JP4634227B2 - Electronic component mounting apparatus and mounting method - Google Patents

Description

  The present invention relates to an electronic component mounting apparatus and mounting method for mounting an electronic component on a thin and flexible substrate.

  Along with the reduction in thickness of electronic devices, resin substrates having a thickness of 100 μm or less, for example, about 40 to 60 μm, are adopted as substrates on which semiconductor chips as electronic components used in the electronic devices are mounted.

  When mounting a semiconductor chip on the above substrate, a method of bonding (mounting) gold and tin by eutectic with heat and pressure, a method of bonding with an adhesive at the bonding boundary, and heat and pressure. A method of joining using ultrasonic vibration is known.

  Among them, the method of joining with ultrasonic vibration in combination with heat and pressure not only has a short time required for joining, but also has an advantage that it can be joined at a lower temperature than other joining methods. Bonding at a low temperature is indispensable for mounting a semiconductor chip with a narrower pitch in the future because it has little thermal effect due to thermal expansion or the like on mounting accuracy.

  In a mounting apparatus that also uses ultrasonic vibration, an adsorption portion is provided in an ultrasonic horn provided in a mounting head, and a semiconductor chip is adsorbed and held on the adsorption portion. On the other hand, when a semiconductor chip is mounted on a substrate, the substrate is supported by a mounting stage. A suction groove for sucking and holding the substrate is formed on the upper surface of the mounting stage to prevent the substrate from shifting during mounting.

  Then, when the semiconductor chip held by the suction portion of the ultrasonic horn is mounted on the substrate, the ultrasonic vibration of the ultrasonic horn is transmitted to the bonding interface between the semiconductor chip and the substrate. As a result, the semiconductor chip is mounted on the substrate by solid phase diffusion of the metal parts in contact with each other between the substrate and the semiconductor chip.

  Thus, when a semiconductor chip is mounted on a substrate, even if the thin and flexible substrate is sucked and held on the mounting stage, the substrate is not securely adhered to the upper surface of the mounting stage due to bending of the substrate. There is.

  In such a state, when the semiconductor chip is mounted on the substrate while applying ultrasonic vibration by the ultrasonic horn, the substrate held on the mounting stage by the semiconductor chip that is ultrasonically vibrated together with the ultrasonic horn is also in the same phase as the semiconductor chip. It may cause sonic vibration. In other words, the substrate may move with the semiconductor chip that vibrates ultrasonically on the mounting stage.

  When the substrate is ultrasonically vibrated together with the semiconductor chip, the ultrasonic vibration is difficult to act on the bonding interface between the substrate and the semiconductor chip. For this reason, the semiconductor chip is not surely mounted on the substrate, and a desired bonding strength may not be obtained.

  In order to apply ultrasonic vibration having sufficient strength to the bonding interface between the substrate and the semiconductor chip, it is conceivable to increase the ultrasonic vibration, that is, increase the amplitude of the vibration. However, if the ultrasonic vibration is increased to obtain the bonding strength, the vibration may damage the semiconductor chip, which is not preferable.

  SUMMARY OF THE INVENTION An object of the present invention is to provide an electronic component mounting apparatus and mounting method capable of reliably bonding an electronic component to a substrate without increasing ultrasonic vibration.

The present invention is a mounting apparatus for mounting an electronic component on a flexible substrate,
A mounting head having an ultrasonic horn for holding the electronic component and applying ultrasonic vibration to the electronic component;
A mounting stage provided with a convex portion for supporting a portion on which the electronic component is mounted by at least the mounting head of the substrate;
The board has a pair of holding members that hold and fix the board so that the board cannot move. When the electronic component is mounted on the board by the mounting head, the electronic parts of the board held and fixed by the holding member are mounted. A holding means for mechanically holding the substrate on the mounting stage so as to be elastically deformed by pressing the portion against the convex portion ;
An opening corresponding to the convex portion is formed in the pair of sandwiching members, and at least one of the pair of sandwiching members or the mounting stage is in a state where the upper and lower surfaces of the substrate are sandwiched and fixed by the pair of sandwiching members. The electronic component mounting apparatus is characterized in that when driven, the convex portion enters the opening, and elastically deforms the portion of the substrate on which the electronic component is mounted .

