As a means for solving the above problems, an integrated circuit such as an LSI or the like in which a circuit for performing processing using a clock supplied from an oscillator is formed on one surface of the lead frame on the other side of the lead frame A device may be considered which is disposed on the surface and integrally sealed with a resin.

  However, when manufacturing the device, it is necessary to perform resin sealing in consideration of the influence of the oscillator newly disposed in the package on the flow of the resin. Otherwise, air contained in the resin can not be discharged well, and a cavity or the like may be generated inside the device.

  In addition, when the oscillator is taller than the integrated circuit, it is difficult to arrange the lead frame at the center along the height direction of the mold, so the pressure on the lead frame from the injected resin However, it may not be uniform on one side and the other side of the lead frame. In this case, if the lead frame is to be placed at the center along the height direction of the mold, it is necessary to adjust the height dimension of the cavity of the mold to the oscillator, so There is a problem that the thickness of the sealing resin of the semiconductor device is increased as compared with the case where the semiconductor device is not disposed at the center along the height direction.

  In view of the above facts, the present invention can resin-seal a lead frame in which an oscillator and an integrated circuit are disposed without generating a cavity in the resin, and the lead frame is vertically moved during resin sealing. It is an object of the present invention to provide a method of manufacturing a semiconductor device which can effectively prevent the displacement of the semiconductor device.

In a first aspect of the method of manufacturing a semiconductor device according to the present invention, the method comprises: providing an oscillator on the top surface of a die pad; providing an integrated circuit on the bottom surface of the die pad; and bottom surfaces of leads separated from the die pad. Placing the die pad, the oscillator and the integrated circuit inside a mold having a first portion provided through an opening, and injecting a resin from the opening into the mold And.
In a second aspect of the method of manufacturing a semiconductor device according to the present invention, the method further comprises: providing an oscillator and an integrated circuit on the lower surface of the die pad; and providing an opening between the lower surface of the lead separated from the die pad. The method further comprises the steps of: disposing the die pad, the oscillator, and the integrated circuit in a mold having one portion; and injecting a resin into the mold from the opening.

  According to the present invention, the lead frame in which the oscillator and the integrated circuit are arranged can be resin-sealed without generating a cavity in the resin, and the lead frame may be vertically displaced during the resin-sealed. A method of manufacturing a semiconductor device that can be effectively prevented is provided.

1 is a perspective view of an integrated energy meter provided with a semiconductor device according to a first embodiment. FIG. 2 is a partially broken view of the semiconductor device according to the first embodiment as viewed from the back surface. It is line 3-3 in FIG. 2 sectional drawing. It is an exploded perspective view showing a resonator concerning a 1st embodiment. FIG. 2 is a block diagram for explaining an LSI of the semiconductor device according to the 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 it 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 view which shows the modification of the semiconductor device concerning a 1st embodiment. It is a flowchart which shows the flow of the 1st frequency correction process which concerns on 1st Embodiment. It is a flow chart which shows the flow of the 2nd frequency amendment processing concerning a 1st embodiment. It is a figure which shows the relationship of the temperature in the semiconductor device concerning 1st Embodiment, and a frequency deviation. It is a block diagram for demonstrating LSI of the semiconductor device concerning 2nd Embodiment. (A) is a figure which shows an example of the clock value of the oscillator of the semiconductor device concerning a 2nd embodiment, (b) is an example of the clock value of the reference signal oscillator of the semiconductor device concerning a 2nd embodiment FIG. It is a flow chart which shows the flow of the 1st frequency amendment processing concerning a 2nd embodiment. It is a flow chart which shows a flow of frequency error derivation processing concerning a 2nd embodiment. It is a timing chart in frequency error derivation processing concerning a 2nd embodiment, (a) is a figure showing a count start time, and (b) is a figure showing a count stop time. It is a flow chart which shows the flow of the 2nd frequency amendment processing concerning a 2nd embodiment. It is a block diagram for demonstrating another example of LSI of the semiconductor device concerning 2nd Embodiment. It is a block diagram for demonstrating another example of LSI of the semiconductor device concerning 2nd Embodiment. It is the partially broken figure which looked at the semiconductor device concerning a 3rd embodiment from the back. 21 is a cross-sectional view taken along line 21-21 of FIG. It is the partially broken figure which looked at the semiconductor device concerning a 4th embodiment from the back. It is an explanatory view for explaining a lead frame of a semiconductor device concerning a 4th embodiment. It is the partially broken figure which looked at the semiconductor device concerning a 5th embodiment from the back. It is line 14-14 in FIG. 24 sectional drawing. (A)-(e) is explanatory drawing which shows the procedure which arrange | positions an oscillator and LSI on a lead frame and wire-bonds it 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. It is line 18-18 in FIG. 28 sectional drawing. FIG. 18 is a block diagram showing an example of a state in which a conventional semiconductor device having a built-in time measurement function is connected to an oscillator. FIG. 18 is a block diagram showing an example of a state in which a conventional semiconductor device having a built-in time measurement function is connected to an oscillator. 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 attached drawings.

<Configuration>

  As shown in FIG. 1, the integrated energy meter 10 including the semiconductor device of the first embodiment is attached to the upper surface of a fixing plate 102 fixed to an outer wall 100 such as a house, and mainly includes a main body 12 and a main body A transparent cover 14 covering the portion 12 and a connection portion 16 provided at the lower portion of the main body portion 12 are provided.

  From the lower side of the connection portion 16, the power supply side wiring 18 and the load side wiring 20 are connected, and a current is supplied to the integrated power meter 10. The main body 12 is a box having a rectangular shape in a plan view, and a measurement is performed inside the main body 12 to measure an integrated power amount according to a signal output from a semiconductor device 24 and the semiconductor device 24 described later. A power amount measuring circuit 22 as a means is mounted on a substrate (not shown). In FIG. 1, for convenience of explanation, the sizes of the power amount measuring circuit 22 and the semiconductor device 24 are exaggerated.

