Patent Publication Number: US-8117742-B2

Title: Fabrication method of semiconductor integrated circuit device

Description:
This application is a Continuation application of application Ser. No. 12/118,348, filed May 9, 2008, now U.S. Pat. No. 7,681,308 which is a Continuation application of application Ser. No. 11/320,888, filed Dec. 30, 2005, now U.S. Pat. No. 7,377,031 which is a Continuation application of application Ser. No. 10/682,028, filed Oct. 10, 2003, now U.S. Pat. No. 7,037,760 the contents of which are incorporated herein by reference in their entirety. 
    
    
     BACKGROUND OF THE INVENTION 
     The present invention relates to a fabrication technique for use in the manufacture of a semiconductor integrated circuit device, and, more particularly, to a technique which is applicable to resin molding in assembly using boards. 
     In conventional resin molding, opening degree adjustment means, which adjusts the opening degree of each air vent portion, is provided to the air vent portion of a mold, and a driving mechanism is provided to drive the opening degree adjustment means (for example, refer to Patent Document 1: Japanese Unexamined Patent Publication No. Hei 10(1998)-92853 (FIG. 1)). 
     To perform transfer molding by mounting semiconductor integrated circuit chips on a multilayered printed wiring circuit board or the like and inserting the multilayered printed wiring circuit board or the like between molds, in contrast to general lead frames having a relatively small thickness error or the like, the thickness error is relatively large, and, hence, various drawbacks arise. 
     That is, when the thickness is excessively small, a gap is formed between an upper mold and a peripheral portion of the board, and, hence, the leaking of sealed resin occurs. Accordingly, to compensate for the small thickness, the clamping force is increased so as to depress the board by approximately 1% of the thickness, thus preventing the leaking of sealed resin. However, in this case, when the thickness is excessively large, excessive deformation arises in the board. 
     Further, it may be considered that the occurrence of voids or the like due to clogging of resin in the air vent portion can be suppressed by preliminarily preparing data corresponding to the thickness of a lead frame at the time of performing resin molding (resin filling) and adjusting the opening degree adjustment means in the air vent portion of a sealed mold by inputting such data at the time of resin sealing. However, in such a resin sealing operation, there arise drawbacks in that each time the thickness of the lead frame is changed, it is necessary to perform the operation of inputting data, and, at the same time, it is necessary to prepare input data for adjusting the opening degree adjustment means corresponding to the frame thickness. 
     Further, when the resin sealing operation is performed using a resin-made board which is softer than the lead frame, unevenness is liable to occur on a surface of the board due to warping of the board or the presence/non-presence of wiring, and, hence, in the above-mentioned resin sealing operation, there arises a drawback in that the opening degree adjustment of the air vent portion in response to a change in the thickness of the board and the shape of the surface of the board is extremely difficult. 
     Further, when it is necessary to perform resin molding of a plurality of boards using one mold at a time, the above-mentioned method requires a driving mechanism for the open degree adjustment means in the sealing mold for every air vent portion, and, hence, the structure of the sealing mold becomes complicated and large-sized. 
     Accordingly, it is an object of the present invention to provide a method of fabrication of a semiconductor integrated circuit device which can enhance the yield rate of products. 
     It is a further object of the present invention to provide a method of fabrication of a semiconductor integrated circuit device which can reduce the fabrication cost. 
     It is a still further object of the present invention to provide a method of fabrication method of a semiconductor integrated circuit device which can prevent the occurrence of drawbacks at the time of transporting boards in succeeding steps. 
     It is another object of the present invention to provide a method of fabrication of a semiconductor integrated circuit device which can reduce the mold clamping force. 
     The above-mentioned and other objects and novel features of the present invention will become apparent from the description of this specification and the attached drawings. 
     SUMMARY OF THE INVENTION 
     A summary of typical aspects of the invention disclosed in the present application is as follows. That is, the present invention is characterized by the fact that resin molding is performed by filling sealing resin in the inside of a cavity in a state in which the depths of air vents in a mold for resin molding are set to a fixed value. 
     Further, a summary of various features of the present invention will be described in the following paragraphs. 
     1. A method of fabrication of a semiconductor integrated circuit device comprises the steps of: 
     (a) preparing a multilayered printed wiring circuit board; 
     (b) mounting semiconductor chips on the multilayered printed wiring circuit board; 
     (c) arranging the multilayered printed wiring circuit board over which the semiconductor chips are mounted on a mold surface of a mold for resin molding and, thereafter, closing the mold; and 
     (d) filling sealing resin in the inside of a cavity formed in the mold such that respective depths of a plurality of air vents formed through the cavity are set to a fixed value by projecting movable pins provided for respective air vents toward the air vent side by pushing using the pressure of a spring. 
     2. A method of fabrication of a semiconductor integrated circuit device comprises the steps of: 
     (a) preparing a multilayered printed wiring circuit board; 
     (b) preparing a mold for resin molding which includes a cavity and a plurality of air vents which are formed to communicate with the cavity, wherein movable pins are provided for respective air vents and a cavity-side depths of the movable pins in the air vents are set to be greater than the depths of the movable pins at the outside of the movable pins; 
     (c) mounting semiconductor chips on the multilayered printed wiring circuit board; 
     (d) arranging the multilayered printed wiring circuit board over which the semiconductor chips are mounted on a mold surface of the mold and, thereafter, closing the mold; and 
     (e) filling sealing resin in the inside of the cavity such that respective depths of the plural air vents are set to a fixed value using movable pins provided for respective air vents. 
     3. A method of fabrication of a semiconductor integrated circuit device comprising the steps of: 
     (a) preparing a multilayered printed wiring circuit board; 
     (b) mounting semiconductor chips on the multilayered printed wiring circuit board; 
     (c) arranging the multilayered printed wiring circuit board over which the semiconductor chips are mounted on a mold surface of a mold for resin molding and, thereafter, closing the mold; and 
     (d) filling sealing resin in the inside of the cavity such that respective depths of the plural air vents which are formed to be communicated with the cavity of the mold are set to a fixed value by projecting movable pins provided for respective air vents. 
