JP5020897B2 - Release film adsorption method for compression mold and compression mold - Google Patents

Description

  The present invention relates to the technical field of a compression molding die that compresses a resin or the like into a predetermined shape.

  Conventionally, a compression mold 10 shown in FIG. 5 is known (see Patent Document 1).

  The compression molding die 10 includes an upper die 12 and a lower die 14, and the lower die 14 is a compression in which the frame die 16 having a through hole 16B and a through hole 16B are fitted so as to be able to advance and retreat. This is a compression molding die that includes a die 18 and seals the semiconductor product A in a cavity formed by the upper die 12 and the lower die 14. The frame-shaped mold 16 is supported by a spring 24 and can move in the vertical direction relative to the compression mold 18.

  In the compression mold 10, for example, ETFE (fluororesin) is used on the surface of the lower mold 14 (the frame mold 16 and the compression mold 18) in order to improve the releasability of the molded product after sealing. Resin sealing is performed with a release film (release film) 28 interposed therebetween (see FIGS. 6 and 7). Further, a slight gap (cavity gap) is formed between the through hole 16B of the frame-shaped mold 16 and the compression mold 18 so that the release film 28 is not twisted or wrinkled during sealing. It is possible to suck and fix the release film 28 by sucking air in the cavity from the gap. This suction is realized by the vacuum pump 30 via the suction path 22. Further, suction holes 20 are provided on the surface (opposing surface) of the frame-shaped mold 16 so that the release film 28 is not displaced, so that the release film 28 can be fixed by suction during sealing.

  When resin sealing is performed with a compression mold, a cavity space into which a semiconductor product (molded product) or a resin as a sealing material is charged needs to be formed. Therefore, as shown in FIG. 6, the step D is formed by slightly denting the position of the surface 18A of the compression mold 18 with respect to the position of the surface 16A of the frame mold 16. The level of the step D here is, for example, about 1/4 to 1/1 of the thickness of the molded product. The reason why this is set is to prevent the release film 28 from stretching and to prevent wrinkles and the like from occurring in the molded product due to the presence of the excess release film. That is, since the molded product always has a certain thickness, in order to absorb the thickness, the release film 28 corresponding to the step is secured in advance, and the local area of the release film 28 at the time of resin sealing (during compression) While preventing the target (especially around the cavity) from being stretched at the same time, it prevents wrinkles and twists in the excessive amount (length) of the release film from being transferred to the molded product side. Yes.

  As a result of the step D being formed, a recess 40 is formed on the surface of the lower mold 14, and a space X partitioned by the recess 40 and the release film 28 is further formed.

  If compression molding is performed in the presence of such a space X, wrinkles or twists may occur in the release film 28. Therefore, prior to the compression step, the release film 28 is placed along the recess 40 (release). The mold film 28 needs to be in contact with the surface 18A of the compression mold 18). Therefore, the space X is depressurized via the suction path 22 and the work of bringing the release film 28 along the recess 40 is performed.

JP 2005-186523 A

  However, at this time, a step D (about 1/4 to 1/1 of the thickness of the molded product) is set for reasons such as preventing the release film from being stretched and preventing wrinkles, and the space X is decompressed to release the release film 28. When trying to lie along the recess 40, only the release film 28 located in the vicinity of the gap between the through hole 16B of the frame-shaped mold 16 and the compression mold 18 (that is, the gap communicating with the suction path 22) is the first. There may be a phenomenon in which the surface 18A of the compression mold 18 comes into contact with air and remains in the vicinity of the center. That is, as shown in FIG. 7, when the mold is viewed in cross section, the release film 28 contacts only at the left and right portions Y of the surface 18 </ b> A of the compression mold 18, and an air pocket is formed in the central portion Z. It is a phenomenon.

