JP5737122B2 - Mold release recovery sheet and mold release processing method using the same - Google Patents

Description

  The present invention relates to a mold release recovery sheet used for smoothly releasing a molded product from various molds for thermosetting resin composition molding materials, etc., and finishing the appearance of the molded product satisfactorily. The present invention relates to a mold release processing method using the same.

  For example, in the process of resin-sealing a semiconductor element by transfer molding, a molding process using a molding die (resin sealing process) using a thermosetting resin molding material such as an epoxy resin composition for semiconductor sealing as a sealing material ) Is repeated. When the molding process using the thermosetting resin molding material is repeated many times, as the number of repetitions (number of shots) increases, the mold surface of the molding die, particularly the cavity surface, exudes from the molding material. Contaminating components such as burrs, burrs, and dust are sequentially stacked and accumulated. Such a contaminating component significantly reduces the releasability when the molded product is taken out of the mold, and causes a phenomenon such as rough skin on the surface of the molded product.

  For this reason, conventionally, the surface of the mold (cavity surface) has been cleaned at every fixed number of molding repetitions (number of shots). As the cleaning method, for example, a cleaning resin mainly composed of a melamine resin is poured into a mold in the same manner as in transfer molding using an ordinary semiconductor sealing resin composition, and the melamine resin is mainly used in that state. A method of cleaning a mold cavity surface by heat-curing a cleaning resin as a component so that contaminated components are integrally attached to the cured product and the cured product is taken out of the mold cavity in that state. Can be given.

  In addition, a method has been proposed in which a cleaning sheet mainly composed of unvulcanized rubber is used instead of the cleaning resin mainly composed of the melamine resin (see Patent Document 1). In this cleaning method using a cleaning sheet mainly composed of unvulcanized rubber, the mold is clamped in a state where the cleaning sheet is sandwiched between an upper mold and a lower mold, which are divided into two halves. Then, the cleaning sheet is filled into the cavity, and heat-molded in that state, so that the contaminating components are integrally attached to the cleaning sheet, and in this state, the cleaning sheet is taken out from the cavity of the mold. The cavity surface is cleaned.

  When the mold has been cleaned by the cleaning method as described above, the mold release agent component for promoting mold release properties has also been removed from the mold surface. When a semiconductor element is resin-sealed using a thermosetting resin composition such as an epoxy resin molding material for semiconductor encapsulation, the cured product of the thermosetting resin composition is firmly bonded to each molding part of the mold and molded. The product had a problem that it was very difficult to release from the mold.

  Therefore, it is necessary to apply a mold release agent to the mold surface in advance, for example, to apply the mold release agent to the mold surface by spray injection, or to release the mold in advance in a thermosetting resin or unvulcanized rubber fabric. By using a sheet material containing an agent, sandwiching it in a mold and curing it by transferring a mold release agent contained in a thermosetting resin or unvulcanized rubber fabric to the mold surface A method of applying a release agent to the mold surface is performed (see Patent Documents 2 and 3).

Japanese Patent Laid-Open No. 10-226799 JP 2002-161189 A JP 2003-183479 A

  However, in the method of applying the release agent to the mold surface by spraying, since it depends on the operator's sense of application, the application amount varies and it becomes difficult to apply uniformly to the entire mold surface. There is a problem that the appearance of the molded product is impaired due to uneven application of the agent. In addition, the method of applying a release agent to the mold surface using a sheet material that contains a release agent in advance in the thermosetting resin or unvulcanized rubber fabric may be sufficient depending on the type of the release agent. There arises a problem that the mold release effect cannot be obtained or the molded product is fogged.

  On the other hand, the epoxy resin composition for semiconductor encapsulation used when resin-sealing a semiconductor element using a molding die such as transfer molding contains various mold release agents. In consideration of the released release agent, it has been practiced to apply the release agent to the mold surface using a sheet material containing a release agent appropriately selected according to the release agent. As described above, a complicated operation of selecting and using a release agent contained in the sheet material in accordance with the type of the sealing material is required.

  The present invention has been made in view of such circumstances, and can provide good releasability regardless of the type of sealing material used at the time of mold molding, and can be released from the mold surface after cleaning. It is an object of the present invention to provide a mold release recovery sheet capable of uniformly and easily applying an agent and a mold release treatment method using the same.

