JP2006339676A - Manufacturing method of semiconductor device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a manufacturing property in assembling a semiconductor device using a metallic mold cleaning sheet. <P>SOLUTION: In the cleaning sheet 29, through holes 29a are formed at a location corresponding to a cavity. In addition, slits 29b and cut portions 29c for a flow cavity are formed at the corner of the periphery of the through hole 29a. The slits, the cut portions and the through holes are formed between first and second molds of the metallic mold and used when cleaning the inside of the metallic mold to enhance a cleaning effect of the metallic mold. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a semiconductor manufacturing technique, and more particularly, to a technique effective when applied to the cleaning effect of cleaning in a molding die for a semiconductor device and improvement of manufacturability.

  In a state where the lead frame is clamped between the main surfaces of the molding die, a cleaning resin formed of melamine resin or the like is injected into the molding die and cured on the lead frame, so that the dirt together with the cleaning resin is removed. There is a technique for removing and cleaning the molding die (see, for example, Patent Document 1).

A molten cleaning resin is inserted in the cavity of the mold that is closed by inserting a sheet-like member that can be impregnated and permeated with the molten cleaning resin between the parting surfaces of the opened mold. (For example, refer to Patent Document 2).
JP-A-1-95010 JP-A-6-254866

  In the resin sealing process of the resin-encapsulated semiconductor device, since resin molding is repeated many times, the inside of the molding die filled with the sealing resin, that is, the upper die that forms a pair of molding dies and Dirt such as resin burrs, oil or dust accumulates around the cavity, runner, air vent, and calblock of the lower mold.

  Such dirt adversely affects the molding quality and also reduces the releasability when the product is taken out from the molding die. Therefore, the operator needs to clean the molding die every certain number of shots. There is.

  However, since it takes a considerable amount of time to clean the molding die by an operator, a technique that can clean the molding die in a short time is required.

  Therefore, as a response to such a demand, as described in JP-A-1-95010 (Patent Document 1), a lead frame on which a semiconductor chip is not mounted (hereinafter referred to as a dummy lead frame) is used. Clamping is performed between the main surfaces (mating surfaces) of the molding die, and a cleaning resin formed of melamine resin or the like is injected into the molding die and cured, so that dirt is attached to the surface of the cleaning resin for cleaning. A method of cleaning by removing dirt together with resin has been performed.

  There is also a method in which the cleaning resin is directly poured into the cavity at a high pressure or normal pressure without using a dummy lead frame or the like.

  However, according to this technique, since an expensive dummy lead frame is used for cleaning, not only is it uneconomical, but also a dummy lead frame having a specific shape suitable for the molding die is placed at a predetermined position. Since it is set and clamped, accuracy for positioning the molding die and the dummy lead frame is required. Furthermore, the resin formed in the cull and runner parts of the molded cleaning resin is separated from the lead frame, and it takes a considerable amount of time to remove the separated resin from the molding die. Is bad. Further, the separated cals and runners may get stuck in the sliding part of the mold apparatus, and as a result, may cause a failure.

  Therefore, as a technique for solving such a problem, a technique described below has been devised.

  As described in JP-A-6-254866 (Patent Document 2), a sheet-like member made of a cotton cloth (nonwoven fabric) that can be impregnated and permeated with a cleaning resin is clamped between molds that are opened, The process comprises a step of filling a molten cleaning resin into a cavity of a mold that is closed.

As described in the above-mentioned known example, a liquid cleaning resin is injected with a cleaning resin and chemical-impregnated and permeable sheet sandwiched between upper and lower mold main surfaces (mating surfaces). In addition to reducing the positioning accuracy required between the molding die and the sheet, the cleaning resin is also applied to the portion where the sheet is sandwiched between the upper and lower mold main surfaces. In addition, there is an advantage that the mold penetrates and the mold can be cleaned.

  However, in the above-described technique, when the cleaning resin is filled in the cavity, the sheet-like member moves up and down (lifts) in the cavity, so that the sheet-like member becomes resistant to the flow of the cleaning resin. A phenomenon occurs in which the cleaning resin does not reach every corner of the cavity.

  As a result, there is a problem that dirt remains in the corners of the cavity and the cleaning in the cavity becomes insufficient.

  Here, on the mating surface of the molding die, there is a flow cavity communicating with the corner of the outer peripheral portion of the cavity (air or sealing resin is allowed to escape to this, air is entrained from the gate or sealed in the cavity). And a concave portion such as an air vent is formed.

  However, when cleaning the molding die using the molding die cleaning sheet, it is difficult for the cleaning resin to enter around the corner of the cavity, and as a result, the cleaning resin does not enter the flow cavity or air vent during cleaning. The cavities and air vents are not cleaned. Therefore, there is a problem of insufficient filling of the sealing resin into the cavities when the product after cleaning is molded.

  Furthermore, if the sealing resin does not easily flow around the corner of the cavity, the cleaning resin does not get entangled with the portion corresponding to the vicinity of the corner of the cavity of the mold cleaning sheet. Even when the cleaning resin is removed from the mold mating surface together with the molding die cleaning sheet, the cleaning resin remains and it takes time to remove the molding die cleaning sheet and the cleaning resin from the mating surface. Is a problem.