  On the front of the main body 12, a horizontally long liquid crystal display 15 is provided. The liquid crystal display 15 displays the amount of used power per unit time measured by the power amount measuring circuit 22, the integrated amount of power used for each time zone, and the like. Although the integrated energy meter 10 according to the present embodiment is an electronic energy meter using the energy measuring circuit 22 as the measuring means, the present invention is not limited to this, and for example, the disk can be rotated to It may be an inductive watt-hour meter to measure.

  Next, the detailed configuration of the semiconductor device 24 according to the present embodiment will be described. In the following description, the horizontal direction in 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 sectional view of the semiconductor device 24 shown in FIG. It explains as a direction. As shown in FIGS. 2 and 3, the outer shape of the semiconductor device 24 is rectangular 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, the LSI 30 as an integrated circuit mounted on the back surface (second surface) of the lead frame 26, and the mold resin 32 as a sealing material are included.

  The lead frame 26 is a plate member 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 as a mounting portion provided in the central portion A die pad 26A, a suspension lead 26B extending diagonally outward from the die pad 26A, and a plurality of leads (terminals) 38 provided between adjacent suspension leads 26B are configured.

  The leads 38 are elongated members extending toward the central portion of the die pad 26A, and a plurality of leads 38 are formed at predetermined intervals around the die pad 26A. In the present embodiment, sixteen leads 38 are formed between the adjacent suspension leads 26B. The lead 38 is composed of 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, they are pressed down by the press and extend in parallel with the die pad 26A (see FIG. 3). The tip of the inner lead 38A closest to the die pad 26A is covered with a plating film 40. Although the plating film 40 is formed of silver (Ag) as an example in the present embodiment, the plating film is not limited to this, and for example, the plating film may be formed of a metal such as gold (Au).

  The outer lead 38B is exposed downward from the mold resin 32 and bent downward, and its tip end is parallel to the inner lead 38A. That is, it is a gull wing lead. In addition, 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 central portion of the lead frame 26 is a flat member formed in a rectangular shape in plan view, and on the right side of the central portion of the die pad 26A, two openings penetrating in the thickness direction of the die pad 26A. 26C is formed. The opening 26C is formed in a horizontally long rectangular shape, and is provided to face the external electrode 34 of the 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, and an adhesive (the oscillator mounting beam 42 on the surface of the lead frame 26 An oscillator 28 is mounted via the not shown) (see FIG. 4). In other words, the openings 26C are respectively provided on both sides of the oscillator mounting beam 42. The oscillator 28 is a rectangular electronic component whose longitudinal direction is the vertical direction. In this embodiment, the oscillator 28 is externally attached to a general-purpose semiconductor device 24 mounted on a general electronic device at a frequency of 32.768 kHz. A possible oscillator 28 is used.

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

  The package body 46 is a box having an open top, and a pedestal 47 to which the vibrating reed 44 is fixed is formed at the bottom of one end side in the longitudinal direction. The base of the vibrating reed 44 is fixed to the pedestal 47 so as to be able to vibrate, and by bonding the package body 46 and the lid 48 in a vacuum state, the vibrating reed 44 is hermetically sealed. Further, on both ends of the lower surface of the package main body 46, external electrodes 34 as terminals electrically connected to the excitation electrode 44A of the vibrating reed 44 are formed with a predetermined distance L1 apart. Further, the width L2 of the oscillator mounting beam 42 is formed 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 main body 46, and as shown in FIG. 2, the size of the external electrode 34 is the electrode pad 50 formed on the LSI 30 described later, and the electrode for oscillator 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, on the back surface of the lead frame 26, an LSI 30 as an integrated circuit or a semiconductor chip is mounted at the center of the die pad 26A via an adhesive (not shown). The LSI 30 is a rectangular thin-walled electronic component, and the right end of the LSI 30 covers the opening 26C by half. For this reason, when projected in plan view, the oscillator 28 and the LSI 30 are disposed so as to overlap. 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.

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

  At the outer peripheral end of the LSI 30 on the oscillator 28 side, an oscillator electrode pad 54 is provided separately from the electrode pad 50. Two oscillator electrode pads 54 are provided at the center of the LSI 30 in the vertical direction, and are located between the electrode pads 50. That is, the oscillator electrode pad 54 placement region (first region) is formed in the central portion, and the region from the center portion to the end of the side on which the oscillator electrode pad 54 is provided, and the remaining three. The 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 the 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 central portion 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 oscillator electrode pad 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 made 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 connecting the oscillator electrode pad 54 and the external electrode 34 than the distance between the bonding wire 52 connecting the electrode pad 50 and the inner lead 38A. The distance between the pad 50 and the bonding wire 52 connecting 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 are three-dimensionally crossed, as shown in FIG. As shown in FIG. 5, the bonding wire 52 connecting the electrode pad 50 and the inner lead 38A is formed to straddle the bonding wire 52 connecting the oscillator electrode pad 54 and the external electrode 34. There is. That is, in order to prevent a short circuit of bonding wire 52, a vertex of bonding wire 52 connecting oscillator electrode pad 54 and external electrode 34 is a bonding connecting electrode pad 50 and inner lead 38A. It is formed to be lower than the top of the wire 52.

  The height of the vertex of bonding wire 52 connecting oscillator electrode pad 54 and external electrode 34 is lower than the height of the vertex of bonding wire 52 connecting all electrode pads 50 and inner lead 38A. Or the height of the apex of the bonding wire 52 connecting the electrode lead 50 between the oscillator electrode pad 54 and the external electrode 34 and the inner lead 38A. .