To achieve the above object, the present invention provides a mold release recovery sheet for applying a release agent to a thermoforming mold, wherein the mold release recovery sheet is an unvulcanized rubber fabric. And the following components (A) and (B), the total content of the following components (A) and (B) is 8 to 25 weights per 100 parts by weight of unvulcanized rubber fabric And the weight ratio of the following component (A) and component (B) is (A) :( B) = 6: 4 to 4: 6 and contains the following component (C) A mold release recovery sheet made of a sheet molding material is a first gist.
(A) A montanic acid ester wax.
(B) Polyethylene-based wax.
(C) Dimethylpolysiloxane.

  And this invention uses the said mold release recovery sheet | seat, the mold release process which transcribe | transfers and apply | coats the mold release agent contained in the said mold release recovery sheet | seat on the molding surface of the metal mold | die for thermoforming The method is the second gist.

  The present inventor can impart good releasability regardless of the type of sealing material used at the time of mold forming, and forms a uniform release agent film on the mold surface after cleaning. In order to obtain a product capable of imparting a good releasability, intensive studies were conducted. As a result, the above-mentioned montanic acid ester wax and polyethylene wax are used together as a release agent component instead of using them individually as in the past, and the total content is a specific ratio with respect to the unvulcanized rubber fabric. And using a mold release recovery sheet made of a sheet molding material containing the release agent component and dimethylpolysiloxane, and the weight ratio of the two is set to a specific ratio. , Good release properties can be imparted to various sealing materials, and the release agent component will exude from the mold release recovery sheet during molding and be applied uniformly to the mold surface. The inventors have found that a uniform release agent film can be formed, and have reached the present invention.

  As described above, the present invention uses an unvulcanized rubber fabric as a base material, and contains the above components (A) and (B), which are release agent components, and also includes the components (A) and (B). The total content is a specific amount with respect to the unvulcanized rubber fabric, and the weight ratio of both the components (A) and (B) is a specific ratio, and further from the sheet molding material containing the component (C) This is a mold release recovery sheet. For this reason, the contained release agent component exudes and adheres to the mold surface to form a uniform release agent film. Moreover, good releasability can be imparted regardless of the type of sealing material used at the time of mold forming. Therefore, as a result of forming a uniform release agent film on the mold surface using the mold release recovery sheet of the present invention, the mold release of the molded product due to uneven application of the release agent component and compatibility of the release agent A mold release effect can be stably obtained without causing defects. For this reason, the resulting molded product does not become cloudy, and an excellent appearance can be obtained.

  That is, the mold release recovery sheet of the present invention is sandwiched between the molds, heat-molded, and then the sheet is separated from the cleaned and mirror-finished mold surface by a simple operation. A mold agent film can be formed uniformly. Therefore, non-uniform coating of a release agent by conventional spray coating, deterioration of molding conditions and work environment, etc. are not caused. And since the said operation | work process using the metal mold release recovery sheet | seat of this invention is very simple, the improvement of the work | work efficiency of the provision work of a mold release agent is implement | achieved.

  And when content of (C) component is 0.2-7 weight part with respect to 100 weight part of unvulcanized rubber cloth, after forming a release agent film uniformly on the mold surface, it is heat-cured. The released mold release recovery sheet can be easily peeled from the mold.

  In addition, when a plurality of linear cuts are provided in parallel at a predetermined interval in one direction on the sheet surface of the mold release recovery sheet, in use, the sheets can be easily stacked by folding along the cuts. Can be made. At this time, the individual block pieces delimited by the parallel cuts are connected to each other at the bottom of the cuts, so that they are stacked orderly without shifting when folded, and each block piece crosses. There is no accumulation in the state. For this reason, the obtained stacked product does not have an irregular shape. In addition, the complicated work of measuring the dimensions of the sheets and cutting them to the same size or stacking the cut sheets while aligning them becomes unnecessary, and the work is simplified.

  Further, when the mold release recovery sheet is used by being bonded to one side or both sides of the sheet-like base material, the sheet is difficult to tear when taken out from the mold after molding, and the workability of taking out is improved.