In addition, in the mating surface of a molding die for performing molding such as SOP (Small Outline Package) having a long and narrow sealing portion and QFN (Quad Flat Non-Leaded Package) using a matrix frame, the mating surface and the outer end portion of the cavity When the distance to the edge of the mold is relatively short (for example, 10 mm or less), the cleaning resin leaked from the cavity protrudes from the mold cleaning sheet during the cleaning of the mold, and the mold It adheres over the side surface connected from the mating surface.

In such a case, it takes time to remove the cleaning resin adhering to the side surface of the molding die, and as a result, the efficiency of the cleaning operation of the molding die is problematic.

  An object of the present invention is to provide a technique capable of improving the productivity by improving the cleaning effect of the molding die and shortening the time of the cleaning operation.

  The above and other objects and novel features of the present invention will be apparent from the description of this specification and the accompanying drawings.

  Of the inventions disclosed in this application, the outline of typical ones will be briefly described as follows.

  That is, the present invention provides (a) an upper mold including a recess that defines a cavity for sealing a semiconductor chip, and a recess that faces the upper mold and defines a cavity for sealing the semiconductor chip. A step of preparing a mold having a lower mold including, and (b) a step of preparing a cleaning sheet for the mold having a through hole whose shape is formed along the side of the cavity; c) setting the cleaning sheet in the mold so that the through hole of the cleaning sheet is disposed in the cavity and between the upper mold and the lower mold; and (d) (C) sandwiching the cleaning sheet between the upper mold and the lower mold; and (e) removing the mold cleaning resin from the key so that a part of the cleaning sheet is adhered to a part of the cleaning sheet. (F) after the step (e), the step of removing the cleaning sheet and the cleaning resin from the mold, and (g) after the step (f), A step of placing a lead frame having the semiconductor chip in the mold so that the semiconductor chip is placed in the cavity; and (h) after the step (g), a sealing resin is placed in the cavity. Filling and sealing the semiconductor chip.

  Of the inventions disclosed in the present application, effects obtained by typical ones will be briefly described as follows.

  The productivity of the semiconductor device can be improved by significantly reducing the time required for cleaning the molding die and improving the cleaning effect of the molding die.

  In the following embodiments, the description of the same or similar parts will not be repeated in principle unless particularly necessary.

  Further, in the following embodiment, when it is necessary for the sake of convenience, the description will be divided into a plurality of sections or embodiments, but they are not irrelevant to each other unless otherwise specified. The other part or all of the modifications, details, supplementary explanations, and the like are related.

  Also, in the following embodiments, when referring to the number of elements (including the number, numerical value, quantity, range, etc.), particularly when clearly indicated and when clearly limited to a specific number in principle, etc. Except, it is not limited to the specific number, and it may be more or less than the specific number.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. Note that components having the same function are denoted by the same reference symbols throughout the drawings for describing the embodiments, and the repetitive description thereof will be omitted.

(Embodiment 1)
FIG. 1 is a perspective view showing an example of the structure of a transfer mold apparatus that performs molding using the molding die cleaning sheet according to Embodiment 1 of the present invention, and FIG. 2 shows a resin molding portion of the transfer mold apparatus shown in FIG. FIG. 3 is a view showing an example of the structure of the molding die cleaning sheet according to the first embodiment of the present invention, (a) is a plan view, and (b) is A in (a). FIG. 4 is a plan view showing an example of a state where a molding die cleaning sheet is arranged on the mating surface of the second die of the molding die provided in the resin molding portion shown in FIG. FIG. 5 is a partial cross-sectional view showing an example of a state during cleaning in the molding die using the molding die cleaning sheet shown in FIG. 3, and FIG. 6 is a semiconductor manufactured by the method for manufacturing a semiconductor device of the present invention. Example of device structure Parts is a perspective view showing the cross-section.

  The transfer mold apparatus shown in FIG. 1 is of a multi-pot type, and is used, for example, to seal the semiconductor chip 24 shown in FIG. 6 and the inner leads 20 electrically connected to the semiconductor chip 24 with a resin. It is what is done.

  The transfer mold apparatus includes a first mold 3 that is an upper mold, a second mold 4 that is a lower mold that is paired with the first mold 3, and a resin that includes the first mold 3 and the second mold 4. A molding unit 5, a loader 1 for carrying a workpiece (for example, a lead frame after die bonding and wire bonding) into the resin molding unit 5, and an unloader 2 for taking out the workpiece from the resin molding unit 5 are provided. In the transfer molding apparatus, the lead frame to which the semiconductor chip 24 (see FIG. 6) is bonded is carried into the resin molding part 5 from the loader 1 shown in FIG. Etc. are resin-sealed. A QFP (Quad Flat Package) 19, which is a resin-encapsulated semiconductor device that has finished resin molding, is carried out to the unloader 2 and accommodated therein.

  Further, the resin molding portion 5 shown in FIG. 2 includes a cavity 6 having a shape corresponding to the sealing portion 22 of the QFP 19 shown in FIG. 6, a cull 7, a runner 8, a pot 9, a plunger 10, and an ejector plate. 11, 15, ejector pins 12, 16, a gate 13, and an air vent 14 are provided.

  Further, as shown in FIG. 4, a predetermined shape cavity 6 in which the semiconductor chip 24 is arranged is formed at a plurality of locations on the mating surface 26 of the second mold 4 of the molding die 28 (see FIG. 2). (Note that the cavity 6 is also formed on the mating surface 26 of the first mold 3 in the same manner as the second mold 4).

