Patent ID: 12208984

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

A tape affixing apparatus according to a preferred embodiment of the present invention will be described hereinbelow with reference to accompanying drawings.

(Tape Affixing Apparatus2)

As illustrated inFIG.1, a tape affixing apparatus, generally denoted by the reference sign2, includes at least a frame support table4for supporting an annular frame F thereon, a lifting and lowering unit6for lifting and lowering the frame support table4, a tape affixing unit8disposed in facing relation to the frame support table4, and a controller10. These components of the tape affixing apparatus2will be described in detail below.

(Lifting and Lowering Unit6)

The lifting and lowering unit6includes a vertically extending guide member12that supports the frame support table4such that the frame support table4can be lifted and lowered and a lifting and lowering mechanism, not illustrated, mounted on the guide member12. The lifting and lowering mechanism may be of a structure having a vertically extending ball screw that is operatively coupled to the frame support table4and that extends along the guide member12and an electric motor for rotating the ball screw about its central axis. When the lifting and lowering mechanism is actuated, it rotates the ball screw about its central axis, causing the frame support table4to be selectively lifted and lowered along the guide member12.

(Tape Affixing Unit8)

The tape affixing unit8includes a tape uncoiler14for paying out a tape T, a tape take-up reel16for winding up the tape T that has been used, and a presser roller18disposed between the tape uncoiler14and the tape take-up reel16and movable from one end to the other end of the annular frame F supported on the frame support table4while pressing the tape T paid out from the tape uncoiler14to affix the tape T to the annular frame F.

(Tape Uncoiler14of the Tape Affixing Unit8)

The tape uncoiler14includes a support roller20for supporting thereon a tape roll R of the tape T rolled into a tubular form before it is used, a delivery roller22disposed below the support roller20, an electric motor, not illustrated, for rotating the delivery roller22about its central axis, and a driven roller24rotatably held against the delivery roller22with the tape T paid out from the tape roll R interposed therebetween, the driven roller24being rotatable as the delivery roller22rotates. The tape T of the tape roll R is combined with a peel-off sheet P affixed to one surface of the tape T. Therefore, the tape roll R is made up of the tape T and the peel-off sheet P that are affixed to each other and coiled together.

The tape uncoiler14operates as follows. When the electric motor is energized, it rotates the delivery roller22, rotating the driven roller24in unison therewith, thereby pulling the tape T from the tape roll R. The tape T thus supplied from the tape roll R is sandwiched between the delivery roller22and the driven roller24. When the tape T has passed between the delivery roller22and the driven roller24, the peel-off sheet P is peeled off from the tape T and trained around the driven roller24to be wound up by a peel-off sheet roller26for retrieval.

(Tape Take-Up Reel16of the Tape Affixing Unit8)

The tape take-up reel16includes a take-up roller28for winding up the tape T that has been used, an electric motor, not illustrated, for rotating the take-up roller28about its central axis, and a pair of parallel guide rollers30disposed between the delivery roller22and the take-up roller28. One of the guide rollers30that is closer to the frame support table4is lower than the other of the guide rollers30.

The tape take-up reel16operates as follows: When the electric motor is energized, it rotates the tape take-up roller28about its central axis, pulling the used tape T where a circular opening To (seeFIG.1) has been left by a circular tape blanked out of the tape T from the tape roll R. When pulled, the used tape T is guided by the guide rollers30and wound up by the take-up roller28.

(Presser Roller18of the Tape Affixing Unit8)

As illustrated inFIGS.2and3, the presser roller18that can be lifted and lowered by presser roller positioning means, not illustrated, is positioned selectively in an upper standby position illustrated inFIG.2and a lower pressing position illustrated inFIG.3. While being positioned in the lower pressing position, the presser roller18can be moved in a Y-axis direction by presser roller moving means, not illustrated.

The Y-axis direction is indicated by the arrow Y inFIGS.1through5. An X-axis direction is indicated by the arrow X inFIGS.1through5and is perpendicular to the Y-axis direction. A Z-axis direction is indicated by the arrow Z inFIGS.1through5and represents a vertical direction perpendicular to the X-axis direction and the Y-axis direction. An XY plane that is defined by the X-axis direction and the Y-axis direction lies substantially horizontal.

(Cutting Mechanism32of the Tape Affixing Unit8)

According to the present embodiment, as illustrated inFIG.1, the tape affixing unit8includes a cutting mechanism32including a circular cutter44rotatable in abutment against the annular frame F to blank a circular tape out of the tape T. The cutting mechanism32includes a Z-axis guide member34extending in the Z-axis direction, a Z-axis movable member36movably supported on the Z-axis guide member34for movement in the Z-axis direction, and Z-axis feed means, not illustrated, for moving the Z-axis movable member36in the Z-axis direction. The Z-axis feed means may have a ball screw operatively coupled to the Z-axis movable member36and extending in the Z-axis direction and an electric motor for rotating the ball screw about its central axis.

