JP7124005B2 - semiconductor equipment - Google Patents

Description

The present invention relates to semiconductor devices.

2. Description of the Related Art In recent years, there is an increasing demand for measuring integrated power consumption for each time zone in a measuring device such as a power meter that measures integrated power consumption. Along with this, there is a measuring instrument capable of measuring power and time by configuring a semiconductor device by providing an oscillator and an integrated circuit inside the measuring instrument. In addition, the integrated circuit is mounted on the front surface of the lead frame, the piezoelectric resonator (oscillator) is mounted on the back surface of the lead frame, and the terminals of the integrated circuit and the lead frame, and the integrated circuit and the oscillator are connected with bonding wires. There is a piezoelectric oscillator that does this (for example, Patent Document 1).

However, after the integrated circuit is mounted on the front surface of the lead frame, the lead frame is turned over and the oscillator is mounted on the back surface, which makes it difficult to improve production efficiency. Therefore, it is conceivable to mount the oscillator and the integrated circuit side by side on one side of the lead frame. Connections between integrated circuits and lead frames have become difficult.

JP 2007-234994 A

SUMMARY OF THE INVENTION An object of the present invention is to provide a semiconductor device in which production efficiency is improved and connection between an integrated circuit and a lead frame is facilitated.

In the semiconductor device according to claim 1, a sealing resin having a front surface, a back surface facing the front surface, a side surface connecting the front surface and the back surface, and an integrated circuit having electrode pads are mounted in a first region. and a second area adjacent to the first area; and a second surface opposite to the first surface, the second surface corresponding to the first area. 3 and a fourth area adjacent to the third area and on which an oscillator having an external terminal is mounted, the die pad being sealed with a sealing resin. and a lead having a sealing portion disposed between the back surface and the die pad and sealed with a sealing resin, and an exposed portion including a bent portion bent toward the back surface and exposed from the side surface of the sealing resin. and a first bonding wire connecting the electrode pad and the external terminal, and a second bonding wire connecting the electrode pad and the sealing portion , wherein the first region and the fourth region are on the surface of the die pad. It is characterized in that the first bonding wire and the second bonding wire do not overlap in direction and three-dimensionally cross each other .

Since the present invention has the above configuration, it is possible to provide a semiconductor device that improves production efficiency and facilitates connection between an integrated circuit and a lead frame.

1 is a perspective view of an integrating watt-hour meter including a semiconductor device according to a first embodiment; FIG. FIG. 2 is a partially cutaway view of the semiconductor device according to the first embodiment as seen from the rear surface; 3 is a cross-sectional view taken along line 3-3 of FIG. 2; FIG. 1 is an exploded perspective view showing an oscillator according to a first embodiment; FIG. 2 is a block diagram for explaining the LSI of the semiconductor device according to the first embodiment; FIG. 8A to 8E are explanatory diagrams showing a procedure of arranging an oscillator and an LSI on a lead frame and wire-bonding them in the manufacturing method of the semiconductor device according to the first embodiment; FIG. 4A to 4D are explanatory diagrams showing procedures for sealing a lead frame, an oscillator, and an LSI with resin in the manufacturing method for manufacturing the semiconductor device according to the first embodiment; FIG. FIG. 4 is a partially broken view showing a modified example of the semiconductor device according to the first embodiment; 4 is a flowchart showing the flow of first frequency correction processing according to the first embodiment; 6 is a flowchart showing the flow of second frequency correction processing according to the first embodiment; It is a figure which shows the relationship of the temperature and frequency deviation in the semiconductor device which concerns on 1st Embodiment. It is a block diagram for explaining LSI of the semiconductor device according to the second embodiment. (a) is a diagram showing an example of the clock value of the oscillator of the semiconductor device according to the second embodiment, and (b) is an example of the clock value of the reference signal oscillator of the semiconductor device according to the second embodiment. It is a figure which shows. 9 is a flowchart showing the flow of first frequency correction processing according to the second embodiment; 9 is a flowchart showing the flow of frequency error derivation processing according to the second embodiment; 8A and 8B are timing charts in the frequency error derivation process according to the second embodiment, where (a) is a diagram showing when counting is started, and (b) is a diagram showing when counting is stopped. 9 is a flowchart showing the flow of second frequency correction processing according to the second embodiment; FIG. 10 is a block diagram for explaining another example of the LSI of the semiconductor device according to the second embodiment; FIG. 10 is a block diagram for explaining another example of the LSI of the semiconductor device according to the second embodiment; FIG. 12 is a partially cutaway view of the semiconductor device according to the third embodiment as seen from the rear surface; 21 is a cross-sectional view taken along line 21-21 of FIG. 20; FIG. FIG. 11 is a partially cutaway view of a semiconductor device according to a fourth embodiment as seen from the rear surface; It is an explanatory view for explaining a lead frame of a semiconductor device concerning a 4th embodiment. FIG. 12 is a partially cutaway view of the semiconductor device according to the fifth embodiment as seen from the rear surface; FIG. 25 is a cross-sectional view taken along line 14-14 of FIG. 24; 13A to 13E are explanatory diagrams showing a procedure of wire bonding the oscillator and the LSI on the lead frame in the manufacturing method of the semiconductor device according to the fifth embodiment; FIG. 11A to 11D are explanatory diagrams showing procedures for sealing a lead frame, an oscillator, and an LSI with resin in a manufacturing method for manufacturing a semiconductor device according to a fifth embodiment; FIG. FIG. 12 is a partially cutaway view of the semiconductor device according to the sixth embodiment as seen from the rear surface; FIG. 29 is a cross-sectional view taken along line 18-18 of FIG. 28; 1 is a block diagram showing an example of a state in which a conventional semiconductor device with a built-in timekeeping function and an oscillator are connected; FIG. 1 is a block diagram showing an example of a state in which a conventional semiconductor device with a built-in timekeeping function and an oscillator are connected; FIG. 1 is a schematic cross-sectional view showing a conventional packaged general semiconductor device; FIG.

(First embodiment)
A semiconductor device according to the present invention will be described in detail below 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 the upper surface of a fixing plate 102 fixed to an outer wall 100 of a house or the like. It is composed of a transparent cover 14 that covers the portion 12 and a connection portion 16 that is provided at the bottom of the main body portion 12 .