  In addition, a plurality of cylindrical pots 9 in which a sealing resin such as a tablet is set are formed through a predetermined position of the second mold 4, and each of the first molds 3 corresponding to the pots 9 is formed. In this portion, a cull 7 is provided as shown in FIG.

  Further, from the cull 7, a plurality of runners 8 connected to the plurality of cavities 6 are branched and formed, and the first mold 3 and the second mold 4 are in close contact with each other. The upper side of the pot 9 is closed by the cull 7, and the pot 9 is communicated with the plurality of cavities 6 through the cull 7 and the runner 8. An air vent 14 is formed outside the cavity 6 to allow the air in the cavity 6 to escape to the outside so as to completely fill the resin.

  Next, the molding die cleaning sheet (hereinafter, simply referred to as a cleaning sheet) 17 according to the first embodiment shown in FIG. 3 will be described.

  The cleaning sheet 17 is disposed between the first mold 3 and the second mold 4 of the molding die 28 to clean the inside of the molding die 28 when the semiconductor chip 24 is not molded. And covers the entire mating surface (parting surface other than the cavity) 26 of the molding die 28 when disposed between the first die 3 and the second die 4, and the cavity of the molding die 28. The through-hole 17a corresponding to 6 is formed.

  The through hole 17a formed in the cleaning sheet 17 of the first embodiment is formed in substantially the same shape as the opening 6a of the cavity 6 (see FIG. 2).

  That is, the through-hole 17a is formed in a quadrangle that is substantially the same as or slightly smaller than the shape and size of the opening 6a of the cavity 6 of the first mold 3 and the second mold 4.

  Thus, at the time of cleaning, only the cleaning sheet 17 is clamped by the first mold 3 and the second mold 4, and in this state, the cleaning resin 25 shown in FIG. 6, the cleaning resin 25 passes through the through-hole 17a of the cleaning sheet 17, and as a result, the cleaning resin 25 becomes a resistance in the cavity 6 so that the cleaning sheet 17 does not lift up in every corner of the cavity 6. Filled.

  Accordingly, the inside of the cavity 6 can be sufficiently cleaned.

  Further, as shown in FIG. 4, the cleaning sheet 17 according to the first embodiment is of a size and shape that covers the entire mating surface 26 of the second mold 4 (the same applies to the first mold 3). is there.

  That is, the second mold 4 is formed to have a size that can be guided by the positioning wetting 18 for positioning the upper and lower molds provided on each of the outer peripheral sides of the mating surface 26 of the second mold 4. When the cleaning sheet 17 is placed on the four mating surfaces 26, the cleaning sheet 17 may be placed in accordance with the positioning wetting 18 on each side, and high precision between the molding die 28 and the molding die 28 is achieved. There is no need to perform positioning.

  Further, the cleaning sheet 17 according to the first embodiment is formed of, for example, 100% paper, cloth, or nonwoven fabric having heat resistance and flexibility, and it is preferable that the cleaning sheet 17 is formed of nonwoven fabric.

  Further, the thickness of the cleaning sheet 17 is, for example, about 0.6 mm when the first mold 3 and the second mold 4 are clamped.

  Further, the QFP 19 shown in FIG. 6 is an example of a semiconductor device that is assembled by being molded by the transfer mold device shown in FIG. 1, and electrically connects the electrode of the semiconductor chip 24 and the inner lead 20 corresponding thereto. The bonding wire 21 to be connected, the sealing portion 22 formed by resin-sealing the semiconductor chip 24, the inner lead 20 and the bonding wire 21, and the inner lead 20 are connected to and project outside from the sealing portion 22. The outer leads 23 are external terminals, and each outer lead 23 is formed in a gull wing shape.

  Next, a method for manufacturing the semiconductor device according to the first embodiment will be described.

  The manufacturing method of the semiconductor device includes the step of molding (resin sealing) the semiconductor chip 24 using the transfer mold apparatus shown in FIG. 1 and the molding of the transfer mold apparatus using the cleaning sheet 17 shown in FIG. And a cleaning process inside the mold 28.

  First, in the wire bonding step, the semiconductor chip 24 and the inner lead 20 of the lead frame that is a work are electrically connected by the bonding wire 21.

  Thereafter, in the molding step, the semiconductor chip 24, the inner lead 20 electrically connected to the semiconductor chip 24, and the bonding wire 21 are sealed with a sealing resin using the transfer molding apparatus shown in FIG.

  Here, the resin sealing (molding) step in the molding step of the first embodiment will be described.

  First, a solid sealing resin (tablet) heated by a preheater is set on the plunger 10 shown in FIG. 2, and then a lead frame in which the semiconductor chip 24 and the inner lead 20 are wire-bonded, It is conveyed from the loader 1 shown in FIG.

  In this state, the cavity 6 is included between the first mold 3 and the second mold 4 forming the molding mold 28 by moving the second mold 4 toward the first mold 3. Form a space. Thereafter, when the sealing resin in a molten state is pushed out to the cull 7 by the plunger 10, the sealing resin flows into the cavity 6 through the runner 8 and the gate 13.

  Further, the sealing resin filled in the cavity 6 is thermally cured by heat and curing, and then the mold is opened when the second mold 4 is moved downward.