     4. A method of fabrication of a semiconductor integrated circuit device according to the above-mentioned paragraph 3, wherein grooves are formed over respective distal ends of the plural movable pins and air inside the cavity is leaked to the outside of the cavity through the grooves formed in the respective movable pins at the time of filling resin in the inside of the cavity. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is an enlarged partial cross-sectional view showing one example of the structure of a mold to be used in a method of fabrication of a semiconductor integrated circuit device according to an embodiment of the present invention, as seen when the mold is in an open state; 
         FIG. 2  is an enlarged partial cross-sectional view showing the structure of a cross section taken along a line A-A in  FIG. 1 ; 
         FIG. 3  is a cross-sectional view of an enlarged portion showing one example of the structure of air vents at the time of filling resin in the inside of the mold shown in  FIG. 1 ; 
         FIG. 4  is an enlarged partial cross-sectional view showing the structure of a cross section taken along a line B-B in  FIG. 3 ; 
         FIG. 5  is a partial cross-sectional view showing one example of the movable pin supporting structure of an upper mold of the mold shown in  FIG. 1 ; 
         FIG. 6  is a plan view showing one example of the cavity-side structure of the upper mold shown in  FIG. 5 ; 
         FIG. 7  is a partial cross-sectional view showing one example of the structure of a lower mold of the mold shown in  FIG. 1 ; 
         FIG. 8  is a plan view showing one example of the structure of a mold surface of the lower mold shown in  FIG. 7 ; 
         FIG. 9  is an enlarged partial cross-sectional view showing the structure of a portion C in  FIG. 5 ; 
         FIG. 10  is an enlarged partial plan view showing the structure of a portion D in  FIG. 5 ; 
         FIG. 11  is an enlarged partial cross-sectional view showing the structure of a cross section taken along a line E-E in  FIG. 10 ; 
         FIG. 12  is a plan view showing one example of the structure of the upper mold of a mold for collective molding used in the method of fabrication of a semiconductor integrated circuit device according to an embodiment 1 of the present invention; 
         FIG. 13  is a plan view showing one example of the structure of the lower mold which constitutes a pair together with the upper mold shown in  FIG. 12 ; 
         FIG. 14  is a cross-sectional view showing one example of the structure of the semiconductor integrated circuit device which is assembled by the method of fabrication of a semiconductor integrated circuit device according to embodiment 1 of the present invention; 
         FIG. 15  is a plan view showing one example of the structure of the multi-cavity printed wiring circuit board which is used by the method of fabrication of a semiconductor integrated circuit device according to embodiment 1 of the present invention; 
         FIG. 16  is an enlarged cross-sectional view showing one example of the relationship between the printed wiring circuit board and guide pins at the time of resin molding in the method of fabrication of a semiconductor integrated circuit device according to embodiment 1 of the present invention; 
         FIG. 17  is a plan view showing one example of the printed wiring circuit board structure after resin molding in the method of fabrication of a semiconductor integrated circuit device according to embodiment 1 of the present invention; 
         FIG. 18  is a plan view showing one example of a dicing line for dividing a wafer into pieces after resin molding in the method of fabrication of the semiconductor integrated circuit device of the embodiment 1 according to present invention; 
         FIG. 19  is a plan view showing one example of the structure of runners and culls after resin molding in the method of fabrication of a semiconductor integrated circuit device according to embodiment 1 of the present invention; 
         FIG. 20  is a plan view showing one example of the structure after dividing wafer into pieces in the method of fabrication of a semiconductor integrated circuit device according to embodiment 1 of the present invention; 
         FIG. 21  is a bottom view showing one example of the structure after dividing wafer into pieces in the method of fabrication of a semiconductor integrated circuit device according to embodiment 1 of the present invention; 
         FIG. 22  is a perspective view showing the structure of a semiconductor integrated circuit device according to a modification assembled by the method of fabrication of a semiconductor integrated circuit device according to embodiment 1 of the present invention; 
         FIG. 23  is a side view showing with a part broken away of the structure of the semiconductor integrated circuit device shown in  FIG. 22 ; 
         FIG. 24  is a plan view showing one example of the structure at the time of completion of resin molding in the manufacture of the semiconductor integrated circuit device shown in  FIG. 22 ; 
         FIG. 25  is a plan view showing one example of the structure of an upper mold of a mold for simultaneously molding a plurality of semiconductor integrated circuit devices used in the method of fabrication of a semiconductor integrated circuit device according to an embodiment 2 of the present invention; 
         FIG. 26  is a plan view showing one example of the structure of a lower mold which constitutes a pair with the upper mold shown in  FIG. 25 ; 
         FIG. 27  is a plan view showing one example of the structure of a printed wiring circuit board after resin molding in the method of fabrication of a semiconductor integrated circuit device according to the embodiment 2 of the present invention; 
         FIG. 28  is a cross-sectional view showing one example of the structure of a semiconductor integrated circuit device assembled by the method of fabrication of a semiconductor integrated circuit device according to the embodiment 2 of the present invention; and 
         FIG. 29  is a bottom view showing one example of the structure of the semiconductor integrated circuit device shown in  FIG. 28 . 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     Embodiments of the present invention will be explained in detail in conjunction with the accompanying drawings. 
     Although the explanation will be mainly focused on an example applied to a sheet mold (an example applied to an upper side sheet) hereinafter, the present invention is not limited to such an application. When a sheet is not used, the leaking of resin or the like is liable to easily occur, and, hence, there exists large possibility that the application of the present invention becomes necessary. Further, when a sheet is used, due to a coupled effect between the present invention and the sheet, it is estimated that the mass productivity and the effect of preventing leaking of resin or the like can be largely enhanced. 
     In this specification, when “multilayered printed wiring circuit board” is referred to, this implies printed wiring circuit boards in two or more layers. Here, “two layers” means that there are two wiring layers. Further, “wiring” includes a land array, an electrode matrix and the like besides usual printed wiring. Further, when “semiconductor integrated circuit device”, “integrated circuit chip”, “semiconductor chip”, “semiconductor pellet” and the like are referred to in this specification, they include not only those elements which are prepared on a silicon wafer, but also those elements which are prepared on other types of board, such as a TFT liquid crystal substrate or the like, unless otherwise specified accordingly. 
     Further, in the embodiments described hereinafter, when it is necessary for the sake of convenience, the explanation is made by dividing the invention into a plurality of sections or a plurality of embodiments. However, unless otherwise specified particularly, these embodiments are not irrelevant to each other and there exists the relationship that one embodiment is a modification, a detailed explanation or a complementary explanation of a portion or the whole of the other embodiments. 
     Further, in the embodiments described hereinafter, when reference is made to the number and the like (including a number, numerical values, quantity, range and the like) of elements, unless otherwise specified and unless it is apparent that the number and the like of elements are definitely limited to the specific number in principle, the number and the like are not limited to such specific number and may be a number above or below the specific number. 