  Once such a phenomenon occurs, it takes a very long time to completely discharge the air in the air reservoir portion. For example, even if the suction from the suction path 22 is continued and the air in the air pool is removed, the already contacted portion becomes a barrier and takes time. In addition, even if the suction and release film 28 are once uncovered and the suction operation is performed again, time is unavoidably required.

  On the other hand, there is a method of preventing the formation of air pockets by gently performing suction from the suction path 22 in advance, but it is inevitable that the time until completion of the work becomes long even with such a method.

  That is, the occurrence of the above phenomenon affects the cycle time of the apparatus, resulting in a decrease in the productivity of the apparatus and an increase in cost per unit.

  The present invention has been made to solve such problems, and prevents the phenomenon of air accumulation between the mold surface and the release film when the pressure in the space is reduced. It is an issue.

  The present invention provides a release film on the surface of a compression mold having a frame-shaped mold having a through-hole and a compression mold disposed so as to be able to advance and retreat in the through-hole. A mold release film adsorbing method for adsorbing, wherein a first step is formed by denting a position of the surface of the compression mold with respect to a position of the surface of the frame-shaped mold, and the surface of the compression mold At the same time as or after the formation of the concave portion, the release film is supplied so as to cover at least the surface of the compression mold including the concave portion, thereby being partitioned by the release film and the concave portion. A step of forming a first space, and a step of moving at least one of the frame-shaped mold and the compression mold in a direction in which the first step is eliminated in a state where the pressure in the first space is reduced. Through the above, It is intended to attain.

  At the same time, the present invention separates the surface of a compression mold having a frame-shaped mold having a through-hole and a compression mold that is fitted to the through-hole so as to be able to advance and retract. A mold release film adsorption method for adsorbing a mold film, the step of supplying the mold release film so as to cover the surface of the compression mold, and the compression with respect to the position of the surface of the frame mold A step of forming a first step by recessing the position of the surface of the mold to form a recess in the surface of the compression molding mold, and as a result of forming the recess, a partition is formed by the recess and the release film. Forming the first space, and moving at least one of the frame-shaped mold and the compression mold in a direction in which the first step is extinguished in a state where the pressure in the first space is reduced. The above-mentioned problem is solved by going through a process.

  That is, the first step is set in advance to such an extent that the release film cannot physically contact the entire surface of the compression mold even if the pressure in the first space is reduced. Then, the mold release film is made convex toward the first space by reducing the pressure in the first space, and further, the frame-shaped mold and the compression mold in the direction of eliminating the first step. By moving at least one of the molds, the convex release film is gradually brought into contact with the surface of the compression mold. By passing through such a process, it is possible to adsorb the release film along the recess without causing air accumulation between the surface of the compression mold and the release film.

  After such a step (procedure), in the process of moving at least one of the frame-shaped mold and the compression mold in the direction of eliminating the first step, the mold release covering the recess When the film is viewed in plan, the release film comes into contact with the surface of the compression mold in order from the portion corresponding to the center of the concave portion toward the periphery.

  Of course, since the appropriate level of the first step can vary depending on the degree of pressure reduction with respect to the first space and the properties of the release film, the first level difference is set to a predetermined parameter (for example, the pressure reduction of the first space). It is desirable to make it variable according to the degree, the nature of the release film, and the like.

  In another aspect, the present invention includes a first mold and a second mold disposed to face the first mold, and the second mold includes a through hole. A compression mold having a frame-shaped mold and a compression mold that is fitted and disposed in the through-hole so as to be able to advance and retreat, the frame-shaped mold for sucking a release film First suction means formed on the opposing surface of the first suction means, and second suction means formed using a fitting gap between the frame-shaped mold and the compression mold to suck the release film And a first relative position of the surface of the compression mold with respect to a position of the surface of the frame-shaped mold at the time when the release film is sucked by the first suction means, and the second suction means. The second relative position after changing the relative position of the surface of the frame-shaped mold while sucking the release film can be arbitrarily set. It is also possible to capture as compression mold, characterized in that it comprises a set means.

