JP4644756B2 - Spiral contact bonding method - Google Patents

Description

  The present invention relates to a method for bonding a spiral contact used in a semiconductor device inspection apparatus or the like on a substrate, and more particularly to a minute and precise bonding method suitable for mass production.

  FIG. 10 is a plan view of a spiral contactor (SC) which is the background art of the present invention. As shown in FIG. 10, the spiral contactor (SC) is composed of a plurality of spiral contacts 7 arranged in accordance with connection terminals arranged in a grid pattern or a grid pattern at predetermined positions on a substrate or the like. The outermost peripheral portion 7c of the cylindrical contact 7 has an annular shape and is fixed to the substrate, but has a spiral contact that rises from the inner contact and extends to the inner periphery (see, for example, Patent Document 1).

Also, in a cream solder printing machine that prints cream solder for mounting electronic components at predetermined positions on the printed circuit board in the printed circuit board manufacturing process, it is half as thin as a means to prevent the occurrence of defects such as chip standing. A cream solder printing machine (multi-layered printing) consisting of a first metal mask with holes and a second metal mask with holes specially processed on a metal mask of normal thickness and a stage for rolling cream solder ( For example, there was Patent Document 2).
Japanese Patent No. 3340243 (paragraphs 0006 to 0008, 0013, FIG. 1) Japanese Patent Laid-Open No. 7-9659 (paragraph 0009, FIG. 1)

  However, it relates to a method for bonding a minute contact among the spiral contacts used in semiconductor device inspection equipment, etc., to the wiring conductor of a printed circuit board precisely and firmly, and is stable for a long period of time, including conductivity, after bonding. A joining method suitable for mass production that can be maintained has not been established.

  Accordingly, the present invention aims to solve the above-described problems and provide a joining method suitable for mass production in which the connection between the minute spiral contact and the wiring conductor on the substrate is ensured and firmly joined. To do.

In order to solve the above-mentioned problem, a spiral contactor joining method according to claim 1 includes a stamping step (S1) for forming a depression (3) at a predetermined position of a copper foil (1), and the copper foil (1). ), A resist coating step (S2) for applying the photosensitive resist (5) to the punched surface (4), a photomask step (S3) for closely contacting or projecting the photomask (6), and a fixing resist by exposure and development. A developing and fixing step (S4) for forming (5a), a plating step (S5) for forming the spiral contact (7) with a metal film, a resist removing step (S6) for removing the fixing resist (5a), Polyimide which laminates the polyimide plate (8) having a hole (8a) through which the inner periphery of the spiral contact (7) can project in alignment with the plated surface (1a) of the copper foil (1). A laminating step (S7); A polyimide pressure-bonding step (S8) for heat-pressing the polyimide plate (8) to the plated surface (1a) of the copper foil (1), an etching step (S9) for removing the copper foil (1), and the polyimide plate (8) is attached to the pallet jig (9) for easy movement, and then the spiral contact (7) is placed on the conical jig (10) to form a solid and annealed to store the shape. A forming step (S10), an adhesive application step (S11) for applying a thermosetting adhesive (12) containing a conductive material to a plate (11) as a jig for applying the adhesive (12), and An adhesive transfer step (S12) for transferring the adhesive (12) applied to the plate (11) to the outermost joint surface (7a) of the spiral contact (7); and a substrate (13) before mounting ) (13a) A bonding preparation step (S13) for positioning the bonding surface (7a) to face the wiring contact (13a) disposed on the surface layer of the substrate (13), and the spiral contactor A thermocompression bonding step (S14) for thermocompression bonding (7) and a jig removing step (S15) for removing the pallet jig (9) are provided.

In addition to the invention according to claim 1 , the bonding method of the spiral contactor (7) according to claim 2 is characterized in that metal particles (12a) having a uniform particle diameter are provided in the adhesive (12) as a conductive medium. It is characterized by being mixed.

Method for joining spiral contactor (7) according to claim 3, in addition to the invention described in claim 1 or claim 2, wherein the adhesive (12) is based on the thermosetting epoxy, mixed the The metal particles (12a) include any of silver (Ag), tin (Sn), copper (Cu), and lead (Pb).

