JP4455198B2 - Resin sealing device - Google Patents

Description

  The present invention relates to a resin sealing device that collectively molds a plurality of semiconductor elements on a semiconductor substrate, a mounting substrate, or a lead frame.

  With the miniaturization and thinning of semiconductor elements, batch molding of resin sealing is becoming popular. The conventional transfer molding method is also used for batch molding, but a substrate or lead frame with multiple semiconductor elements is set in the cavity formed between the upper and lower molds. Since it is necessary to pour the resin from the resin, it is disadvantageous because the resin mold product has a strict structure against the resin flow when the resin mold product is made thin and has a large cavity.

  Therefore, in order to solve this problem, as shown in FIG. 5, the cavity block 1 and the clamper 2 constituting the upper mold and the lower mold 3 in the cavity formed between the lower mold 3 are formed. A substrate (or lead frame) 5 on which a plurality of semiconductor elements 4 are mounted is set, and a resin tablet 6 is arranged at the center, and then the substrate 5 is clamped against the lower mold 3 by the clamper 2 and heated. While the cavity block 1 presses the resin tablet 6 against the lower mold 3, as shown in FIG. 6, there is a resin sealing device that covers the portions of the plurality of semiconductor elements 4 with the semiconductor element part mold resin 6 </ b> A. (For example, refer to Patent Document 1).

This resin sealing device pressurizes the resin tablet 6 supplied directly onto the substrate 5 and molds it in a lump. Since the resin is covered on the semiconductor element 4, the resin flow is facilitated. It is suitable for reducing the thickness of the resin mold product and increasing the cavity of the mold space. Further, the resin residue can escape from the overflow gate 8 to the relief piston 7 to absorb the volume fluctuation of the mold part, and the resin mold product can be made to have a constant thickness. In FIG. 6, 7A is a relief piston portion resin, and 8A is an overflow gate portion resin. However, when a semiconductor element having a wire bond portion is molded by resin molding, it is inconvenient to use a solid resin tablet. Therefore, the cavity block 1 and the lower mold 3 shown in FIG. It is necessary to previously melt the resin in the cavity portion on one side.
No. 2000-252311

  As described above, in the conventional resin sealing device, in order to achieve the constant thickness of the resin mold product, the volume fluctuation (resin tablet error, mounting semiconductor element size variation, the number of mounted semiconductor elements, etc. In order to absorb (volume fluctuation), an overflow structure composed of the relief piston 7 and the overflow gate 8 is essential.

  By the way, when the resin thickness of the semiconductor element part mold resin 6A is a normal thickness (for example, about 0.5 mm), the overflow structure may be provided only on one side of the cavity. FIG. 7 is a view showing a resin mold product having a semiconductor element part mold resin 6A, a relief piston part resin 7A, and an overflow gate part resin 8A molded in such an overflow structure.

  However, when the resin thickness is thin (for example, 0.3 mm or less), it is difficult to achieve a constant thickness with the overflow structure on one side. This is because the resin is diffused from the center of the cavity toward the outer periphery, so that the remaining resin that is biased to the opposite side of the overflow gate 8 must pass through the cavity to reach the overflow gate 8, but the resin thickness is thin. In this case, the resin resistance becomes high, and it becomes difficult to discharge the resin from the opposite side of the overflow gate 8 to the overflow gate 8. For this reason, defective resin filling occurs.

  In order to prevent this, it is necessary to take measures such as increasing the filling pressure or providing overflow gates 8 at the four corners of the cavity and providing relief pistons 7 on both sides. FIG. 8 is a view showing a resin molded product having the semiconductor element part molding resin 6A, the relief piston part resin 7A, and the overflow gate part resin 8A molded in the overflow structure provided on both sides as described above.

  However, when the filling pressure is increased, the semiconductor element may be damaged. In addition, when the overflow structure is provided on both sides, the mold and the press structure become complicated (when pressure control by servo is performed, it is difficult to control a plurality of relief pistons in a balanced manner), etc. Increase in equipment cost and maintenance man-hours.

  The objective of this invention is providing the resin sealing apparatus which enabled thickness reduction and constant thickness of the resin mold product, avoiding the above-mentioned problem.

  According to a first aspect of the present invention, there is provided a resin sealing device in which a cavity block, a clamper, and a first mold form a cavity, and an overflow gate is formed in the clamper so as to be continuous with the cavity. A relief piston is formed on the clamper so as to be continuous. A substrate or a lead frame on which a plurality of semiconductor elements are mounted is set on the first mold in the cavity, and a resin is set on the semiconductor elements. The substrate or lead frame is clamped by the clamper, the cavity block is pressurized to melt and diffuse the resin, a plurality of semiconductor elements on the substrate or lead frame are collectively resin-molded, and the remainder Resin that allows the resin to escape from the overflow gate to the relief piston In the stopper device, a sub-runner is formed by a notch groove on an outer peripheral portion of the cavity-side surface of the cavity block, and the sub-runner and the overflow gate are continuous as a resin flow path during the pressurization. And

  According to a second aspect of the present invention, in the resin sealing device according to the first aspect, the sub-runner is formed endlessly on an outer peripheral portion of the cavity-side surface of the cavity block.