     Further, in the embodiment described hereinafter, it is needless to say that constituent elements (including element steps and the like) are not always indispensable unless otherwise specified or unless they are considered indefinitely indispensable in principle. 
     In the same manner, in the embodiments described hereinafter, when reference is made with respect to the shape, the positional relationship and the like of the constituent elements, unless otherwise specified or unless it is indefinitely considered unreasonable in principle, these shapes and positional relationships substantially include those which approximate or are similar to these shapes. The same goes for the above-mentioned numerical values and ranges. 
     Further, in all of the drawings, constitutional elements which have the same functions are given the same symbols and a repeated explanation thereof is omitted. 
     Embodiment 1 
     This embodiment 1 is directed to a method of fabrication of a semiconductor integrated circuit device in which the semiconductor integrated circuit device is assembled such that a printed wiring circuit board is used and a sealing body  44  (see  FIG. 14 ) is formed over the board by performing resin molding on the board. 
     In the explanation of this embodiment 1, a CSP (Chip Size Package)  43 , which is assembled using a multi-cavity printed wiring circuit board (board)  40 , as shown in  FIG. 15 , is taken as an example of the semiconductor integrated circuit device. 
     The CSP  43  shown in  FIG. 14  is a thin semiconductor package of a chip laminated type. With respect to the structure of the CSP  43 , the CSP  43  is constituted of a printed wiring circuit board (board)  41 , which has a main surface  41   a  and a back surface  41   b , wherein a chip mounting region  40   b  and leads  41   c , which constitute a plurality of lines shown in  FIG. 15 , are formed over the main surface  41   a . Two semiconductor chips  4  are mounted on the chip mounting region  40   b  of the main surface  41   a  of the printed wiring circuit board  41  by lamination, and a plurality of wires  5  respectively connect bonding electrodes  4   b  of respective semiconductor chips  4  and the leads  41   c  which correspond to the bonding electrodes  4   b . The sealing body  44  seals the semiconductor chips  4  and the plural wires  5  with resin, and solder balls  42  are mounted on the back surface  41   b  of the printed wiring circuit board  41  and constitute a plurality of external terminals. 
     Here, the CSP  43  is formed by using a multi-cavity printed wiring circuit board  40  over which a plurality of device regions (device forming regions)  40   c , respectively having chip mounting regions  40   b , are formed over a main surface  40   a  in a matrix array. In a resin sealing (resin molding) step after wire bonding, the plural device regions  40   c , which are arranged in a matrix array, are covered with one cavity of a mold  6  and resin sealing is collectively formed (hereinafter, such resin sealing method is referred to as collective molding); and, thereafter, the resin sealed structure is divided into pieces by dicing so as to form the CSP  43 . 
     Here, the printed wiring circuit board  41  is a thin board which is constituted by forming wiring made of copper or the like over a resin board made of glass-epoxy-based resin or the like. Further, the sealing body  44  is made of epoxy resin, for example, and is formed by resin molding. Further, the wires  5  are formed of a gold line, for example. 
     Next, the structure of an upper mold  7 , which constitutes a first mold and a lower mold  8 , which constitutes a second mold, will be explained with reference to  FIG. 1 , which molds are used in the resin sealing step of the method of fabrication of the semiconductor integrated circuit device of this embodiment 1. Here, with respect to the first mold and the second mold, the second mold may be constituted by the upper mold  7  and the first mold may be constituted by the lower mold  8 . 
     First of all, as shown in  FIG. 1  and  FIG. 5 , the upper mold  7  is mainly constituted of cull blocks  7   a  and a cavity block  7   b , wherein one collective cavity  7   h , which is capable of covering the main surface  40   a  of the multi-cavity printed wiring circuit board  40  at the time of performing resin sealing, is formed in the cavity block  7   b.    
     Further, around the collective cavity  7   h , as shown in  FIG. 6 , a plurality of air vents  7   c , a plurality of culls  7   d  and a plurality of gates  7   i  are formed. Among these elements, the plural gates  7   i  and the plural air vents  7   c  are formed in parallel respectively along two opposing longitudinal sides of the rectangular collective cavity  7   h  such that they face each other, while the culls  7   d  are formed in a plural number in the vicinity of the gates  7   i.    
     Further, in the upper mold  7 , there are a plurality of movable pins  1 , which are formed such that the movable pins  1  project into respective air vents  7   c , and return pins  7   f , which separate the upper mold  7  from the lower mold  8  at the time of releasing the mold  6  after resin filling. As shown in  FIG. 1 , respective movable pins  1  are connected to movable pin driving springs  2  such that the movable pins  1  are capable of applying a load of approximately 9.8 Newton to 49 Newton (1-5 kg) to the multi-cavity board  40  and are formed such that the movable pins  1  project respectively into the air vents  7   c.    
     The mold according to this embodiment 1 includes the plural air vents  7   c , and it is capable of performing resin molding by filling sealing resin  9 , as shown in  FIG. 3 , while setting the depths of respective air vents  7   c  to a fixed value irrespective of the board thickness and the state of the board surface, such as an unevenness at the time of resin molding. 
     Accordingly, the movable pins  1  which have the distal ends thereof respectively projected into the air vents  7   c  corresponding to respective air vents  7   c  are formed, and grooves  1   a  which constitute air passages, as shown in  FIG. 11 , are formed in distal ends of respective movable pins  1 . 
     Further, the movable pins  1  are connected with the movable pin driving springs  2  in the inside of the upper mold  7  such that the load, which is far smaller compared with the clamping force of the mold  6  and is set at a level which does not deform or damage the board, is applied to the multi-cavity printed wiring circuit board  40  at the time of clamping the mold, as shown in  FIG. 3 . Here, the clamping force of the mold  6  is, for example, 150,000 Newton or approximately 15,000 kg-weight per one board in a display unit of a general-purpose device, wherein a portion of the board where the clamping force acts is an annular region having a width of approximately 1 mm around an outer portion of the mold cavity. Taking a rectangular collective mold board having a size of 151 mm×66 mm as an example, the annular region has a size of 148 mm×60 mm, a width of 0.8 mm and an area of 352 mm 2 . Further, the load which is far smaller compared with the clamping force of the mold frame  6  and does not deform or damage the board is, for example, 9.8 Newton to 49 Newton and is approximately 1-5 kg-weight in a display of a general-purpose device (indicating a value per one movable pin). Taking the movable pin  1  having a diameter of 6 mm as an example, a portion over which this force acts is a cylindrical cross-sectional area which is approximately 28 mm 2 . 
