JP6407042B2 - Semiconductor device and manufacturing method thereof - Google Patents

Description

  The present invention relates to a semiconductor device and a manufacturing method thereof.

  In recent years, electronic devices are required to operate with low current consumption for reducing power consumption and environmental load, and stable and reliable operation under a high temperature environment typified by in-vehicle products. A semiconductor device responsible for the main configuration of an electronic device can also be regarded as a kind of resistance. When a current flows, heat corresponding to on-resistance (internal resistance when electricity is passed) is generated. The generated heat has various effects not only on the semiconductor device itself but also on the electronic equipment in which it is incorporated. Therefore, in order to avoid such heat, it is essential to take measures against heat from the semiconductor package. Yes.

  The heat in a semiconductor device is radiated from the semiconductor chip that is the heat source to the air that is the final heat release destination, but most of the radiated heat is transferred from the external terminals to the printed circuit board and transferred to the air. Through. Therefore, a structure that promotes conduction from the semiconductor device to the printed circuit board is important. As a semiconductor device having high heat dissipation, a semiconductor device in which the back surface of a die pad is exposed from a sealing resin has been proposed. (For example, refer to Patent Document 1).

JP-A-9-199639

  However, in the semiconductor device disclosed in Patent Document 1, when resin sealing is performed, resin flows between the back surface of the die pad and the mold, and a thin burr called a flash burr is easily formed.

  5 and 6 illustrate a resin sealing process of a semiconductor device having a conventional structure. FIG. 5 is a diagram showing the back surface of the die pad after resin sealing. Although the back surface shape is provided with the groove 10b on the bottom surface of the die pad 3, the flash burr 9 is formed from the sealing resin 8 to the die pad 3. FIG. 6A is an enlarged plan view of a main part of the flash burr 9 region, and FIG. 6B is an enlarged cross-sectional view of the main part. The flash burr 9 is also formed in the die pad region inside the groove 10 b beyond the groove 10 b provided in the die pad 3. As apparent from FIG. 6B, the resin enters the gap between the mold 13 and the reference surface 11 on the back surface of the die pad and fills the groove 10b, so that the resin also enters the inner region. Thus, the flash burr 9 is formed.

This flash burr reduces heat dissipation. To remove this flash burr, it is necessary to add a complicated process such as electrolytic burr floating and alkali electroless dipping.
The present invention has been made in view of the above problems, and an object of the present invention is to obtain a semiconductor device with high heat dissipation.

Means for solving the above-described problems are as follows.
First, a semiconductor chip, a die pad for fixing the semiconductor chip via an adhesive, a plurality of leads extending toward the side of the die pad, a bonding wire for connecting the semiconductor chip and the lead, A semiconductor device comprising a resin for sealing a semiconductor chip, wherein a die pad for mounting the semiconductor chip is provided with an arc groove continuously on a back surface of the die pad for mounting the semiconductor chip. The device.

Further, the semiconductor device is characterized in that a dam is formed at a side end of the arc groove, which is raised from a reference surface on the back surface of the die pad.
Further, the semiconductor device is characterized in that the arc groove has an elliptical shape.

  A step of molding a lead frame; a die bonding step of fixing a semiconductor chip to a die pad; a wire bonding step of connecting the semiconductor chip and the lead via a wire; and a step of resin-sealing the semiconductor chip. In the method of manufacturing a semiconductor device, the method for manufacturing a semiconductor device is characterized in that, in the step of forming the lead frame, arc grooves are continuously provided on the back surface of the lead frame.

Further, the semiconductor device manufacturing method is characterized in that the arc groove is formed and a dam is formed at a side end of the arc groove.
The arc groove is formed by press working or laser processing.

  By using the above means, a flash burr does not adhere to the back surface of the die pad of the semiconductor device, and a semiconductor device having good heat dissipation can be obtained.

It is a top view of the semiconductor device of the present invention. It is a top view which shows the die pad back surface of the semiconductor device of this invention. It is a principal part enlarged view of the semiconductor device of this invention. 4 is a manufacturing flow of the semiconductor device of the present invention. It is a top view which shows the die pad back surface of the semiconductor device of a conventional structure. It is a principal part enlarged view of the semiconductor device of a conventional structure.

Embodiments of the present invention will be described with reference to the drawings.
As shown in FIG. 1, a resin-encapsulated semiconductor device 1 includes a semiconductor chip 2, a die pad 3 that fixes the semiconductor chip 2, and leads 6 that extend outward from the periphery of the die pad 3. . The semiconductor chip 2 is composed of, for example, a semiconductor substrate and a wiring layer provided on the semiconductor substrate, and is bonded and fixed to the die pad 3. The die pad 3 and the lead part 6 have conductivity, and are formed of a metal such as an Fe—Ni alloy or a Cu alloy, for example. There are a plurality of lead inner portions 6a around the die pad. In this embodiment, four lead inner portions 6a are arranged on one side of the die pad 4 and four on the opposite side. Then, the suspension lead base 5a is fixed to the die pad 3 on the other two sides different from the above-mentioned two sides in close proximity to the lead inner portion 6a, and the suspension lead outer portion 5b extends from the suspension lead base 5a. The lead inner portion 6a is electrically connected to a pad on the semiconductor chip 2 through a bonding wire 7 having conductivity. The bonding wire 7 is a gold wire or a copper wire.