  By applying the present invention, it is possible to shorten the time for adsorbing the release film to the surface of the compression mold, improve the cycle time of the apparatus, improve the productivity of the apparatus, and prevent the cost per unit from increasing. It becomes.

  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 diagram illustrating a method for adsorbing a release film according to the present invention, and is a diagram illustrating a state before depressurization in a space X is started. Similarly, FIG. 2 is a view showing a state in which the release film is convex downward due to the reduced pressure in the space X. FIG. FIG. 3 is a view similarly showing a state in which the release film is adsorbed on the surface of the compression mold by the movement of the mold. FIG. 4 is a diagram similarly showing a state where the release film has been adsorbed.

<Composition of compression mold>
In the embodiment described below, since the release film is adsorbed only in the lower mold, the description will focus on the portion corresponding to the lower mold.

  The compression molding die 100 is composed of an upper die (first die: not shown) and a lower die (second die) 114 disposed to face the upper die. The lower mold 114 includes a frame-shaped mold 116 having a through hole 116B and a compression mold 118 that is fitted in the through hole 116B so as to be able to advance and retract. A press mechanism (not shown) is connected to the upper mold and the lower mold 114 so that both molds can be contacted and separated at a predetermined timing. Further, a pressing mechanism 116C is provided on the outer periphery of the frame-shaped mold 116, and the relative position (vertical direction) of the frame-shaped mold 116 with respect to the compression mold 118 can be arbitrarily changed. Yes.

  A release film (release film) 128 is supplied to the surface (opposing surface) of the lower mold 114 by a supply mechanism (not shown). The release film 128 is provided in order to make it easy to take out the sealed product from the lower mold 114. For example, ETFE (fluororesin) is used as a main raw material. Further, the upper mold 114 and the lower mold 114 have a built-in heater (not shown) so that the mold can be heated.

  An adsorption hole (first suction means) 120 capable of adsorbing and holding the release film 128 is formed on the surface (opposing surface) 116A of the frame mold 116. Further, a gap between the compression mold 118 and the frame mold 116 (more precisely, a gap between the outer peripheral surface of the compression mold 118 and the inner peripheral surface of the through hole 116B of the frame mold 116) G, A second suction means is formed by the suction path 122 communicating with the gap G. A vacuum pump (not shown) is connected to the suction hole 120 and the suction path 122 so that suction can be performed independently.

  Further, a step setting means (not shown) that can arbitrarily set the relative position of the surface 118A of the compression mold 118 with respect to the position of the surface 116A of the frame-shaped mold 116 is provided.

<Compression molding method>
Next, a specific resin sealing method using the compression mold 100 will be described.

  The upper die 114 and the lower die 114 are separated at a predetermined interval by the action of the press mechanism. Also, a release film 128 is supplied between the upper mold and the lower mold 114 by a release film supply mechanism. At this time, the position of the surface 116A of the frame-shaped mold 116 is positioned higher than the position of the surface 118A of the compression mold 118 by the action of the spring 124. That is, a step (first step) D is formed, and the recess 140 is formed on the surface (opposing surface) of the lower mold 114 by the step D (first relative position). Further, the step D formed in the present embodiment is set at a level that exceeds at least the thickness of the molded product.

  Subsequently, the press mechanism operates to raise the lower mold 114 in a state where the step D is formed. As a result, the lower mold 114 comes into contact with the release film 128 (more strictly, it comes into contact with the surface 116A of the frame-shaped mold 116), and the state shown in FIG. 1 is obtained. By the contact, a space X defined by the recess 140 and the release film 128 is formed.

  Due to its nature, the release film 128 undergoes thermal expansion when it receives heat from the mold, causing thermal contraction. By maintaining the state in which only the surface 116A portion of the frame-shaped mold 116 is in contact as described above for a certain period of time, the release film 128 in the contacted portion undergoes thermal shrinkage. Furthermore, this thermal contraction generates a tensile force against the release film 128 in the central portion (the portion corresponding to the space X), thereby reducing the wrinkles and slackness of the portion and stabilizing the film adsorption work described later. Yes.