A power supply side wiring 18 and a load side wiring 20 are connected from below the connecting portion 16 to supply a current to the integrating watt-hour meter 10 . The body portion 12 is a rectangular box in plan view, and inside the body portion 12, there are a semiconductor device 24 described later, and a measuring device for measuring integrated electric energy in accordance with a signal output from the semiconductor device 24. A power amount 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 on the 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 integrated power amount used for each time period, and the like. Note that the integrating watt-hour meter 10 according to the present embodiment is an electronic watt-hour meter using the watt-hour measuring circuit 22 as a measuring means, but is not limited to this. An inductive watt-hour meter for measurement may also be used.

Next, a detailed configuration of the semiconductor device 24 according to this embodiment will be described. In the following description, the horizontal direction of the semiconductor device 24 in plan view shown in FIG. described as a direction. As shown in FIGS. 2 and 3, the external shape of the semiconductor device 24 is rectangular in plan view, and includes a lead frame 26 serving as a skeleton and a surface (first surface) of the lead frame 26 mounted thereon. LSI 30 as an integrated circuit mounted on the back surface (second surface) of lead frame 26, and mold resin 32 as a sealing material.

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 is provided in the center as a mounting portion. It includes a die pad 26A, suspension leads 26B extending 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 central portion of the die pad 26A, and are formed in plurality at predetermined intervals around the die pad 26A. In this embodiment, 16 leads 38 are formed between adjacent suspension leads 26B. The leads 38 are composed of an inner lead 38A located on the die pad 26A side and an outer lead 38B located on the outer peripheral edge side of the semiconductor device 24. The inner lead 38A is below the die pad 26A. , and extends parallel to the die pad 26A (see FIG. 3). Also, the tip of the inner lead 38A closest to the die pad 26A is covered with a plating film 40. As shown in FIG. In this embodiment, as an example, the plating film 40 is made of silver (Ag), but the plating film is not limited to this, and may be made of metal such as gold (Au).

The outer lead 38B is exposed from the mold resin 32 and bent downward, and the tip thereof is parallel to the inner lead 38A. That is, it has a gull wing lead. Further, the outer leads 38B are coated with a solder plating film. As a material for 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 in the central part of the lead frame 26 is a plate-like member formed in a rectangular shape in a plan view. 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, which will be described later (see FIG. 4).

The area between the two openings 26C serves as an oscillator mounting beam 42 as an oscillator mounting area extending in the left-right direction. (not shown), the oscillator 28 is mounted (see FIG. 4). In other words, openings 26C are provided on both sides of the oscillator mounting beam 42, respectively. The oscillator 28 is a rectangular electronic component whose longitudinal direction is the vertical direction. A viable oscillator 28 is used.

As shown in FIG. 4, the oscillator 28 includes a resonator element 44, a package body 46 that houses the resonator element 44, and a lid body 48, and has a rectangular shape in plan view. . The vibrating piece 44 is a crystal vibrating piece in which an excitation electrode 44A is formed on the surface of a tuning-fork crystal piece made of artificial quartz. When a current is passed through the excitation electrode 44A, the vibrating piece 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 crystal, vibrating bars made of lithium tantalate (LiTaO ₃ ) or lithium niobate (LiNbO ₃ ) may also be used. Furthermore, a MEMS vibrating piece made of silicon may be used.

The package body 46 is a box-shaped body with an open top, and a pedestal 47 to which the vibrating reed 44 is fixed is formed on the bottom of one end in the longitudinal direction. The base of the vibrating bar 44 is fixed to the pedestal 47 so that it can vibrate, and the package main body 46 and the lid 48 are joined in a vacuum state, so that the vibrating bar 44 is hermetically sealed. External electrodes 34 as terminals electrically connected to the excitation electrodes 44A of the vibrating bars 44 are formed at both ends of the lower surface of the package body 46 with a predetermined distance L1 therebetween. Further, the width L2 of the oscillator mounting beam 42 is formed narrower than the distance between the external electrodes 34 .

The external electrodes 34 are formed to have the same width as the package body 46, and as shown in FIG. It is larger than the pad 54. Also, the opening 26C of the die pad 26A is formed larger than the external electrode 34. As shown in FIG.

As shown in FIGS. 2 and 3, on the rear surface of the lead frame 26, an LSI 30 as an integrated circuit or semiconductor chip is mounted at the center of a 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. Therefore, when projected in plan view, the oscillator 28 and the LSI 30 are arranged so as to overlap each other. When the lead frame 26 is viewed from the LSI 30 side, the external electrodes 34 of the oscillator 28 are exposed through the opening 26C.

A plurality of electrode pads 50 electrically connected to the internal wiring of the LSI 30 are provided along the edges of the rectangular LSI 30 on the outer periphery of the lower surface. The electrode pads 50 are made of metal such as aluminum (Al) or copper (Cu), and 16 electrodes 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, such as by increasing or decreasing the number of sides on which oscillator electrode pads 54, which will be described later, are provided. Also, the electrode pads 50 are connected to the inner leads 38A by bonding wires 52, respectively. In this embodiment, 16 electrode pads 50 are provided on each side of the LSI 30 so as to match the number of leads 38. You may use it for other uses.

An electrode pad 54 for oscillator is provided separately from the electrode pad 50 at the outer peripheral end portion 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 positioned between the electrode pads 50 . That is, an oscillator electrode pad 54 placement area (first area) is formed in the central portion, and areas from the central portion to the ends of the sides where the oscillator electrode pads 54 are provided, and the remaining three An electrode pad 50 arrangement area (second area) is formed on the side. Further, the oscillator electrode pads 54 are connected to the external electrodes 34 of the oscillator 28 by bonding wires 52 through the openings 26C. The bonding wire is a linear conductive member made of metal such as gold (Au) or copper (Cu).