It is a perspective view which shows the mold release recovery sheet | seat which is an example of embodiment of this invention. It is explanatory drawing which shows the notch formation state of the said mold release recovery sheet. It is an enlarged side view which shows the notch part of the said mold release recovery sheet | seat. It is explanatory drawing which shows the usage method of a mold release recovery sheet | seat. It is explanatory drawing which shows the usage method of a mold release recovery sheet | seat. It is explanatory drawing which shows the usage method of a mold release recovery sheet | seat. It is explanatory drawing which shows the effect | action of the said mold release recovery sheet | seat. It is explanatory drawing which shows the effect | action of the said mold release recovery sheet | seat.

Next, embodiments of the present invention will be described in detail.
《Release mold release sheet》
The mold release recovery sheet of the present invention (hereinafter sometimes referred to simply as “sheet”) is based on an unvulcanized rubber fabric as a base material, and a montanate ester wax (component A), polyethylene It is obtained by molding into a sheet using a molding material containing a system wax (component B) and dimethylpolysiloxane (component C).

<Unvulcanized rubber fabric>
Examples of the unvulcanized rubber constituting the unvulcanized rubber fabric include natural rubber (NR), chloroprene rubber (CR), butadiene rubber (BR), acrylonitrile-butadiene rubber (NBR), and ethylene-propylene-terpolymer. Rubber [EPT (EPDM)], ethylene-propylene rubber (EPM), styrene-butadiene rubber (SBR), isoprene rubber (IR), butyl rubber (IIR), silicone rubber (Q), fluorine rubber (FKM) and the like. . These may be used alone or in combination of two or more. These unvulcanized rubbers become vulcanized rubber vulcanized in the mold.

  Preferred as the unvulcanized rubber is that BR, EPT (EPDM), EPM, SBR, and NBR are used independently from the viewpoint of low contamination during molding using a mold and low odor during vulcanization. Used or a mixture thereof. Specific examples include a mixture of BR and EPT (EPDM).

  The EPT will be described in detail. The EPT is a terpolymer composed of an α-olefin (particularly propylene) and a polyene monomer. Examples of the polyene monomer include dicyclopentadiene, 1,5-cyclooctadiene, 1,1- Cyclooctadiene, 1,6-cyclododecadiene, 1,7-cyclododecadiene, 1,5,9-cyclododecatriene, 1,4-cycloheptadiene, 1,4-cyclohexadiene, norbornadiene, methylene norbornene, Examples include 2-methylpentadiene, 1,5-hexadiene, 1,6-heptadiene, methyl-tetrahydroindene, 1,4-hexadiene and the like.

The copolymerization ratio of each monomer in the EPT is preferably a terpolymer in which ethylene is 30 to 80 mol%, polyene monomer is 0.1 to 20 mol%, and the remainder is an α-olefin. More preferably, ethylene is 30 to 60 mol%. And as said EPT, it is preferable to use that whose Mooney viscosity ML1 _{+ 4} (100 degreeC) is 20-70.

  Specific examples of such EPT include Mitsui EPT4021, Mitsui EPT4045, Mitsui EPT4070, etc., manufactured by Mitsui Chemicals.

As said EPM, it is preferable to use the thing whose ethylene content is 30-80 mol% and Mooney viscosity ML1 _{+ 4} (100 degreeC) is 20-70.

  Specific examples of such EPM include Mitsui EPT0045 manufactured by Mitsui Chemicals.

Moreover, as said SBR, it is preferable to use that whose styrene content is 15-30 mol% and whose Mooney viscosity ML1 _{+ 4} (100 degreeC) is 20-80, Preferably it is 35-60.

  Specific examples of such SBR include JSR-1502, JSR-1507, JSR-1778 and the like manufactured by Nippon Synthetic Rubber.

And as said NBR, acrylonitrile content is 20-60 mol%, More preferably, it is 25-45 mol%, Mooney viscosity ML1 _{+ 4} (100 degreeC) is 20-85, More preferably, it is 30-70. It is preferable to use it.

  Specific examples of such NBR include N-234L, N-230S, and N-230SH manufactured by Nippon Synthetic Rubber.