  FIG. 2 is a plan view showing the back surface structure of the die pad. The back surface of the die pad 3 is not covered with the sealing resin 8 and is exposed to the outside. At the time of sealing by resin sealing, the flash burr 9 may flow from the outer peripheral portion of the back surface of the die pad 3 toward the center, and FIG. 2 shows such a state. An arc groove 10a for damming the flash burr 9 is provided around the back surface of the die pad 3 that is not covered by resin sealing. The groove of the circular arc groove 10a is a groove formed of a circular arc portion of a circle, and is continuously formed by being shifted little by little so that a plurality of circular arc grooves partially overlap. That is, in the circular arc groove 10a, grooves formed of a plurality of circles or arcs are continuously formed so as to partially overlap. In FIG. 2, the individual grooves are circles, and the circular grooves are continuously formed with partial overlap. The circular arc groove 10a is provided along the outer peripheral portion of the back surface and makes a round.

  3 is an enlarged view of a main part of the semiconductor device of the present invention, FIG. 3A is a plan view, and FIG. 3B is a cross-sectional view taken along the line AA of FIG. As shown in FIG. 3A, the arc groove 10a for damming the flash burr 9 provided on the back surface of the die pad 3 has an arc shape and is continuously formed. Further, as shown in FIG. 3B, the arc groove 10 a that dams the flash burr 9 has a dam 12 that rises higher than the reference surface 11 on the back surface of the die pad 3 at its side end. Thereby, even if the sealing resin 8 flows from the outer peripheral portion to the center portion of the die pad 3, the resin is dammed because the dam 12 is higher than the reference surface 11. In addition, the arc groove 10a overlaps on the inflow path of the sealing resin 8 by continuously forming the shape in an arc shape, and the encapsulating resin 8 is reliably dammed by the arc groove 10a. The flash burr 9 is not formed inside the die pad where the continuous arc groove 10a is not disposed.

  In addition, in FIG. 3, although the circular arc groove 10a which consists of a perfect circle is illustrated, it is good also as an elliptical shape. In the case of a perfect circle or ellipse, the complete circle or ellipse does not necessarily have to be formed, and an arc-shaped groove that is a part of the perfect circle or ellipse is superposed along the outer periphery of the die pad. Is also possible. In order to form an elliptical shape by laser processing, the optical axis of the laser may be inclined with respect to the lead frame surface.

  FIG. 4 shows a manufacturing flow of the semiconductor device of the present invention. First, a flat metal plate made of an Fe—Ni alloy or a Cu alloy is prepared, and punched and pressed to form a lead frame. The arc groove 10a can be formed by pressing the lead frame with a mold or laser processing. The dam 12 at the side end of the arc groove 10a can be formed by raising the side end of the groove during press processing or laser processing. (S1). Next, a semiconductor chip is placed on the die pad via a die bonding paste (S2). The subsequent wire bonding step S3 is a step of connecting the electrodes on the semiconductor chip and the leads of the lead frame with wires.

  After the appearance inspection in the assembly inspection step S4, the semiconductor chip on the die pad is covered with a resin (S5). At this time, as shown in FIG. 3 (b), the tip of the dam 12 contacts the mold 13 and plays a role of blocking the flow of the resin. Then, excess resin deburring is performed (S6). In the case of a conventional semiconductor device, the flash burr 9 is subsequently removed, but this step is not necessary in the manufacturing process of the semiconductor device of the present invention, and this step is performed through a lead plating step S7 and a lead cutting step S8. The semiconductor device of the invention is completed.

In the above description, the arc groove is provided in the lead frame in step S1, but the groove may be formed before the resin sealing step, that is, before the step S4.
Although the embodiment of the present invention has been described in detail with reference to the drawings, the specific configuration is not limited to this embodiment, and includes design changes and the like within a scope not departing from the gist of the present invention.

DESCRIPTION OF SYMBOLS 1 Semiconductor device 2 Semiconductor chip 2a Semiconductor chip bottom face 2b Semiconductor chip total thickness 3 Die pad 3a Die pad bottom face 5 Hanging lead 5a Hanging lead base part 5b Hanging lead outer part 6 Lead 6a Lead inner part 6b Lead outer part 7 Bonding wire 8 Sealing resin 9 Flash burr 10a Arc groove 10b Groove 11 Reference surface 12 Dam 13 Mold S1 Lead frame forming process S2 Die bonding process S3 Wire bonding process S4 Assembly inspection process S5 Resin sealing process S6 Resin deburring process S7 Lead plating process S8 Lead cutting process

Claims (6)

A semiconductor chip; a die pad that fixes the semiconductor chip to the surface via an adhesive; a plurality of leads extending from the periphery of the die pad; a bonding wire that connects the semiconductor chip and the lead; and the semiconductor A sealing resin for sealing the chip;
In a semiconductor device comprising:
The back surface of the die pad is not covered with the sealing resin and is exposed,
A plurality of circles or circular arc grooves provided continuously are formed around the back surface that is not covered with the sealing resin so as to partially overlap a plurality of circles or arcs that are parts of the circles. A semiconductor device.   The semiconductor device according to claim 1, further comprising a dam that is raised at a side end of the arc groove from a reference surface on the back surface of the die pad.   3. The semiconductor device according to claim 1, wherein a plurality of circles constituting the arc groove or an arc that is a part of the circle is elliptical. A step of forming a lead frame, a die bonding step of fixing the semiconductor chip to a die pad, a wire bonding step of connecting the semiconductor chip and the lead via a wire, and a step of sealing the semiconductor chip with a sealing resin; A method of manufacturing a semiconductor device comprising:
In the step of forming the lead frame, an arc groove provided continuously so that a plurality of circles or arcs that are part of the circle partially overlap is provided around the back surface of the die pad of the lead frame ; wherein the sealing to process, the back surface of the die pad is not covered with the sealing resin, the exposure to a method of manufacturing a semiconductor device according to claim Rukoto.   5. The method of manufacturing a semiconductor device according to claim 4, wherein the arc groove is formed and a dam is formed at a side end of the arc groove.   6. The method of manufacturing a semiconductor device according to claim 4, wherein the arc groove is formed by press working or laser processing.

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