  The holding means is preferably a clamp member that presses and holds the substrate supported by the mounting stage on the mounting stage.

The present invention is a mounting method for mounting an electronic component on a flexible substrate,
Positioning the substrate with respect to a mounting stage having a convex portion that supports a portion on which the electronic component of the substrate is mounted ;
Mounting the electronic component on the substrate positioned while applying ultrasonic vibration to the electronic component;
When mounting the electronic component on the substrate, the substrate is held immovably by a pair of clamping members formed with openings corresponding to the convex portions, and a portion of the substrate on which the electronic component is mounted is mounted. The convex part is pressed into contact with the convex part, and the convex part enters the opening to elastically deform a portion of the substrate on which the electronic component is mounted, and the substrate is mechanically held and fixed to the mounting stage so as not to move. Process,
An electronic component mounting method characterized by comprising:

  According to the present invention, when mounting the electronic component on the substrate while applying ultrasonic vibration to the electronic component, the ultrasonic vibration of the electronic component is transmitted to the substrate in order to hold the substrate mechanically immovable with respect to the mounting stage. In this case, it is possible to prevent the substrate from vibrating on the mounting stage due to vibration with the electronic component. As a result, the electronic component can be securely bonded to the substrate.

  Embodiments of the present invention will be described below with reference to the drawings.

  1 to 5 show an embodiment of the present invention, and the flip chip type mounting apparatus shown in FIG. 1 includes a wafer stage 1 as a component supply unit. The wafer stage 1 has an X table 3, a Y table 4 and a θ table 5 sequentially provided on a base 2, and a wafer holder 8 on which a semiconductor wafer 7 is held as described later is provided on the θ table 5. ing. That is, the wafer holder 8 is provided so as to be driven in the horizontal direction. The semiconductor wafer 7 is divided into semiconductor chips 6 which are a large number of square electronic components.

  The semiconductor chip 6 is taken out by a pickup tool 11 constituting a pickup device. The pickup tool 11 is L-shaped and can be driven to rotate within a range of 180 degrees between a position indicated by a chain line and a position indicated by a solid line in FIG. A suction nozzle 13 that vacuum-sucks 6 is provided. Further, the pickup tool 11 can be driven in the X, Y direction (horizontal direction) and Z direction (vertical direction) by a driving means (not shown).

  The base 2 is provided with a support 15 at a position facing the wafer stage 1. On the upper surface of the support 15, a first base 16 having one end fixed to the support 15 and the other end protruding in the direction of the wafer stage 1 is provided horizontally. A stage table 17 is provided on the upper surface of the other end of the first base 16.

  The stage table 17 is provided with a Y table 18, an X table 19 provided on the Y table 18 and driven in the X direction to be in contact with and away from the wafer stage 1, and the X and Y provided on the X table 19. The mounting stage 20 is driven in the direction. The mounting stage 20 can be driven in a Z direction orthogonal to a plane formed by the X and Y directions by a driving source (not shown). The mounting stage 20 is provided with a heater (not shown), and a rectangular convex portion 20a is provided on the upper surface.

  A conveyance guide 21 is provided above the mounting stage 20. A substrate 22 having a thickness of 100 μm or less, for example, 40 to 50 μm, on which the semiconductor chip 6 taken out from the wafer holder 8 is mounted by the pickup tool 11 as will be described later is transported to the transport guide 21 in a predetermined direction. It has become so.

  The substrate 22 is formed of a thin material having a thickness of 100 μm or less, that is, a material that is elastically deformable, such as polyimide. When the substrate 22 is cut to a predetermined length, the pitch is fed.

  A second base 25 is provided horizontally at one end of the first base 16 with a first spacer fixed via a first spacer 24. The second base 25 is shorter in length than the first base 16, and the other end protrudes toward the wafer stage 1.

  A camera table 26 is provided on the upper surface of the other end of the second base 25. The camera table 26 has a Y table 27. On the Y table 27, an X table 28 driven in the X direction is provided. On the X table 28, an attachment member 29 driven in the X and Y directions is provided.

