JP4464366B2 - Cleaning method of compression mold - Google Patents

Description

  The present invention relates to a technical field of compression molding dies used for resin sealing of semiconductor products.

  Conventionally, a compression mold 1 shown in FIG. 8 is known (see Patent Document 1).

  The compression mold 1 includes an upper mold 10 and a lower mold 20, and the lower mold 20 includes a frame mold 22 having a through portion 22H and a bottom mold 24 disposed through the through portion 22H. This is a compression mold for resin-sealing a semiconductor product in a cavity 40 formed by the mold 10 and the lower mold 20. Reference numeral 30 denotes a cylinder capable of bringing the lower mold 20 into contact with or separated from the upper mold 10.

  Although not shown, in the compression mold, for example, PTFE (polytetrafluoroethylene) is formed on the cavity surface of the lower mold (frame mold and bottom mold) in order to improve the releasability of the molded product after sealing. The resin is sealed with a release film made of fluoroethylene). In addition, a slight gap (cavity gap) is provided between the penetrating part of the frame mold and the bottom mold so that the release film is not twisted or wrinkled during sealing. The air is sucked. The surface of the frame mold is provided with a plurality of suction holes so that the release film does not shift, and the release film can be fixed by suction during sealing.

  As a mold cleaning method, a method described in Patent Document 2 is known.

  In the cleaning method described in Patent Document 2, for example, a rubber-based cleaning member is put into a cavity, and then the upper die and the lower die are compressed in the same procedure as in normal molding, and a resin residue or the like is applied to the cleaning member. The mold is cleaned by adhering.

JP 2004-130730 A Japanese Patent Laid-Open No. 10-226799

  However, when the method described in Patent Document 2 is used for cleaning a compression mold, there are the following problems.

  First, there is a problem that the cleaning member enters a gap for sucking air in the cavity (a gap between the through-hole of the frame mold and the bottom mold; hereinafter, sometimes simply referred to as “cavity gap”). . During cleaning, a release film cannot be interposed on the surface of the lower mold as in normal resin sealing (cannot be cleaned if there is a release film), so the cleaning member compressed at high pressure loses its escape. This is considered to be caused by entering the gap.

  Second, there are a plurality of release film suction holes on the surface of the frame mold, but the cleaning member compressed by cleaning spreads flatly by compression and enters the suction holes. was there.

  The present invention has been made to solve such problems, and is used for a cleaning method in which a cleaning member does not enter and remain in a cavity gap or an adsorption hole for a frame-type release film, and for the cleaning. A protective plate for cleaning is provided.

  The present invention includes an upper mold and a lower mold, and the lower mold includes a frame mold having a penetrating portion and a bottom mold disposed so as to penetrate the penetrating portion. A compression molding mold cleaning method for cleaning a cavity surface by interposing and compressing a cleaning member, wherein the bottom surface protrudes from the top surface of the frame mold, and the bottom step The above-mentioned problem is solved by cleaning the compression molding die through a compression process in which the cleaning member is compressed with the upper surface of the mold protruding from the upper surface of the frame mold.

  By passing through the compression step while the bottom mold protrudes from the frame mold, the compression pressure applied to the cleaning member can be drastically reduced at a position off the top surface of the bottom mold (the top surface of the frame mold). In addition to this, the viscosity of the cleaning member itself and the shape characteristic that a “step” exists at the boundary between the bottom mold and the frame mold also suppresses the cleaning member from entering the cavity gap immediately below the step. (It will be described later).

  The present invention further includes a hole portion into which the protruding bottom mold can be fitted between the preparation step and the compression step, and the frame die surface by fitting the hole portion into the bottom die. It is more preferable in the following point that the cleaning is performed through a process of mounting a protective plate capable of covering the suction holes provided in the lower mold on the lower mold.

  By using this method, it is possible to reliably prevent the cleaning member spreading in the compression process from entering the suction holes provided on the surface of the frame mold.

  Further, it is more preferable that the compression step is performed with a release film interposed between the upper mold and the cleaning member in the following points.

  By using this method, it is possible to prevent the cleaning member from entering a hole (for example, a suction hole for sucking and holding a molded product) provided on the upper mold surface. Moreover, since the release film can use the release film used in the normal sealing work process as it is, there is no need to prepare a dedicated object separately.

  By applying the present invention, it is possible to prevent the cleaning member from entering an unnecessary portion, so that it is not necessary to further clean the intrusion residue of the cleaning member.

  Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a structural view of a compression mold for carrying out the method according to the present invention, and FIG. 2 is a cross-sectional view taken along the line II-II in FIG. FIG.

  The compression mold 100 is composed of an upper mold 110 and a lower mold 120. The upper mold 110 and the lower mold 120 can be brought into contact with and separated from each other by, for example, a press mechanism (not shown).