  Further, the center of the LSI 30 and the center CP of the rectangular parallelepiped oscillator 28 are disposed in parallel so that they substantially coincide with each other on the X axis. That is, the shift width in the Y-axis direction from the X-axis of the center CP of the oscillator 28 is narrower than the width in the Y-axis direction of the central portion. In such an arrangement state, the bonding wire 52 connects the oscillator electrode pad 54 provided near the center of any one side of the LSI 30 and the external electrode 34 spaced apart at both ends in the longitudinal direction of the oscillator 28. doing. At the same time, bonding wires 52 connect the electrode pads 50 arranged so as to sandwich the oscillator electrode pad 54 and the inner leads 38A arranged parallel to the Y-axis direction with the electrode pads 50.

  Furthermore, since the oscillator electrode pad 54 is provided apart from the electrode pad 50, the bonding wire 52 connecting 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 which is lower than the oscillator 28 of the bonding wire 52 passes. That is, crossing near the apex of the bonding wire 52 connecting the oscillator electrode pad 54 and the external electrode 34 can be avoided, and three-dimensional crossing can be efficiently performed. Furthermore, since the height of the top of the bonding wire 52 connecting the electrode pad 50 and the inner lead 38A can be reduced, the height of the package can also be reduced.

  Further, the connection position of the bonding wire 52 in the external electrode 34 of the oscillator 28 is shifted from the center position of the oscillator 28 toward the inner lead 38A in the X-axis direction. This connection can reduce the contact of the bonding wire 52 with the end of the LSI 30. 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 manner, it is possible to reduce the number of crossings of the bonding wire 52 connecting the electrode pad 50 and the inner lead 38A.

  The oscillator 28, the LSI 30, and the lead frame 26 are sealed by 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 form a void inside, and the height of the mold resin 32 is twice or more as high as 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. Further, 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, in the LSI 30, an oscillation circuit 51, a frequency dividing circuit 53, a timing circuit 56, a temperature sensor 58, a control unit 60, and a register unit 70 are incorporated. The oscillation circuit 51 is connected to the oscillator 28 and causes the oscillator 28 to oscillate. The divider circuit 53 divides the signal (in the present embodiment, the frequency of 32.768 kHz) output from the oscillator 28 to obtain a predetermined clock (for example, 1 Hz). The timer circuit 56 measures time based on the signal divided by the divider circuit 53, and transmits the time to the control unit 60. The temperature sensor 58 measures the temperature of the LSI 30 and transmits the temperature to the control unit 60. Note that the temperature of the oscillator 28 electrically connected to the LSI 30 can be identical to the temperature of the LSI 30 by being disposed on the same lead frame in the vicinity of the LSI 30. That is, the temperature sensor 58 can measure the temperature of the oscillator 28 disposed around the LSI 30 with high accuracy. The control unit 60 causes the liquid crystal display 15 to display the integrated power amount per unit time and the like measured by the power amount measuring circuit 22 based on the time measured by the clock circuit 56 (see FIG. 1). 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 the correction of the oscillation frequency described later. The LSI 30 also incorporates an arithmetic circuit that performs arithmetic operations and an internal power supply.

<Manufacturing procedure>
Hereinafter, the 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 such that the lead 38 is positioned below. The mounting table 2 is formed with a recess 3 for accommodating the oscillator 28 when the lead frame 26 is turned upside down in a state where the oscillator 28 is fixed to the first surface. Also, the oscillator 28 is enclosed in the package 29 on the tape and transported with the external electrode 34 directed downward. In the lead frame 26, an opening 26C is formed in advance by press processing or the like.

  Next, as shown in FIG. 6B, the package 29 is unsealed, the oscillator 28 is taken out by the picker 4, and the first surface of the die pad 26A, that is, the upper surface in FIG. The oscillator 28 is disposed so that the 28 external terminals 34 overlap the opening 26C, and is fixed to the die pad 26A with an adhesive. When the oscillator 28 is enclosed in the package 29 with the external electrode 34 facing upward, the picker 4 with a rotation mechanism is used, and after the oscillator 28 is taken out by the picker 4, rotation is performed. Preferably, the oscillator 28 is turned upside down by a mechanism and the external terminal 34 is directed downward before being mounted on the first surface of the die pad 26A.

  After the oscillator 28 is fixed to the first surface of the die pad 26A, as shown in FIG. 6C, the lead frame 26 is turned upside down and mounted on the mounting table 2. Thus, the lead frame is mounted 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 in the second surface opposite to the first surface of the die pad 26A. The LSI 30 is fixed to the The second surface in FIG. 6D is the 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 connected by the wire 52. At that time, the height of the apex of the bonding wire 52 connecting the oscillator electrode pad 54 of the LSI 30 and the external electrode 34 of the oscillator 28 corresponds to that of the bonding wire 52 connecting the electrode pad 50 of the LSI 30 and the lead 38. Connect so as to be lower than the height of the vertex. After the oscillator electrode pad 54 of the LSI 30 and the external electrode 34 of the oscillator 28 are connected by bonding wires first, the electrode pads 50 and the leads 38 of the LSI 30 are jumped over the bonding wire 52. It connects by the bonding wire 52. Also, the bonding wire 52 connecting the oscillator electrode pad 54 of the LSI 30 and the external electrode 34 of the oscillator 28 and the bonding wire 52 connecting the electrode pad 50 and the lead 38 are connected so as to form a three-dimensional crossing. . 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 vertex 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. Connect as you cross.