  Such unvulcanized rubber is usually blended with a crosslinking agent. The crosslinking agent is not particularly limited, and examples thereof include sulfur, 1,3-di (t-butylperoxyisopropyl) benzene, and n-butyl-4,4-bis (t-butylperoxy) valerate. , Organic peroxides such as 1,1-di (t-butylperoxy) -3,3,5-trimethylcyclohexane, and the like. These may be used alone or in combination of two or more. And it is preferable to set the compounding quantity of the said crosslinking agent in the range of 1-3 weight part with respect to 100 weight part of said unvulcanized rubbers.

<Component A: Montanate ester wax>
As the montanic acid ester wax (component A) blended in the unvulcanized rubber fabric, for example, a montanic acid ester having a dropping point of 200 ° C. or lower, preferably 50 to 150 ° C., more preferably 50 to 120 ° C. A system wax is used. Specific examples include OP manufactured by Clariant. In the present invention, the dropping point means the following. For example, when grease is taken as an example, this grease softens by heating, but it shows a liquid state at a certain temperature or higher. The temperature at which this liquefied grease is dropped from the bottom of the container of the measurement tester is called the dropping point. The grease dropping test is in accordance with JIS K 2220. Therefore, the dropping point of the release agent used in the present invention is a value measured according to the above method.

<B component: polyethylene wax>
As a polyethylene-type wax (B component) mix | blended with unvulcanized rubber cloth with the said montanic acid ester-type wax (A component), a dropping point is 200 degrees C or less, for example, Preferably it is 50-150 degreeC, for example. A polyethylene wax having a temperature of 50 to 120 ° C. is used. Specific examples include PED-521 manufactured by Clariant. The dropping point in this case is the same as the dropping point described in the above component A.

  The total content of the montanic acid ester wax (component A) and the polyethylene wax (component B) needs to be 8 to 25 parts by weight with respect to 100 parts by weight of the unvulcanized rubber fabric. More preferably, it is 15-25 weight part. That is, if the total content is too small, a sufficient amount of the release agent component oozes out, so that a uniform release agent film cannot be formed on the mold surface. Releasability cannot be obtained. And when there is too much total content, the application quantity of the mold release agent component with respect to the metal mold | die surface will become excess, an application | coating nonuniformity will be produced, or formation of the film | membrane of a uniform mold release agent component cannot be performed, and a subsequent shaping | molding process ( This is because poor appearance is likely to occur in the resin sealing step).

  Moreover, the weight ratio of the said montanic acid ester type | system | group wax (A component) and polyethylene-type wax (B component) needs to be (A component) :( B component) = 6: 4-4: 6. Particularly preferred is 5: 5. That is, if the weight ratio of the montanic acid ester wax (component A) is too large, for example, when mold-molding using a sealing material blended with polyethylene wax, the releasability from the mold is poor, This is because molding defects are likely to occur in the subsequent molding process (resin sealing process). In addition, if the weight ratio of the montanic acid ester wax (component A) is too small, for example, when the mold material is molded using a sealing material blended with the montanic acid ester wax, the releasability from the mold is inferior, This is because molding defects are likely to occur in the subsequent molding process (resin sealing process).

  Thus, the present invention provides a total content of a montanic acid ester wax (component A) and a polyethylene wax (component B), and further, a montanic acid ester wax (component A) and a polyethylene wax (component B). In order to make the weight ratio of each of the specific ranges, the mold release recovery sheet of the present invention is sandwiched between molds in which the mold surface is cleaned and mirror-finished, and heated and vulcanized, so that unvulcanized The release agent component exudes from the rubber fabric and adheres to the mold surface, forming a uniform release agent film on the mold surface, and sealing with resin regardless of the sealing material used. A good molded product can be obtained without causing fogging or the like in the appearance of the semiconductor device.

<C component: dimethylpolysiloxane>
The dimethylpolysiloxane (C component) blended into the unvulcanized rubber fabric together with the above-mentioned montanic acid ester wax (component A) and polyethylene wax (component B) is a release agent for easily peeling the sheet from the mold. For example, one having a viscosity of 10 to 10,000 cSt is used. Specific examples include SH200 manufactured by Toray Dow Corning, KF96 manufactured by Shin-Etsu Chemical Co., Ltd., and the like.

