JP2010182958A - Semiconductor device and method of manufacturing semiconductor device - Google Patents

Abstract

A semiconductor device with good heat dissipation and a method for manufacturing the semiconductor device are provided.
A semiconductor device in which a semiconductor chip 1 having a concavo-convex portion on the back surface, and an inclined shape is formed on a concave bottom surface and a convex end portion of the concavo-convex portion is resin-sealed, and a manufacturing method thereof A step of forming an uneven portion on the back surface of the semiconductor chip 1, a step of fixing the semiconductor chip 1 on the tab 5 of the lead frame via an adhesive, a step of wire bonding the semiconductor chip 1 and the inner lead, The process includes a step of resin-sealing so as to cover the semiconductor chip 1, the inner lead, and the wire bonding wire 7, and the step of fixing the semiconductor chip 1 and the tab 5 is performed in a reduced pressure atmosphere.
[Selection] Figure 4

Description

  The present invention relates to a semiconductor device with improved heat dissipation and a method for manufacturing the semiconductor device.

  A conventional semiconductor chip is a semiconductor device (FIG. 6) mounted on a lead frame with a back-grinded back surface and resin-sealed (FIG. 6) or a semiconductor device (FIG. 7) provided with a metal protruding electrode, and is usually made of glass. It is used by being mounted on a circuit board such as epoxy or ceramic. In that case, in order to prevent malfunction caused by heat generation of the semiconductor device, a semiconductor device configured by providing a heat transfer pattern in the circuit board or stacking a heat dissipation silicon chip and a semiconductor chip is used. Therefore, prevention of malfunction has been attempted (see, for example, Patent Document 1).

JP-A-4-230057

  However, in a conventional semiconductor device, a structure in which a silicon chip for heat dissipation larger than that of the semiconductor device is stacked on the semiconductor device is not suitable for high-density mounting or mounting in a narrow space.

  When a conventional semiconductor device (FIG. 6) is mounted on a circuit board that does not have sufficient heat transfer patterns, heat generated from the semiconductor chip is accumulated in the semiconductor chip and cannot be efficiently radiated to the outside. Therefore, there is a concern about malfunction due to heat.

  The present invention has been made in view of the above problems, and an object thereof is to provide a semiconductor device with good heat dissipation and a method for manufacturing the same.

  In order to solve the above problems, the semiconductor device of the present invention has the following structure.

  A semiconductor device having a semiconductor chip covered with a resin mold, wherein the semiconductor chip has a concavo-convex portion on the back surface, and an inclined shape is formed on the concave bottom surface and the convex end portion of the concavo-convex portion. Semiconductor device to be used.

  Also, a semiconductor device having a semiconductor chip with a protruding electrode formed on the surface, having a concavo-convex portion on the back surface of the semiconductor chip, and inclined shapes are formed on the concave bottom surface and the convex end portion of the concavo-convex portion. A semiconductor device characterized by the above.

  Further, the following method was used to manufacture the semiconductor device.

  A method of manufacturing a semiconductor device having a semiconductor chip covered with a resin mold, the step of forming an uneven portion on the back surface of the semiconductor chip, and the step of fixing the semiconductor chip on a tab of a lead frame with an adhesive A step of wire bonding the semiconductor chip and the inner lead, and a step of resin sealing so as to cover the semiconductor chip, the inner lead and the wire for wire bonding, and the fixing step is performed in a reduced pressure atmosphere. A method for manufacturing a semiconductor device is provided.

  Further, the semiconductor device manufacturing method is characterized in that a rounded and inclined shape is given to the uneven portion.

  With the semiconductor device and the method for manufacturing the semiconductor device described above, a semiconductor device with good heat dissipation can be obtained.

It is sectional drawing and the back view which show the Example of the semiconductor chip by this invention. Enlarged sectional view of an uneven portion of a semiconductor chip according to the present invention It is sectional drawing which shows the Example of the semiconductor chip by this invention. It is sectional drawing which shows the Example of the semiconductor device by this invention. It is sectional drawing which shows the Example of the semiconductor device by this invention. It is sectional drawing which shows the conventional semiconductor device. It is sectional drawing which shows the conventional semiconductor device.

  Embodiments of the present invention will be described below with reference to the drawings.

  FIG. 1A is a sectional view showing the structure of a semiconductor chip according to the first embodiment of the present invention. The back view of the semiconductor chip is shown in FIGS.

  The semiconductor chip 1 shown in a sectional view in FIG. 1A is made of a semiconductor substrate, has a semiconductor element on the surface of the semiconductor substrate, and has a concavo-convex shape 12 on the back surface. As shown, the bottom surface of the recess and the end of the protrusion have an inclined shape 13. FIG. 1B shows a stripe-shaped groove 2, FIG. 1C shows a lattice-shaped groove 2, and FIG. 1D shows the back surface of a semiconductor chip having a plurality of holes 3.

  The semiconductor chip 1 is formed by forming a stripe-like groove 2 and a lattice-like groove 3 by using a dicing blade after backside grinding (back grinding) of the wafer, and then performing isotropic silicon etching with a silicon etching apparatus. The damage layer formed on the uneven portion of the semiconductor chip is removed by blade processing. By performing this isotropic etching, the steep portions of the concavo-convex portions are rounded, and as shown in FIG. 2, a rounded inclined shape is formed on the bottom side surface of the concave portions and the end portions of the convex portions. By doing so, the adhesive 4 when the semiconductor chip 1 is fixed to the tab 5 can easily enter the concavo-convex portion 12 and not only enhance heat dissipation but also prevent damage to the semiconductor chip due to stress applied to the semiconductor chip. be able to. The groove depth at this time is determined according to the thickness of the semiconductor chip and the thickness of the semiconductor element.

