JP3949072B2 - Pressurizing device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a pressurizing apparatus that pressurizes a workpiece with a pressurizing die and performs processing such as pressure bonding on the workpiece, and a method of mounting a circuit element such as an integrated circuit chip on a substrate.
[0002]
[Prior art]
As a method for mounting a circuit element on a substrate, a method is known in which an adhesive film is disposed between the substrate and the circuit element, the circuit element is pressed and heated toward the substrate, and then pressure-bonded. A thermosetting anisotropic conductive film may be used as the adhesive film, and in this case, the elements can be bonded and wired at the same time. Further, a thermoplastic material, a non-conductive film, a conductive or non-conductive paste may be used. The circuit element mounting process using these adhesive films will be described. First, the adhesive film is placed on the circuit element mounting position on the substrate, and the circuit element is placed thereon. The surface of the adhesive film has adhesiveness, and the circuit element is temporarily fixed or pressure-bonded by being slightly pressed when the circuit element is placed. The circuit element is provided with electrodes called bumps for electrical connection with the outside. Wiring is located at a position facing the bump on the substrate when the element is placed. When the circuit element is placed on the substrate and pressed, the bump and the wiring protrude from the surroundings, so that the adhesive film between them is further pressed and becomes conductive. . Further, the adhesive film bonds the substrate and the circuit element by heating, and the main pressure bonding is performed.
[0003]
Further, a technique for simultaneously mounting a plurality of circuit elements is described in Patent Document 1 below. The apparatus described in this document absorbs a difference in height of a plurality of circuit elements by this buffer layer and pressurizes them simultaneously to perform mounting. Examples of the buffer layer include sheets rich in rubber-like elasticity, bags containing gas or liquid, and balloons.
[0004]
[Patent Document 1]
Japanese Patent Application Laid-Open No. 10-256311 (left column on page 3, FIG. 2)
[0005]
[Problems to be solved by the invention]
As described above, in a conventional apparatus, a sheet having rubber-like elasticity has been proposed as a buffer layer. However, in a sheet of silicon rubber or the like, the pressure in a high circuit element portion is increased, and the sheet is applied. The uniformity of the pressure was not sufficient. In addition, when bags containing gas or liquid are used, the strength of the bag is insufficient, and a sufficient pressure cannot be obtained.
[0006]
The present invention has been made in consideration of the above-described problems, and an object thereof is to uniformly pressurize a plurality of circuit elements and mount them.
[0007]
[Means for Solving the Problems]
The pressurizing apparatus according to the present invention includes a plurality of pressurizing molds to sandwich an object to be pressed, and at least one of the pressurizing mold and the object to be pressed has a fluid flexible layer of fluid material and flexibility. Pressurization is performed with an intervening intervening pad interposed. The fluid and flexible material can be a gel material.
[0008]
By applying pressure through a fluid flexible layer, it is possible to apply pressure even to the lower part of the uneven workpiece. For example, if it is used as a pressurizing device when a circuit element is pressure-bonded on a substrate, pressurization can be performed almost evenly even if the height of each circuit element is different.
[0009]
Further, the interposed pad may have a frame disposed so as to surround the fluid flexible layer, and further, a surface that is stretched on an opening front surface of the frame and is in contact with the object to be pressed. A film-like member to be formed and a seal body that covers a gap between the frame body and the pressurizing mold can be provided.
[0010]
These frame body, film-like member, and seal body accommodate and hold the fluid flexible layer. Further, the membrane member prevents the material constituting the fluid flexible layer from flowing laterally with respect to the pressurizing direction, thereby preventing the workpiece from being displaced.
[0011]
Further, the interposed pad may include a porous flexible layer disposed on the opposite side of the fluid flexible layer to the side facing the object to be pressed .
[0012]
Furthermore, the material of the fluid flexible layer can be a gel material.
[0013]
In addition, the method for mounting a circuit element on another substrate according to another aspect of the present invention includes a step of placing an adhesive film on the substrate and a circuit element superimposed thereon, and the circuit element is fluid. And pressurizing the substrate with a pressurizing die through a fluid flexible layer containing a flexible material and pressing the substrate. The fluid and flexible material can be a gel material.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention (hereinafter referred to as embodiments) will be described with reference to the drawings. In the embodiments described below, the workpiece is a substrate such as an electronic circuit and a circuit element mounted on the substrate, and pressurization is performed to achieve crimping and predetermined electrical connection. Is done.