  Subsequently, the ejector plate 15 is moved downward and the ejector plate 11 is moved upward. As a result, the ejector pins 12 and 16 protrude to complete the mold opening, and the resin-sealed resin-sealed QFP (semiconductor device) 19 is taken out. In this resin sealing, hundreds of shots are repeated per day. Therefore, the inside of the molding die 28 filled with the sealing resin, that is, the first die 3 and the second die 4 of the molding die 28. Resin burrs and dirt (attachments) such as oil and dust accumulate on the mating surface (including the periphery of the air vent 14, cavity 6, runner 8, and cal 7).

  Therefore, it is necessary to perform a cleaning process of the molding die 28 in the molding process in order to remove the dirt.

  For the QFP 19, the lead frame is then cut in a cutting step, thereby completing the assembly of the QFP 19 as shown in FIG.

  Next, the cleaning process (molding die cleaning method) of the first embodiment will be described.

  First, the cleaning sheet 17 shown in FIG. 3, which is formed of a nonwoven fabric and covers the entire mating surface 26 of the molding die 28 and has a through hole 17 a corresponding to the cavity 6 of the molding die 28, is prepared.

  Subsequently, the mold temperature of the molding die 28 is set to 170 ° C. to 180 ° C., for example.

  Thereafter, as shown in FIG. 4, the cleaning sheet 17 is disposed on the entire mating surface 26 with the through hole 17 a corresponding to the cavity 6, and in this state, the second mold 4 is directed toward the first mold 3. Move closer.

  By this approaching movement, the cleaning sheet 17 is clamped by being sandwiched between the first mold 3 and the second mold 4, and then the cleaning resin 25 is supplied to the cavity 6.

  At this time, as shown in FIG. 5, the cleaning resin 25 is passed through the through hole 17 a of the cleaning sheet 17 in the cavity 6 to fill the corners of the cavity 6 with the cleaning resin 25.

  Subsequently, the cleaning resin 25 is cured, and then the second mold 4 is moved downward to separate the first mold 3 and the second mold 4 and perform mold opening.

  Further, the ejector plate 15 is moved downward and the ejector plate 11 is moved upward. As a result, the ejector pins 12 and 16 protrude to complete the mold opening.

  Thereafter, the cleaning resin 25 and the cleaning sheet 17 are released from the molding die 28.

  That is, the cleaning sheet 17 and the cleaning resin 25 resin-molded on the sheet are taken out.

  Thereby, the inside of the molding die 28 is cleaned.

  In addition, after cleaning the inside of the molding die 28 using the cleaning sheet 17 shown in FIG. 3, when starting again (molding), the semiconductor chip 24 is disposed in the cavity 6 of the molding die 28, and thereafter The semiconductor chip 24 is resin-sealed by supplying a sealing resin to the cavity 6 by a method similar to the molding method.

  According to the molding die cleaning sheet of the first embodiment and the semiconductor device manufacturing method using the same, the following operational effects can be obtained.

  That is, the through hole 17 a corresponding to the cavity 6 is formed in the cleaning sheet 17, so that when the cleaning resin 25 is supplied and filled in the cavity 6, the cleaning resin 25 is removed from the cleaning sheet 17. Since it can pass through the through-hole 17a, the cleaning resin 25 is spread to every corner of the cavity 6 without obstructing the flow of the cleaning resin 25 in the cavity 6 regardless of the filler contained in the cleaning resin 25 or the resin injection pressure. Can be made.

  As a result, dirt at the corners of the cavity 6 can also be removed by the cleaning resin 25 that has spread to every corner of the cavity 6.

  Thereby, the cavity 6 of the molding die 28 can be sufficiently cleaned, and hence the cleaning effect can be improved.

  Further, the cleaning sheet 17 covers the entire mating surface 26 of the molding die 28 at the time of cleaning, so that the cleaning resin 25 formed by the cavity 6, the mating surface 26 (parting surface), the cull 7 and the gate 13 is formed. Since they are connected by the cleaning sheet 17, after the cleaning resin 25 is cured, when the cleaning sheet 17 is taken out, it can be taken out in an integrated state without being separated on the cleaning sheet 17.

  Therefore, the cleaning sheet 17 can be easily attached to and detached from the molding die 28, and thus the cleaning sheet 17 after cleaning can be easily processed.

  As a result, it is possible to shorten the cleaning work time using the cleaning sheet 17.

  Further, since the cleaning sheet 17 covers the entire mating surface 26 of the molding die 28, the cleaning resin 25 is applied to the cleaning sheet 17 at the pot 9 entrance of the molding die 28, around the cull 7, and even at the air vent 14. The dirt can be removed by entanglement. As a result, the resin burr can be removed, and the working time can be greatly reduced.

  Further, by covering the entire mating surface 26 of the molding die 28 with the cleaning sheet 17, it is possible to clean a portion of the molding die 28 where the cleaning resin 25 does not contact.

  Further, not only the number of lead frames or the like set in the molding die 28 but also the entire mating surface 26 of the molding die 28 is covered by one cleaning sheet, so that the molding die 28 of the cleaning sheet 17 is covered. This eliminates the need for highly accurate positioning.

  At that time, as in the first embodiment, by using the cleaning sheet 17 formed of a non-woven fabric, positioning for the molding die 28 as in the case of using a conventional dummy lead frame is used. No need for pin processing or positioning pin hole processing.