The two oscillator electrode pads 54 provided in the center of the LSI 30 in the vertical direction are spaced 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 54 for the oscillator and the adjacent electrode pad 50 are not wire-bonded. The distance between the wire-bonded electrode pads 50 and the oscillator electrode pads 54 may be longer than the distance between the wire-bonded electrode pads 50 . In other words, on the electrode pads 50 of the LSI 30, the distance between the bonding wires 52 connecting the oscillator electrode pads 54 and the external electrodes 34 is greater than the distance between the bonding wires 52 connecting the electrode pads 50 and the inner leads 38A. The distance between the pad 50 and the bonding wire 52 connecting the inner lead 38A is longer.

Here, the bonding wires 52 connecting the oscillator electrode pads 54 and the external electrodes 34 and the bonding wires 52 connecting the electrode pads 50 and the inner leads 38A intersect each other. 2, the bonding wires 52 connecting the electrode pads 50 and the inner leads 38A are formed so as to straddle the bonding wires 52 connecting the oscillator electrode pads 54 and the external electrodes 34. there is That is, in order to prevent the bonding wires 52 from short-circuiting, the vertexes of the bonding wires 52 connecting the electrode pads 54 for the oscillator and the external electrodes 34 are the bonding wires connecting the electrode pads 50 and the inner leads 38A. It is formed so as to be lower than the top of the wire 52 .

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 height of the apex of the bonding wire 52 connecting all the electrode pads 50 and the inner leads 38A. or lower than the top of the bonding wire 52 connecting the electrode pad 50 between the oscillator electrode pad 54 and the external electrode 34 and the inner lead 38A. .

Also, the center of the LSI 30 and the center CP of the rectangular parallelepiped oscillator 28 are arranged in parallel so as to substantially match on the X-axis. That is, the deviation width of the center CP of the oscillator 28 in the Y-axis direction from the X-axis is narrower than the width of the central portion in the Y-axis direction. In such an arrangement state, the bonding wires 52 connect the oscillator electrode pads 54 provided near the center of any one side of the LSI 30 to the external electrodes 34 arranged separately at both longitudinal ends of the oscillator 28 . is doing. At the same time, bonding wires 52 connect the electrode pads 50 arranged so as to sandwich the oscillator electrode pads 54 and the inner leads 38A arranged parallel to the electrode pads 50 in the Y-axis direction.

Furthermore, since the oscillator electrode pads 54 are provided apart from the electrode pads 50, the bonding wires 52 connecting the electrode pads 50 and the inner leads 38A connect the oscillator electrode pads 54 and the external electrodes 34. It passes through the portion of the bonding wire 52 that is lower than the oscillator 28 . That is, it is possible to avoid crossing by passing near the vertex of the bonding wire 52 connecting the electrode pad 54 for the oscillator and the external electrode 34, and to achieve an efficient three-dimensional crossing. Furthermore, since the height of the apex of the bonding wire 52 connecting the electrode pad 50 and the inner lead 38A can be kept low, the height of the package can also be reduced.

Further, the connection position of the bonding wire 52 to 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. By connecting in this way, it is possible to reduce the contact of the bonding wire 52 with the edge of the LSI 30 . On the other hand, in the X-axis direction, the center of the external electrode 34 is shifted toward the center of the oscillator 28 . By connecting in this manner, it is possible to reduce the number of crossings with the bonding wires 52 that connect the electrode pads 50 and the inner leads 38A.

The oscillator 28, the LSI 30, and the lead frame 26 are sealed with a mold resin 32, forming the outline of the semiconductor device 24. FIG. The mold resin 32 is filled so as not to form a void inside, and the height of the mold resin 32 is at least twice the height of the inner leads 38 . In other words, the distance H1 from the surface of the mold resin 32 on which the oscillator 28 is mounted to the center of the inner lead 38 is longer than the distance H2 from the surface of the mold resin 32 on which the LSI 30 is mounted to the center of the inner lead 38 . The distance H3 from the surface of the mold resin 32 on which the LSI 30 is mounted to the center of the die pad 26 is longer than the distance H2 from the surface of the mold resin 32 on which the LSI 30 is mounted to the inner leads . In this embodiment, a thermosetting epoxy resin containing a silica-based filler is used as the mold resin 32, but the resin is not limited to this, and a thermoplastic resin, for example, may be used.

Next, the internal configuration of the LSI 30 will be described. As shown in FIG. 5, the LSI 30 incorporates an oscillation circuit 51, a frequency dividing circuit 53, a timer circuit 56, a temperature sensor 58, a control section 60, and a register section . The oscillator circuit 51 is connected to the oscillator 28 and causes the oscillator 28 to oscillate. The frequency dividing circuit 53 frequency-divides the signal (with a frequency of 32.768 kHz in this embodiment) output from the oscillator 28 to generate a predetermined clock (for example, 1 Hz). The clock circuit 56 measures time based on the signal divided by the frequency divider circuit 53 and transmits the time to the control section 60 . A temperature sensor 58 measures the temperature of the LSI 30 and transmits it to the controller 60 . The temperature of the oscillator 28, which is placed in the vicinity of the LSI 30 on the same lead frame and is electrically connected to the LSI 30, can be identified with the temperature of the LSI 30. FIG. That is, the temperature sensor 58 can accurately measure the temperature of the oscillator 28 arranged around the LSI 30 . Based on the time measured by the timer circuit 56, the control unit 60 causes the liquid crystal display 15 to display the integrated electric energy per unit time measured by the electric energy measuring circuit 22 (see FIG. 1). The register section 70 is composed of 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 correction of the oscillation frequency, which will be described later. In addition, the LSI 30 also incorporates an arithmetic circuit for performing arithmetic operations and an internal power supply.

<Manufacturing procedure>
A procedure for manufacturing the semiconductor device 24 will be described below.
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 downward. The mounting table 2 is formed with a recessed portion 3 for receiving the oscillator 28 when the lead frame 26 is turned upside down with the oscillator 28 fixed to the first surface. Further, the oscillator 28 is enclosed in a package 29 on a tape and conveyed with the external electrodes 34 facing downward. An opening 26C is previously formed in the lead frame 26 by press working 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 attached to 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 external terminal 34 of 28 overlaps 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, a picker 4 with 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 on the first surface of the die pad 26A after turning the oscillator 28 upside down by a mechanism and directing the external terminals 34 downward.