  According to the present invention, the remaining resin can be absorbed by only one relief piston only by forming the sub-runner, reducing the molding defect rate without complicating the mold structure and the press structure, It is possible to realize a thin and constant thickness of the resin mold product. Further, even when a general-purpose resin (spiral 100 cm, melting point viscosity about 500 poise) is used, a stable thin film (0.3 mm or less) can be formed. Further, when applied to a MAP (Mold Arrey Package) substrate or lead frame, the sub-runner can be positioned at a portion corresponding to an unused area of a molded area.

  FIG. 1 is an explanatory diagram of a state before pressing using the resin sealing device of the embodiment of the present invention, and FIG. 2 is an explanatory diagram of a state after pressing. 1 is a cavity block, 2 is a clamper, and these constitute an upper mold. Reference numeral 3 denotes a lower mold (first mold) on which a substrate (or lead frame) 5 on which a semiconductor element 4 is mounted is set. 6 is a resin tablet. 7 is a relief piston formed in a part of the clamper 2, and 8 is an overflow gate formed in a part of the clamper 2 so that the relief piston 7 and the cavity communicate with each other. An overflow structure is formed by the relief piston 7 and the overflow gate 8. Is configured. 9 and 10 are springs.

  In such a structure, in this embodiment, an endless cutout groove is provided in the outer peripheral portion of the lower surface of the cavity block 1 to form the sub-runner 11 as a resin flow path communicating with the overflow gate 8 during heating and pressurization. That is, the overflow structure of the present embodiment includes the relief piston 7, the overflow gate 8, and the sub runner 11.

  In the resin sealing apparatus of the present embodiment, a substrate 5 on which a plurality of semiconductor elements 4 are mounted is set on a lower mold 3 of a cavity surrounded by a cavity block 1, a clamper 2 and a lower mold 3, If the resin tablet 6 is set at the center and heated and pressurized in the same manner as before, the resin flow diffuses from the center of the cavity to the periphery and reaches the sub-runner 11, and the remainder of the resin is finally It is absorbed by the relief piston 7 through the overflow gate 8.

  Thus, by providing the sub-runner 11, the portion of the sub-runner 11 becomes a relatively large resin flow path as shown in FIG. 3, and the resin flow in the entire cavity is promoted (particularly on the opposite side of the overflow gate 8). Control with one relief piston 7 is possible. As a result, the resin mold product can be made thinner and constant without complicating the mold structure and the press structure.

  FIG. 4 is a view showing a resin mold product having a semiconductor element part mold resin 6A, a relief piston part resin 7A, and an overflow gate part resin 8A molded with the overflow structure of this embodiment. A protruding rib 6A1 corresponding to the sub-runner 11 is formed around the semiconductor element portion molding resin 6A.

  When the substrate (or lead frame) is for MAP (a type in which a plurality of IC chips are batch-molded), the outermost peripheral part of the cavity is different from the normal individual piece formation because it is separated into individual pieces by a dicing blade It is possible to provide an unused area (an area not used as a product), and when such a MAP substrate or lead frame is used, a rib 6A1 is formed in the unused area, and the rib 6A1 There is no semiconductor element in the portion. That is, this embodiment is suitable for a MAP substrate and a lead frame. The semiconductor element part mold resin 6A is then separated into individual semiconductor elements by a dicing blade or the like.

  The sub liner 11 provided by forming a notch groove on the outer periphery of the lower surface of the cavity block 1 is preferably endless as described above from the viewpoint of lowering the resin flow path resistance, but is not limited thereto. For example, on the side opposite to the side where the relief piston 8 is provided, even if the sub-liner 11 is not partially provided, the resin flow path resistance does not increase so much.

It is explanatory drawing of the state before the press which uses the resin sealing apparatus of a present Example. It is explanatory drawing of the state after the press which uses the resin sealing apparatus of a present Example. It is the enlarged view of the part of the overflow gate of this example, and a sub runner. It is a top view of the resin mold product by the resin sealing apparatus of a present Example. It is explanatory drawing of the state before the press which uses the resin sealing apparatus of a prior art example. It is explanatory drawing of the state after the press which uses the resin sealing apparatus of a prior art example. It is a top view of the resin mold product by the resin sealing apparatus of a prior art example. It is a top view of the resin mold product by the resin sealing apparatus of another prior art example.

Claims (2)

A cavity block, a clamper, and a first mold form a cavity, an overflow gate is formed in the clamper so as to be continuous with the cavity, and a relief piston is formed in the clamper so as to be continuous with the overflow gate. Become
A substrate or lead frame on which a plurality of semiconductor elements are mounted on the first mold in the cavity is set and resin is set on the semiconductor element, and the substrate or lead frame is clamped by the clamper, The cavity block is pressurized to melt and diffuse the resin, and a plurality of semiconductor elements on the substrate or lead frame are collectively molded, and the remaining resin is allowed to escape from the overflow gate to the relief piston. In the resin sealing device,
A resin runner characterized in that a sub-runner by a notch groove is formed in an outer peripheral portion of the cavity-side surface of the cavity block so that the sub-runner and the overflow gate are continuous as a resin flow path during the pressurization. Stop device. In the resin sealing device according to claim 1,
The resin runner is characterized in that the sub-runner is formed endlessly on the outer peripheral portion of the cavity-side surface of the cavity block.

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