  The content of the dimethylpolysiloxane (component C) is preferably 0.2 to 7 parts by weight, particularly preferably 0.5 to 1.5 parts by weight with respect to 100 parts by weight of the unvulcanized rubber fabric. is there. That is, if the content of dimethylpolysiloxane (component C) is too small, the mold releasability from the mold tends to deteriorate, and if the content is too large, the strength of the sheet itself is reduced and the sheet is torn off. This is because the workability such as the above tends to deteriorate.

<Other additives>
And in the mold release recovery sheet molding material of the present invention, in addition to the unvulcanized rubber, the cross-linking agent and the A to C components, other additives such as a reinforcing material, a pigment, an adsorbent, etc., as necessary Can be blended appropriately.

  Examples of the reinforcing material include inorganic reinforcing agents (fillers) such as silica, calcium carbonate, aluminum hydroxide, and titanium oxide. These may be used alone or in combination of two or more. The compounding amount of the reinforcing material is preferably 10 to 50 parts by weight with respect to 100 parts by weight of the unvulcanized rubber fabric.

  Examples of the pigment include titanium dioxide and carbon. These may be used alone or in combination of two or more. The blending amount of the pigment is preferably 1 to 20 parts by weight with respect to 100 parts by weight of the unvulcanized rubber fabric.

  Examples of the adsorbent include silica and calcium carbonate. These may be used alone or in combination of two or more. The blending amount of the adsorbent is preferably 0.5 to 10 parts by weight with respect to 100 parts by weight of the unvulcanized rubber fabric.

  The mold release recovery sheet of the present invention can be produced, for example, as follows. That is, an unvulcanized rubber as a base, a specific release agent, a crosslinking agent and other additives, and a mold cleaner as necessary are blended and kneaded in a batch kneader, and then an extruder. A mold release recovery sheet can be produced by forming a sheet or strip using a roll or roll. In this case, the thickness of the mold release recovery sheet is usually set to 3 to 10 mm.

  Then, when using the mold release recovery sheet of the present invention, from the viewpoint of ease of mold installation work using the mold release recovery sheet, for example, as shown in FIG. A sheet 10 in which a plurality of linear notches 11 that can fold the sheet 10 are provided in parallel at a predetermined interval is preferably used. Preferably, the sheet | seat 10 with which the striped pattern was formed in the sheet | seat 10 surface is mention | raise | lifted. And the sheet | seat 10 is folded using the said notch | incision 11, and it can stack now orderly.

  The sheet 10 provided with such an incision 11 is produced as follows. That is, after the rolled sheet obtained as described above is cut into a predetermined shape and size to form the sheet 10, a cut 11 is formed on the surface of the sheet 10. For example, as shown in FIG. 2, such a slit 11 is formed using a ribbon slitter in which disk-shaped cutting blades 13 are attached to a rotating shaft 12 at predetermined intervals, and the cutting blades 13 are removed from the upper surface of the sheet 10. A notch 11 parallel to the width direction of the sheet 10 is formed by biting and moving by a predetermined depth. This operation is repeated to form parallel cuts 11 at regular intervals over the entire upper surface of the sheet 10. And the sheet | seat 10 is divided | segmented into the block piece 10a of the same size by each said notch 11. FIG. As described above, since the cuts 11 are formed at regular intervals, the cuts 11 also function as a measure when folded, and the sheet 10 is cut according to the size of the mold or cavity to be processed. It is easy to fold and fold.

  Further, as shown in FIG. 3, the distance D between the leading end of the cut 11 provided in the sheet 10 and the surface of the sheet 10 facing the leading end of the cut 11 is set to about 0.1 to 0.8 mm. Is preferable, and about 0.2 to 0.5 mm is more preferable. That is, if the distance D is too small, the block pieces 10a are likely to be separated from each other, and conversely if the distance D is too large, folding becomes difficult.

  Furthermore, as another aspect of the mold release recovery sheet of the present invention, an aspect in which the above mold release recovery sheet is bonded to one side or both sides of a sheet-like substrate is used. The sheet in such an embodiment can be obtained, for example, by pressing and laminating a mold release recovery sheet on one or both sides of a sheet-like base material. In this way, by using a sheet-like base material on which one or both sides of the mold release recovery sheet are bonded, the sheet is difficult to tear when being taken out from the mold after molding, and the taking out workability is good. The effect of becoming is obtained.