     This is because, in the structure of the mold  6  according to the embodiment 1, the resin injection pressure is not directly applied to the respective air vents  7   c , and, hence, as the spring force applied to the movable pins  1 , the load at a level which allows the movable pins  1  to slightly push the board is sufficient. Accordingly, only the load of approximately 9.8 Newton to 49 Newton (1-5 kg) is applied to the movable pins  1  using the movable pin driving springs  2 . 
     Further, the movable pins  1  are formed such that the amount of movement thereof in the vertical direction (N indicated in  FIG. 3  and  FIG. 9 ) becomes 100-200 μm, for example. 
     Due to such a constitution, even when there exists irregularities with respect to the thickness of the board or an unevenness is formed attributed to wiring or the like on the surface of the board depending on the positions of the board, at the time of clamping the molds, the distal ends of respective movable pins  1  which project into the air vents  7   c  at respective board positions automatically correspond to the board condition at respective board positions so that the distal ends of respective movable pins  1  are brought into close contact with the board. 
     Here, even when the stop positions of respective movable pins  1  in the vertical direction differ depending on the irregularities of the thickness of the board and the condition of the board surface, such as an unevenness, provided that the depths of the grooves  1   a  formed in the distal ends of respective movable pins  1  are set to a fixed value, it is possible to set the depths for respective air vents  7   c  to a fixed value, and, hence, the sealing resin  9  can be filled by automatically setting the depths of respective air vents  7   c  to a fixed value. 
     Here, the depths of the air vents  7   c  will be further explained. 
     The air vent  7   c  can be classified into four portions consisting of a movable-pin front portion, a movable-pin portion (or an air vent main portion), a movable-pin rear portion and a release portion, which portions are arranged in sequence in the direction from the cavity (collective cavity  7   h ) to a flow passage. To explain the movable-pin front portion, assuming that the tolerance of the thickness of the resin board is approximately ±30 μm, for example, even when the board has the largest thickness, by setting the depth of the air vent  7   c  to approximately 60 to 70 μm, an effective air vent depth of approximately 30 to 40 μm can be ensured. In this case, when the film  3  which constitutes the sheet is applied, the depth is not measured from the upper mold surface, but is measured from the lower surface of the sheet, as shown in  FIG. 9 . When there is no sheet, it is needless to say that the depth is measured from the surface of the upper mold. Accordingly, assuming that the usual thickness of the sheet is 50 μm, it is estimated that the actual thickness of the sheet becomes approximately 30 μm as a result of elongation at the time of molding the sheet, and, hence, the depth of mechanical cuts for the air vents becomes the above-mentioned value+the actual thickness of the sheet in performing the sheet molding. By setting the depth of cuts to approximately 40 to 50 μm at the movable pin portion, the value can be automatically ensured. It is sufficient to set the depth of the cuts to approximately 50 to 60 μm at the movable-pin rear portion. This is because the movable-pin rear portion is immediately connected with the releasing portion having a depth of approximately 150 μm. 
     By setting the effective depth of the main portion of the air vents  7   c  to a fixed value irrespective of the thickness of the printed wiring circuit board or the like (including the lead frame) in the above-mentioned manner, it is possible to effectively prevent leaking of resin without excessively increasing the clamping force (for example, in the above-mentioned example, a clamping force having up to 5000 kg-weight per one board can excessively deform the board). 
     Further, when the tolerance of the thickness of the board is slightly set in the minus direction, a leaking of the resin is liable to easily occur. In the mold  6  according to the embodiment 1, since the movable pin  1  projects beyond the mold surface  7   g , the movable pin functions as a plug and leaking of the sealing resin  9  (leaking of resin) is prevented. 
     In the mold  6  according to the embodiment 1, as shown in  FIG. 1 , the depth differs between the depth (L) of the cavity side (movable pin front portion) of the movable pin  1  in the air vent  7   c  and the depth (M) of the outside (movable-pin rear portion) of the movable pin  1 , wherein the depth (L) of the cavity side of the movable pin  1  is set to be greater than the depth (M) of the outside of the movable pin  1 . For example, it is preferable to set the depth L to approximately 60 to 70 μm and the depth M to approximately 50 to 60 μm. 
     Due to such a constitution, even when a deformation, such as a warp, occurs in the vicinity of a path leading from the gate  7   i  to the cavity on the board, there is no possibility that the air vent  7   c  in the vicinity of the gate  7   i  will be clogged by the board, and, hence, the air vent  7   c  in the vicinity of the gate  7   i  can be reliably ensured. 
     Next, the width of the air vent  7   c  will be explained. 
     In the mold  6  according to this embodiment 1, as shown in  FIG. 10 , the vent width (P) of the air vent  7   c  at the cavity side of the movable pin  1  is set to be smaller than the pin diameter (Q) of the movable pin  1 . In other words, the pin diameter (Q) of the movable pin  1  is set to be larger than the vent width (P) of the air vent  7   c  at the cavity side of the movable pin  1 . 
     For example, assuming that the pin diameter (Q) of the movable pin  1  is 5 mm, it is preferable to set the vent width (P) of the air vent  7   c  at the cavity side to approximately 4 mm and the vent width (S) of the air vent  7   c  at the outside of the movable pin  1  to approximately 5 mm, and the width (R) of the groove  1   a  of a distal end of the movable pin  1  to 2 to 3 mm. 
     Accordingly, the movable pins  1  function as plugs and stop any leaking of resin which occurs when the tolerance of the thickness of the board is slightly set in the minus direction, and, hence, leaking of the sealing resin  9  (leaking of resin) can be surely prevented. 
     In the mold  6  of this embodiment 1, movable-pin rammers (pusher rods)  7   j , as shown in  FIG. 9 , which makes the movable pins  1  project to the air vent side when the mold  6  is released, are formed over the upper mold  7 . Due to such a constitution, when the mold  6  is released, it is possible to further push the movable pins  1  so as to make the movable pins  1  project into the air vent side with the use of the movable-pin rammers  7   j.    