The cutting mechanism32also includes an electric motor38fixed to a lower surface of the distal end of the Z-axis movable member36and an arm40rotatably coupled to the electric motor38for rotation about an axis extending in the Z-axis direction. The arm40has a lower surface from which first and second support plates42aand42bhang at respective positions spaced from each other. The circular cutter44is rotatably supported on the first support plate42afor rotation about an axis perpendicular to the Z-axis direction. When the circular cutter44is rotated about the axis, it follows a circular path along the outer circumferential edge of an annular frame F placed on the frame support table4. A presser roller46is rotatably supported on the second support plate42bfor rotation about an axis perpendicular to the Z-axis direction.

(Controller10)

The controller10includes a computer having a central processing unit (CPU) for performing arithmetic processing operations according to control programs, a read only memory (ROM) for storing the control programs, etc., and a read/write random access memory (RAM) for storing results of the arithmetic processing operations performed by the CPU. The controller10controls operation of the lifting and lowering unit6and the tape affixing unit8.

(Annular Frame F)

The annular frame F to which the tape T is affixed by the tape affixing apparatus2is of an annular shape having a circular opening Fa defined centrally therein for accommodating a wafer therein.

(Tape T)

The tape T may include an adhesive tape having a sticky layer, i.e., a glue layer, on a surface thereof or a thermocompression bonding sheet having no sticky layer. The thermocompression bonding sheet includes a sheet of thermoplastic synthetic resin, e.g., polyolefin resin, which can be softened or fused to develop sticky power when heated to a temperature in the vicinity of its melting point.

The peel-off sheet P is affixed to the sticky layer of the adhesive tape. On the other hand, the peel-off sheet P may be affixed or may not be affixed to a pressure-bonding surface of the thermocompression bonding sheet. In a case where a thermocompression bonding sheet free of the peel-off sheet P is used as the tape T, the tape affixing apparatus2may not include the peel-off sheet roller26as it does not need to retrieve the peel-off sheet P.

In a case where the tape T includes a thermocompression bonding sheet, at least one of the frame support table4and the presser roller18incorporates a heater and a temperature sensor, both not illustrated. When the thermocompression bonding sheet is affixed to the annular frame F, at least one of the frame support table4and the presser roller18is heated by the heater to a temperature in the vicinity of the melting point of the thermocompression bonding sheet.

Operation of the tape affixing apparatus2thus constructed will be described below. First, before an annular frame F is placed on the frame support table4, the frame support table4is placed in a position capable of receiving an annular frame F, i.e., the position illustrated inFIGS.1and2, and the presser roller18is put in the upper standby position. The tape T is paid out from the tape roll R. After the peel-off sheet P has been peeled off from the tape T by the driven roller24, the tape T is positioned above the frame support table4while being kept taut without slackening over the frame support table4. In a case where the tape T includes an adhesive tape, the sticky layer thereof faces downwardly toward the frame support table4.

Then, an annular frame F unloaded from frame storage means, not illustrated, that houses a plurality of annular frames F by frame unloading means, not illustrated, is placed on the frame support table4. The controller10actuates the lifting and lowering unit6and the presser roller positioning means to position the frame support table4in an affixation start position and also to position the presser roller18in the lower pressing position as illustrated inFIG.3, thereby affixing the tape T to one end of the annular frame F on the frame support table4while applying tension to the tape T.

When the frame support table4is positioned in the affixation start position and the presser roller18is positioned in the lower pressing position, as described above, the tape T over the frame support table4is pressed downwardly by the presser roller18at one end of the annular frame F and slanted at an elevation angle α upwardly from the presser roller18toward the lower guide roller30, as illustrated inFIG.3.

Then, while the presser roller18is pressing the tape T downwardly against the annular frame F, the presser roller moving means rollingly moves the presser roller18toward the other end of the annular frame F in the Y-axis direction. The tape T can thus be affixed to the annular frame F while the tape T is being kept under uniform tension.

When the presser roller18is rollingly moved in the Y-axis direction by the presser roller moving means, it is important to keep the tension applied to the tape T constant by lifting the frame support table4with the lifting and lowering unit6in synchronism with the presser roller18as it is moved. Specifically, as illustrated inFIGS.4and5, the controller10controls the lifting and lowering unit6to lift the frame support table4progressively in synchronism with the presser roller18as it is moved, so that the elevation angle α is kept constant.

In a case where the tape T includes a thermocompression bonding sheet, the temperature of an upper surface of the frame support table4or the temperature of an outer circumferential surface of the presser roller18is adjusted to a temperature for softening or fusing the tape T, and then the presser roller18is rollingly moved in the Y-axis direction while keeping the tape T under constant tension, thereby thermocompression-bonding the tape T to the annular frame F. When the tape T is thermocompression-bonded to the annular frame F, the frame support table4is progressively lifted in synchronism with the presser roller18as it is moved, so that the elevation angle α is kept constant.