  The attachment member 29 is provided with a camera unit 31. The camera unit 31 has a case 31a formed in a hollow box shape as shown in FIG. 2, and a first camera that images the substrate 22 transported along the transport guide 21 in the case 31a. 32 and a second camera 33 that images the semiconductor chip 6 delivered from the pickup tool 11 to a mounting tool 50 described later. Each of the cameras 32 and 33 is composed of a CCD (solid state imaging device).

  Imaging windows 36 are respectively formed on the lower surface and the upper surface of the tip of the camera unit 31. A mirror 38 having two reflecting surfaces 37 inclined at an angle of 45 degrees with respect to the imaging window 36 is accommodated in the distal end portion of the camera unit 31. Light incident from the lower imaging window 36 and reflected by one reflecting surface 37 enters the first camera 32. Light incident from the upper imaging window 36 and reflected by the other reflecting surface 37 enters the second camera 33.

  As shown in FIG. 2, the image pickup signals from the cameras 32 and 33 are input to an image processing unit (not shown) provided in the control device 39, where they are processed and converted into digital signals. ing. The control device 39 is provided on the support 15 as shown in FIG.

  As shown in FIG. 1, a third spacer 41 is provided on the upper surface of one end of the second base 25. The third spacer 41 is provided with a fourth base 42 horizontally with one end fixed. A head table 43 is provided on the upper surface of the other end of the fourth base 42. The head table 43 has a Y table 44. An X table 45 driven in the X direction is provided on the upper surface of the Y table 44. An attachment body 46 that is driven in the X and Y directions is provided on the upper surface of the X table 45.

  A Z table 47 is provided on the front end surface of the mounting body 46, and a mounting head 48 driven in the Z direction perpendicular to the plane formed by the X direction and the Y direction is provided on the Z table 47. Yes. A θ table 49 is provided at the tip of the mounting head 48, and the mounting tool 50 including the ultrasonic horn 52 having the suction portion 51 is provided on the θ table 49.

  When the pick-up tool 11 picks up the semiconductor chip 6 from the wafer holder 8, the pick-up tool 11 rotates about 180 degrees in the clockwise direction indicated by the arrow in FIG. The nozzle 13 is directed upward. That is, the semiconductor chip 6 is inverted so that the upper and lower surfaces are reversed.

  In this state, the head table 43 operates to position the mounting head 48 above the suction nozzle 13 of the pickup tool 11. Next, when the pickup tool 11 is raised, the suction portion 51 of the ultrasonic horn 52 provided in the mounting head 48 receives the semiconductor chip 6 sucked and held by the suction nozzle 13.

  The wafer stage 1, the pickup tool 11, the stage table 17 provided with the mounting stage 20, the camera table 26 provided with the camera unit 31, and the head table 43 provided with the mounting tool 50 are driven by the control device 39. To be controlled.

  The wafer holder 8 is held horizontally on the upper surface of a support 60 whose lower end is attached to the θ table 5. A wafer ring (both not shown) on which an adhesive sheet is stretched is detachably held on the wafer holder 8. The semiconductor wafer 7 diced into a large number of rectangular semiconductor chips 6 is attached to the upper surface of the adhesive sheet.

  On the lower surface side of the pressure-sensitive adhesive sheet, a backup body 65 fixed to a fixing portion (not shown) is arranged in a state not interlocking with the horizontal movement of the wafer holder 8. A suction hole 64 penetrating in the axial direction is formed in the central portion of the backup body 65. A suction pump 66 is connected to the suction hole 64.

  The wafer holder 8 is positioned at a height where the lower surface of the adhesive sheet contacts the upper surface of the backup body 65 where the suction hole 64 is opened. Furthermore, the semiconductor chip 6 attached to the upper surface of the adhesive sheet is imaged by an imaging camera 67 disposed above the wafer holder 8.

  The control device 39 moves the wafer holder 8 in the horizontal direction so that the semiconductor chip 6 picked up by the suction nozzle 13 is positioned corresponding to the suction hole 64 of the backup body 65 based on the imaging signal from the imaging camera 67. To position.