Method for joining spiral contactor (7) according to claim 4, in addition to the invention according to any one of claims 1 to 3, wherein the thickness of the plating process (S5) 15 to 30 [mu] m It is characterized in that gold (Au) is plated with a thickness of 0.5 μm or less on a nickel nickel plate.

According to the method for bonding spiral contacts according to the present invention, a large amount of minute spiral contacts can be accurately and reliably bonded to an arbitrary position on a substrate, and can be stably held even after being fixed. It becomes possible to provide a bonding method suitable for production. Further, it is possible to provide a spiral contactor contact resistance excellent in less durability.

  According to the method for joining spiral contacts according to claim 1, a minute and precise spiral contact (7) is connected to the wiring conductor (13 a) disposed on the surface layer of the substrate (13) and the electrical / mechanical device. It is possible to provide a joining method suitable for mass production that ensures reliable joining and is stably held even after fixing.

According to the joining method of the spiral contact according to claim 2, it is possible to secure the function and effect of the invention according to claim 1.

According to the joining method of the spiral contact according to claim 3, it is possible to secure the function and effect of the invention according to claim 1 or claim 2.

According to the method for joining spiral contacts according to claim 4 , it is possible to provide a spiral contactor (SC) having a smaller contact resistance value (Ω) and excellent durability.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 to 3 and FIGS. 5 to 7, S 5 to S 15, S 25 to S 34, and in particular, the sectional view of the final completed state shown in S 15 and S 34 is AA in FIG. 10. It matches so that it may correspond with arrow sectional drawing.

<First embodiment>
Hereinafter, the first embodiment will be described with reference to FIGS. FIG. 1 is an enlarged cross-sectional view showing the first six steps in the method for joining spiral contacts according to the embodiment.
As shown in FIG. 1, a minute recess 3 having a diameter and a depth of approximately 5 to 20 μm is stamped at a predetermined position of the copper foil 1 by a punching process 2 (S1). The recess 3 is for forming a female mold for forming the spike 7b described after the plating step (S5) described later. The tip of the spike 7b is formed so as to be sharpened, and when the spiral contactor 7 is mounted on the substrate 13 in the subsequent process (FIG. 3, S14), the spike 7b is inserted into the substrate 13 like a thumbtack. Used to fix. Incidentally, in the embossing step (S1), only one example is a method of embossing at the punch 2, as other methods, may be a method, for example by etching or the like.

Subsequently, in the resist coating step (S2), the photosensitive resist 5 is uniformly coated on the punched surface 4 with the depression 3 formed by punching.
Then, the photomask 6 in which the outline of the spiral contact 7 is drawn is covered on the surface of the photosensitive resist 5a by the photomask process (S3). At this time, if the film or the like forming the photomask 6 has the same dimensions as the product, the photomask 6 is superposed on the surface of the photosensitive resist 5 so as to be closely baked, and if the dimensions are different, projection for photolithography (development) is performed. The exposure is performed by projecting the photomask 6 at an appropriate magnification. By doing so, the distinction between the portion covered by the photomask 6 and shielded from light and the portion that can be exposed without being covered is clarified.

  The entire spiral contact 7 (FIG. 10) in a completed state is arranged on the substrate 13 (see FIG. 3) and is distinguished by being called a spiral contactor (hereinafter abbreviated as “SC”).

When the surface of the fixing resist 5a is developed and fixed in the next developing and fixing step (S4), the portion covered with the photomask 6 including the punched portion is in a state where the copper foil 1 is exposed without forming a resist film. . On the other hand, on the surface of the copper foil 1 exposed without being covered with the photomask 6, a resist film of the fixing resist 5 a is formed as a reverse image (negative) of the spiral contact 7.

Next, in the plating step (S5), the metal material is plated only at the portions where the copper foil is exposed including the recesses 3 to form the spiral contact 7. On the other hand, the resist coating is not plated.
As a result, the photomask 6 is plated only on the portion where the photosensitive resist is blocked and the fixing resist 5a is not fixed, and the photomask 6 forming the spiral contact 7 is traced. At this stage, the outline of the spiral contact 7 is formed on the surface of the copper foil with high accuracy by photolithography (printing) technology.