     The movable-pin rammers  7   j  are configured such that the movable-pin rammers  7   j  are held by a rammer holder  71 , and the rammer holder  7   l  is capable of pushing the movable-pin rammers  7   j  in response to the spring force of a movable-pin pushup spring  7   k . Due to such a constitution, by pushing out the movable pins  1  to the air vent side with the use of the movable-pin rammers  7   j  at the time of releasing the mold  6 , even when the sealing resin  9  intrudes at the peripheries of the movable pins  1 , it is possible to prevent the operation of the movable pins  1  from being worsened, and, hence, it is possible to ensure a sufficient maintenance of the operation of the movable pins  1 . 
     Further, in the mold  6  according to the embodiment 1, the resin molding is performed over the board, and, hence, a plurality of suction holes  7   m ,  8   f  are formed in the upper mold  7  and the lower mold  8 , respectively, such that upper and lower films  3  (sheets) are sucked and brought into close contact with the mold surfaces  7   g ,  8   h  at the time of performing resin molding. These films  3  are used for preventing the adhesion of resin to the wiring over the board and damage to the wiring at the time of clamping the molds. By arranging the films  3  respectively on the mold surface  7   g  of the upper mold  7  and the mold surface  8   h  of the lower mold  8  at the time of resin molding, by suction applied to the respective films  3  through the suction holes  7   m ,  8   f  and by heating the mold  6  at a given temperature (for example, approximately 180° C.), the films  3  are brought into close contact with the respective mold surfaces  7   g ,  8   h  and, thereafter, the resin is filled. 
     Here, as shown in  FIG. 1 , the suction holes  7   m  are formed in the upper frame  7  in the vicinity of the movable pins  1 . By applying suction to the film  3  through the suction holes  7   m  before clamping the mold and also by heating the mold  6  to a given temperature so as to bring the film  3  into close contact with the mold surface  7   g , as shown in  FIG. 2 , it is possible to bring the film  3  into contact with the grooves  1   a  formed in the distal ends of the movable pins  1 , such that the film  3  follows the contour of the grooves  1   a . Accordingly, even when the film  3  is arranged on the mold surface  7   g , it is possible to form the grooves  1   a  in the distal ends of the movable pins  1  at the time of clamping the molds, as shown in  FIG. 4 . 
     Here, the films  3  which are used for resin molding are, for example, formed of a thin film, such as a fluorine-based film material which has a thickness of approximately 50 μm and is extremely flexible. 
     On the other hand, the lower mold  8  of the mold  6  is, as shown in  FIG. 7 , mainly constituted of pot holders  8   b  and a cavity block  8   c , wherein a plurality of pots  8   d  are formed in the pot holder  8   b  corresponding to the plural culls  7   d  formed in the upper mold  7 . Plungers  8   g , as shown in  FIG. 16 , which push out the sealing resin  9 , are arranged in the respective pots  8   d.    
     Further, in the cavity block  8   c  of the lower mold  8 , a lower-mold cavity  8   e  is formed, as shown in  FIG. 8 , while guide pins  8   a , which guide the board, such as the multi-cavity board  40  arranged on the mold surface  8   h , are mounted on the cavity block  8   c.    
     Here,  FIG. 12  shows an upper mold  7  which is capable of resin-molding two sheets of multi-cavity boards  40  at one time, wherein collective cavities  7   h  for arranging two sheets of multi-cavity boards  40  are respectively formed at both sides of a collective sealing cull  7   d , while a plurality of air vents  7   c  are formed in parallel at sides of the collective cavities  7   h  opposite to the cull  7   d . Each air vent  7   c  has a structure which allows the air vent  7   c  to communicate with the collective cavity  7   h  so as to release air at the time of resin filling. Further, in each air vent  7   c , the movable pin  1  is arranged in a projected manner. 
     Further,  FIG. 13  shows the structure of the lower mold  8  which forms a pair with the upper mold  7  shown in  FIG. 12 . 
     Next, the method fabrication of the semiconductor integrated circuit device (CSP  43 ) of the embodiment 1 will be explained. 
     First of all, the multi-cavity board  40  shown in  FIG. 15 , is prepared, over which a plurality of device areas  40   c  are formed in a matrix array, each of which has the chip mounting area  40   b  including a chip mounting portion and a plurality of leads  41   c  (see  FIG. 14 ). 
     Thereafter, on the chip mounting areas  40   b  of the device areas  40   c  of the main surface  40   a  of the multi-cavity board  40 , semiconductor chips  4  are mounted by means of an adhesive or the like. Since the CSP  43  of the embodiment 1 is of a chip stacking type, here, firstly, the semiconductor chips  4  at the lower stage are mounted on the chip mounting areas  40   b  of the respective device areas  40   c , and, subsequently, the semiconductor chips  4  at the upper stage are mounted on the semiconductor chips  4  of the lower stage. 
     After the mounting of the chips by stacking is completed, wire bonding is performed. That is, the bonding electrodes  4   b  of the semiconductor chips  4  at the lower stage and the lead  41   c  corresponding to the bonding electrodes  4   b  are connected to each other by the wires  5 , while the bonding electrode  4   b  of the semiconductor chip  4  at the upper stage and the lead  41   c  corresponding to the bonding electrode  4   b  are connected by the wires  5 . 
     Thereafter, resin molding is performed. 
     First of all, the upper mold  7  and the lower mold  8  are, for example, heated to a temperature of 180 degree; and, at the same time, as shown in  FIG. 1 , in the upper mold  7  and the lower mold  8 , respectively, by applying suction the respective upper and lower films  3  through the suction holes  7   m ,  8   f , the respective films  3  are brought into close contact with the respective mold surfaces  7   g ,  8   h.    
     Here, at the upper mold  7  side, the movable pins  1  are arranged in the respective air vents  7   c  in a state such that the distal ends of movable pins  1  are projected. When suction is applied to the film  3  through the sucking hole  7   m , the film  3  follows the shape of the mold surface  7   g  as shown in  FIG. 1  and is brought into close contact with the mold surface  7   g . At the same time, the film also follows the shape of a groove  1   a  formed in the distal end of the movable pin  1  and is brought into close contact with the groove  1   a  as shown in  FIG. 2 . On the other hand, at the lower mold  8  side as well, the film  3  is brought into close contact with the mold surface  8   h.    
     Under such a situation, the semiconductor chips  4  are mounted on the mold surface  8   h  of the lower mold  8 , and, at the same time, the multi-cavity board  40  over which the wire bonding is already completed is arranged on the mold surface  8   h  of the lower mold  8 . Here, the multi-cavity board  40  is positioned by the guide pins  8   a , as shown in  FIG. 16 . 