  The positioned semiconductor chip 6 is sucked by the suction nozzle 13. The suction nozzle 13 that sucks the semiconductor chip 6 rotates 180 degrees from the state shown by the chain line in FIG. 1 and turns upward. In this state, the lower end of the suction portion 51 of the ultrasonic horn 52 provided on the mounting head 48 is positioned so as to face the semiconductor chip 6 sucked and held by the suction nozzle 13.

  After positioning or at the time of positioning, the mounting head 48 descends to a position where the lower end surface of the suction portion 51 comes into contact with the semiconductor chip 6 and sucks the semiconductor chip 6 to the tip. The mounting head 48 adsorbing the semiconductor chip 6 rises and returns to above the substrate 22 and then descends, and the semiconductor chip 6 is mounted on the mounting portion of the substrate 22 as described later.

  When the semiconductor chip 6 is mounted on the substrate 22, the substrate 22 is mechanically held and fixed by holding means. As shown in FIGS. 3 to 5, the holding means has a pair of flat plate-like sandwiching members 71a and 71b. The pair of sandwiching members 71a and 71b are disposed so as to face the upper and lower surfaces of the substrate 22 supported by the transport guide 21, and the substrate 22 is shown in FIG. 3 by the opening / closing drive mechanism 72 (shown in FIG. 5). As shown in FIG. 5, the holding state is driven and the holding state is released as shown in FIG.

  Rectangular openings 73a and 73b are formed in the pair of clamping members 71a and 71b, respectively. The openings 73a and 73b are formed in such a size that the protrusion 20a protruding from the upper surface of the mounting stage 20 can enter. That is, when the pair of clamping members 71a and 71b clamp the substrate 22, the mounting stage 20 is driven in the upward direction.

  As a result, the protrusion 20a enters the opening 73a of the lower holding member 71a and the opening 73b of the upper holding member 71b as shown in FIG. When entering the opening 73b of the upper clamping member 71b, the flexible substrate 22 is elastically deformed along the shape of the upper surface side of the convex portion 20a by the convex portion 20a.

  As shown in FIG. 5, the opening / closing drive mechanism 72 has a lower drive source 74 and an upper drive source 75 whose drive is controlled by the control device 39. The drive sources 74 and 75 are provided with drive shafts 74a and 75a that are driven back and forth in the axial direction. Cams 76 and 77 having inclined surfaces inclined at an angle of 45 degrees are provided at the tips of the drive shafts 74a and 75a, respectively, with the inclined surfaces inclined in the opposite directions.

  Cam followers 81 and 82, which are rotatably provided on one side of the movable bodies 78 and 79, are in rolling contact with the inclined surfaces of the cams 76 and 77, respectively. The pair of movable bodies 78 and 79 are provided so as to be movable in the vertical direction along the linear guide 83. The lower movable body 78 is elastically urged in the upward direction by a spring (not shown), and the upper movable body 79 is elastically urged in the downward direction by a spring (not shown). That is, the movable bodies 78 and 79 are biased in the direction in which the cam followers 81 and 82 are pressed against the inclined surfaces of the cams 76 and 77.

  Attachment members 84 and 85 are connected to the other side surfaces of the pair of movable bodies 78 and 79 at one end, and these attachment members 84 and 85 extend along the width direction of the substrate 22. One end and the other end of the pair of upper and lower clamping members 71a and 71b are connected and fixed to the mounting members 84 and 85 via connecting members 84a and 85a, respectively.

  Therefore, if the drive shafts 74a and 74b are driven forward and backward in the axial direction by the pair of drive sources 74 and 75, the pair of upper and lower clamping members 71a and 71b are driven in the closing direction or the opening direction depending on the driving direction. Will be.

  When the semiconductor chip 6 is mounted on the substrate 22 by the mounting apparatus having such a configuration, the substrate 22 is transported along the transport guide 21 with the pair of clamping members 71a and 71b being opened. When the portion of the substrate 22 on which the semiconductor chip 6 is mounted is transported to a position facing the convex portion 20a of the mounting stage 20, the transport of the substrate 22 is stopped and the pair of clamping members 71a and 71b are driven in the closing direction. The Thereby, the portion of the substrate 22 corresponding to the mounting stage 20 is clamped and fixed by a pair of clamping members 71a and 71b as shown in FIG.