  The oscillator 28 and the LSI 30 are fixed to the lead frame 26 (die pad 26A) according to the procedure shown in FIGS. 6A to 6E, and the LSI 30 is connected to the oscillator 28 by the procedure shown in FIG. 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 made between the LSI 30 and the lead 38 of the lead frame. Similar to the connection, it can be made from the second surface of the die pad 26A and is efficient. In addition, since the oscillator 28 and the LSI 30 are directly connected by the bonding wire 32 without passing through the lead frame 26, the case where the oscillator 28 and the LSI 30 are connected via the lead frame 26 or a bonding wire Wiring resistance can be reduced as compared to the case of drawing around and connecting 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, in the semiconductor device 24, the first surface of the lead frame 26 (die pad 26A), that is, the surface to which the oscillator 28 is fixed is the upper surface, and the lead frame 26 (die pad The second surface 26A), that is, the surface on which the LSI 30 is fixed, is fixed to the inside of the cavity 6 of the mold 5 so that the lower surface is the lower surface. Here, since the oscillator 28 is thicker than the LSI 30, the semiconductor device 24 has the cavity 6 so that the lead frame 26 (die pad 26A) is positioned below the center of the cavity 6 in the mold 6 in the height direction. It is placed inside. Further, the outer lead 38 B is made to project to the outside of 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, as shown by the arrow a in FIG. 7B, the mold resin 32 is injected from the injection port 7 provided along the lower surface of the lead frame 26. Here, as described above, since the lead frame 26 (die pad 26A) is fixed so as to be positioned lower than the center in the height direction of the cavity 6 in the mold 5, first, the mold resin 32 is It is injected along the lead frame 26 (die pad 26A). Here, since the injected mold resin 32 has a characteristic that it tends to flow into the larger space, it flows above the lead frame 26 from, for example, the gap between the rear end of the lead frame 26 and the die pad 26A. Although it is intended to be included, since the path is blocked by the oscillator 28, as shown by the arrow b in FIG. 7C, it flows so as to go under the lead frame 26.

  Thereafter, as shown by the arrow c in FIG. 7D, the mold resin 32 also flows into the upper surface side of the lead frame 26. Then, 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, since 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, when the semiconductor device 24 is sealed with the mold resin 32, the lead frame 26 is It has to be arranged below the center in the height direction of the cavity 6 of the mold 5. Thus, when there is a large 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 from the injection port 7 into the cavity 6 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 flow path of the mold resin 32 is adjusted using the oscillator 28, and the mold resin 32 is first introduced below the lead frame 26 to support the lead frame 26 by the mold resin 32 injected into the cavity 6. Can be expected. Therefore, the lead frame 26 is prevented from being displaced along the vertical direction inside the cavity 6 while the mold resin 32 is being injected.

<Function>

  Next, operations of the semiconductor device 24 and the integrated energy 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 by the mold resin 32 and integrated, and the LSI 30 includes the oscillation circuit 51, the divider 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 integrated energy meter 10 shown in FIG. That is, it is not necessary to separately mount the oscillator 28 and the divider circuit 53 on the substrate. Therefore, the time and effort for adjusting the connection between the oscillator 28 and the semiconductor device 24 is also unnecessary.

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

  Further, as shown in FIG. 2, the external electrode 34 of the oscillator 28 and the electrode pad 54 for the oscillator of the LSI 30 are directly connected by the bonding wire 52 through the opening 26C. Therefore, wiring can be performed at the shortest distance without 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 electrode pad 54 for the oscillator are uniform, the tension applied to the bonding wire 52 can be equalized, and the bonding wire 52 is broken or bent. It is possible to prevent contact due to Further, since the wiring can be performed without the lead frame 26, the signal can be smoothly transmitted from the oscillator 28 to the LSI 30 because it is not easily affected by noise. Further, noise is likely to be generated between the bonding wires 52 formed in parallel, but the bonding wire 52 connecting the oscillator electrode pad 54 and the external electrode 34 is different from the other bonding wires 52. Since the three-dimensional crossing occurs, interference between the bonding wire 52 connecting the oscillator electrode pad 54 and the external electrode 34 and the other bonding wire 52 can be reduced. In particular, oscillation is caused 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.

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

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

  In the present embodiment, all the inner leads 38A are connected to the electrode pads 50 of the LSI 30, but the present invention is not limited to this, as in the modification shown in FIG. The die pad 26A may be grounded by connecting it to the die pad 26A and connecting the outer lead 38B to the ground. In this case, the die pad 26A can be suppressed from being charged. Further, since the LSI 30 and the oscillator 28 are disposed 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.

  Further, in the present modification, the oscillation circuit 51 is disposed in the vicinity of the oscillator electrode pad 54, and the 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 digital signals, 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. As an example of the digital circuit unit 55, there is a CPU or the like.

<Correction of oscillation frequency>

  Next, a frequency correction process 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 in the semiconductor device 24 is normal temperature (here, 25 ° C.), the semiconductor device 24 has a reference temperature (hereinafter, also referred to as “low temperature”) lower than normal temperature. The temperature is measured by the temperature sensor 58 in each case where the temperature is higher than the normal temperature (hereinafter also referred to as "high temperature"). Then, for example, after shipment, 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 generated due to manufacturing variations of the temperature sensor 58.

  The above-described register unit 70 (see FIG. 5) indicates a temperature measurement value register 71 storing 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 a temperature measured by the temperature sensor 58 when the ambient temperature is normal temperature, 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 to each register via the data bus 76.

  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 temperature, normal temperature, and high temperature in order to correct the frequency error of the oscillator 28. Then, the first frequency correction processing of storing the temperature obtained by the measurement in the low temperature register 72, the normal temperature register 73, and the high temperature register 74 as trimming data is performed.

  For example, at the time of shipping test, the tester first places the semiconductor device 24 inside a thermostatic bath in which the temperature in the bath is set to normal temperature. Then, the user causes the semiconductor device 24 to execute the first frequency correction process by causing the semiconductor device 24 to input, for example, a measurement operation signal for starting measurement of the temperature by the temperature sensor 58. At this time, the user causes the semiconductor device 24 to input the measurement operation signal by, for example, connecting a device that outputs the measurement operation signal to the lead 38 of the semiconductor device 24. Further, 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 for executing the first 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 the storage unit of the control unit 60. Note that the timing of execution is not limited to this.