  Examples of the sheet-like substrate include a paper sheet or a fabric sheet. Examples of the paper sheet include Japanese paper, western paper, synthetic paper, mixed paper, and the like, and examples of the fabric sheet include woven fabric, non-woven fabric, knitted fabric, and the like. The nonwoven fabric is preferably used because the surface is an appropriate rough surface. Examples of the long fiber material include nylon, polyester, polypropylene, and the like. Among these, polyester is preferable from the viewpoint of heat resistance. Furthermore, as the nonwoven fabric, a spunbonded nonwoven fabric is preferable from the viewpoint of mechanical strength, uniformity, and processability. And although the thickness of the sheet-like base material is set suitably, it is preferable to set to 0.1-0.5 mm, for example.

  The thickness of the mold release recovery sheet of the present invention is appropriately set in consideration of the depth of the mold cavity to be processed, handling workability, etc., for example, 3-5 mm It is preferable to set.

《Die release treatment method》
The mold release processing method using the mold release recovery sheet of the present invention is performed as follows, for example, by loading into a mold for molding a semiconductor device. That is, the mold release recovery sheet is in an unvulcanized state, and the unvulcanized mold release recovery sheet is loaded into a molding die and contained in the sheet by heat vulcanization. The specific release agent is exuded, and the release agent is transferred and applied to the mold surface. As a result, a uniform release agent film is formed on the molding die surface.

  A mold release treatment method using such a mold release recovery sheet will be described in detail step by step.

  First, a mold release recovery sheet of the present invention is prepared. As described above, the mold release recovery sheet is provided with a cut and is folded into two using the cut. Next, as shown in FIG. 4, the folded mold release recovery sheet 10 is disposed between the upper mold 1 in which the concave portion 3a is formed and the lower mold 2 in which the concave portion 3b is formed. As shown in FIG. 5, the upper mold 1 and the lower mold 2 are fastened, the mold release recovery sheet 10 is sandwiched, and compression molding is performed. Then, the mold release recovery sheet 10 is filled into the cavity 3 formed of the recess 3a formed in the upper mold 1 and the recess 3b formed in the lower mold 2 by the pressure during molding, and the mold surface Pressure contacted. In this state, the unvulcanized rubber is heated and vulcanized to form vulcanized rubber by heat at the time of molding, and the release agent oozes out from the sheet 10 that is vulcanized rubber at that time, and the mold release is performed on the surface of the cavity 3. The agent is transferred and applied, and a uniform release agent film is formed on the surface of the cavity 3. Next, as shown in FIG. 6, the upper mold 1 and the lower mold 2 are opened after a predetermined time has elapsed, and the mold release recovery sheet 10 that has been vulcanized rubber is peeled from the upper and lower molds 1 and 2. In this way, the mold release process is performed.

  As described above, as the mold release recovery sheet, as shown in FIG. 1, as shown in FIG. 1, a plurality of linear cuts that allow the mold release recovery sheet 10 to be folded on the surface of the sheet 10 itself. 11 is preferably provided in parallel at a predetermined interval.

  When using such a mold release recovery sheet, as shown in FIG. 7, the required number of block pieces 10a from the entire mold release recovery sheet 10 is cut and cut from the notch 11 portion. . In this cutting, the mold release recovery sheet 10 may be grasped with fingers and bent repeatedly along the notch 11 or may be cut with a knife or the like. Next, as shown in FIG. 8 (in the figure, four block pieces 10a are cut out), the mold is released along the notch 11 with the upper surface (the notch 11 forming surface) of the mold release recovery sheet 10 facing outside. The mold release recovery sheet 10 is bent, and further bent until the back surfaces of the mold release recovery sheets 10 come into contact with each other, and the block pieces 10a are stacked as shown in FIG. At the time of this folding, the block pieces 10a are connected to each other at the bottom portion 11a of the cut 11 so that they are not separated from each other. As described above, the block pieces 10a are neatly stacked in a state where the block pieces 10a are neatly aligned in the length direction and the width direction by only a simple operation of folding, and the block pieces 10a are not stacked in a crossed state. ing. Therefore, it is not necessary to measure the dimensions of the mold release recovery sheet 10 and cut them to the same size, or to arrange the block pieces 10a that are spaced apart one by one.