  Thereafter, the adsorption of the adsorption holes 120 is started, and the release film 128 is adsorbed and fixed to the surface 116A of the frame-shaped mold 116. At this time, the release film 128 and the surface 118A of the compression mold 118 are not in contact with each other due to the presence of the step D and the fact that suction from the suction path 122 has not started.

  Subsequently, the suction from the suction path 122 is started, and the space X is depressurized. As shown in FIG. 2, the release film 128 covering the concave portion 140 is in a “convex downward” state by this decompression. In other words, when the release film 128 covering the recess 140 is viewed in plan, the part of the release film 128 corresponding to the center of the recess 140 is located at the apex of “convex downward”. Become.

  In the present embodiment, a part of the release film 128 (downwardly protruding vertex) is in contact with the surface 118B of the compression mold 118 in a state where the space X is depressurized. There is no problem. Rather, the non-contact can more reliably prevent the occurrence of “air accumulation” by “move movement” described below.

  Subsequently, as shown in FIG. 3, the push-down mechanism 116C operates to push down the frame-shaped mold 116 downward. That is, the position of the surface 116A of the frame-shaped mold 116 is moved in a direction to approach the position of the surface 118A of the compression mold 118 (the direction in which the step D is eliminated). By this operation, the release film 128 in the “convex downward” state comes into contact with the surface 118A of the compression mold 118 in order from the apex portion to the periphery. During the process, suction from the suction path 122 is continued, and the space X is maintained in a reduced pressure state.

  In the above description, only the frame mold 116 is moved, but the compression mold 118 may be moved, or both may be moved. That is, the same effect can be exhibited as long as the relative movement is made in the “direction in which the step D disappears”.

  Thereafter, the pressing of the compression mold 116 by the pressing mechanism 116C is completed, and the pressure reduction in the space X is also completed, and the release film 128 is adsorbed along the surface 118A of the compression mold 118 (second relative position). ). That is, the release film 128 is adsorbed along the recess 140 (see FIG. 4).

  By adsorbing the release film 128 through such a process, an air pocket is not generated between the surface 118A of the compression mold 118 and the release film 128.

  Thereafter, after the resin as the sealing material is supplied to the concave portion 140, the upper die and the lower die 114 come into contact with each other, and compression molding is performed.

  The step D can be changed (variable) according to a predetermined parameter. For example, parameters such as the degree of decompression in the space X, the sealing thickness, the type and nature of the release film 128 to be used, and the sealing temperature may be parameters (a single parameter or a plurality of parameters may be considered). ), An optimal step D can be formed. However, it is desirable that a level difference at least at a level exceeding the thickness of the molded product is secured.

  In the present invention, the supply of the release film 128 is not necessarily performed after the step D is formed. That is, the step D may be formed at the same time when the release film 128 is supplied to the surface (opposing surface) of the lower die 114, or the release film 128 is supplied to the surface (opposing surface) of the lower die 114. A step D may be formed later.

  In the present embodiment, the release film 128 is supplied to the lower mold 114 side. However, even when the upper and lower molds are reversed, the release film 128 is supplied to the upper mold side. Thus, the same effect can be obtained. Furthermore, when both surfaces of the semiconductor product are sealed with resin, the release film 128 can be supplied to both the upper and lower molds, and the same effect can be obtained with both molds.

  The present invention is suitable not only for a compression molding die for sealing a substrate on which a semiconductor chip or the like is mounted with a resin, but also when the resin is compression molded into a predetermined shape.