Next, the plating process (S5) shown in FIG. 1 and (S25) shown in FIG. 5 are plated with nickel Ni to a thickness of 15 to 30 μm and plated with Au at a thickness of 0.5 μm or less. It is possible to provide an SC having a small value (Ω) and excellent durability.
Then, if the resist is removed by the resist removing step (S6), only the spiral contact 7 remains on the surface of the copper foil.

  FIG. 2 is an enlarged cross-sectional view showing six steps following FIG. In the polyimide lamination step (S7) shown in FIG. 2, a polyimide plate 8 having a hole 8a through which a conical portion that rises elastically from the spiral contact 7 constituting the SC shown in FIG. After placing on the surface of the copper foil 1 on which the spiral contact 7 is formed, the polyimide plate 8 is heated and pressure-bonded to the outermost peripheral portion 7c of the spiral contact 7 in a polyimide pressure bonding step (S8). The positions and diameters of the holes 8a are formed so as to realize the planar arrangement of SC shown in FIG.

  Next, the copper foil 1 is removed by etching in the etching step (S9). As a result, the outermost peripheral portion of the spiral contact 7 is fixed to the back side of the polyimide plate 8. The conical portion that rises elastically in the spiral contact 7 can rise up in a spiral from the back to the front through the hole 8 a of the polyimide plate 8.

  In the next forming step (S10), the pallet jig 9 is attached to the polyimide plate 8 to facilitate the movement, and the central part is pushed up from the bottom of the spiral contact 7 with the conical mold, that is, the conical jig 10. The shape of the spiral contact 7 that has been raised from the back through the hole 8a of the polyimide plate 8 is stored in the spiral contact 7. At this time, the shape is adjusted in the manner of ironing and then hot pressing is performed. However, since the spiral contact 7 is metal, annealing (annealing) forming is performed to form a three-dimensional spiral spring. 7 is detached from the conical jig 10.

On the other hand, a plate on which a thermosetting adhesive is thinly and uniformly applied is prepared in the adhesive application step (S11), and is prepared for the adhesive transfer step (S12). Then, by the adhesive transfer step (S12), the thermosetting adhesive 12 (paste) is applied from the plate 11 to the joint surface (paste) 7a of the outermost peripheral portion 7c (see FIG. 10) of the spiral contactor 7. The bonding surface 7a is brought into contact with the plate 11 for transfer. That is, it is a process of applying paste to the margin.
The plate 11 functions like a jig for applying a bonding agent to a very limited bonding surface 7a, but is much more efficient and uniform than applying manually by a spatula or the like. Can guarantee sex. Therefore, it is adopted as a method suitable for mass production.

FIG. 3 is an enlarged cross-sectional view showing three steps just before the end after FIG.
In the bonding preparation step (S13), the position is adjusted so that the bonding surface 7a of the outermost peripheral portion 7c of the spiral contactor 7 faces the wiring conductor 13a at a predetermined position on the substrate 13 before mounting, and the thermocompression bonding step (S14). ), The spiral contact 7 is thermocompression-bonded to the wiring conductor 13 a formed on the surface layer of the substrate 13. At this time, the joint surface 7a to which the thermosetting epoxy as the adhesive 12 is applied is firmly fixed to the substrate 13 by thermocompression bonding. In addition, a large number of spikes 7b protrude from the joint surface 7a, and these spikes 7b and the spiral contact 7 are an integral metal having good conductivity, and are connected to the wiring conductor 13a of the substrate 13. Since it pierces like this, there exists an effect which improves both electroconductivity and fixation strength.

  It is well known and well known that metals are in contact with a mating material and can maintain a semi-permanent bonding state with a certain strength under a certain pressure and temperature. And although the adhesive 12 is used for the purpose of complementing the mechanical strength of this joined state, this adhesive 12 does not intervene on the metal joint surface, and forms a paste pool in the gap other than the metal joint surface, Maintains adhesive strength. Therefore, there is no adverse effect as an insulator that hinders the conductivity of the metal joint surface.

  If the pallet jig 9 is removed in the next jig removing step (S15), the SC in which the spiral contact 7 is firmly bonded to a predetermined position on the substrate 13, that is, the wiring conductor 13a is completed. These processes have many in common with the manufacturing process of the printed circuit board 13 used for electronic devices compatible with mass production, and can be carried out efficiently by introducing them on the extension line of conventional technology and equipment, This is a manufacturing method suitable for mass production.