  Therefore, the cost of the molding die 28 can be reduced.

  Further, since no dummy lead frame is used, there is no occurrence of misalignment due to the misalignment of the dummy lead frame.

  Further, since the entire mating surface 26 of the molding die 28 is covered with one cleaning sheet 28, not only the number of the lead frames set in the molding die 28 at the time of molding, but also a single cleaning sheet 17 is set. As a result, the cost of the cleaning operation can be reduced.

  By using the cleaning sheet 17 of the first embodiment, it is not necessary to use an expensive dummy lead frame for cleaning, so that the cost for cleaning the molding die 28 can be reduced.

  Further, the cleaning sheet 17 has a through hole 17a corresponding to the opening 6a of the cavity 6 and covers the entire mating surface 26 of the molding die 28 at the time of cleaning, so that the cleaning workability is not deteriorated. The cleaning effect can be improved.

  In the manufacturing process of the semiconductor device such as the QFP 19 of the first embodiment, the time required for cleaning the molding die 28 can be greatly reduced, and the cleaning effect of the molding die 28 can be improved. The productivity of the semiconductor device can be improved.

(Embodiment 2)
7 is a plan view showing an example of the structure of the molding die cleaning sheet according to the second embodiment of the present invention, and FIG. 8 is a state in which the molding die cleaning sheet shown in FIG. 7 is arranged on the mating surface of the molding die. FIG. 9 is a plan view showing the structure of a molding die cleaning sheet according to a modification of the molding die cleaning sheet shown in FIG.

  In the second embodiment, a modified example of the molding die cleaning sheet used in the cleaning process of the molding die 28 shown in FIG. 2 in the manufacturing process of the semiconductor device described in the first embodiment will be described.

  That is, the cleaning sheet (molding mold cleaning sheet) 29 shown in FIG. 7 has through-holes 29a at locations corresponding to the cavities 6 of the molding die 28, like the cleaning sheet 17 described in the first embodiment. Are formed, and in addition to this, notches such as slits 29b and flow cavity notches 29c are formed at the corners of the outer periphery of the through hole 29a.

  Note that the through hole 29a is approximately the same size as the cavity 6 of the molding die 28 or slightly smaller than that.

  Further, as shown in FIG. 8, the slit 29b and the flow cavity cutout portion 29c are formed at locations corresponding to the flow cavity 27 (concave portion) communicating with the cavity 6 of the second mold 4, of which The flow cavity cutout 29c is a cutout formed in substantially the same shape as the flow cavity 27.

  Here, the flow cavity 27 allows the air in the cavity 6 and the sealing resin in the resin injection to escape to improve the air entrainment from the gate 13 and the filling balance of the sealing resin in the cavity 6. Is.

  Therefore, the slit 29b and the flow cavity notch 29c sufficiently supply the cleaning resin 25 shown in FIG. 5 to the flow cavity 27 and the air vent 14 which are recesses communicating with the cavity 6 when the molding die 28 is cleaned. It is for filling.

  That is, when the cleaning resin 25 is injected into the cavity 6, the cleaning resin 25 is filled into the cavity 6 through the through hole 29 a of the cleaning sheet 29, and the cleaning resin 25 is cleaned at the corner of the cavity 6. The sheet 29 passes through the flow cavity cutout 29 c and the slit 29 b and flows into the flow cavity 27 and the air vent 14.

  Accordingly, the cleaning resin 25 can be entangled with the cleaning sheet 29 through the flow cavity cutout portion 29c and the slit 29b, and the cleaning resin 25 can be filled into the flow cavity 27 and the air vent 14 in this state.

  As a result, the cleaning resin 25 after the curing of the cleaning resin 25 can be removed from the second mold 4 along with the removal of the cleaning sheet 29 from the molding mold 28.

  Whether the slit 29b is formed as the cut portion or the flow cavity cut portion 29c is formed, the flow cavity 27 disposed at a position far from the gate 13 of the second mold 4 has a cleaning resin 25. However, it is preferable to form the flow cavity cutout portion 29c instead of the slit 29b.

  Further, since the cleaning resin 25 is relatively easy to flow into the flow cavity 27 on the gate 13 side, a slit 29b is formed here.

  Therefore, in the modification example shown in FIGS. 7 and 8 (QFP 19 cleaning sheet 29 shown in FIG. 6), only the flow cavity 27 arranged at the farthest position from the gate 13 is used as the flow cavity cutout portion 29c. The other three corners are slits 29b.

  On the other hand, a modified example (BGA (Ball Grid Array) cleaning sheet 29) shown in FIG. 9 shows a case where slits 29b are formed at four corners, and a flow cavity cutout portion 29c (see FIG. 7). ) And the slit 29b formed at any corner of the cavity 6 is not particularly limited, and the width and length of the slit 29b or the shape of the cut-out portion 29c for the flow cavity are also particularly limited. is not.

  The material and thickness of the cleaning sheet 29 of the second embodiment are the same as those of the cleaning sheet 17 of the first embodiment.

  Further, regarding the other structure of the cleaning sheet 29 of the second embodiment and the method of manufacturing the semiconductor device using the cleaning sheet 29, the manufacturing of the semiconductor device using the cleaning sheet 17 described in the first embodiment is described. Since it is the same as the method, the redundant description is omitted.