[0015]
FIG. 1 is a conceptual diagram for explaining a mounting method of a circuit element such as an integrated circuit chip according to the present embodiment. As shown in FIG. 1A, wirings 12 are formed on the surface of the substrate 10 in a predetermined pattern. On the substrate 10, a thermosetting adhesive sheet 14 for bonding and wiring and a circuit element 16 are arranged at predetermined positions. On the surface of the circuit element 16 facing the substrate 10 (lower surface in the figure), there are provided projections called bumps 18 serving as electrical contacts. The wiring 12 and the bump 18 are located at positions facing each other with the adhesive sheet 14 interposed therebetween. In other words, the position where the wiring 12 is provided is determined based on the mounting position of the circuit element 16.
[0016]
Next, as shown in FIG. 1 (b), a flexible layer having fluidity located above of the circuit element 16 and the substrate 10 (hereinafter, the fluidity of a flexible layer) 22, yet the flowable flexible layer The surface of the circuit element 16 is brought into contact with the upper surface by stroking the pressure mold located above . Then, the pressurizing mold is further stroked to cause the fluid flexible layer 22 to wrap around the side of the circuit element 16 and the adhesive sheet 14 as indicated by arrows in the figure.
[0017]
As shown in FIG. 1 (c), the circuit element 16 and the adhesive sheet 14 to be pressed are integrally pressed so as to press from the periphery, in the drawing, from above and from the side. As described above, each of the wiring 12 and the bump 18 protrudes from the surface on which the wiring 12 and the bump 18 are arranged. When pressed, the portion of the adhesive sheet 14 sandwiched between the wiring 12 and the bump 18 is further compressed. The compressed portion becomes conductive, and a conductive state is established between the wiring 12 and the bump 18. Further, the pressure type is provided with a heater, and the adhesive sheet 14 is cured by the heat from the heater, and the circuit element 16 is pressure-bonded.
[0018]
FIG. 2 is a diagram showing a schematic configuration of a pressurizing device for crimping an integrated circuit chip. The apparatus includes a lower mold 30 on which workpieces such as the substrate 10, the adhesive sheet 14, and the circuit element 16 are placed, and the lower mold 30 that faces the lower mold 30 and is the object to be pressed. An upper die 32 and a side die 34 surrounding the side of the space between the upper die 32 and the lower die 30 facing each other are provided. A seal mold 36 is disposed so as to surround the outer side of the side mold 34. The seal mold 36 seals this space in order to decompress the space surrounded by the upper mold 32, the lower mold 30, and the side mold 34.
[0019]
The lower end of the side mold 34 in the figure is a frame body 40 that supports the intervening pad 38. The interposition pad 38 is composed of two film-like members 42 and 44 that are directly supported by the frame body 40, and a flexible body in which two kinds of flexible materials accommodated between the two film-like members form a layer. 46. Since the flexible body 46 is surrounded by the frame body 40, when the pressure is applied by the mold, the flexible body 46 can efficiently and reliably transmit the pressure to the workpiece. A film-like member 42 (hereinafter referred to as a film-like member 42) on the lower mold 30 side is stretched over the entire opening of the frame body 40 and is pressed against the workpiece during processing. The film-like member 42 can be made of a rubber material such as silicon rubber, for example. Moreover, it can also be set as rubber | gum films | membranes, such as a silicone rubber which used textiles, such as a polyimide fiber, as a core material. In addition to the function of holding the flexible body as described above, the film-like member 42 has a function of preventing the lateral displacement of the workpiece caused by the flow of the material constituting the flexible body described below, particularly the lateral flow. For example, when the circuit element 16 is pressure-bonded to the substrate 10, the circuit element 16 may be displaced due to the lateral flow in the flexible body 46, and the wiring 12 and the bump 18 (see FIG. 1) may be displaced. The film-shaped member 42 is prevented from shifting the crimping position by restricting the lateral movement of the circuit element 16 or the like. As described above, when fibers are used as the core material, deformation in the in-plane direction of the film-like member 42 is suppressed by the core material, which is more effective with respect to the displacement of the crimping position. In addition, the film-like member 42 may be a laminate of a rubber film and a metal thin film. A film-like member 44 on the upper mold 32 side has an opening at the center, and a sealing member that prevents the accommodated flexible body 46 from entering and leaking into the gap between the upper mold 32 and the side mold 34. (Hereinafter, the membranous member 44 is referred to as a seal member 44).
[0020]
The peripheral portions of the film-like member 42 and the seal member 44 are supported so as to be sandwiched between the layers of the frame body 40 constituted by three layers. In each layer of the frame body, concavities and convexities that fit each other are formed on surfaces facing each other. The film-like member 42 and the seal member 44 are bitten by these irregularities, and these are firmly held and fixed.