  4A and 4B are enlarged cross-sectional views of a portion A on the joining surface shown in step S15 in FIG. 3, where FIG. 4A shows before joining and FIG. 4B shows after joining. As shown in FIG. 4, the spiral contact 7 is thermocompression-bonded to the wiring conductor 13a formed on the surface layer of the substrate 13, so that each of a large number of spikes 7b protruding from the joint surface 7a becomes the wiring conductor 13a of the substrate 13. It sticks like a thumbtack and is fixed.

  Hereinafter, an operation of ensuring electrical continuity on the joint surface 7a will be described. The thermosetting adhesive 12 applied to the joint surface 7a of the spiral contactor 7 was made of single particles of Ag, Sn, Cu, or Pb, or alloy fine particles containing any of them, and the diameter thereof was made uniform. It is mixed in the form of a sphere and forms a conductive paste.

<Second Embodiment>
Hereinafter, the second embodiment will be described with reference to FIGS. FIG. 5 is an enlarged cross-sectional view showing the first six steps of the spiral contactor joining method according to the second embodiment. As shown in FIG. 5, the copper foil 1 is prepared by a copper foil preparation step (S21). This copper foil 1 has a shape corresponding to the plane of the substrate 13 (see S31 to S34) on which the SC completed as a product is mounted and arranged, and is a temporary base corresponding to the mounting and arrangement of the SC.

  A photosensitive resist 5 is applied to one side of the copper foil 1 by a resist coating step (S22). Then, the photomask 6 is adhered or projected in the photomask process (S23), and exposed and developed in the development and fixing process (S24) to form the fixing resist 5a. Further, after plating the metal film on the surface of the copper foil 1 without the fixing resist 5a by the plating step (S25) to form the spiral contact 7, the fixing resist (5a) is removed by the resist removing step (S26).

  FIG. 6 is an enlarged cross-sectional view showing the middle five steps following FIG. In the polyimide laminating step (S27), a polyimide plate 8 having holes 8a formed so that the inner periphery of the spiral contactor 7 can protrude is aligned with the plated surface 1a of the copper foil 1 and laminated. After the polyimide plate 8 is thermocompression bonded to the plated surface 1a of the copper foil 1 in the step (S28), the copper foil 1 is removed in the etching step (S29).

  In FIG. 6, in the forming process (S30) shown next, the polyimide plate 8 is attached to the pallet jig 9 for easy movement, and the spiral contact 7 is put on the conical jig 10 to form a three-dimensional shape. Annealed and memorized.

  On the other hand, for the substrate 13 immediately before the spiral contactor 7 is mounted, as the adhesive printing step (S31), the surface layer of the substrate 13 is thermally cured including a conductive material on the wiring conductor 13a provided. The mold adhesive 12 is printed. In this embodiment, ACP in which silver balls having a diameter of several μm and a uniform particle diameter are mixed is used as the conductive material, and the relationship is epoxy instead of printing ink and silver balls instead of pigment. Then, an appropriate amount of printing is performed only on necessary portions by a known precise printing technique using a cream solder printer (see Patent Document 2).

  FIG. 7 is an enlarged cross-sectional view showing the three steps just before the end after FIG. In the joining preparation step (S32) shown in FIG. 7, the joining is performed so that the joining surface 7a 'faces the joining portion of the wiring conductor (13a), and the spiral is placed in a predetermined position of the wiring conductor 13a by the subsequent thermocompression bonding step (S33). The contact 7 is heat-pressed. Finally, the pallet jig 9 is removed by the jig removing step (S34), and the process is completed. According to this joining method of spiral contacts, the minimum and accurate adhesive 12 is used without waste, and the minute and precise spiral contact 7 is electrically connected to the wiring conductor 13a disposed on the surface layer of the substrate 13. It is possible to provide a joining method suitable for mass production that ensures reliable mechanical / mechanical joining and maintains stable after fixing.