  According to the cleaning sheet 29 and the method of manufacturing a semiconductor device using the same according to the second embodiment, when the cleaning resin 25 is injected into the cavity 6 when the molding die 28 shown in FIG. The cleaning resin 25 can be passed through notches such as the slits 29b of the sheet 29 and the notches 29c for the flow cavities.

  Accordingly, the cleaning resin 25 can be filled in the recesses such as the flow cavity 27 and the air vent 14 during cleaning, and the cleaning resin 25 can be entangled and attached to the cleaning sheet 29 through the cut portion.

  Therefore, after the cleaning resin 25 is cured, the cleaning sheet 29 is peeled from the second mold 4 to fill the recesses (the flow cavity 27 and the air vent 14) of the mating surface 26 of the second mold 4. Since the cleaning resin 25 is removed, the cleaning effect of the recesses can be improved, and the cleaning resin 25 can be reliably removed together with the cleaning sheet 29. Therefore, the cleaning resin 25 can be easily removed from the recesses. It can be carried out.

  As a result, the cleaning time of the molding die 28 using the cleaning sheet 29 can be shortened.

  Note that the notches such as the flow cavity notch 29c and the slit 29b corresponding to the recess at the location facing the gate 13 of the second mold 4 (location relatively distant from the gate 13) correspond to the recess. By adopting a different shape, the cleaning effect of the recess can be further improved.

(Embodiment 3)
10A and 10B are diagrams showing an example of the structure of the molding die cleaning sheet according to the third embodiment of the present invention. FIG. 10A is a plan view, and FIG. 10B is a cross-sectional view taken along line BB in FIG. 11 is a plan view showing an example of a state in which the molding die cleaning sheet shown in FIG. 10 is arranged on the mating surface of the molding die, and FIG. 12 is an enlarged partial sectional view taken along the line C-C shown in FIG. is there.

  In the third embodiment, similar to the second embodiment, a modification of the molding die cleaning sheet used in the cleaning process of the molding die 28 shown in FIG. 2 in the manufacturing process of the semiconductor device described in the first embodiment. Will be described.

  That is, the frame-equipped cleaning sheet (molding mold cleaning sheet) 30 shown in FIG. 10 covers the entire mating surface 26 of the molding die 28 in the same manner as the cleaning sheet 17 described in the first embodiment. A cleaning sheet 30a in which a through hole 30b is formed at a location corresponding to the cavity 6, and a frame that can be disposed along the peripheral edge portion 26a of the mating surface 26 outside the plurality of cavities 6 of the mating surface 26 of the molding die 28. And a reinforcing sheet 30c in the shape of a sheet.

  The through hole 30b formed in the cleaning sheet 30a is approximately the same size as or slightly smaller than the cavity 6 of the molding die 28.

  Here, the frame-equipped cleaning sheet 30 according to the third embodiment is a lower mold when the cleaning resin 25 (see FIG. 5) is injected when the molding mold 28 is cleaned as shown in FIG. Cleaning from the mating surface 26 of the molding die 28 by increasing the clamping force outside the cavity 6 when the molding die 28 is clamped by the second die 4 and the first die 3 as the upper die. This prevents the resin 25 from leaking out.

  That is, as shown in FIG. 10, the framed cleaning sheet 30 includes a cleaning sheet 30 a in which through holes 30 b are formed according to the cavities 6 shown in FIG. 11 and a plurality of mating surfaces 26 of the second mold 4. A frame-shaped reinforcing sheet 30 c that can be disposed along the peripheral edge 26 a of the mating surface 26 is bonded to the outside of the cavity 6.

  Thus, when cleaning the molding die 28, as shown in FIG. 11, the cleaning sheet 30a is disposed on the entire mating surface 26 with the through holes 30b of the cleaning sheet 30a corresponding to the cavities 6, In addition, the frame-shaped reinforcing sheet 30 c is disposed on the mating surface 26 along the peripheral edge portion 26 a of the mating surface 26 outside the plurality of cavities 6.

  The cleaning sheet 30 with a frame according to the third embodiment has a cleaning sheet 30a and a reinforcing sheet 30c as shown in FIG. 10 attached in advance. Therefore, when performing cleaning, The framed cleaning sheet 30 is disposed on the mating surface 26 of the second mold 4.

  Thereafter, as shown in FIG. 12, the cleaning sheet 30a and the reinforcing sheet 30c are clamped by the first mold 3 and the second mold 4, and further, the cavity 6 in this clamped state is clamped as shown in FIG. Then, the cleaning resin 25 is injected, the cavity 6 is filled with the cleaning resin 25, and the cleaning resin 25 is cured, and then the cleaning resin 25 is removed together with the cleaning sheet 30 a from the mating surface 26 of the molding die 28. The mold 28 is cleaned.

  Note that the frame-equipped cleaning sheet 30 shown in FIG. 10 is, for example, a relatively elongated sealing portion 22 in a semiconductor device (see FIG. 6; however, in the QFP 19 shown in FIG. 6, the sealing portion 22 is substantially square). When molding a semiconductor device such as a SOP having a sapphire or a QFN using a matrix frame, the mating surface 26 of these molding dies 28 has an outer end portion of the cavity 6 and a peripheral portion 26a of the mating surface 26. When the distance (L shown in FIGS. 11 and 12) is relatively short (for example, when L is 10 mm or less), the cleaning resin 25 leaked from the cavity 6 during the cleaning of the molding die 28 is the molding die cleaning. L may be sticking over the side surface connected from the mating surface 26 of the molding die 28 so as to protrude from the sheet for use, and the L is 10 mm or less. Against UNA SOP or cleaning of the mold 28 for QFN, is more effective.