After fixing the oscillator 28 to the first surface of the die pad 26A, the lead frame 26 is turned upside down and mounted on the mounting table 2 as shown in FIG. 6(c). As a result, the lead frame is mounted on the mounting table 2 with the first surface facing downward. At this time, the oscillator 28 is housed in the recessed portion 3 of the mounting table 2 .

After the lead frame 26 is turned upside down and mounted on the mounting table 2, as shown in FIG. LSI 30 is fixed to . The second surface in FIG. 6(d) is the upper surface of the die pad 26A.

Finally, as shown in FIG. 6E, the electrode pads 50 of the LSI 30 and the leads 38 are connected by bonding wires 52, and the oscillator electrode pads 54 of the LSI 30 and the external electrodes 34 of the oscillator 28 are bonded together. A semiconductor device 24 is formed by connecting with a 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 is the height of the bonding wire 52 connecting the electrode pad 50 of the LSI 30 and the lead 38. Connect so that it is lower than the height of the vertex. Also, after first 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 of the LSI 30 and the lead 38 are connected so as to jump over the bonding wire 52 . A bonding wire 52 is used for connection. Also, the bonding wires 52 connecting the oscillator electrode pads 54 of the LSI 30 and the external electrodes 34 of the oscillator 28 and the bonding wires 52 connecting the electrode pads 50 and the leads 38 are connected so as to intersect each other. . At this time, the bonding wires 52 connecting the electrode pads 50 of the LSI 30 and the leads 38 are shifted from the tops of the bonding wires 52 connecting the electrode pads 54 for the oscillator of the LSI 30 and the external electrodes 34 of the oscillator 28. Make connections so that

By fixing the oscillator 28 and the LSI 30 to the lead frame 26 (die pad 26A) and connecting the LSI 30 and the oscillator 28 according to the procedure shown in FIGS. , the connection between the LSI 30 and the oscillator 28 is also the same as the connection between the LSI 30 and the leads 38 of the lead frame. Similar to the connection, it can be made from the second surface of the die pad 26A, which is efficient. Further, since the oscillator 28 and the LSI 30 are directly connected by the bonding wire 32 without the lead frame 26 interposed therebetween, the oscillator 28 and the LSI 30 may be connected through the lead frame 26, or the bonding wire may be used as a lead wire. Wiring resistance can be reduced as compared with the case where wiring is routed and connected on 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 semiconductor device 24 is placed so that the first surface of the lead frame 26 (die pad 26A), that is, the surface on which the oscillator 28 is fixed is the upper surface. 26A), i.e., the surface on which the LSI 30 is fixed, is fixed inside the cavity 6 of the mold 5 so that it faces downward. Here, since the oscillator 28 is thicker than the LSI 30, the semiconductor device 24 is arranged in the cavity 6 so that the lead frame 26 (die pad 26A) is positioned below the center of the cavity 6 in the height direction of the mold 5. placed inside. Further, the outer leads 38B are projected outside the mold 5 while the semiconductor device 24 is fixed inside the cavity 6. As shown in FIG.

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

After that, the mold resin 32 also flows into the upper surface side of the lead frame 26 as indicated by an arrow c in FIG. 7(d). 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 .

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

In the semiconductor device 24, the oscillator 28 is fixed on the upper surface of the lead frame 26 (die pad 26A), and the LSI 30 is fixed on the lower surface. It needs to be arranged below the height direction center of the cavity 6 of the mold 5 . When there is a wide space above the lead frame 26 in this manner, the mold resin 32 tends to flow into the upper side of the lead frame 26 .

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

However, by adjusting the flow path of the mold resin 32 using the oscillator 28 and causing the mold resin 32 to first flow below the lead frame 26, the lead frame 26 is supported by the mold resin 32 injected into the cavity 6. can be expected. Therefore, the lead frame 26 is prevented from being displaced in the vertical direction inside the cavity 6 during the injection of the molding resin 32 .

<Action>

Next, the operation of the semiconductor device 24 and the integrated watt-hour meter 10 according to this embodiment will be described. In the semiconductor device 24 according to the present embodiment, the oscillator 28 and the LSI 30 are sealed with a mold resin 32 and integrated. Therefore, time can be measured simply by mounting the semiconductor device 24 on the substrate inside the watt-hour meter 10 shown in FIG. That is, there is no need to separately mount the oscillator 28, the frequency dividing circuit 53, and the like on the substrate. Therefore, the time and effort required for adjusting the connection between the oscillator 28 and the semiconductor device 24 is eliminated.

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

Furthermore, as shown in FIG. 2, the external electrodes 34 of the oscillator 28 and the oscillator electrode pads 54 of the LSI 30 are directly connected by bonding wires 52 through the openings 26C. Therefore, the shortest wiring is possible without the lead frame 26, and the wiring resistance can be reduced. In addition, since the length of the two bonding wires 52 connecting the external electrode 34 and the electrode pad 54 for the oscillator is uniform, the tension applied to the bonding wires 52 can be made equal, so that the bonding wires 52 are prevented from breaking or bending. can prevent contact with In addition, since the wiring can be performed without passing through the lead frame 26, it is less likely to be affected by noise, so signals can be smoothly transmitted from the oscillator 28 to the LSI 30. Noise is likely to occur between the bonding wires 52 formed in parallel. Because of the three-dimensional crossing, 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. The influence of noise on child 28 can be reduced. Furthermore, since the external electrodes 34 are larger than the oscillator electrode pads 54, wire bonding can be easily performed.

Further, since 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 each other when projected in a plan view, the oscillator 28 and the LSI 30 are mounted on 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 arranged side by side on one side of the semiconductor device 24 .

Also, since the LSI 30 is positioned in 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. This facilitates the wire bonding work and improves the yield.