  In step S101, the control unit 60 determines whether a predetermined time (for example, several hours) has elapsed since the measurement operation signal is input. The predetermined time may be a time necessary 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 by the temperature sensor 58. The measurement value of the temperature sensor 58 is stored in the temperature measurement value storage register 71. In addition, when acquiring a measurement value by the temperature sensor 58, measurement is performed each time a predetermined time (for example, one minute) elapses, and a value obtained by averaging a plurality of measurement values obtained by a plurality of measurements is used as a measurement 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 constant temperature bath is the normal temperature (here, 25 ° C.) and sets the measured value in the constant temperature bath. If the temperature is high, the temperature is stored in the high temperature register 74. If the temperature set in the thermostatic chamber is low, the temperature is stored in the low temperature register 72, and the first frequency correction process is finished. The first frequency correction process may be performed in advance in the wafer state.

  The tester places the semiconductor device 24 inside the thermostatic bath in which the temperature in the bath is set high, in addition to the state in which the semiconductor device 24 is placed inside the thermostatic bath in which the temperature in the bath is set to normal temperature. In each of the above-described state and the state in which the semiconductor device 24 is disposed inside the thermostatic bath 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. As a result, the measurement values of 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 second frequency correction processing to be described later is performed at a predetermined timing after shipment.

  For example, after shipment, the user causes the semiconductor device 24 to execute the second frequency correction process by causing the semiconductor device 24 to input, for example, a derived operation signal for starting the derivation of the frequency correction value. At this time, the user inputs the derived operation signal, for example, by connecting a device that outputs the derived operation signal to the lead 38 of the semiconductor device 24. 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 for executing the second frequency correction process is a program that is executed at the timing when the derived operation signal is input after the shipment of the semiconductor device 24, and is stored in advance in the storage unit of the control unit 60.

  In step S201, 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 S203, the control unit 60 derives a correction value of the oscillation frequency of the oscillator 28 (hereinafter, also referred to as "frequency correction value") using the measurement value acquired in step S201.

FIG. 11 is a view showing the relationship between the temperature and the frequency deviation in the semiconductor device according to the present embodiment. FIG. 11 shows not the frequency error obtained in the actual temperature environment, but the theoretical value obtained by calculation using a quadratic function. The above quadratic function is expressed by the following equation (1). In the following equation (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 the storage unit of the control unit 60.

  In the first embodiment, although the frequency deviation f is unknown, the secondary temperature coefficient a which is known, the measured value at normal temperature stored in the normal 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 low temperature measurement value 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 in order to minimize the frequency deviation at the temperature T0 at normal temperature.

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

  In step S205, the control unit 60 stores data indicating the frequency correction value derived in step S203 in the frequency correction register 75. Then, in the semiconductor device 24, the frequency divider circuit 53 generates a clock signal from the signal input from the oscillator circuit using the frequency correction value stored in the frequency correction register 75, thereby the oscillation frequency of the oscillator 28. Correction is performed.

  Thus, according to the semiconductor device 24 according to the first embodiment, at the time of shipment, the measurement value by the temperature sensor 58 under the environmental temperature of 3 points of the semiconductor device 24 is prepared as trimming data, and the trimming data is By deriving the frequency correction value in the original manner, it is possible to obtain a frequency correction value based on highly accurate temperature information without depending on manufacturing variations of the temperature sensor 58 for each semiconductor device 24.

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

  However, in the semiconductor device 24 according to the present embodiment, since the temperature sensor 58 and the oscillator 28 are integrally sealed, the ambient temperature of the temperature sensor 58 and the ambient temperature of the oscillator 28 become the same. The temperature of the oscillator 28 can be measured with high accuracy by the temperature sensor 58 that the LSI 30 has, so that the temperature difference between the oscillator 28 and the temperature sensor 58 prevents the accuracy of the frequency correction from being lowered.

Second Embodiment

  Next, a semiconductor device 24 according to a second embodiment of the present invention will be described. The same components as those of the first embodiment are denoted by the same reference numerals, and the description thereof is 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”) used as a reference when correcting the oscillation frequency of the oscillator 28 with respect to the LSI 30A. The clock generator provided with the reference signal oscillator 80 is connected. 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 includes the measurement counter 81, the reference counter 82, and the clock signal from the oscillation circuit 57 to the outside. It further comprises an output terminal 83 for outputting.

  As shown in FIGS. 13A and 13B, the reference signal oscillator 80 is an oscillator such as a quartz oscillator 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") by 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 under the control of the control unit 60, receives a clock signal from the reference signal oscillator 80 and counts the number of clocks of the clock signal. Count. As shown in FIGS. 13 (a) and 13 (b), the reference counter 82 and the measurement counter 81 count the number of clocks substantially simultaneously at the same time in synchronization 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.

  Further, 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 normal temperature (25 ° C.) in the low temperature register 72. Stores the data indicating the temperature measured by the temperature sensor 58 and the frequency error at that temperature when the reference temperature is used, and the temperature sensor 58 measures the temperature in the room temperature register 73 when the ambient temperature is the room temperature (25 ° C.) Stored in the high temperature register 74. When the ambient temperature is set to a reference temperature higher than normal temperature (25.degree. C.), the temperature measured by the temperature sensor 58 and the temperature are stored. Data indicating frequency error is stored, and frequency correction register 75 is derived from the data indicating frequency error described above. That data indicating the frequency correction value is stored.

<Correction of oscillation frequency>

  For example, at the time of shipping test, the user first arranges the semiconductor device 24 inside a thermostatic bath in which the temperature in the bath is set to a normal temperature (here, 25 ° C.). Then, the user causes the semiconductor device 24 to execute the first frequency correction process by causing the semiconductor device 24 to input, for example, a measurement operation signal for starting measurement of the temperature by the temperature sensor 58. At this time, the user causes the semiconductor device 24 to input the measurement operation signal by, for example, connecting a device that outputs the measurement operation signal to the lead 38 of the semiconductor device 24. Further, 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 for executing the first frequency correction process 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 the storage unit of the control unit 60.