It is a figure which shows the adsorption | suction method of the release film concerning this invention, Comprising: The figure which showed the state before the pressure reduction in the space X was started It is a figure which shows the adsorption | suction method of the release film concerning this invention, Comprising: The figure which showed the state by which the release film became convex downward by the pressure reduction in the space X It is a figure which shows the adsorption | suction method of the release film concerning this invention, Comprising: The figure which showed the state in which a release film is adsorbed | sucked to the surface of a compression mold by movement of a metal mold | die The figure which shows the adsorption | suction method of the release film concerning this invention, Comprising: The figure which showed the state which adsorption | suction of the release film was completed Compression molding die described in Patent Document 1 The figure which showed the state before adsorb | sucking a release film with the compression mold described in patent document 1 The figure which showed the state after adsorb | sucking a release film with the compression mold described in patent document 1

Explanation of symbols

DESCRIPTION OF SYMBOLS 100 ... Compression molding die 114 ... Lower die 116 ... Frame-shaped metal mold | die 116A ... The surface (opposite surface) of frame-shaped metal mold | die
116B ... Through-hole 116C ... Push-down mechanism 118 ... Compression mold 118A ... Surface (opposite surface) of compression mold
120 ... Suction hole 122 ... Suction path 124 ... Spring 140 ... Recess D ... Step X ... First space

Claims (7)

Mold release for adsorbing a release film to the surface of a compression mold having a frame-shaped mold having a through-hole and a compression mold that is fitted to the through-hole so as to be able to advance and retreat A film adsorption method,
A first step is formed by denting the position of the surface of the compression mold with respect to the position of the surface of the frame-shaped mold, and at the same time or after forming the recess on the surface of the compression mold. Forming a first space defined by the release film and the recess by supplying the release film so as to cover at least the surface of the compression mold including the recess;
A step of moving at least one of the frame-shaped mold and the compression mold in a direction in which the first step is extinguished in a state where the pressure in the first space is reduced. Film adsorption method. Mold release for adsorbing a release film to the surface of a compression mold having a frame-shaped mold having a through-hole and a compression mold that is fitted to the through-hole so as to be able to advance and retreat A film adsorption method,
Supplying the release film so as to cover the surface of the compression molding mold;
Forming a first step by denting the position of the surface of the compression mold with respect to the position of the surface of the frame-shaped mold, and forming a recess in the surface of the compression mold;
As a result of forming the recess, forming a first space defined by the recess and the release film;
A step of moving at least one of the frame-shaped mold and the compression mold in a direction in which the first step is extinguished in a state where the pressure in the first space is reduced. Film adsorption method. In claim 1 or 2,
At the time of decompression of the first space, the release film is placed in the first space with the portion corresponding to the center of the recess when the release film covering the recess is viewed in plan. A mold release film adsorbing method characterized by being convex toward the surface. In any one of Claims 1 thru | or 3,
The mold release film adsorption method, wherein the first step is set to such an extent that the mold release film does not contact the surface of the compression mold even if the pressure in the first space is reduced. In any one of Claims 1 thru | or 4,
In the process of moving at least one of the frame-shaped mold and the compression mold in the direction of eliminating the first step, when the release film covering the recess is viewed in plan view, The release film adsorbing method, wherein the release film contacts the surface of the compression mold in order from the portion corresponding to the center toward the periphery. In any one of Claims 1 thru | or 5,
The mold release film adsorption method, wherein the first step is variable in accordance with a predetermined parameter. A first mold and a second mold disposed opposite to the first mold, wherein the second mold includes a frame-shaped mold having a through hole and the through hole; A compression mold having a compression mold that is fitted and arranged so as to be able to advance and retreat;
First suction means formed on the opposing surface of the frame-shaped mold for sucking the release film;
Second suction means formed by utilizing a fitting gap between the frame-shaped mold and the compression mold to suck the release film;
A first relative position of the surface of the compression mold with respect to a position of the surface of the frame-shaped mold at the time when the release film is sucked by the first suction means, and the separation by the second suction means. A step setting means capable of arbitrarily setting the second relative position after changing the relative position of the surface of the frame-shaped mold while sucking the mold film.

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