In this embodiment, all the inner leads 38A are connected to the electrode pads 50 of the LSI 30, but this is not limitative, and any inner lead 38A may be connected by 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 grounding the outer lead 38B. In this case, it is possible to prevent the die pad 26A from being charged. In addition, 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 addition, in this modified example, an oscillator circuit 51 is arranged near the oscillator electrode pad 54 , and a digital circuit section 55 is arranged so as to surround the oscillator circuit 51 . The digital circuit section 55 is a circuit section that processes digital signals, and noise is less likely to occur than other elements. Therefore, it is possible to reduce the influence of noise that the oscillation circuit 51 receives from other elements (especially the analog circuit section) built in the LSI 30 . An example of the digital circuit section 55 is a CPU.

<Correction of oscillation frequency>

Next, frequency correction processing for correcting temperature-dependent errors in the oscillation frequency of the oscillator 28 in the semiconductor device 24 according to the present embodiment will be described.

For example, when the semiconductor device 24 is shipped, if the temperature of the LSI 30 inside the semiconductor device 24 is normal temperature (here, 25° C.), a reference temperature lower than normal temperature (hereinafter also referred to as “low temperature”) is set. The temperature is measured by the temperature sensor 58 in each of the cases where the temperature is set to a reference temperature (hereinafter also referred to as "high temperature") that is higher than normal temperature. After shipment, for example, the semiconductor device 24 corrects the frequency error of the oscillator 28 by using the temperature obtained by this measurement as trimming data in consideration of the measurement error caused by the manufacturing variation of the temperature sensor 58 .

The above-described register unit 70 (see FIG. 5) includes 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 the temperature measured by the temperature sensor 58 when the ambient temperature is high. and a frequency correction register 75 for storing correction values for the oscillation frequency of the oscillator 28 derived from the data indicating these temperatures. Each register is connected to the control section 60 via the data bus 76 , and the control section 60 reads and writes each register via the data bus 76 .

In order to correct the frequency error of the oscillator 28, the temperature of the semiconductor device 24 is measured by the temperature sensor 58 when the temperature of the semiconductor device 24 is low, normal, and high. Then, 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 constant temperature bath in which the temperature inside the bath is set to room temperature. Then, the user causes the semiconductor device 24 to execute the first frequency correction processing by inputting a measurement operation signal for starting temperature measurement by the temperature sensor 58, for example. At this time, the user inputs the measurement operation signal to the semiconductor device 24 by, for example, connecting a device that outputs the measurement operation signal to the lead 38 of the semiconductor device 24 . The measurement operation signal also includes information indicating whether the temperature set in the constant temperature bath is room temperature, high temperature, or low temperature.

FIG. 9 is a flow chart showing the flow of the first frequency correction process in the semiconductor device 24 according to this embodiment. A 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 means of the control section 60 . 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 passed since the measurement operation signal was input. It should be noted that the predetermined time is preferably the time required for the internal temperature of the semiconductor device 24 (the temperature of the LSI 30) to match the temperature of the constant temperature bath.

If it is determined in step S101 that the predetermined time has elapsed, the controller 60 acquires the measured value from the temperature sensor 58 in step S103. Note that the measured value by the temperature sensor 58 is stored in the temperature measurement value storage register 71 . In addition, when acquiring the measured value by the temperature sensor 58, the measurement is performed every time a predetermined time (for example, 1 minute) elapses, and the average value of a plurality of measured values obtained by multiple measurements is used as the measured value. You can get it.

In step S105, the control unit 60 stores the obtained measured value in the normal temperature register 73 when the temperature set in the constant temperature bath is the normal temperature (here, 25° C.), and If the temperature is high, it is stored in the high temperature register 74, and if the temperature set in the constant temperature bath is low, it is stored in the low temperature register 72, and the first frequency correction process ends. Note that the first frequency correction process may be performed in advance in the wafer state.

In addition to placing the semiconductor device 24 inside a constant temperature bath set to a room temperature, the tester places the semiconductor device 24 inside a constant temperature bath set to a high temperature. The semiconductor device 24 is caused to perform the processes of steps S101 to S105 in each of the state in which the semiconductor device 24 is placed inside the constant temperature bath in which the temperature inside the bath is set to a low temperature. As a result, the values measured 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 processing, which will 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 processing by inputting a derivation operation signal for starting derivation of the frequency correction value. At this time, the user inputs the derived operation signal by, for example, connecting a device that outputs the derived operation signal to the lead 38 of the semiconductor device 24 . Alternatively, the semiconductor device 24 may perform the second frequency correction process at regular intervals.

FIG. 10 is a flowchart showing the flow of second frequency correction processing in the semiconductor device 24 according to this 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 shipment of the semiconductor device 24, and is stored in advance in the storage means of the control unit 60.

In step S201, the control unit 60 acquires the measured 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 for the oscillation frequency of the oscillator 28 (hereinafter also referred to as "frequency correction value") using the measured value obtained in step S201.

FIG. 11 is a diagram showing the relationship between temperature and frequency deviation in the semiconductor device according to this embodiment. Note that FIG. 11 does not show 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 represented by the following equation (1). In the following equation (1), f is the frequency deviation, a is the secondary temperature coefficient, T is the measured temperature, _T0 is the peak temperature, and b is the peak error. The secondary temperature coefficient a is a constant predetermined according to the individual difference of the oscillator 28 and stored in advance in the storage means of the controller 60 .

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

In the derivation of the frequency correction value, for example, if the measured value by the temperature sensor 58 is -8°C in a measurement environment of -10°C, a correction corresponding to +2°C is required. . In the product at the shipping stage, the temperature under the actual environment is derived by reading the measured values of three points of room temperature, high temperature and low temperature stored in each register through the data bus 76 and 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 values of two adjacent registers may be used to derive the temperature under the actual environment.

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 uses the frequency correction value stored in the frequency correction register 75 to generate a clock signal from the signal input from the oscillation circuit, thereby increasing the oscillation frequency of the oscillator 28. is corrected.

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

In a conventional packaged semiconductor device, as shown in FIG. 32, when driving the semiconductor device, the ambient temperature Ta (° C.) of the semiconductor device, the package surface temperature Tc (° C.), and the chip surface temperature Tj (° C.) are different for each. 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.

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 are the same. The temperature sensor 58 of the LSI 30 can measure the temperature of the oscillator 28 with high accuracy, so that the temperature difference between the oscillator 28 and the temperature sensor 58 can prevent the accuracy of frequency correction from deteriorating.