  The upper mold 110 is a mold for holding a molded product conveyed by an external conveyance mechanism, and is used to attract and hold the conveyed molded product on the surface of the upper mold 110 (surface on the lower mold 120 side). Are provided (not appearing on the drawing). Moreover, the recessed part (it does not appear on drawing) in which the guide post 123 (it mentions later for details) with which the frame type | mold 122 is inserted is provided.

  The lower mold 120 includes a frame mold 122, a bottom mold 124, a clamp spring 126, and a lower mold base 128. A frame mold 122 is disposed on the lower mold base 128 via a clamp spring 126. The frame mold 122 can be moved up and down with respect to the lower mold base 128 by a driving source (not shown), and can be stopped at an arbitrary position with respect to the lower mold base 128. Further, a penetrating part 122H (see FIG. 2) is provided in the approximate center of the frame mold 122, and the bottom mold 124 is arranged in such a manner as to penetrate the penetrating part 122H. Since the bottom mold 124 is fixed to the lower mold base 128, the frame mold 124 moves up and down, so that the frame mold 122 and the bottom mold 124 move relatively up and down. A slight gap (cavity gap: see FIG. 2) G is provided between the penetrating portion 122H of the frame mold 122 and the bottom mold 124 penetrating the penetrating portion 122H. The air in the cavity can be sucked by using it. In addition, guide posts 123 are respectively arranged on the upper surfaces of the four corners of the frame mold 122. By inserting the guide posts 123 into recesses provided on the surface of the upper mold 110, the upper mold 110, the lower mold 120, and Can contact with high accuracy. A plurality of suction holes (release film suction holes) 122V are provided around the through-hole 122H on the surface of the frame mold 122 (the surface in the direction of the upper mold 110).

  Further, although not a component constituting the compression molding die 100, a guide post hole 150G into which the guide post 123 can be fitted in the cleaning protective plate 150 used when the compression molding die 100 is cleaned. In addition, a bottom mold hole 150H having a shape similar to the shape of the cavity surface (upper mold side surface) of the bottom mold 124 is formed. The cleaning protection plate 150 is designed such that when the guide post 123 is fitted into the guide post hole 150G, the bottom mold hole 150H corresponds to the cavity surface of the bottom mold 124 at the same time. The size of the bottom mold hole 150H is designed to be slightly larger than the cavity surface of the bottom mold 124. The cleaning protection plate 150 is made of, for example, stainless steel and can be used repeatedly. A specific method of use will be described below.

  Next, the cleaning procedure for the compression mold 100 will be described.

  First, the surface (upper surface) of the bottom mold 124 is protruded from the surface (upper surface) of the frame mold 122 (preparation step). For example, as shown in FIG. 2, the surface of the bottom mold 124 is protruded by a height H from the surface of the frame mold 122. This protrusion amount can be adjusted as appropriate in consideration of the mold to be cleaned, the cleaning member used for cleaning, the temperature, the size of the cavity gap G, the thickness of the cleaning protective plate 150 used, and the like. Is possible. In addition, as described below, when cleaning is performed using the cleaning protection plate 150, adjustment is made so that the bottom mold 124 protrudes from the bottom mold hole 150H even when the cleaning protection plate 150 is attached. Is required. In this preparation step, the position of each die (upper die 110, frame die 122, bottom die 124) is stored in advance in a control unit (not shown) that controls the movement of the compression mold (for example, cleaning). A dedicated switch is provided as a mode), and the preparation process work is easy.

  Next, the cleaning protection plate 150 is attached to the lower mold 120. Specifically, the guide posts 123 are attached so as to be fitted into the guide post holes 150G provided in the cleaning protection plate 150, respectively. In the cleaning protection plate 150, when the guide post 123 is inserted into the guide post hole 150G, the bottom mold hole 150H is designed to correspond to the cavity surface of the bottom mold 124 at the same time. The protruding bottom mold 124 is fitted into the bottom mold hole 150H of the cleaning protection plate. The shape of the bottom mold hole 150H provided in the cleaning protection plate 150 is similar to the shape of the cavity surface of the bottom mold 124 and is configured to be slightly larger, so that it can be easily fitted. It has become. Note that the attachment of the cleaning protection plate 150 is not necessarily performed after the preparation step, and the procedure may be such that the cleaning protection plate 150 is attached before entering the preparation step.

  Next, the cleaning member 160 is disposed on the cavity surface of the bottom mold 124 as shown in FIG. A commercially available cleaning member 160 can be widely used. For example, a rubber member or an epoxy resin member can be used without limitation. It is not always necessary to dispose the cleaning member 160 on the cavity surface of the bottom mold 124 after the process of attaching the cleaning protection plate 150. Before entering the process of attaching the cleaning protection plate 150, the above-described preparation is performed. The procedure may be such that the cleaning member 160 is arranged before entering the process.