  Here, the frame-shaped reinforcing sheet 30c has a thickness of about 0.1 to 0.2 mm, for example, and is preferably formed of a nonwoven fabric, paper, copper, a fluororesin, or the like.

  Further, like the frame-equipped cleaning sheet 30 of the third embodiment, the cleaning sheet 30a and the reinforcing sheet 30c may be attached in advance, or both may be prepared without being attached, and at the time of cleaning, The cleaning mold may be performed by sequentially disposing on the mating surface 26 of the molding die 28.

  Further, the framed cleaning sheet 30 according to the third embodiment is also effective for a semiconductor device using a matrix frame other than SOP and QFN, or a BGA using a tape substrate.

  The material and thickness of the cleaning sheet 30a in the cleaning sheet 30 with a frame according to the third embodiment are the same as those of the cleaning sheet 17 according to the first embodiment.

  Further, the manufacturing method of the semiconductor device using the framed cleaning sheet 30 of the third embodiment is the same as the manufacturing method of the semiconductor device using the cleaning sheet 17 described in the first embodiment. The duplicate description is omitted.

  According to the cleaning sheet 30 with frame and the manufacturing method of the semiconductor device using the same according to the third embodiment, the through-hole 30b of the cleaning sheet 30a of the cleaning sheet 30 with the frame is formed when the molding die 28 is cleaned. The reinforcing sheet 30c is disposed on the entire mating surface 26 so as to correspond to the cavity 6, and the reinforcing sheet 30c is disposed on the mating surface 26 along the peripheral edge portion 26a of the mating surface 26 outside the plurality of cavities 6. Is clamped by the first mold 3 and the second mold 4 of the molding die 28 and cleaning is performed, whereby the clamping force of the molding die 28 can be improved. As a result, the cleaning resin 25 at the time of cleaning can be improved. Leakage from the mating surface 26 of the molding die 28 can be prevented.

  Accordingly, since the cleaning resin 25 can be prevented from adhering to the side surface of the molding die 28, there is no need to remove it, and as a result, the efficiency of the cleaning operation of the molding die 28 can be improved.

  Further, by using the frame-equipped cleaning sheet 30 to which the reinforcing sheet 30c is attached, the cleaning resin 25 can be prevented from leaking from the mating surface 26 of the molding die 28 during cleaning. 6 and the flow cavity cutout portion 29c (see FIG. 8) can be sufficiently filled, and as a result, the effect of cleaning the recesses such as the cavity 6 and the flow cavity cutout portion 29c can be improved.

  In particular, when the distance between the outer end of the cavity 6 and the peripheral edge 26a of the mating surface 26 in the molding die 28 is relatively short (for example, when the distance L shown in FIG. 11 is 10 mm or less), the reinforcing sheet The framed cleaning sheet 30 having 30c is particularly effective.

  Further, by using the cleaning sheet 30 with the frame having the reinforcing sheet 30c, leakage of the cleaning resin 25 from the mating surface 26 of the molding die 28 during cleaning can be prevented. It is possible to easily attach and remove the framed cleaning sheet 30 to the frame 26.

  Further, when the cleaning sheet 30a is a non-woven fabric, the use of the reinforcing sheet 30c can prevent the cleaning sheet 30a from expanding and contracting. As a result, the efficiency of the cleaning operation of the molding die 28 can be further improved. .

  Although the invention made by the present inventor has been specifically described based on the embodiments of the invention, the present invention is not limited to the embodiments of the invention, and various modifications can be made without departing from the scope of the invention. It goes without saying that it is possible.

  For example, in the first, second, and third embodiments, the case where the cleaning sheets 17, 29, and 30a are formed of a nonwoven fabric has been described. However, the material of the cleaning sheets 17, 29, and 30a is limited to the nonwoven fabric. Instead, it may be made of other materials such as paper or other cloth.

  Further, the thicknesses of the cleaning sheets 17, 29, 30a are not limited to those described in the first, second, and third embodiments, and various thicknesses can be used.

  Further, the size of the cleaning sheets 17, 29, and 30 a may be slightly smaller than the mating surface 26 as long as the mating surface 26 of the molding die 28 is covered almost entirely.

  Also, the through holes 17a, 29a, and 30b formed in the cleaning sheets 17, 29, and 30a are not limited to those in the first, second, and third embodiments, and various shapes are formed. Further, the size may be larger than the opening 6a of the cavity 6 as long as the size is substantially the same as the opening 6a of the cavity 6 or is large enough to allow the cleaning resin 25 to pass therethrough. Or small.

  In the molding dies 28 of the first, second, and third embodiments, the lead frame may be a multiple-row single-row type or a matrix frame, and in any case However, the cost of the cleaning operation can be reduced.