(Second embodiment)

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

As shown in FIG. 12, in the semiconductor device 24 according to the second embodiment, a clock signal used as a reference when correcting the oscillation frequency of the oscillator 28 (hereinafter also referred to as a "reference clock signal") is supplied to the LSI 30A. ) is connected to the clock generator 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 outputs 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 output is further provided.

As shown in FIGS. 13A and 13B , the reference signal oscillator 80 is an oscillator such as a crystal oscillator having an oscillation frequency higher than that of the oscillator 28 . Incidentally, 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 from the oscillator 28 (hereinafter also referred to as “measurement clock signal”) from the oscillation circuit 51 under the control of the control unit 60 . A counter that counts the number of clocks of a clock signal. The reference counter 82 is connected to a clock generator having a reference signal oscillator 80, receives a clock signal from the reference signal oscillator 80, and counts the clock number of the clock signal under the control of the control section 60. count. As shown in FIGS. 13A and 13B, the reference counter 82 and the measurement counter 81 are synchronized with each other and count the number of clocks substantially simultaneously within the same time period. Note that the measurement counter 81 and the reference counter 82 may be operated in synchronization with each other based on the operation signal, or a synchronous counter may be used.

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

<Correction of oscillation frequency>

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

FIG. 14 is a flow chart showing the flow of the first frequency correction process in the semiconductor device 24 according to this 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 means of the control unit 60.

In step S301, the control unit 60 determines whether or not a predetermined time (for example, several hours) has passed since the measurement operation signal was input. The predetermined time is preferably the time required for the internal temperature of the semiconductor device 24 (the temperature of the LSI 30) to match the temperature of the constant temperature bath.

If it is determined in step S301 that the predetermined time has passed, the controller 60 acquires the measured value from the temperature sensor 58 in step S303. Note that the measured value by the temperature sensor 58 is stored in the temperature measurement value storage register 71 . Moreover, the temperature sensor 58 has been tested to confirm that its measurement accuracy is equal to or higher than a predetermined reference value, and it is guaranteed that the temperature sensor 58 can measure temperature with high accuracy. Alternatively, a measurement value obtained by the temperature sensor 58 may be used for correction.

In step S<b>305 , the control unit 60 performs frequency error derivation processing for deriving an error in the oscillation frequency of the oscillator 28 . FIG. 15 is a flowchart showing the flow of frequency error derivation processing according to this embodiment. 16A and 16B are timing charts in the frequency error derivation process according to the present embodiment, in which (a) is a diagram showing the start of counting, and (b) is a diagram showing the stop of counting.

In step S<b>401 , the control section 60 outputs a correction operation signal to the measurement counter 81 . The measurement counter 81 that has received the correction operation signal starts operating 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. FIG.

Upon receiving the start signal, the reference counter 83 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 this embodiment). If it is determined in step S407 that the value is not equal to or 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.

Upon receiving the stop signal, the reference counter 82 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 S<b>413 , the control unit 60 acquires the count value of the reference counter 82 .

In step S415, the control unit 60 derives the error of the oscillation frequency of the oscillator 28 from the count value of the reference counter 82 acquired in step S413. In other words, the control unit 60 controls the count value (that is, 32,768) obtained within the same period of time in the measurement clock signal by the oscillator 28 as a reference signal oscillation capable of measuring time with higher precision than the oscillator 28 . By comparing with the count value of the reference clock signal by the element 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 assumed that the oscillator 28 has accurately timed one second. , the oscillation frequency error (frequency correction value) is set to 0 because it is not necessary to correct the oscillation frequency error. 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 reduced by the error. , that is, 0.2 ppm, and the oscillation frequency error (frequency correction value) is +0.2 ppm. Further, 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. That is, it is necessary to slow down by 1.0 ppm, and the oscillation frequency error (frequency correction value) is -1.0 ppm.

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

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

In addition to the state in which the semiconductor device 24 is placed inside the constant temperature bath whose temperature inside the bath is set to normal temperature, the user places the semiconductor device 24 inside the constant temperature bath whose temperature inside the bath is set to a high reference temperature. and in a state in which the semiconductor device 24 is placed inside a constant temperature bath in which the temperature inside 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 measured by the temperature sensor 58 and the oscillation frequency error 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 at a predetermined timing after shipment, the oscillation frequency of the oscillator 28 indicates the frequency correction value stored in the frequency correction register 75. Correction is performed using the data based on equation (1) described above. Note that the secondary temperature coefficient a and the vertex error b in the second embodiment are determined by the frequency error derived at each temperature. It should be noted that the frequency error may be obtained by linear approximation from the difference between the values of the oscillation frequency error stored in the register at a temperature higher than the temperature to be determined and in the register at a temperature lower than the temperature to be determined. Then, when the system is reset or periodically, when a predetermined signal is input via the lead 38, or when the oscillation frequency of the oscillator 28 is corrected using the above equation (1), a second A frequency correction process is performed.

The user causes the semiconductor device 24 to execute the second frequency correction processing by inputting a derivation operation signal for starting the derivation of the frequency correction value, for example. At this time, the user inputs the derived operation signal by, for example, 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 second frequency correction processing in the semiconductor device 24 according to this embodiment. A 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 means of the control section 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 measured value by 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 obtained in step S503 is different from the temperature measured in the constant temperature bath (for example, the temperature obtained in step S303). Note that if this determination is unnecessary, after performing the process of step S503, the process of step S505 may be skipped and the process may proceed to step S505.

If it is determined in step S505 that the temperatures do not differ, 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 the frequency error in step S507 by performing the same processing as in step S305 described above. In step S507, the control unit 60 derives the second-order temperature coefficient a and the vertex error b by substituting the data stored in each register of the register unit 70 into the above 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 do not differ, a frequency correction value is derived and stored using the temperature and frequency errors stored in the low temperature register 72, normal temperature register 73, and high temperature register 74. 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 dividing circuit 53 corrects the signal input from the oscillation circuit based on the frequency correction value stored in the frequency correction register 75, thereby correcting the oscillation frequency of the oscillator 28. conduct.