  Further, in FIG. 8, the four block pieces 10a are cut out, folded from the center, and the two block pieces 10a are stacked on the two block pieces 10a. For example, the three block pieces 10a are stacked on the three block pieces 10a and the six block pieces 10a are used. The number of block pieces 10a can be cut out and folded, and stacked in an appropriate size.

  An example of a mold to be used for the mold release recovery sheet of the present invention is, for example, a mold for semiconductor device molding such as transfer molding, in which repetitive molding is performed using a thermosetting resin composition. It is done.

  The thermosetting resin composition used as a molding material in a mold for molding a semiconductor device, which is an example of a target for use of the mold release recovery sheet of the present invention, is, for example, an epoxy resin composition mainly composed of an epoxy resin. Can be given. And the said epoxy resin composition is normally mix | blended with the epoxy resin used as the said main ingredient, and normally various additives, such as an inorganic filler and a mold release agent, are mix | blended suitably.

  Next, examples will be described together with comparative examples. However, the present invention is not limited to these examples.

  First, the following blending components were prepared.

[Ethylene-propylene-diene rubber (EPDM)]
Made by Mitsui Chemicals, EPT 4045 [Mooney viscosity (ML _{1 + 4} 100 ° C.) 45]
[Butadiene rubber (BR)]
JSR, BRO1 [Mooney viscosity (ML _{1 + 4} 100 ° C.) 45]
[Nitrile-butadiene rubber (NBR)]
J215, N215SL

[Reinforcing material (hydrated amorphous silica)]
NIPSEAL LP (hydrous amorphous silica) manufactured by Tosoh Corporation

[Titanium dioxide (pigment)]
SR-1 manufactured by Sakai Chemical
[Carbon (pigment)]
Carbon # 40 manufactured by Mitsubishi Chemical Corporation

[Montanic acid ester wax (component A)]
Drop point 96-102 ° C (manufactured by Clariant, Licowax OP)
[Polyethylene wax (component B)]
Drop point 103-108 ° C (manufactured by Clariant, Licowax PED-521)

[Silicone oil (component C)]
SH200 manufactured by Toray Dow Corning

[Crosslinking agent]
1,3-di (t-butylperoxyisopropyl) benzene (manufactured by NOF Corporation, perbutyl P)

[Adsorbent]
NIPSEAL LP manufactured by Tosoh Corporation

[Examples 1-13, Comparative Examples 1-7, Conventional Examples 1-2]
The components shown in Tables 1 to 3 below are blended in the proportions shown in the same table, kneaded with a batch kneader, and then formed into a sheet having a thickness of 5 mm using a rolling roll. A mold release recovery sheet was prepared.

  Using the mold release recovery sheets of the example product, the comparative product, and the conventional product thus obtained, the mold release treatment for the mold was evaluated as follows. That is, by previously cleaning a mold for sealing a semiconductor element (BGA mold: ball grid array mold) with strong alkali and distilled water, followed by heat curing in the mold using a melamine resin. A cleaning process was performed. After this cleaning process, the mold release recovery sheet is sandwiched between molds, and a conditioning process is performed twice by molding at 175 ° C. for 4 minutes, followed by two types of sealing resins, a montanic acid wax-based seal. By sealing the resin under molding conditions of 175 ° C. × 90 seconds using a stop resin (manufactured by Nitto Denko Corporation, ST-3000) and a polyethylene wax-based sealing resin (manufactured by Nitto Denko Corporation, GE-7470). (Semiconductor device) was molded. The molded package has a size of 50 mm × 50 mm × thickness 0.7 mm.

[Moldability (Peelability)]
○: The sheet peeled from the mold without any problem.
Δ: Tearing occurred when the sheet was peeled from the mold.
X: The sheet adhered to the mold, and the sheet remained in the mold.

[Model familiarity]
A package was molded in 10 consecutive shots under the same package molding conditions. The release property from the mold of the package at this time was evaluated.
○: The package was released from the mold without any problem.
Δ: There was some sticking to the mold, but release was possible.
X: The package adhered to the mold, and cracks and cracks occurred.

[Appearance of molded product]
Of the packages molded in 10 consecutive shots under the same package molding conditions, the package appearance of the three packages molded in the first shot and the three packages molded in the last 10 shots The presence or absence of dirt (such as rough skin) was visually observed and evaluated.
○: There was no problem in all package appearances.
Δ: Slight dirt was observed on the appearance of at least one package.
X: Dirt was clearly observed in the appearance of at least one package.