  (S2) (S22) resist coating process, (S3) (S23) photomask process, (S4) (S24) development fixing process, (S5) (S25) plating process, (S6) Resist removing step shown in (S26), polyimide lamination step shown in (S7) and (S27), polyimide pressure-bonding step shown in (S8) and (S28), etching step shown in (S9) and (S29), (S10) ( The forming steps shown in S30) have substantially the same contents, and the S numbers are only matched before and after.

  FIG. 8 is an enlarged cross-sectional view of a portion B shown in step S33 of FIG. 7, where (a) shows a state during joining and (b) shows a state after joining. As shown in FIG. 8 (a), the adhesive 12 contains spherical metal particles 12a. As shown in FIG. 8 (b), the bonding surface 7a 'is pressed against the wiring conductor 13a. The spherical metal particles 12a are crushed and exhibit a function as a conductive medium between the joint surface 7a 'and the substrate 13a.

  Note that an anisotropic conductive paste (ACP) may be adopted for the adhesive 12, and in the case of ACP, it exhibits conductivity only in the pressurized direction, and the reason can be seen from FIG. 8 (b). This is because the conductive metal particles 12a sandwiched and crushed between the metals to be joined by pressure bonding can ensure an electrically conductive state with a wide contact area. Such metal particles 12a have a uniform sphere diameter, so that the total sum of the areas to be pressed is maximized and the electrical contact is improved. If the diameters are not uniform, there will be a difference in the degree of crushing of the metal particles 12a sandwiched between the gaps of the metals to be joined, and the relatively small grains may not be crushed at all and may not come into contact with each other. The function as a conductive medium cannot be exhibited.

  The present invention has a remarkable effect against the background of the establishment of a technique for uniformizing the diameter of the spheres of metal fine particles mixed in ACP. In this embodiment, the ACP mixed with silver balls having a diameter of about several μm is excellent as a conductive medium because the silver balls etc. that are heat-pressed in a state of being sandwiched between the metal and flattened are flattened. It functions and is strongly bonded by the base thermosetting epoxy. However, at present, the ACP metal balls are expensive, and it is desirable to exhibit conductivity in a direction other than the crushed direction. Therefore, it is desirable to use conductive metal particles 12a not limited to ACP.

  Since the conduction mechanism of ACP is generally understood and well known, further detailed explanation is omitted, but the metal that becomes the conductive medium that is flattened by being sandwiched between the gaps between the metals to be joined is Sn-based. In the case of solder mixed with Pb, Ag, Cu, etc., it can be explained by a conductive mechanism close to soldering, and in the case of ACP, the necessary and sufficient conductivity can be ensured if pressure contact is conducted. There is no need for heat welding as in soldering. In other words, pressure contact conduction between dissimilar metals is the main, and welding is an auxiliary element, so there is no need for high-temperature heating exceeding the melting point of the metal, and a heating temperature that cures the thermosetting adhesive is sufficient. .

  9A and 9B are cross-sectional views of the microconnector according to the third embodiment, in which FIG. 9A shows a state where sheet-like connection terminals are placed, and FIG. (C) is the state which clamped the microconnector.

  As shown in FIG. 9A, the sheet-like contact 20 is bonded so as to protrude on one surface of the polyimide plate 8 by the thermocompression bonding steps S14 and S33 shown in the first embodiment or the second embodiment. The spiral contact 7 thus formed is configured such that two sheets are bonded together back to back so as to protrude from both sides of the polyimide plate 8. The spiral contact 7 of the sheet-like contact 20 is placed at a position in contact with the wiring conductor 13 a on the substrate 13.

  Next, as shown in FIG. 9B, the FPC board 17 is overlaid so that the wiring conductor 13a of the FPC board 17 is in contact with the spiral contactor 7, and then the polyimide as shown in FIG. 9C. By sandwiching the spiral contact 7 disposed on both surfaces of the plate 8 between the substrate 13 and the FPC 17, the conductivity of the respective wiring conductors 13a is ensured.

  That is, once the FPC board 17 is pressed by a pressure contact means (not shown), as shown in FIG. 9C, the spiral connection terminals 7 and 7 arranged on both surfaces are connected to the wiring conductor 13a of the board 13 and the FPC. The wiring conductor 13a provided on the substrate 7 is elastically deformed into a flat plate shape while being energized to make electrical connection. As a result, the contacts of the spiral connection terminals 7 and 7 disposed on both the upper and lower surfaces of the sheet-like connection terminal 20 can improve the reliability of electrical connection.