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 manufacturing variations of the oscillator 28, stable timekeeping can be achieved. can be engraved.

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

Further, according to the semiconductor device 24 according to the second embodiment, even if the number of terminals is limited, by replacing the unused terminals resulting from the built-in oscillator 28 with other functions (for example, serial communication, addition of I2C, etc.), High functionality can be realized.

In this embodiment, the reference signal oscillator 80, the measurement counter 81, and the reference counter 82 are used to derive the error in the oscillation frequency of the oscillator 28. However, the error derivation method is not limited to this. A predetermined time (in this embodiment, 1 second (32,768 CLK)) in the clock signal output from the oscout terminal output from is compared with the predetermined time accurately measured by another method. , the oscillator 28 may be used to measure how long the predetermined time is actually measured.

Further, after correcting the error of the oscillation frequency of the oscillator 28 in the semiconductor device 24 according to the second embodiment, if necessary, the measurement error of the temperature sensor 58 in the semiconductor device 24 according to the first embodiment is corrected. 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 has an output terminal 84 , and the error (frequency correction value) of the oscillation frequency of the oscillator 28 derived by the control section 60 is output to the outside of the semiconductor device 24 through the output terminal 84 . You may make it output via. As a result, periodic calibration can be performed to detect deterioration in the characteristics of the reference clock generator.

Further, as shown in FIG. 19, the LSI 30A of the semiconductor device 24 may connect the measurement counter 81 with a highly accurate clock generator 85 that serves as a reference for 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 and the count value of the reference counter 82. . For example, assuming that 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 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 will be the same value, but the characteristics of the reference signal oscillator 80 will change. If so, there will be a difference 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 controller 60 determines whether the difference is within a predetermined allowable error range, and outputs the determination result. 8 output terminal 84. This makes it possible to carry out periodic calibration for detecting deterioration in the characteristics of the clock generator provided with the reference signal oscillator 80 .

As shown in FIG. 19, even if the LSI 30A of the semiconductor device 24 includes the clock generator 85, the clock signal output from the oscillation circuit 51 and the A selector 86 that selectively inputs either 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 similarly to 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 invention will be described. In addition, the same code|symbol is attached|subjected about the structure same as 1st Embodiment, and description is abbreviate|omitted. As shown in FIGS. 9 and 10, an oscillator 28 is mounted via an adhesive on an oscillator mounting beam 206 on the surface of a lead frame 202 constituting a semiconductor device 200 according to this 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 shifted to the left from the central portion of the die pad 202A so as not to overlap the opening 202C formed in the die pad 202A. Therefore, the entire surface of the LSI 30 is adhered 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 electrode pads 50 of the LSI 30 and the inner leads 38A are connected by the bonding wires 52 to form the semiconductor device 200, as in the semiconductor device 24 of the first embodiment, as shown in FIGS. 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).

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

(Fourth embodiment)

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

The die pad 302A is located in 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 above, below, and to the left of the die pad 302A, and the resonator mounting beam 302D extends to the right of the die pad 302A. Further, 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, and the LSI 30 is fixed to the second surface opposite to the first surface. , and electrode pads 50 of the LSI 30 and the leads 38 are connected by bonding wires 52 to form the semiconductor device 300, as in the semiconductor device 24 of the first embodiment, as shown in FIGS. be. The procedure for sealing the semiconductor device 300 with the molding resin 32 is similarly shown in FIGS. 7(a) to 7(d).

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

Also, by making the die pad 302A 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 separate due to the increased contact area between the mold resin 32 and the LSI 30. In particular, when the semiconductor device 300 is mounted on a substrate by reflow or the like, the semiconductor device 300 is heated, and there is a risk that 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, it is possible to ensure the adhesion even during heating.

Furthermore, inside the outer frame portion 302B, the support beams 302C and the oscillator mounting beams 302D are arranged in a cross shape (lattice shape), and the oscillator 28 is mounted so as to cross the oscillator mounting beams 302D perpendicularly. Therefore, it is possible to prevent the support beam 302C and the external electrode 34 of the oscillator 28 from coming into contact with each other and short-circuiting. Alternatively, the support beam 302C for supporting the die pad 302A may be removed and the outer frame portion 302B and the die pad 302A may be connected to each other only by the oscillator mounting beam 302D as a cantilever.

(Fifth embodiment)

Next, a semiconductor device 400 according to a fifth embodiment of the invention will be described. In addition, the same code|symbol is attached|subjected about the structure same as 1st Embodiment, and description is abbreviate|omitted. As shown in FIGS. 24 and 25, a stepped portion 404 is provided on a die pad 402A located in the central portion of the lead frame 402 according to this 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. Therefore, the die pad 402A is divided into a lower mounting surface 402B and an upper second mounting surface 402C with the stepped portion 404 as a boundary.

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

The oscillator 28 is mounted on the second mounting surface 402C via an adhesive. Here, the second mounting surface 402C is located above the first mounting surface 402B by the thickness difference 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 are at the same height. It's becoming

As shown in FIG. 25, the bonding wires 412 connecting the electrode pads 50 and the inner leads 408A are formed across the bonding wires 412 connecting the oscillator electrode pads 54 and the external electrodes 34. It is That is, in order to prevent the bonding wires 412 from short-circuiting, the vertexes of the bonding wires 412 connecting the electrode pads 54 for the oscillator and the external electrodes 34 are the bonding wires connecting the electrode pads 50 and the inner leads 408A. It is formed so as to be lower than the top of the wire 412 .

<Manufacturing procedure>

A procedure for manufacturing the semiconductor device 400 will be described below.

First, as shown in FIG. 26(a), the lead frame 402 is mounted on the mounting table 2 of the bonding apparatus 1 so that the inner leads 408A are positioned upward and the die pad 402A is positioned downward. The mounting table 2 is formed with a step 8 for holding a portion of the die pad 402A on which the second mounting surface 402C is formed. In this state, both the first mounting surface 402B and the second mounting surface 402C face upward. Further, the oscillator 28 is enclosed in a package 29 on a tape and conveyed with the external electrode 34 directed upward. A step portion 404 is formed in advance on the lead frame 402 by press working 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 electrodes 34 of the oscillator 28 face upward as shown in FIG. 26(c). The oscillator 28 is placed 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, a picker 4 with 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 on the first surface of the die pad 26A after turning the oscillator 28 upside down by a mechanism and directing the external electrode 34 upward.