After the tape T has been affixed to the annular frame F, the circular cutter44and the presser roller46of the cutting mechanism32of the tape affixing unit8are lowered to press the circular cutter44against the tape T on the annular frame F and also to press the presser roller46against the annular frame F through the tape T from above. Then, the electric motor38is energized to rotate the arm40and move the circular cutter44and the presser roller46in a circle along the annular frame F. The circular cutter44thus moved cuts the tape T along the outer circumferential edge of the annular frame F, severing off a portion of the tape T protruding radially outwardly from the outer circumferential edge of the annular frame F, or in other words, blanking a circular tape out of the tape T and leaving the circular tape on the annular frame F.

Furthermore, since the presser roller46presses the annular frame F through the tape T from above, the annular frame F and the tape T are prevented from being shifted in position on the frame support table4while the circular cutter44is cutting the tape T. The tape T from which the circular tape has been blanked out, i.e., the used tape T where the circular opening To has been left by the circular tape blanked out of the tape T, is wound up by the tape take-up reel16.

Then, the frame support table4is lowered by the lifting and lowering unit6to a position where a tape-affixed annular frame F, i.e., the annular frame F with the blanked-out circular tape affixed thereto, can be delivered from the frame support table4. Thereafter, tape-affixed annular frame delivery means, not illustrated, delivers the tape-affixed annular frame F from the frame support table4to an apparatus, not illustrated, that affixes a wafer to the circular tape of the tape-affixed annular frame F while positioning the wafer in the opening Fa of the tape-affixed annular frame F. The wafer to be affixed to the tape T of the tape-affixed annular frame F may include a wafer50illustrated inFIG.6Aor a wafer50′ illustrated inFIG.6B, for example.

The wafer50illustrated inFIG.6Ahas a face side50ahaving a device region56that includes a plurality of devices52such as ICs or LSI circuits formed in respective areas demarcated by a grid of projected dicing lines54and an outer circumferential excess region58surrounding the device region56. InFIG.6A, a boundary60between the device region56and the outer circumferential excess region58is indicated by two-dot-and-dash lines for illustrative purposes. Actually, however, lines representing the boundary60do not exist on the wafer50.

The wafer50has a reverse side50bon which a ring-shaped protruding stiffener62is formed on and along the outer circumferential excess region58. The ring-shaped protruding stiffener62is thicker than the device region56. The wafer to be affixed to the circular tape of the tape-affixed annular frame F may be free of any ring-shaped protruding stiffener. For example, the wafer50′ illustrated inFIG.6Bhas no ring-shaped protruding stiffener on a reverse side50b′ opposite a face side50a′ thereof.

For affixing the wafer50to the circular tape, also referred to as a “tape T,” of the tape-affixed annular frame F, the reverse side50bof the wafer50may be affixed to the tape T as illustrated inFIG.7Aor the face side50aof the wafer50may be affixed to the tape T as illustrated inFIG.7B. For affixing the wafer50′ free of a ring-shaped stiffener to the tape T, the reverse side50b′ of the wafer50′ may be affixed to the tape T as illustrated inFIG.8Aor the face side50a′ of the wafer50′ may be affixed to the tape T as illustrated inFIG.8B.

According to the present embodiment, as described above, inasmuch as the tape T is affixed to the annular frame F while the tape T is being kept under uniform tension, the tape T is prevented from developing wrinkles when the wafer50or50′ is affixed to the tape T of the tape-affixed annular frame F.

After the wafer50with the ring-shaped stiffener62has been affixed to the tape T, an annular groove is formed in the wafer50along the base of the ring-shaped stiffener62by way of laser ablation on a laser processing apparatus or by way of cutting on a dicing apparatus. Then, the ring-shaped stiffener62is peeled off from the tape T. At this time, the tape T is prevented from developing wrinkles because the tape T has been affixed to the annular frame F while being kept under uniform tension according to the present embodiment.

More specifically, the tape affixing apparatus2is able to affix the tape T to the annular frame F while keeping the tape T under uniform tension large enough to prevent the tape T from developing wrinkles when the ring-shaped stiffener62is removed from the wafer50affixed to the tape T of the tape-affixed annular frame F.

As described above, since the tape affixing apparatus2according to the present embodiment prevents the tape T from developing wrinkles when the ring-shaped stiffener62is removed from the wafer50affixed to the tape T of the tape-affixed annular frame F, no trouble is caused at the time of dividing the wafer50into individual device chips.

The present invention is not limited to the details of the above described preferred embodiment. The scope of the invention is defined by the appended claims and all changes and modifications as fall within the equivalence of the scope of the claims are therefore to be embraced by the invention.