  In step S301, the control unit 60 determines whether a predetermined time (for example, several hours) has elapsed since the measurement operation signal is 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 by the temperature sensor 58. The measurement value of the temperature sensor 58 is stored in the temperature measurement value storage register 71. Further, the temperature sensor 58 has been confirmed by a test that the measurement accuracy is equal to or greater than a predetermined reference value, and it is guaranteed that the temperature sensor 58 can perform temperature measurement with high accuracy. Alternatively, the correction may be performed using the measurement value of the temperature sensor 58.

  In step S305, the control unit 60 performs frequency error derivation processing for deriving an error of the oscillation frequency of the oscillator. FIG. 15 is a flowchart showing a flow of frequency error derivation processing according to the present embodiment. FIG. 16 is a timing chart in the frequency error derivation process according to the present embodiment, (a) is a diagram showing the count start time, and (b) is a diagram showing the count stop time.

  In step S401, the control unit 60 outputs a correction operation signal to the measurement counter 81. In step S403, the measurement counter 81 having received the correction operation signal starts operation, starts counting the clock value of the clock signal by the oscillator 28, and outputs a start signal to the reference counter 82.

  In step S405, the reference counter 83 that has received the start signal starts counting of the clock value of the clock signal by the reference signal oscillator 80. 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 greater than or equal to a predetermined value (32.768 corresponding to one second in the present embodiment). If it is determined in step S407 that the measured value is not greater than the predetermined value, the measurement counter 81 continues counting.

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

  In step S411, the reference counter 82 that has received the stop signal stops counting. 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 S <b> 415, the control unit 60 derives an error of the oscillation frequency of the oscillator 28 from the count value of the reference counter 82 acquired in step S <b> 413. That is, the control unit 60 can perform reference signal oscillation that can count the count value (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. The error of the oscillation frequency of the oscillator 28 is derived by comparing with the count value of the reference clock signal by the oscillator 80.

  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)", it can be estimated that one second can be accurately counted by the oscillator 28. The error of the oscillation frequency does not need to be corrected with 0, and the error (frequency correction value) of the oscillation frequency is 0. On the other hand, for example, if the count value of the reference counter 82 is "10000002 (decimal number)", it can be inferred that the oscillation frequency of the oscillator 28 is delayed by 0.2 ppm, and the oscillation frequency of the oscillator 28 It is necessary to make correction so as to be faster by 0.2 ppm, that is, the error of the oscillation frequency (frequency correction value) is +0.2 ppm. Also, for example, if the value of the reference counter 82 is “9999990 (decimal number)”, the oscillation frequency of the oscillator 28 is advanced by 1.0 ppm, so the oscillation frequency of the oscillator 28 is equal to that error, That is, it is necessary to make it slow by 1.0 ppm, and the error of the oscillation frequency (frequency correction value) is set to -1.0 ppm.

  In step S417, the control unit 60 stops the output of 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 their operation when the input of the correction operation signal is stopped.

  In step S307, the control unit 60 adds the measured value of the temperature acquired in step S303 and the frequency error derived in step S415 to the normal temperature register 73 when the temperature set in the thermostatic chamber is normal temperature. If the temperature set in the constant temperature bath is high, the high temperature register 74 is stored, and if the temperature set in the constant temperature bath is low, the low temperature register 72 is stored, and the first frequency correction processing program Finish.

  In addition to the state in which the semiconductor device 24 is disposed inside the thermostatic bath in which the temperature in the bath is set to a normal temperature, the user operates 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 inside the thermostatic bath in which the temperature in the tank is set to a low reference temperature, the semiconductor device 24 is caused to perform the processing of steps S301 to S309. Thereby, the measured value of the temperature by the temperature sensor 58 and the error of the oscillation frequency of the oscillator 28 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 performing the above-described processing, 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. It is corrected based on the above-mentioned equation (1) using the data. The secondary temperature coefficient a and the vertex error b in the second embodiment are determined by the frequency error derived at each temperature. The frequency error may be determined by linear approximation from the difference between the value of the error of the oscillation frequency stored in the register of the temperature higher than the temperature to be determined and the register of the temperature lower. Then, at the time of system reset or periodically, or in response to the input of a predetermined signal through the lead 38, or when correcting the oscillation frequency of the oscillator 28 using the above equation (1), the second will be described later. Frequency correction processing is performed.

  The user causes the semiconductor device 24 to execute the second frequency correction process by causing the semiconductor device 24 to input, for example, a derived operation signal for starting the derivation of the frequency correction value. 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 for executing 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 the storage unit of the control unit 60.

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

  In step S505, the control unit 60 determines whether the temperature acquired in step S503 is different from the temperature measured in the thermostat (for example, the temperature acquired in step S303). If the determination is unnecessary, the process of step S503 may be performed, and then the process may proceed to step S505 without performing the process of step S505.

  If it is determined in step S505 that the temperature is not different, the control unit 60 determines that it is not necessary to change the frequency correction value, and ends the second frequency correction process.

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

  In step S511, 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, the frequency correction value is derived and stored using the temperature and frequency errors stored in the low temperature register 72, the normal temperature register 73, and the high temperature register 74. Do. On the other hand, if it is determined in step S505 that the temperature is different, a frequency correction value is derived and stored using the frequency error derived in step S507.

  Then, in the semiconductor device 24, the frequency divider circuit 53 corrects the signal input from the oscillator circuit 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 when the frequency deviation differs depending on the temperature due to the manufacturing variation of the oscillator 28, the timekeeping is always stable. It is possible to engrave.

  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 if 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 the free terminal due to the built-in oscillator 28 with another function (for example, serial communication, I2C addition, etc.) Higher 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. The clocking of a predetermined time (1 second (32, 768 CLK in the present embodiment)) in the clock signal output from the oscout terminal output from is compared with the predetermined time accurately clocked by another method. The oscillator 28 may measure how long the clocking of the predetermined time actually takes.

  In addition, after correcting the error of the oscillation frequency 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 may be corrected, if necessary. You may make the correction which considered.