It is an expanded sectional view which shows the first 6 processes among the joining methods of the spiral contactor which concerns on embodiment. It is an expanded sectional view which shows 6 processes following FIG. FIG. 3 is an enlarged cross-sectional view showing three steps immediately after completion following FIG. 2. It is an expanded sectional view of the A part in the joint surface shown to S15 process of FIG. 3, (a) has shown before joining, (b) has shown after joining. It is an expanded sectional view which shows the first 6 processes among the joining methods of the spiral contactor which concerns on 2nd Embodiment. FIG. 6 is an enlarged cross-sectional view showing five steps following FIG. 5. FIG. 7 is an enlarged cross-sectional view showing three steps just before completion following FIG. 6. It is an expanded sectional view of B section shown to S34 process of FIG. 7, (a) is in the middle of joining, (b) has shown after joining. It is sectional drawing of the microconnector which concerns on 3rd Embodiment, (a) is the state which mounted the sheet-like connection terminal, (b) is a mode that each terminal approaches the other party which an FPC board connects, (c ) Is a state where the micro connector is clamped. It is a top view of the spiral contactor which is background art of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Copper foil 1a Plating surface 2 Punch 3 Indentation 4 Punch processing surface 5 Photoresist 5a Fixing resist 6 Photomask 7 Spiral contact 7a, 7a 'Joining surface 7b Spike 7c Outermost peripheral part 8 Polyimide board 8a Hole 9 Pallet jig 10 Cone jig 11 Plate 12 (thermosetting type) adhesive 12a Metal particle 13 Substrate 13a Wiring conductor ACP Anisotropic conductive paste SC Spiral contactor

Claims (4)

An embossing step (S1) for forming a depression (3) at a predetermined position of the copper foil (1);
A resist coating step (S2) for applying a photosensitive resist (5) to the punched surface (4) of the copper foil (1);
A photomask step (S3) for closely contacting or projecting the photomask (6);
A developing and fixing step (S4) of exposing and developing to form a fixing resist (5a);
A plating step (S5) for forming a spiral contact (7) with a metal coating;
A resist removing step (S6) for removing the fixing resist (5a);
Polyimide which laminates the polyimide plate (8) having a hole (8a) through which the inner periphery of the spiral contact (7) can project in alignment with the plated surface (1a) of the copper foil (1). A laminating step (S7);
A polyimide pressure bonding step (S8) in which the polyimide plate (8) is heat bonded to the plated surface (1a) of the copper foil (1);
An etching step (S9) for removing the copper foil (1);
The polyimide plate (8) is attached to a pallet jig (9) for easy movement, and then the spiral contact (7) is covered with a conical jig (10) to form a three-dimensional shape and annealed. Forming process (S10) to be stored;
An adhesive application step (S11) for applying a thermosetting adhesive (12) containing a conductive material to a plate (11) as a jig for applying the adhesive (12);
An adhesive transfer step (S12) for transferring the adhesive (12) applied to the plate (11) to the outermost joint surface (7a) of the spiral contact (7);
A bonding preparation step (S13) for aligning the bonding surface (7a) on the wiring conductor (13a) at a predetermined position on the substrate (13) before mounting;
A thermocompression bonding step (S14) of thermocompression bonding the spiral contact (7) to the wiring conductor (13a) disposed on the surface layer of the substrate (13);
And a jig removing step (S15) for removing the pallet jig (9). The method for joining spiral contacts (7) according to claim 1, wherein metal particles (12a) having a uniform particle diameter are mixed in the adhesive (12) as a conductive medium. The adhesive (12) is based on a thermosetting epoxy, and the mixed metal particles (12a) contain either silver (Ag), tin (Sn), copper (Cu), or lead (Pb). The method of joining spiral contacts (7) according to claim 1 or 2 , characterized in that The claims 1, characterized in that plated gold (Au) to a thickness of 15~30μm a plating step (S5) below Cascade 0.5μm over plated with nickel (Ni) according to claim 3 The joining method of the spiral contactor (7) of any one of Claims.

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