     Further, a plurality of device areas  40   c  of the multi-cavity board  40  are collectively covered with one collective cavity  7   h  of the upper mold  7  and, thereafter, the upper mold  7  and the lower mold  8  of the mold  6  are clamped together by closing them, as shown in  FIG. 3 . 
     Here, since the movable pins  1  are projected in the respective air vents  7   c , slightly before the upper mold  7  and the lower mold  8  are completely closed, the distal ends of the movable pins  1  are brought into contact with the main surface  40   a  of the multi-cavity board  40 . Further, immediately after such a contact, the upper mold  7  and the lower mold  8  are closed. Thereafter, since a spring force is always applied to the movable pins  1  by the movable-pin driving springs  2 , even after clamping the upper mold  7  and the lower mold  8  together, each movable pin  1  pushes against the multi-cavity board  40  toward the lower mold  8  side. 
     That is, since the spring force of the movable pin driving springs  2  is relatively small (for example, from 9.8 Newton to 49 Newton: 1-5 kg) compared with the mold clamping force (for example, 150,000 Newton: 15,000 kg), even after clamping the molds together, each movable pin  1  pushes against the multi-cavity board  40  in the direction of the mold surface  8   h  of the lower mold  8  in each air vent  7   c . Here, since the load applied by pushing is extremely small, it is possible to prevent the multi-cavity board  40  from being deformed or damaged. 
     Due to such a constitution, an air passage in each air vent  7   c  is attributed to the depth and the width of the groove  1   a  formed in the distal end of the movable pin  1 . Since the grooves  1   a  formed in the respective movable pins  1  have the same depth and the same width in respective air vents  7   c , irrespective of irregularities in the thickness of the board or the surface condition of the board, such as unevenness in respective air vents  7   c , it is possible to form the air vent structure shown in  FIG. 4 . As a result, the depths of respective air vents  7   c  can be set to a fixed value. 
     Thereafter, in a state in which the depths of respective air vents  7   c  are set to a fixed value, as shown in  FIG. 16 , the sealing resin  9  is pushed out by the plunger  8   g  so that the sealing resin  9  is filled in the collective cavity  7   h , as shown in  FIG. 3 . 
     At the time of filling the resin, even when the multi-cavity board  40  is formed with a slightly larger thickness due to irregularities in thickness, the respective air vents  7   c  have a fixed depth due to the grooves  1   a  formed in the distal ends of respective movable pins  1  (the digging depths of the movable pin portions eventually determining the depths of the air vent movable pin portions; in sheet molding, a value obtained by subtracting an actual thickness from the digging depths of the movable pin portions determining the depths of the air vent movable pin portions); and, hence, it is possible to ensure leakage of the air from the collective cavity  7   h , whereby the occurrence of a state in which the sealing resin  9  is not sufficiently filled (a resin unfilled state) can be prevented. 
     Further, even when the multi-cavity board  40  is formed with a slightly smaller thickness due to irregularities in thickness, the respective air vents  7   c  have a fixed depth due to the grooves  1   a  formed in the distal ends of respective movable pins  1  in the same manner; and, hence, the occurrence of any leaking of the resin and the occurrence of a welding defect, which is a defect attributed to voids in a surface of the sealing body, can be obviated. 
     Accordingly, the occurrence of defects can be reduced, and, hence, the yield rate of the products can be enhanced. 
     Especially, when the multi-cavity board  40  is a board which is formed of resin, unevenness attributed to warping of the board or the presence or non-presence of wiring is liable to easily occur. In the mold  6  according to the embodiment 1, the depths of respective air vents  7   c  can be set to a fixed value irrespective of the conditions of the surface of the board. 
     Further, the occurrence of the defects can be reduced and the yield rate can be enhanced in the above-mentioned manner, so that, in an appearance inspection carried out after completion of the resin sealing operation, the inspection flow becomes smooth, and, hence, the throughput of the appearance inspection can be enhanced. 
     Further, the occurrence of any leaking of the resin can be prevented in the air vents  7   c , and, hence, the occurrence of adhesion of resin to the main surface  40   a  of the multi-cavity board  40  outside an allowable range can be prevented. 
     Accordingly, in the succeeding process after completion of resin sealing, for example, when the multi-cavity board  40  is arranged at a chute of a dicer (a board transfer jig), it is possible to prevent the occurrence of drawbacks, for example, where the board cannot be placed in the chute because resin, which adheres to an outer peripheral portion or the like of the board due to leaking of the resin, is caught. 
     Further, the mold  6  according to this embodiment 1 adopts the structure in which the depths of respective air vents  7   c  are automatically set to a fixed value due to the movable pins  1  mounted on the upper mold  7  at the time of clamping the molds, as a mold clamping force, it is sufficient to set a load which is slightly larger than the resin injection pressure irrespective of the structure of the lower mold  8 . As a result, the mold clamping force can be reduced compared with the mold clamping force for the conventional mold. 
     Since the mold clamping force can be reduced in this manner, a load applied to the board at the time of clamping the mold can be reduced, whereby the occurrence of drawbacks, such as the formation of cracks in the board or the deformation of the board can be prevented. 
     Further, since this embodiment adopts a he mold structure in which the depths of respective air vents  7   c  can be set to a fixed value due to the movable pins  1  which are mounted on the upper mold  7  irrespective of the thickness of the board, the allowable range (tolerance) of the thickness of the board, such as the multi-cavity board  40  or the like, can be broadened. Accordingly, the fabrication cost of the board can be reduced, and, hence, the fabrication cost of the semiconductor integrated circuit device, such as CSP  43  or the like, can be reduced. 
     When the resin sealing is finished and the mold  6  is opened, the multi-cavity board  40  which is sealed by resin is taken out from the mold  6 . 
     Here, on the main surface  40   a  of the multi-cavity board  40 , as shown in FIG.  19 , the collective sealing portion  45 , which is formed by the collective molding, is formed, and, at the same time, runner resins  47 , cull resin  48 , gate resin  49  and the like are formed. Thereafter, the runner resin  47 , the cull resin  48 , the gate resin  49  and the like are removed from the collective sealing portion  45  to obtain a state as shown in  FIG. 17 . 
     Further, the multi-cavity board  40  is cut into individual pieces per each device area  40   c . Here, the dicing is performed along dicing lines  46  shown in  FIG. 18 , and the multi-cavity board  40  is cut off together with the collective sealing portion  45 ; and, thereafter, the multi-cavity board  40  is divided into single pieces, as shown in  FIG. 20 . 