  In the first and second embodiments, the semiconductor device molded by the transfer molding device shown in FIG. 1 is the QFP 19 shown in FIG. 6, but the semiconductor device is not limited to the QFP 19, Any other semiconductor device such as SOP may be used as long as it is a semiconductor device that is assembled by being molded by a transfer mold device.

  Furthermore, in the molding dies 28 of the first, second, and third embodiments, the first mold 3 is described as the upper mold and the second mold 4 is defined as the lower mold. 3 may be a lower mold and the second mold 4 may be an upper mold.

  The present invention is suitable for a semiconductor device manufacturing technique using a molding die cleaning sheet.

It is a perspective view which shows an example of the structure of the transfer mold apparatus which molds using the sheet | seat for shaping die cleaning of Embodiment 1 of this invention. It is a fragmentary sectional view which shows the structure of the resin molding part in the transfer mold apparatus shown in FIG. It is a figure which shows an example of the structure of the molding die cleaning sheet | seat of Embodiment 1 of this invention, (a) is a top view, (b) is sectional drawing which follows the AA line of (a). It is a top view which shows an example of the state which has arrange | positioned the sheet | seat for shaping | molding die cleaning to the mating surface of the 2nd metal mold | die provided in the resin molding part shown in FIG. It is a fragmentary sectional view which shows an example of the state at the time of the cleaning in the shaping die using the sheet | seat for shaping die cleaning shown in FIG. It is a perspective view which shows an example of the structure of the semiconductor device manufactured by the manufacturing method of the semiconductor device of this invention in a partial cross section. It is a top view which shows an example of the structure of the sheet | seat for shaping die cleaning of Embodiment 2 of this invention. FIG. 8 is an enlarged partial plan view showing an example of a state where the molding die cleaning sheet shown in FIG. 7 is arranged on the mating surface of the molding die. It is a top view which shows the structure of the sheet | seat for shaping mold cleaning of the modification with respect to the sheet | seat for shaping mold cleaning shown in FIG. It is a figure which shows an example of the structure of the sheet | seat for shaping die cleaning of Embodiment 3 of this invention, (a) is a top view, (b) is sectional drawing which follows the BB line of (a). It is a top view which shows an example of the state which has arrange | positioned the sheet | seat for shaping die cleaning shown in FIG. 10 to the mating surface of a shaping die. It is an expanded partial sectional view which follows the CC line shown in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Loader 2 Unloader 3 1st metal mold 4 2nd metal mold 5 Resin molding part 6 Cavity 6a Opening part 7 Cal 8 Runner 9 Pot 10 Plunger 11 Ejector plate 12 Ejector pin 13 Gate 14 Air vent 15 Ejector plate 16 Ejector pin 17 For cleaning Sheet (molding mold cleaning sheet)
17a Through hole 18 Positioning wetting 19 QFP (semiconductor device)
20 Inner lead 21 Bonding wire 22 Sealing portion 23 Outer lead 24 Semiconductor chip 25 Cleaning resin 26 Matching surface 26a Peripheral portion 27 Flow cavity 28 Molding die 29 Cleaning sheet 29a Through hole 29b Slit 29c Flow cavity cutout portion 30 With frame Cleaning sheet 30a Cleaning sheet 30b Through hole 30c Reinforcing sheet

Claims (7)

(A) having an upper mold including a recess defining a cavity for sealing a semiconductor chip, and a lower mold facing the upper mold and including a recess defining a cavity for sealing the semiconductor chip Preparing the mold,
(B) preparing a cleaning sheet for the mold having a through hole whose shape is formed along the side of the cavity;
(C) setting the cleaning sheet in the mold so that the through hole of the cleaning sheet is disposed in the cavity and disposed between the upper mold and the lower mold;
(D) sandwiching the cleaning sheet between the upper mold and the lower mold;
(E) filling the cavity with a cleaning resin for the mold so that a part thereof is adhered to a part of the cleaning sheet;
(F) After the step (e), removing the cleaning sheet and the cleaning resin from the mold;
(G) after the step (f), placing a lead frame having the semiconductor chip in the mold so that the semiconductor chip is placed in the cavity;
(H) After the step (g), a step of filling the cavity with a sealing resin and sealing the semiconductor chip.   2. The method of manufacturing a semiconductor device according to claim 1, wherein the step (e) is performed by filling the cleaning resin including a plurality of particles.   2. The method of manufacturing a semiconductor device according to claim 1, wherein the step (e) is performed when a part of the cleaning resin permeates a part of the cleaning sheet. Method.   4. The method of manufacturing a semiconductor device according to claim 3, wherein the cleaning resin is cured before the step (f).   2. The method of manufacturing a semiconductor device according to claim 1, wherein the lower mold has a pot portion and a gate portion, and in the step (c), the cleaning resin is set in the pot portion, and in the step (e). The method of manufacturing a semiconductor device, wherein the cleaning resin is filled into the cavity through the gate portion.   2. The method of manufacturing a semiconductor device according to claim 1, wherein the steps (b) to (f) are performed again after repeating the steps (g) to (h) a plurality of times. A method of manufacturing a semiconductor device.   2. The method of manufacturing a semiconductor device according to claim 1, wherein each of the upper mold and the lower mold has a mating surface facing each other, and in the step (d), the cleaning sheet is formed by the upper mold and the lower mold. A method of manufacturing a semiconductor device, wherein the semiconductor device is sandwiched between the mating surfaces of the respective molds.

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