  The shape having the hole 3 as shown in FIG. 1D can be formed by performing anisotropic silicon etching. By performing isotropic silicon etching after the anisotropic silicon etching process, it is possible to form a sloped shape 13 having rounded bottom side surfaces of the recesses and ends of the protrusions.

  The shapes of the groove 2 and the hole 3 shown in FIGS. 1B to 1D can also be obtained by laser processing. In the case of laser processing, since the groove 2 and the hole 3 are formed by melting silicon, the uneven portion does not have a steep portion, but the melted silicon may be scattered on the back surface of the wafer and cause a problem. In such a case, the projection of the molten silicon can be removed by cleaning the wafer after laser processing or grinding the back surface of the wafer slightly (1 to 5 μm).

  FIG. 3 is a cross-sectional view showing a semiconductor chip in which an uneven shape is formed on a SOI structure semiconductor substrate. A buried insulating film 14 is formed on the semiconductor chip 1, and an uneven shape 12 is provided from the vicinity of the lower surface of the buried insulating film 14 to the back surface of the semiconductor chip. By doing in this way, it can be set as the semiconductor chip which has favorable heat dissipation also with the semiconductor substrate of SOI structure which is easy to store heat.

  FIG. 4 is a cross-sectional view of a semiconductor device in which the semiconductor chip described in FIGS. 1 and 3 is sealed with resin. The back surface of the semiconductor chip 1 is fixed to the tab 5 of the lead frame with an adhesive 4 made of a metal paste, and the surface of the semiconductor chip and the lead terminal are wire-bonded with a wire such as a gold wire 7. The semiconductor chip on the tab and a part of the lead terminal (inner lead portion) are sealed with the resin 8, so that only the outer lead is exposed from the resin. In addition, since it is necessary for the adhesive 4 to sufficiently enter the concavo-convex portion 12 of the semiconductor chip 1, it is desirable that the adhesive 4 and the semiconductor chip 1 be fixed in a reduced pressure atmosphere at a pressure lower than atmospheric pressure. By setting it as a pressure-reduced atmosphere, the gas contained in the adhesive agent 4 is deaerated, the deaeration between the adhesive agent 4 and the uneven | corrugated | grooved part 12 is accelerated | stimulated, and the adhesive agent 4 penetrates into the uneven | corrugated | grooved part 12 fully. As a result, the mutual bonding area increases and the heat generated by the semiconductor chip is efficiently transferred to the tab 5.

  FIG. 5 is a cross-sectional view of a semiconductor device mounted on a substrate 9 such as glass epoxy or ceramic. Projecting electrodes 11 are provided on the surface of the semiconductor chip 1 shown in FIGS. 1 and 3 and bonded to the electrode pattern 10 wired on the substrate 9 by reflow or the like. At this time, the unevenness on the back surface of the semiconductor chip 1 has a large surface area and plays the same role as the heat dissipation fin of the heat sink.

  As described above, by providing a damage-free uneven shape on the back surface of the semiconductor chip, a semiconductor device with good heat dissipation can be obtained.

DESCRIPTION OF SYMBOLS 1 Semiconductor chip 2 Groove | channel on the semiconductor chip back surface 3 Hole 4 on the semiconductor chip back surface Adhesive (Ag paste)
5 Tab 6 Lead terminal 7 Gold wire 8 Resin 9 Substrate (glass epoxy or ceramic)
10 Electrode pattern 11 Projection electrode (solder bump, etc.)
12 Uneven shape (uneven portion)
13 Inclined shape (inclined part)
14 buried insulating film

Claims (10)

  A semiconductor device having a semiconductor chip covered with a resin mold, having a concavo-convex portion on a back surface of the semiconductor chip, and having an inclined shape formed on a concave bottom side surface and a convex end portion of the concavo-convex portion. A featured semiconductor device.   A semiconductor device having a semiconductor chip having a protruding electrode formed on the surface, wherein the semiconductor chip has a concavo-convex portion on the back surface, and an inclined shape is formed on the concave bottom surface and the convex end of the concavo-convex portion. A semiconductor device characterized by the above.   3. The semiconductor chip according to claim 1, wherein the semiconductor chip is formed of an SOI structure semiconductor substrate having a buried insulating film, and the concavo-convex portion reaches from the back surface of the semiconductor chip to the vicinity of the lower surface of the buried insulating film. Semiconductor device   4. The semiconductor device according to claim 1, wherein the concave portion of the concave-convex portion is a stripe-shaped groove in a plan view.   4. The semiconductor device according to claim 1, wherein the concave portion of the concave-convex portion is a lattice-like groove in a plan view.   The semiconductor device according to claim 1, wherein the concave portion of the concave and convex portion is a plurality of holes in a plan view. A method of manufacturing a semiconductor device having a semiconductor chip covered with a resin mold,
Forming an uneven portion on the back surface of the semiconductor chip;
Fixing the semiconductor chip on the tab of the lead frame via an adhesive;
Wire bonding the semiconductor chip and the inner lead;
A step of resin sealing so as to cover the semiconductor chip, the inner lead, and the wire for wire bonding,
The method of manufacturing a semiconductor device, wherein the fixing step is performed in a reduced pressure atmosphere.   8. The method of manufacturing a semiconductor device according to claim 7, wherein the step of forming the concavo-convex portion includes a groove forming step using a dicing blade and an isotropic silicon etching step.   8. The method of manufacturing a semiconductor device according to claim 7, wherein the step of forming the concavo-convex portion includes a hole forming step by laser processing and a scattered molten silicon removing step.   8. The method of manufacturing a semiconductor device according to claim 7, wherein the step of forming the uneven portion includes an anisotropic silicon etching step and an isotropic etching step.

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