  If the substrate 22 is sandwiched between the pair of sandwiching members 71a and 71b, the mounting stage 20 is raised, and the convex portion 20a provided on the upper surface of the substrate 22 extends from the opening 73a of the lower sandwiching member 71a to the upper sandwiching member 71b. Enter the opening 73b. Accordingly, the substrate 22 is elastically deformed so as to wrap around the upper surface of the convex portion 20a, and is in close contact with the upper surface of the convex portion 20a.

  When the mounting stage 20 is raised, the semiconductor chip 6 sucked and held by the suction portion 51 of the ultrasonic horn 52 of the mounting head 48 is positioned above the convex portion 20 a of the mounting stage 20. Next, the mounting head 48 is lowered, and the semiconductor chip 6 ultrasonically vibrated by the ultrasonic horn 52 is brought into pressure contact with the portion of the substrate 22 that is held in close contact with the convex portion 20a.

  As a result, the semiconductor chip 6 is bonded to the substrate 22, that is, mounted by the pressure applied by the mounting head 48, the heat of a heater (not shown) provided on the mounting stage 20, and the ultrasonic vibration by the ultrasonic horn 52. .

  The substrate 22 is held by a pair of holding members 71a and 71b, and is held in a state of being elastically deformed by being pressed against the convex portion 20a of the mounting stage 20. That is, the substrate 22 is mechanically held with respect to the mounting stage 20 by the pair of clamping members 71a and 71b.

  For this reason, when the semiconductor chip 6 is mounted on the substrate 22, even if the ultrasonic vibration of the ultrasonic horn 52 is transmitted to the substrate 22, the substrate 22 is displaced with respect to the convex portion 20 a by the ultrasonic vibration. Absent.

  Therefore, since the ultrasonic vibration generated by the ultrasonic horn 52 effectively acts on the bonding interface between the substrate 22 and the semiconductor chip 6, the semiconductor chip 6 can be reliably mounted on the substrate 22. That is, since the semiconductor chip 6 can be reliably bonded to the substrate 22 without increasing the output of the ultrasonic horn 52, the semiconductor chip 6 is not damaged by the energy of ultrasonic vibration.

  Since the substrate 22 is elastically deformed, a part of the substrate 22, that is, a portion where the semiconductor chip 6 is mounted can be brought into close contact with the convex portion 20a. For this reason, the heat of the mounting stage 20 is efficiently transferred from the convex portion 20a to the substrate 22, so that the semiconductor chip 6 can also be mounted reliably.

  In addition, since the substrate 22 does not loosen due to the close contact with the convex portion 20a, the substrate 22 does not interfere with the observation when the vibration of the semiconductor chip 6 is observed with a laser Doppler.

  In the above embodiment, the pair of sandwiching members 71a and 71b that sandwich the substrate 22 are formed in a flat plate shape having the openings 73a and 73b into which the convex portions 20a of the mounting stage 20 enter. A pair of band plate-like or bar-like holding members that respectively hold both ends of the substrate 22 in the width direction may be provided, and both ends of the substrate 22 in the width direction may be held and fixed by these holding members. In the case where the sandwiching member is a pair of strips or rods, not only the width direction of the substrate 22 but also the structure in which both ends are sandwiched simultaneously in the direction orthogonal to the width direction may be used.

  When the substrate 22 is elastically deformed by the convex portion 20a of the mounting stage 20, the mounting stage 20 is driven in the upward direction. However, the clamping member may be lowered, or the mounting stage 20 is raised and the clamping member is lowered. You may make it make it. In short, it is only necessary to drive at least one of the mounting stage and the clamping member so that the substrate 22 can be elastically deformed by the convex portion 20a.

  FIG. 6 shows another embodiment of the present invention. In this embodiment, the convex portion 20a is not formed on the upper surface of the mounting stage 20, and instead, a pair of suction grooves 86 for adsorbing and holding both end portions in the width direction of the lower surface of the substrate 22 are formed.

  On the upper surface side of the mounting stage 20, a flat clamp member 88 having an opening 87 formed in the center is disposed. Both ends of the clamp member 88 in the width direction are connected to rods 89a of a pair of cylinders 89 as vertical drive sources. Therefore, when each cylinder 89 operates, the clamp member 88 is driven up and down.