     Thereafter, as shown in  FIG. 21 , the assembling of the CSP  43  is completed by mounting a plurality of solder balls  42  on the back surface  41   b  of the printed wiring circuit board  41 , which was formed by the division of the multi-cavity board into single pieces. Here, the fixing of the solder balls  42  may be performed on the multi-cavity board  40  before the multi-cavity board  40  is divided into the single pieces by dicing. 
     In assembling the CSP  43  as explained above, at the time of performing the resin sealing, the film  3  (sheet) is arranged in the mold and, thereafter, the resin is filled. Therefore, the mold surface  7   g  of the upper mold  7  is covered with the film  3  at the time of filling the resin; and, hence, there is no possibility that the sealing resin  9  intrudes into the movable pin arranging portions connected to the air vents  7   c . Accordingly, there is no possibility that the sealing resin  9  will become clogged in the above-mentioned movable pin arranging portions, and, hence, it is possible to ensure the reliable operation of the movable pins  1 . 
     It must be noted, however, that the mold  6  according to the embodiment 1 can be used even when the resin sealing is performed without using the film  3 , such as resin sealing using a board such as a lead frame. In this case, there may be a possibility that the sealing resin  9  intrudes in the above-mentioned movable pin arranging portions and the movable pins  1  are not moved due to clogged resin. However, in the mold  6  according to this embodiment 1, it is possible to forcibly push out the movable pin  1  toward the air vent side by means of the movable-pin rammer  7   j  at the time of opening the mold  6 . 
     Accordingly, even when the sealing resin  9  intrudes into the periphery of the movable pin  1 , the smooth operation of the movable pin  1  is maintained, and, at the same time, the maintenance of the operation of the movable pin  1  can be performed. 
     Further, as the mold clamping force, it is sufficient to set a load slightly larger than the resin injection pressure irrespective of the structure of the lower mold  8 . As a result, the mold clamping force can be reduced compared with the mold clamping force used for the conventional mold. Since the mold clamping force can be reduced in this manner, the load applied to the board at the time of clamping the mold can be reduced, and the occurrence of drawbacks, such as the formation of cracks in the board, or the deformation of the board can be obviated. 
     Further, the mold  6  according to the embodiment 1 adopts a structure in which the depths of the respective air vents  7   c  are automatically set to a fixed value at the time of clamping the molds using the movable pins  1  mounted on the upper mold  7 , and, hence, cumbersomeness, such as the preparation of input data for adjusting the opening degree adjustment means in response to the frame thickness in advance, can be avoided, and, hence, the resin sealing operation can be simplified. 
     Further, the mold  6  according to the embodiment 1 adopts a structure in which the depths of respective air vents  7   c  are automatically set to a fixed value at the time of clamping the molds due to the movable pins  1  mounted on the upper mold  7 , and, hence, it is not necessary to provide a large-sized mechanism, such as a driving mechanism for opening degree adjustment means, whereby the constitution of the mold  6  can be simplified. 
     Accordingly, the mold  6  can be miniaturized and the cost of the mold  6  can be reduced. 
     Next, a modification of the embodiment 1 will be explained. 
       FIG. 22  shows a CSP  50 , which uses a multi-layered printed wiring circuit board  51  as a board, and a portion of the inner structure of the CSP  50  is shown in  FIG. 23 . 
     The multi-layered printed wiring circuit board  51  is formed by laminating a plurality of core members  51   c  made of resin or the like. In the example shown in  FIG. 23 , two core members  51   c  are laminated to each other. A respective copper pattern  51   d  is provided to each of the three layers consisting of a main surface  51   a , a back surface  51   b  and the inside of the board. 
     Here, the copper patterns  51   d  formed on the main surface  51   a  and the back surface  51   b  are respectively connected by through-hole wiring  51   f  or the like. Further, the copper patterns  51   d  formed on the main surface  51   a  and the back surface  51   b  are respectively covered with and insulated by a resist film  51   e  (insulation film) except for the connection portions, respectively. 
     In the CSP  50  shown in  FIG. 23 , a semiconductor chip  4  is mounted on the main surface  51   a  of the multi-layered printed wiring circuit board  51  by way of a die bonding member  10 , while the bonding electrode  4   b  formed on the main surface  4   a  of the semiconductor chip  4  and the copper pattern  51   d  formed on the multi-layered printed wiring circuit board  51  are electrically connected by wires  5 , and a plurality of solder ball  53 , serving as outer terminals, are mounted on the copper pattern  51   d  of the back surface  51   b.    
     Further, the semiconductor chip  4  and the plurality of wires  5  are sealed with resin to form a sealing body  52 . 
       FIG. 24  shows the state of a multi-cavity board  54  after collective molding in the assembly of the CSP  50 ; and, collective sealing portion  55 , air vent resin  56  and gate resin  57  are formed over the multi-cavity board  54 . 
     Accordingly, the CSP  50  is formed such that, in the resin sealing step of the assembling operation, the collective sealing portion  55  is formed by sealing the multi-cavity board  54  having the multi-layered printed wiring structure shown in  FIG. 24  with resin by collective molding, and, thereafter, the multi-cavity board  54  is divided into single pieces by dicing. 
     The CSP  50  also can be assembled by the above-mentioned method of fabrication of the semiconductor integrated circuit device of the embodiment 1. When the multi-cavity board  54  having the multi-layered printed wiring structure is used, the irregularities in thickness thereof are large compared with the irregularities in thickness of a board having a single layer structure. Accordingly, the method of fabrication of the semiconductor integrated circuit device of this embodiment 1, in which resin sealing can be performed by setting the depths of the air vents  7   c  to a fixed value irrespective of the thickness of the board, is extremely effective; and, at the same time, the cost of the multi-cavity board  54  can be reduced by alleviating the tolerance of the thickness of the multi-cavity board  54 . 
     Further, although the CSP  43  shown in  FIG. 14  or the CSP  50  shown in  FIG. 22  are assembled by collective molding using the mold shown in  FIG. 12  and  FIG. 13 , with respect to the method of fabrication of the semiconductor integrated circuit device of this embodiment 1, it is not necessary to form a new mold  6  even when the thickness of the board is changed, when the product type is changed, and, hence, the mold  6  can be used in common. 
     Accordingly, the fabrication cost can be reduced. 