[0021]
As described above, the flexible body 46 includes two layers of different materials. A material having flexibility and high fluidity is used for the lower layer, that is, the layer on the workpiece side. Hereinafter, this layer is referred to as a fluid flexible layer 48. The fluid flexible layer 48 corresponds to the fluid flexible layer 22 shown in the conceptual diagram of FIG. Due to the fluidity, the material can sufficiently flow into and fill the concave portions of the uneven workpiece, and a uniform pressure can be applied to the whole during pressurization. Further, it is preferable that the rebound resilience is low, that is, the rebound resilience is low. When the resilience is high, a large repulsive force is generated in a portion where the deformation is large, and the pressure distribution becomes non-uniform. As a material satisfying such characteristics, there is a gel material. For example, Geltech Co., Ltd., high damping heat conductive gel sheet “αGEL (trademark)”, Riken Technos Co., Ltd., thermoplastic elastomer, Kinugawa Rubber Industrial Co., Ltd. super soft elastomer “Frengel (trade name)”, etc. Can be used. Another layer of the flexible body 46 is composed of a porous flexible material (hereinafter, this layer is referred to as a porous flexible layer 50. As the porous flexible material, for example, silicon sponge, fluorine sponge, or the like is used. By providing such a layer, the flow of the fluid flexible layer 48 is ensured by first deforming the porous flexible layer 50 at the initial stage of contact of the flexible body 46 with the workpiece. In addition, when the pressure bonding is finished and the pressure is released, the restoring force of the porous flexible material contributes to the restoration of the fluid flexible layer 48.
[0022]
A cover film 52 is disposed between the upper structure including the upper mold 32 and the interposition pad 38 and the lower mold 30 and the workpiece placed thereon. The cover film 52 is passed between the feed roll 54 and the take-up roll 56, and a new part is moved from the feed roll 54 to the upper side of the work piece every time it is used or after every predetermined number of uses. In addition, the used part is taken up on the take-up roll 56.
[0023]
A first seal ring 58 is disposed on the surface of the seal mold 36 that slides with the side mold 34. A second seal ring 60 is disposed on the surface facing the lower mold 30. By these first and second seal rings 58, 60, when the seal die 34 comes into contact with the lower die 30, the space surrounded by the side die 34, the interposed pad 38, the lower die 30 and the seal die 36 is sealed. . Exhaust air is discharged from the sealed space by the exhaust pump 66 through the exhaust pipes 62 and 64, and the space is depressurized. Further, the exhaust pipe 64 that extends toward the lower mold 30 and exhausts air from here sucks air between them when the work sheet is covered with the cover sheet 52, so that the cover sheet 52 adheres to the work piece. Let Thereby, the movement of the workpiece is suppressed. If the above-described action of the film-like member 42, that is, the action of suppressing the lateral movement of the workpiece is sufficiently achieved, the cover sheet 52 is not used and the intervening pad 38 is brought into direct contact with the workpiece. It can also be made to do.
[0024]
Next, taking the substrate 10 and the circuit element 16 as examples of workpieces, the operation of the pressurizing apparatus of this embodiment when these are crimped will be described. First, as shown in FIG. 2, the substrate 10 and the circuit element 16 are placed on the lower mold 30 with the adhesive sheet 14 interposed therebetween.
[0025]
Next, as shown in FIG. 3, the feeding roll 54 and the take-up roll 56 are lowered, and the upper surface of the lower mold 30 is covered with the cover film 52 together with the substrate 10 and the circuit element 16. In parallel or after this, the upper structure including the seal die 36 is lowered, and the seal die 36 is brought into contact with the upper surface of the lower die 30 covered with the cover film 52. At this time, the intervening pad is not in contact with the circuit element 16 or the like. The space in which the substrate 10 and the circuit elements are disposed is sealed by the first and second seal rings 58 and 60 disposed in the seal mold 36 and the side mold 34, and the space is decompressed by the exhaust pump 66. By sucking air between the cover sheet 52 and the lower mold 30 through the exhaust pipe 64, the cover sheet 52 is in close contact with the lower mold 30, the substrate 10, and the circuit element 16. The space above the cover sheet 52 is also decompressed, and the upper mold 32 is lowered together with the decompression. Since the seal mold 36 is already in contact with the lower mold 30, the other upper structures including the side mold 34 and the upper mold 32 are lowered. At this time, the side mold 34 and the seal mold 36 move relatively, but the first seal ring 58 ensures sealing.