After fixing the oscillator 28 to the first mounting surface 402B, as shown in FIG. Fix with glue 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. Also, the LSI 30 and the oscillator 28 are fixed to the same side surface of the die pad 402A.

After fixing the LSI 30 to the second mounting surface 402C, as shown in FIG. A bonding wire 412 connects the pad 54 and the external electrode 34 of the oscillator 28 .

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

As shown in FIG. 27(a), the semiconductor device 400 is fixed inside the cavity 6 of the mold 5 while being turned upside down from the state shown in FIG. 27(e). At this time, the side of the semiconductor device 400 on which the LSI 30 is mounted is located closer to the injection port 7 for injecting the molding 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 It is preferable to dispose the semiconductor device 400 such that the portion on the mounted side is positioned near the center in the height direction of the cavity 6 . Also, the semiconductor device 400 is arranged so that the outer leads 408B protrude outside the mold 5 .

After fixing the semiconductor device 400 inside the cavity 6, the molding resin 32 is injected into the cavity 6 through the injection port 7 as indicated by the arrow a in FIG. 27(b).

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

However, a step 404 is formed in the lead frame 402 (die pad 402A) in the plate 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 across the step 404. 27(a) to 27(d).

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

After both sides of the lead frame 402 are filled with the mold resin 32 , the mold 5 is heated to harden 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, the lead frame 402 does not need to be inverted 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.

Assuming that the surface on which the bonding wires 412 are formed is the upper surface, the second mounting surface 402C is positioned below the first mounting surface 402B. 408A with the bonding wire 412, the oscillator 28 does not interfere with the bonding wire 412.

Although the first mounting surface 402B and the second mounting surface 402C are provided on the back surface of the lead frame 402 in this embodiment, they may be provided on the front surface of the lead frame 402 without being limited to this. Even in this case, the surface on which the bonding wires 412 are formed is the upper surface, and the second mounting surface 402C is formed below the first mounting surface 402B, so that the oscillator 28 does not interfere with the bonding wires 412. .

In this 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 bonding wires 412 are 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 step is not obstructed.

(Sixth embodiment)

Next, a semiconductor device 500 according to a sixth embodiment of the invention will be described. In addition, the same code|symbol is attached|subjected about the structure same as 1st Embodiment, and description is abbreviate|omitted. As shown in FIGS. 28 and 29, a stepped portion 504 is formed on a die pad 502A located in the central portion of a lead frame 502 according to this embodiment, as in the fifth embodiment. As shown in FIG. 29, the stepped portion 504 is inclined upward from left to right. It is divided into a second mounting surface 502C located thereon.

Both the first mounting surface 502B and the second mounting surface 502C are provided continuously on the rear surface of the lead frame 502 and are parallel to the inner leads 508A. The LSI 30 is mounted on the first mounting surface 502B with an adhesive, and the oscillator 28 is mounted on the second mounting surface 502C with an adhesive. Here, as shown in FIG. 28, the LSI 30 is positioned in the central portion of the lead frame 502, and the right end portion of the LSI 30 covers part of the oscillator . That is, when projected in plan view, the oscillator 28 and the LSI 30 are arranged so as to overlap each other.

The oscillator 28 is fixed to the first mounting surface 502B of the die pad 502A, and the LSI 30 is fixed to the second mounting surface 502C. 26(a) to 26(e) in the same manner as the semiconductor device 400 of the fourth embodiment. Also, 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 this embodiment, the LSI 30 is mounted in the central portion of the lead frame 502, so the distance between the electrode pads 50 of the LSI 30 and the inner leads 508A can be made constant on each side of the LSI 30. FIG. Thereby, wire bonding can be easily performed. Other actions are the same as those of the fifth embodiment.

Although the first to sixth embodiments of the present invention have been described above, the present invention is not limited to these embodiments, and the first to sixth embodiments may be combined and used. It goes without saying that various aspects can be implemented without departing from the gist of the invention. For example, an oscillator containing an oscillation circuit 51 may be used as the oscillator 28 . Also, the opening 26C in FIG. 2 may be a slit-like hole.

REFERENCE SIGNS LIST 1 bonding device 2 mounting table 5 mold 6 cavity 10 integrated watt-hour meter 22 watt-hour 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 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 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 (7)

a sealing resin having a front surface, a back surface facing the front surface, and a side surface connecting the front surface and the back surface;
a first surface configured by a first area on which an integrated circuit having electrode pads is mounted and a second area adjacent to the first area; and a second surface on the opposite side of the first surface. a second surface formed by a third area corresponding to the first area and a fourth area adjacent to the third area and on which an oscillator having an external terminal is mounted; and a die pad sealed in the sealing resin;
a sealing portion disposed between the back surface and the die pad and sealed with the sealing resin; and an exposed portion including a bent portion bent toward the back surface and exposed from the side surface of the sealing resin. a lead having a
a first bonding wire that connects the electrode pad and the external terminal;
a second bonding wire that connects the electrode pad and the sealing portion;
with
the first region and the fourth region do not overlap in the planar direction of the die pad;
The first bonding wire and the second bonding wire three-dimensionally intersect
semiconductor device. the die pad is positioned a first distance from the back surface;
2. The semiconductor device according to claim 1, wherein said sealing portion is arranged at a second distance from said back surface that is shorter than said first distance. 3. The semiconductor device according to claim 2, wherein said second distance is shorter than a third distance from said surface to said sealing portion. 4. The semiconductor device according to claim 1, wherein the second surface is a surface of the die pad on the front surface side. 5. The semiconductor device according to claim 1, wherein the first surface is a surface of the die pad on the back surface side. 6. The semiconductor device according to claim 1, wherein said integrated circuit has said electrode pads on said back surface, and said oscillator has said external terminals on said back surface. 7. The semiconductor device according to claim 1, wherein said second bonding wire connects said electrode pad of said integrated circuit and said rear surface of said sealing portion.

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