  These results are also shown in Tables 1 to 3 below.

  From the above results, the mold release recovery sheet (Example product) blended so that the total content of the A component and the B component is in a specific range and the weight blending ratio of both is a specific ratio is the above sheet. There was no problem with respect to moldability (peelability), mold habituation, and appearance of the molded product, regardless of the type of the sealing resin material used, with respect to the package molded by the mold treated with the mold. This shows that a uniform release agent film was formed on the mold surface.

  On the other hand, the mold release recovery sheet (comparative product) in which the total content of the A component and the B component is out of a specific range and is mixed is not problematic in terms of moldability (peelability) and mold habituation. However, with respect to the appearance of the molded product, dirt was clearly confirmed. In addition, the mold release recovery sheet (comparative example product) in which the total content of the A component and the B component is less than the specified range was blended, but there was no problem with the appearance of the molded product, but the result of inferior mold habituation. became. The mold release recovery sheet (comparative example product) in which the weight blending ratio of the A component and the B component deviates from a specific ratio was satisfactory with respect to the appearance of the molded product, but the comparative product in which a large amount of the A component was blended Is inferior in package releasability in a package using a polyethylene wax-based sealing resin. On the other hand, the comparative product in which a large amount of the B component was blended was inferior in the mold release property of the package using the montanic acid wax-based sealing resin.

  The conventional product that does not contain either component A or component B as the release agent component is inferior in moldability (peelability), and the conventional product that contains only component A is a polyethylene wax-based seal. In the package using the stop resin, the release property of the package and the appearance of the molded product were inferior. On the other hand, the comparative product in which only the B component was blended was inferior in the mold release property of the package using the montanic acid wax-based sealing resin.

  In the above examples, a single-layer mold release recovery sheet made of an unvulcanized rubber composition was used as the mold release recovery sheet. However, a spunbond nonwoven fabric having a thickness of 0.35 mm was used as the sheet-like substrate. A result showing the same effect as described above was obtained even when the mold release recovery sheet was pressure-bonded and laminated on both sides of Asahi Kasei Co., Ltd., ELTAS E01070. Furthermore, since it is a laminated body, the effect that the taking-out property from a metal mold | die becomes favorable was acquired.

  The mold release recovery sheet of the present invention is a transfer used when sealing semiconductor elements by transfer molding using various molding dies for thermosetting resin molding materials, for example, various epoxy resin sealing materials. It is used when imparting good releasability to a mold such as a mold for molding.

10 Mold release recovery sheet 11 Notches

Claims (6)

A mold release recovery sheet for applying a release agent to a thermoforming mold, wherein the mold release recovery sheet is based on an unvulcanized rubber fabric, and the following (A) And (B) component, the total content of the following component (A) and component (B) is 8 to 25 parts by weight with respect to 100 parts by weight of the unvulcanized rubber fabric, B) The gold is characterized in that the weight ratio of the component is (A) :( B) = 6: 4 to 4: 6, and is made of a sheet molding material containing the following component (C): Mold release recovery sheet.
(A) A montanic acid ester wax.
(B) Polyethylene-based wax.
(C) Dimethylpolysiloxane.   The mold release recovery sheet according to claim 1, wherein the total content of the component (A) and the component (B) is 15 to 25 parts by weight with respect to 100 parts by weight of the unvulcanized rubber fabric.   The mold release recovery sheet according to claim 1 or 2, wherein the content of the component (C) is 0.2 to 7 parts by weight with respect to 100 parts by weight of the unvulcanized rubber fabric.   The mold release recovery sheet according to any one of claims 1 to 3, wherein a plurality of linear cuts are provided in parallel in the fixed direction at predetermined intervals on the sheet surface of the mold release recovery sheet. .   The mold release recovery sheet according to any one of claims 1 to 4, wherein the mold release recovery sheet is bonded to one side or both sides of a sheet-like substrate.   Using the mold release recovery sheet according to any one of claims 1 to 5, the mold release agent contained in the mold release recovery sheet is transferred and applied to the molding surface of the thermoforming mold. A mold release treatment method characterized by:

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