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

  As shown in FIG. 18, the semiconductor device 24 includes the output terminal 84, and the error (frequency correction value) of 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 through the Thus, periodic calibration can be performed to find the characteristic deterioration of the reference clock generation device.

  Further, as shown in FIG. 19, the LSI 30A of the semiconductor device 24 may connect the measurement counter 81 with a high precision clock generation device 85 as a reference of calibration. 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, assuming that the frequency of the clock signal of measurement counter 81 is 10 MHz and the frequency of clock generator 85 connected to reference counter 82 is 10 MHz, the clock generator connected with reference signal oscillator 80 and the clock connected to reference counter 82 If the generator 84 generates a clock signal of 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. In this case, a difference occurs between the count value of the measurement counter 81 and the count value of the reference counter 82. When a difference occurs 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 the determination result is obtained. Output to the output terminal 84 of FIG. Thus, periodical calibration can be performed to find the characteristic deterioration of the clock generation device provided with the reference signal oscillator 80.

  Further, as shown in FIG. 19, even when the clock generation device 85 is built in the LSI 30A of the semiconductor device 24, the clock signal output from the oscillation circuit 51 and the clock generation device 85 are provided inside the LSI 30A. A selector 86 may be connected to selectively input one of the output clock signals and output the same to the measurement counter 81. The semiconductor device 24 illustrated in FIG. 19 can function as the semiconductor device 24 illustrated 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. The same components as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. As shown in FIG. 9 and FIG. 10, an oscillator 28 is mounted via an adhesive on the oscillator mounting beam 206 on the surface of the lead frame 202 constituting the semiconductor device 200 according to the present embodiment, 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 on the left side of the central portion of the die pad 202A so as not to overlap with the opening 202C formed in the die pad 202A. Therefore, 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, and the LSI 30 is fixed to the second surface opposite to the first surface, and the oscillator electrode pad 54 of the LSI 30 of the LIS 30 and the external electrode 34 of the oscillator 28 are fixed. The procedure for connecting the electrode pad 50 of the LSI 30 and the inner lead 38A with the bonding wire 52 to form the semiconductor device 200 is the same as in the semiconductor device 24 of the first embodiment, as shown in FIGS. It is. The procedure for sealing the semiconductor device 200 with the mold resin 32 is also as shown in FIGS. 7 (a) to 7 (d).

  The semiconductor device 200 according to the present embodiment can improve the adhesive strength of the LSI 30 as compared to 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. The same components as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. As shown in FIGS. 22 and 23, the lead frame 302 constituting the semiconductor device 300 according to the present embodiment supports the circular die pad 302A and the outer frame portion 302B provided on the outer peripheral side of the die pad 302A. It has a shape that is spanned by 302C and oscillator 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 upper, lower, and left sides 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. The oscillator 28 is mounted via an adhesive.

  The oscillator 28 is fixed to the first surface of the die pad 302A, and the LSI 30 is fixed to the second surface opposite to the first surface, and the oscillator electrode pad 54 of the LSI 30 of the LIS 30 and the external electrode 34 of the oscillator 28 are fixed. The procedure for connecting the electrode pad 50 of the LSI 30 and the lead 38 with the bonding wire 52 to form the semiconductor device 300 is the same 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. 7 (a) to 7 (d).

  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, by making the die pad 302A smaller, the contact area between the mold resin 32 and the LSI 30 becomes larger than that in the first embodiment. Here, since the adhesive force between the LSI 30 and the mold resin 32 is larger than the adhesive force between the LSI 30 and the die pad 302A, the LSI 30 is less likely to be peeled off because the contact area between the mold resin 32 and the LSI 30 is larger. In particular, when the semiconductor device 300 is mounted on a substrate by reflow or the like, the semiconductor device 300 is heated, and the adhesion between the die pad 302A and the mold resin 32 may be reduced. By increasing the contact area between the mold resin 32 and the LSI 30, the adhesion can be ensured even at the time of heating.

  Furthermore, 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 vertically intersecting the oscillator mounting beam 302D. Since the supporting beam 302C and the external electrode 34 of the oscillator 28 come into contact with each other, a short circuit can be suppressed. The support beam 302C supporting the die pad 302A may be removed, and the outer frame portion 302B and the die pad 302A may be connected only by the oscillator mounting beam 302D as a cantilever.

Fifth Embodiment

  Next, a semiconductor device 400 according to a fifth embodiment of the present invention will be described. The same components as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. As shown in FIGS. 24 and 25, the die pad 402A located at the center of the lead frame 402 according to the present embodiment is provided with a stepped portion 404. The stepped portion 404 extends in the vertical direction of the die pad 402A, and as shown in FIG. 14, is inclined upward from left to right. For this reason, the die pad 402A is divided into a first mounting surface 402B positioned below and a second mounting surface 402C positioned above the step 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 402 B via an adhesive, and the electrode pads 50 provided on the lower surface of the LSI 30 and the inner leads 408 A are electrically connected by the bonding wires 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 to straddle the bonding wire 412 connecting the oscillator electrode pad 54 and the external electrode 34. It is done. That is, in order to prevent a short circuit of bonding wire 412, a vertex of bonding wire 412 connecting oscillator electrode pad 54 and external electrode 34 is a bonding connecting electrode pad 50 and inner lead 408A. It is formed to be lower than the top of the wire 412.

<Manufacturing procedure>

  Hereinafter, the 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 such that the inner lead 408A is positioned upward and the die pad 402A is positioned downward. The mounting table 2 is provided with a step 8 for holding a 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. Also, the oscillator 28 is enclosed and transported in the package 29 on the tape with the external electrode 34 directed upward. A stepped portion 404 is formed on the lead frame 402 in advance by press processing or the like.