[0026]
FIG. 4 shows a state in which the lower end of the side mold 34, that is, the lower end of the frame body 40 is in contact with the lower mold 30 and the upper mold 32 is further stroked. When the upper die 32 is further lowered after the side die 34 comes into contact with the lower die 30, the porous flexible layer 50 is deformed, and the fluid flexible layer 48 is also deformed so as to follow the unevenness of the substrate 10 and the circuit element 16. To do. At this time, the cover sheet 52 and the membrane member 42 are similarly deformed. The seal member 44 is bent at a gap between the side mold 34 and the upper mold 32 as shown in the figure, and prevents the material constituting the flexible body 46 from leaking or protruding from this portion. This pressurized state is maintained for a predetermined time. Further, the heater (not shown) provided in the lower mold 30 is heated simultaneously with pressurization to perform pressure bonding. After a predetermined time has elapsed, the upper mold 32, the side mold 34, the seal mold 36, the cover sheet 52, and the like are raised, and the substrate 10 to which the circuit element 16 is pressure bonded is taken out.
[0027]
FIG. 5 is a diagram showing a surface pressure distribution when a rubber layer is provided on the front surface of the upper mold 32 and the substrate and the circuit element are pressed. 6 shows a case where the flexible body 46 is composed of only a fluid flexible layer, and FIG. 7 shows a case where the flexible body 46 is composed of two layers of a fluid flexible layer and a porous flexible layer as in the above-described embodiment. It is a figure which shows pressure distribution. The part where the concentration is higher is the part where the pressure is higher.
[0028]
As shown in FIG. 5, the pressure distribution is non-uniform in the rubber layer. In the case where only the fluid flexible layer of FIG. 6 is provided, it can be seen that the pressure distribution is more uniform than that of rubber, and in the case of FIG. . As described above, even if the flexible body is constituted by only the fluid flexible layer, the pressure distribution can be made uniform to some extent, and this configuration can be adopted depending on the conditions required for the apparatus.
[0029]
According to the above apparatus, when a plurality of circuit elements having different thicknesses are pressure-bonded, the difference in thickness is deformed and absorbed by the flexible body, so that these can be pressure-bonded simultaneously. In addition, when crimping one by one, heat is transferred to adjacent uncrimped circuit elements and the adhesive sheet is cured before crimping. Therefore, it is necessary to increase the spacing between the elements. In other words, since the pressure bonding can be performed at the same time, the distance between the circuit elements can be reduced and the mounting density can be increased.
[0030]
In the above description, the electrical connection between the circuit element and the wiring on the substrate and the adhesion of the circuit element to the substrate are performed using the adhesive sheet, but this is also effective for the solder connection. In addition, an adhesive film that does not have a conductive function can be bonded to a flat or uneven surface instead of an illegal conductive film.
[Brief description of the drawings]
FIG. 1 is a diagram conceptually showing each process of a crimping operation between a substrate and a circuit element.
FIG. 2 is a schematic configuration diagram of a pressure device according to the present embodiment.
FIG. 3 is a diagram showing an intermediate step of an operation for pressure-bonding a substrate and a circuit element in the pressurizing apparatus of the present embodiment.
FIG. 4 is a view showing a pressurizing process for press-bonding a substrate and a circuit element in the pressurizing apparatus of the present embodiment.
FIG. 5 is a diagram showing a surface pressure distribution when pressure is applied through a rubber plate.
FIG. 6 is a diagram showing a surface pressure distribution when pressure is applied only through a fluid flexible layer.
FIG. 7 is a diagram showing a surface pressure distribution when pressure is applied through a flexible body composed of two layers of a fluid flexible layer and a porous flexible layer.
[Explanation of symbols]
10 substrate, 12 wiring, 14 adhesive sheet, 16 circuit element, 18 bump, 22 fluid flexible layer, 30 lower mold, 32 upper mold, 34 side mold, 36 seal mold, 38 intervening pad, 40 frame, 42 film shape Member, 44 sealing member, 46 flexible body, 48 fluid flexible layer, 50 porous flexible layer.

Claims (4)

A pressurizing apparatus that sandwiches an object to be pressed with a plurality of pressurizing molds and pressurizes the pressurizing object,
An intervening pad interposed between at least one pressurizing mold and the object to be pressed and including a fluid flexible layer of a fluid and soft gel material;
A frame that is disposed so as to surround the fluid flexible layer and supports the intervening pad ;
Have
The interposed pad further includes:
A film-like member that is stretched over the entire opening of the frame and forms a surface that contacts the object to be pressed;
A seal body that covers a gap between the frame body and the pressure mold;
Including
A pressurizing device that pressurizes through the intervening pad. 2. The pressurizing apparatus according to claim 1, wherein the film-like member is a rubber film having a woven fabric as a core material. 2. The pressurizing apparatus according to claim 1, wherein the film-like member is a laminate of a rubber film and a metal thin film. It is a pressurization apparatus of any one of Claim 1 to 3, Comprising: The said interposition pad is a porous thing arrange | positioned on the opposite side of the side which opposes a to-be-pressurized object of the said fluid flexible layer. A pressure device including a flexible layer.

Images