     Embodiment 2 
       FIG. 25  is a plan view showing one example of the structure of an upper mold of a mold for simultaneously molding a plurality of semiconductor integrated circuit devices for use in a method of fabrication of a semiconductor integrated circuit device according to an embodiment 2 of the present invention;  FIG. 26  is a plan view showing one example of the structure of a lower mold which constitutes a pair with the upper mold shown in  FIG. 25 ;  FIG. 27  is a plan view showing one example of the structure of the board after resin molding in the fabrication of the semiconductor integrated circuit device according to the embodiment 2 of the present invention;  FIG. 28  is a cross-sectional view showing one example of the structure of a semiconductor integrated circuit device assembled by the method of fabrication of the semiconductor integrated circuit device according to the embodiment 2 of the present invention and  FIG. 29  is a bottom view showing one example of the structure of the semiconductor integrated circuit device shown in  FIG. 28 . 
     The embodiment 2 relates to a method of fabrication of an semiconductor integrated circuit device which is assembled by using a multi-cavity board  60 , wherein a plurality of the boards are arranged on one mold and these plurality of boards are sealed by resin at one time. 
     Here,  FIG. 25  shows an upper mold  7  of the mold for simultaneously molding a plurality of boards. In this embodiment 2, four multi-cavity boards  60  can be sealed by resin at one time. 
     With respect to the upper mold  7  shown in  FIG. 25 , in individual cavities  7   n  which are connected to each other by way of culls  7   d  and runners  7   e , air vents  7   c  are formed, respectively, at a side opposite to the runners  7   e . In the same manner as the mold  6  according to the embodiment 1, movable pins  1  are mounted in respective air vents  7   c . Also with respect to the mold  6  according to the embodiment 2, the movable pins  1  perform a similar movement as that of the movable pins  1  of the mold  6  according to the embodiment 1. 
     On the other hand,  FIG. 26  shows, with respect to the lower mold  8 , which forms a pair with the upper mold  7  shown in  FIG. 25 , a state of the lower mold  8  after arranging a plurality of multi-cavity boards  60  therein and performing resin sealing. 
     The multi-cavity board  60  shown in  FIG. 26  is used for assembling of a card-type package (semiconductor integrated circuit device)  59 , as shown in  FIG. 28 . The card-type package  59  has a structure in which two semiconductor chips  4  are stacked over a main surface  58   a  of a board for cards  58 , and the card-type package  59  has a plurality of semiconductor chips  4  over which other semiconductor chips  4  are mounted close to two semiconductor chips  4 , wherein any semiconductor chips  4  are connected to the board for card  58  by wire bonding. 
     Further, the plural semiconductor chips  4  and wires  5  are sealed by resin by a sealing body  61 , and a plurality of terminals for external connections  64  are formed over a back surface  58   b  of the board for card  58 , as shown in  FIG. 29 . 
     Further,  FIG. 27  shows a state of the multi-cavity board  60  after performing resin molding in the assembling of the card type package  59 , wherein a sealing portion  61 , air vent resin  62  and gate resin  63  of respective packages are formed over the main surface  60   a  of the multi-cavity board  60 . 
     Here, also with respect to the assembling of the card type package  59  of the embodiment 2, the resin sealing can be performed in substantially the same manner as the resin sealing method of the embodiment 1. That is, four multi-cavity boards  60  are arranged over the mold surface  8   h  of the lower mold  8  of the mold  6 , and, thereafter, the mold  6  is clamped and resin sealing is performed. Here, the resin sealing can be performed by setting the depths of the air vents  7   c  to a fixed value irrespective of the thickness of the multi-cavity board  60 . 
     Accordingly, with the use of the method of fabrication of the semiconductor integrated circuit device of the embodiment 2, it is possible to obtain substantially the same advantageous effects as the advantageous effects of the embodiment 1. 
     Further, with the use of the movable pins  1 , which are arranged in respective air vents  7   c , the resin sealing is performed by setting the depths of respective air vents  7   c  to a fixed value irrespective of the thickness of the multi-cavity board  60 . Accordingly, even when a plurality of boards are sealed with resin using one mold  6  at a time in the same manner as the embodiment 2, without being affected by the irregularities of the thickness among the boards, the irregularities are absorbed by the mold  6 , whereby the constitution is very effective. 
     For example, if only one of four multi-cavity boards  60  is formed rather thick, conventionally, a leaking of resin occurs with respect to the other three molds when the resin sealing is performed at the time. However, the resin sealing in assembling of the semiconductor integrated circuit device according to the embodiment 2 is not affected by the irregularities in the thickness among the boards, and, hence, drawbacks such as the leaking of resin, insufficient resin filling and defective welding can be avoided in the same manner as the embodiment 1. 
     Accordingly, the fabrication cost in resin sealing can be reduced. 
     Other method of fabrication of the semiconductor integrated circuit device according to the embodiment 2 and other effects which can be obtained by the other fabrication methods are substantially equal to those of the embodiment 1, and, hence, the repeated explanation thereof is omitted. 
     Although the invention made by inventors of the present has been specifically explained in conjunction with the embodiments 1 and 2, the present invention is not limited to the above-mentioned embodiments 1 and 2, and various modifications can be made without departing from the gist of the present invention. 
     For example, although cases in which the semiconductor integrated circuit device is constituted of the CSP  43 ,  50  and the card type package  59  have been explained in conjunction with the above-mentioned embodiments 1 and 2, the above-mentioned semiconductor integrated circuit device may be constituted of other types of semiconductor integrated circuit device, such as a BGA (Ball Grid Array) type display device, a LGA (Land Grid Array) type display device or the like, provided that the semiconductor integrated circuit device is of the resin sealing type which can be assembled by performing resin sealing using the board. 
     Further, although a case in which the movable pins  1  formed on the upper mold  7  are mounted individually one by one corresponding to respective air vents  7   c  has been considered in connection with the embodiment 1, 2, the movable pins  1  may be constituted by a member such as a movable block piece formed as one body corresponding to a group of the air vents  7   c.    
     Further, the board may be a metal plate, such as a lead frame, irrespective of the board over which the printed wiring is formed. 
     The advantageous effects which are obtained by the invention among the features disclosed in the present application are briefly recapitulated as follows. 
     Since the resin sealing is performed with air vents having depths that are set to a fixed value irrespective of the thickness of the board, insufficient resin filling, leaking of resin or imperfect welding within the cavity can be avoided, and the yield rate of the products can be enhanced.