  Next, as shown in FIG. 26 (b), the package 29 is unsealed, the oscillator 28 is taken out by the picker 4, and as shown in FIG. 26 (c), the external electrode 34 of the oscillator 28 faces upward. The oscillator 28 is disposed on the first mounting surface 402B of the die pad 402A, and 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 with the rotation mechanism is used, and after the oscillator 28 is taken out by the picker 4, rotation is performed. Preferably, the oscillator 28 is turned upside down by a mechanism, and the external electrode 34 is directed upward before being mounted 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. 26 (d), the LSI 30 is placed on the second mounting surface 402C of the die pad 402A, and the electrode pad 50 and the electrode pad 54 for the resonator are upward. Fix with adhesive to face. Since the second mounting surface 402C is formed so as not to overlap with 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. Further, the LSI 30 and the oscillator 28 are fixed to the same surface of the die pad 402A.

  After the LSI 30 is fixed to the second mounting surface 402C, as shown in FIG. 26E, the electrode pad 50 of the LSI 30 and the inner lead 408A of the lead frame 402 are connected by the bonding wire 412 and the electrode for the oscillator of the LSI 30. 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 in a state where the semiconductor device 400 is turned upside down from the state shown in FIG. At this time, the side of the semiconductor device 400 on which the LSI 30 is mounted is 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. It is preferable to arrange the semiconductor device 400 so that the portion on the mounted side is located near the center in the height direction of the cavity 6. In addition, the semiconductor device 400 is disposed such that the outer lead 408 B protrudes to the outside of the mold 5.

  After the semiconductor device 400 is fixed inside the cavity 6, as shown by the arrow a in FIG. 27B, the mold resin 32 is injected from the injection port 7 into the inside of the cavity 6.

  As shown in FIG. 27C, the mold resin 32 injected from the injection port 7 is equal to the upper side and the lower side of the lead frame 402 in the portion where the LSI 30 is fixed in the lead frame 402 (die pad 402A). Flow into

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

  Therefore, as indicated by arrow c in FIG. 27D, the flow velocity below the die pad 402A is lower than the flow velocity above the die pad 402A at the portion where the oscillator 28 of the die pad 402A is fixed. As a result, in the portion of the die pad 402A, since the mold resin is preferentially filled downward, 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 this embodiment, since the oscillator 28 and the LSI 30 are mounted on the back surface of the lead frame 402, there is no need 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.

  Also, assuming that the surface on which the bonding wire 412 is formed is the upper surface, the second mounting surface 402C is located below the first mounting surface 402B, so the electrode pads 50 of the LSI 30 and the inner leads straddle the oscillator 28. The oscillator 28 does not interfere with the bonding wire 412 when connecting the bonding wire 408 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 the first mounting surface 402B and the second mounting surface 402C may be provided on the surface of the lead frame 402. Also 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 interfering with 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. The lower surface of the oscillator 28 may protrude downward from the lower surface of the LSI 30 as long as the difference in level does not hinder the above.

Sixth Embodiment

  Next, a semiconductor device 500 according to a sixth embodiment of the present invention will be described. The same components as those of the first embodiment are denoted by the same reference numerals, and the description thereof is omitted. As shown in FIGS. 28 and 29, in the die pad 502A located at the central portion of the lead frame 502 according to the present embodiment, a stepped portion 504 is formed as in the fifth embodiment. As shown in FIG. 29, the step portion 504 is inclined upward from left to right, and the die pad 502A is upward with the first mounting surface 502B positioned below the step portion 504, and It is divided into a second mounting surface 502C located.

  The first mounting surface 502B and the second mounting surface 502C are both provided continuously on the back surface of the lead frame 502, and are parallel to the inner lead 508A. Also, 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. That is, when projected in a plan view, the oscillator 28 and the LSI 30 are arranged to overlap.

  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 and 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. 26 (a) to 26 (e) 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. 27 (a) to 27 (d).

  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 at each side of the LSI 30. Thereby, wire bonding can be easily performed. The other actions are similar to those of the fifth embodiment.

  The first to sixth embodiments of the present invention have been described above, but the present invention is not limited to these embodiments, and may be used in combination with the first to sixth embodiments. It goes without saying that the invention can be carried out in various modes without departing from the scope of the invention. For example, as the oscillator 28, an oscillator incorporating the oscillation circuit 51 may be used. Further, the opening 26C in FIG. 2 may be a slit-like hole.

REFERENCE SIGNS LIST 1 bonding apparatus 2 mounting table 5 mold 6 cavity 10 integrated power meter 22 power amount measuring circuit (measuring means)
24 semiconductor device 26 lead frame 26C opening 28 oscillator 30 LSI (integrated circuit)
34 External electrode (terminal of oscillator)
50 electrode pad (terminal of integrated circuit)
51 oscillator circuit 52 bonding wire 54 electrode pad for oscillator (terminal of integrated circuit)
55 digital circuit unit 58 temperature sensor 60 control unit 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 202 C 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 (4)

Providing an oscillator on the top surface of the die pad;
Providing an integrated circuit on the underside of the die pad;
Placing the die pad, the oscillator and the integrated circuit inside a mold having a first portion provided via an opening between the die pad and the lower surface of the lead separated from the die pad;
Injecting a resin into the interior of the mold from the opening;
And manufacturing a semiconductor device. The lead has an inner lead relatively short in distance to the die pad, and an outer lead connected to the inner lead and relatively long in distance to the die pad.
The method according to claim 1, wherein the opening is formed between the lower surface of the inner lead and the first portion of the mold. Providing a first bonding wire connecting the oscillator and the integrated circuit;
Providing a second bonding wire connecting the inner lead and the integrated circuit;
The method of manufacturing a semiconductor device according to claim 2, further comprising: Providing an oscillator and an integrated circuit on the lower surface of the die pad;
Placing the die pad, the oscillator and the integrated circuit inside a mold having a first portion provided via an opening between the die pad and the lower surface of the lead separated from the die pad;
Injecting a resin into the interior of the mold from the opening;
And manufacturing a semiconductor device.