  When the clamp member 88 is driven in the downward direction by the cylinder 89, the substrate 22 positioned on the upper surface of the mounting stage 20 can be mechanically held and fixed on the upper surface of the mounting stage 20 by the clamp member 88. .

  Therefore, when the mounting head 48 is lowered and the semiconductor chip 6 sucked and held by the suction portion 51 of the ultrasonic horn 52 is joined to the substrate 22, if the substrate 22 is held and fixed by the clamp member 88, the substrate 22 is The ultrasonic vibration from the ultrasonic horn 52 prevents the movement on the mounting stage 20. That is, compared to the case where the substrate 22 is held on the upper surface of the mounting stage 20 only by the suction groove 86, the substrate 22 is less likely to be displaced on the mounting stage 20 due to ultrasonic vibration, so that the semiconductor chip 6 is reliably bonded. Is possible.

  If the substrate 22 can be mechanically firmly held and fixed to the mounting stage 20 by the clamp member 88, the suction groove 86 may not be formed on the upper surface of the mounting stage 20.

  In addition, the clamp member is divided into two strips instead of a single plate, and can be driven up and down by a cylinder, so that both end portions in the width direction of the substrate are placed on the upper surface of the mounting stage 20 by each clamp member. You may make it hold and fix.

BRIEF DESCRIPTION OF THE DRAWINGS The schematic block diagram of the mounting apparatus which shows one embodiment of this invention. Sectional drawing of the camera unit used for the said mounting apparatus. Sectional drawing which shows a mounting stage and a pair of clamping member. The perspective view which shows a mounting stage and a pair of clamping member. The schematic block diagram of the opening / closing drive mechanism which opens and closes a pair of clamping member. Sectional drawing of the mounting stage and clamp member which show other embodiment of this invention.

Explanation of symbols

  6 ... Semiconductor chip (electronic component), 20 ... Mounting stage, 20a ... Projection, 22 ... Substrate, 48 ... Mounting head, 52 ... Ultrasonic horn, 71a, 71b ... Nipping member (holding means), 73a, 73b ... Opening Part, 74,75 ... drive source, 88 ... clamp member, 87 ... opening.

Claims (3)

A mounting device for mounting an electronic component on a flexible substrate,
A mounting head having an ultrasonic horn for holding the electronic component and applying ultrasonic vibration to the electronic component;
A mounting stage provided with a convex portion for supporting a portion on which the electronic component is mounted by at least the mounting head of the substrate;
The board has a pair of holding members that hold and fix the board so that the board cannot move. When the electronic component is mounted on the board by the mounting head, the electronic parts of the board held and fixed by the holding member are mounted. A holding means for mechanically holding the substrate on the mounting stage so as to be elastically deformed by pressing the portion against the convex portion ;
An opening corresponding to the convex portion is formed in the pair of sandwiching members, and at least one of the pair of sandwiching members or the mounting stage is in a state where the upper and lower surfaces of the substrate are sandwiched and fixed by the pair of sandwiching members. An apparatus for mounting an electronic component, wherein the device is driven to elastically deform a portion of the substrate on which the electronic component is mounted by being driven into the opening .   2. The electronic component mounting apparatus according to claim 1, wherein the holding means is a clamp member that presses and holds the substrate supported by the mounting stage on the mounting stage. A mounting method for mounting an electronic component on a flexible substrate,
Positioning the substrate with respect to a mounting stage having a convex portion that supports a portion on which the electronic component of the substrate is mounted ;
Mounting the electronic component on the substrate positioned while applying ultrasonic vibration to the electronic component;
When mounting the electronic component on the substrate, the substrate is held immovably by a pair of clamping members formed with openings corresponding to the convex portions, and a portion of the substrate on which the electronic component is mounted is mounted. The convex part is pressed into contact with the convex part, and the convex part enters the opening to elastically deform a portion of the substrate on which the electronic component is mounted, and the substrate is mechanically held and fixed to the mounting stage so as not to move. Process,
An electronic component mounting method comprising the steps of:

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