  Subsequently, the release film 170 is interposed between the cleaning member 160 and the upper mold 110. The release film 170 is not specially prepared for the cleaning, and a release film used for resin sealing is used as it is.

  Subsequently, a pressing mechanism (not shown) is operated to bring the upper mold 110 and the lower mold 120 into contact with each other, thereby compressing the cleaning member 160 and cleaning the mold (compression process). The compressed cleaning member 160 is rolled into a flat shape as shown in FIG. 5, for example, and adheres to the cavity surface of the mold (the upper surface of the bottom mold 124, the side surface of the penetrating portion 122H of the frame mold 122, etc.). Take in the dirt and clean it.

  Depending on the degree of contamination of the mold, the compression process is repeated, or the cleaning member 160 is appropriately replaced with a new one, and cleaning is performed repeatedly.

  As shown in FIG. 6, since the upper mold 110 and the bottom mold 124 come into contact with each other with a high pressure in the compression process, the cleaning member 160 sandwiched between the upper mold 110 and the bottom mold 124 spreads around. I will try. On the other hand, since the frame mold 122 is lower than the bottom mold 124 (that is, the bottom mold protrudes: there is a step), the distance between the upper mold 110 and the frame mold 122 is the same as that of the upper mold 110 and the bottom mold 124. Always kept wider than the interval. For this reason, the cleaning member 160 that spreads around due to the high pressure decreases in pressure by reaching this part (the part where the interval is widened). descend. In addition, since the cleaning member 160 itself has an appropriate viscosity derived from the material, the cleaning member that spreads from the bottom mold 124 to the frame mold 122 proceeds vertically in the direction of the cavity gap G immediately below the step. The force is weak and tries to spread further to the surroundings while hanging down in an oblique direction (see FIG. 7). As a result, the cleaning member 160 is prevented from entering the cavity gap. Further, since the cleaning protection plate 150 is used, even if the cleaning member 160 is rolled and expanded to the position of the suction hole 122V provided on the surface of the frame mold 122, the cleaning member 160 spreads on the plate. Therefore, the cleaning member 160 can be completely prevented from entering the suction hole 122V. Furthermore, since the upper mold 110 is in contact with the cleaning member via the lily film 170, the cleaning member 160 does not enter and remain in the suction holes (molded product suction holes) provided on the surface of the upper mold 110.

  Finally, the rolled cleaning member 160 is removed, and the cleaning is completed.

  In addition, after the compression process described above, for example, an operation of inverting the relative positions of the frame mold 122 and the bottom mold 124 (reducing the upper surface of the bottom mold 124 from the upper surface of the frame mold 122) is added. It is also possible to clean the side surface of the through-hole 122H of the frame mold 122 (the surface that forms the cavity during sealing). The cleaning member 160 at this time is already compressed by the compression process, and the cleaning member 160 does not enter the cavity gap even if such an operation is performed.

  INDUSTRIAL APPLICABILITY The present invention can be used for cleaning a compression mold for sealing a semiconductor product with a resin.

Structural drawing of a mold for carrying out the method of the present invention FIG. 2 is a cross-sectional view taken along the arrow II-II line in FIG. 1 and shows only a frame mold and a bottom mold. The figure which showed the example of the arrangement state of a cleaning member Figure showing an example of the state of the release film The figure which showed the example of the state of the cleaning member after a compression process The figure which showed the example of the state of the compression process around a cavity VII part enlarged view in FIG. Structure diagram of compression molding die described in Patent Document 1

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Compression molding die 110 ... Upper die 120 ... Lower die 122 ... Frame die 122H ... Through-hole 122V ... Adsorption hole 123 ... Guide post 124 ... Bottom die 126 ... Clamp spring 128 ... Lower die base 150 ... Protection plate 150G for cleaning ... Guide post hole 150H ... Bottom mold hole 160 ... Cleaning member 170 ... Release film

Claims (3)

An upper mold and a lower mold are provided, and the lower mold has a frame mold having a penetrating part and a bottom mold disposed through the penetrating part, and a cleaning member is interposed between the upper mold and the lower mold A method of cleaning a compression mold that cleans the cavity surface by compressing,
A preparation step in which the upper surface of the bottom mold protrudes from the upper surface of the frame mold;
A compression molding die cleaning method, comprising: a compression step of compressing the cleaning member with the upper surface of the bottom mold protruding from the upper surface of the frame mold. In claim 1,
Between the preparation step and the compression step, the protruding bottom mold has a hole that can be fitted, and the hole is fitted to the bottom mold to cover the suction hole provided on the surface of the frame mold A method for cleaning a compression mold, comprising the step of attaching a possible protective plate to the lower mold. In claim 1 or 2,
The compression process is performed by interposing a release film between the upper mold and the cleaning member. A method for cleaning a compression mold.

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