Bonding apparatus and bonding method

Abstract

Provided are a bonding apparatus and a bonding method that make it possible to increase the productivity of a substrate such as a wafer in bonding bumps or wires on the substrate with a simple configuration.　A bonding stage (5) is formed from a first bonding stage (6) and a second bonding stage (8). The first bonding stage and the second bonding stage are arranged on a rotation table (25) having a θ-axis rotation mechanism (26) rotatable about a θ-axis (27) so as to face each other across the θ-axis and are configured such that the positions of the first bonding stage and the second bonding stage can be switched. The bonding apparatus (1) has an XY-movement mechanism (35) capable of moving the rotation table in the X and Y directions.

Description

Bonding apparatus and bonding method

[0001] The present invention relates to a bonding apparatus and a bonding method, and more particularly to a bonding apparatus and a bonding method for bonding bumps or wires to a substrate placed on a bonding stage.

[0002] 2. Description of the Related Art Bonding devices that form bumps as connection terminals on electrodes of semiconductor chips have been known.

[0003] Patent Document 1 discloses a bonding method for forming bumps on electrodes of a semiconductor chip formed on a wafer. According to Patent Document 1, an X-axis drive mechanism on which a bonding stage is mounted moves the bonding stage to a position where the carrier tape carrying the wafer is pulled out from a magazine, and the carrier tape pushed out of the magazine is transported to a wafer transfer position by the X-axis drive mechanism.

[0004] Thereafter, the bonding stage is moved to the wafer transfer position, the carrier tape is held on the bonding stage, and the bonding stage is moved to the bonding area by the X-axis drive mechanism, where bonding is performed after preheating.

[0005] After the wafer bonding is completed, the bonding stage is transported to the wafer transfer position by the X-axis drive mechanism, and the carrier tape is pushed out using the arm of the X-axis drive mechanism and stored in the magazine.Then, the carrier tape to be bonded next is pulled out from the magazine and bonding is performed.

[0006] Patent No. 6409033

[0007] In bump or wire bonding, the wafer placed on the bonding stage is replaced using the following procedure: Temperature control is important, especially for thin wafers, because rapid heating or cooling can cause the wafer to crack.

[0008] 1. To prevent the wafer from cracking due to the effects of heat, the bonding stage is maintained at a temperature of around several tens to 100°C, at which the wafer is less likely to crack, and the wafer is then mounted on the bonding stage. 2. After the wafer is mounted, the vacuum suction mechanism of the bonding stage is turned on to secure the wafer. 3. The heater of the bonding stage is also turned on to heat the wafer. 4. The bonding stage then moves to the bonding position. 5. It is confirmed that the temperature of the bonding stage has risen to the specified bonding temperature, and bonding begins. 6. After bonding is completed, the heater of the bonding stage is turned off. 7. The bonding stage is also moved to the cooling position. 8. The bonding stage is cooled by cooling air blowing or waits until the temperature of the bonding stage drops to the specified cooling temperature naturally. 9. Once the temperature of the bonding stage has gradually cooled to around several tens to 100°C (a temperature at which the wafer is less likely to crack due to heat), the wafer is removed from the bonding stage.

[0009] In this way, the wafer is mounted on the bonding stage, bonded, and the bonded wafer is removed. The procedure from step 1 is repeated for bonding the next wafer.

[0010] The above procedure requires heating time for the temperature of the bonding stage to rise from the standby temperature to the bonding temperature and cooling time for the temperature to fall from the bonding temperature to the standby temperature each time a wafer is bonded, and productivity is reduced because bonding cannot be performed during these heating and cooling periods.

[0011] As described above, with the conventional technology, after the wafer bonding is completed, it takes time to cool it down, exchange it, and then heat it up again. For example, it takes 6 to 7 minutes to cool it down from 150°C to 100°C, and about the same amount of time to heat it up from 100°C to 150°C after the wafer exchange.

[0012] For this reason, wafer exchange requires approximately 13 to 15 minutes, during which the bonding stage cannot be used for bonding, and therefore bonding operations are stopped.

[0013] In this situation, the inventors of the present invention have conducted extensive research and experimentation to improve upon the above-mentioned problems, and have come up with the idea of ​​the present invention, which solves the problem of conventional methods where the bonding operation is stopped during wafer replacement, wafer heating, and wafer cooling, by dividing the bonding stage into two stages, one for wafer replacement and one for bonding, and rotating the turntable on which the two bonding stages are mounted to switch between the stages for wafer replacement and bonding, so that while one stage is being used for wafer replacement, the other stage is performing bonding. This simple configuration reduces the loss of bonding operation time associated with wafer replacement and makes it possible to increase production numbers.

[0014] SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a bonding apparatus and a bonding method that can improve productivity of bonding substrates such as wafers with a simple configuration.

[0015] In order to achieve the above object, the bonding apparatus of the present invention is a bonding apparatus that bonds bumps or wires to a substrate placed on a bonding stage via a bonding head, the bonding stage consisting of a first bonding stage and a second bonding stage, the first bonding stage and the second bonding stage being arranged opposite each other via the θ axis on a rotary table having a θ axis rotation mechanism that can rotate around the θ axis, and the positions of the first bonding stage and the second bonding stage can be swapped by rotating the rotary table around the θ axis using the θ axis rotation mechanism, and the bonding apparatus is characterized by having an XY movement mechanism that can move the rotary table in the X and Y directions.

[0016] Furthermore, the first bonding stage and the second bonding stage in the bonding apparatus of the present invention are characterized in that they can be moved to a bonding area and a transfer position for the substrate outside the bonding apparatus by rotating the rotary table and moving it in the X and Y directions.

[0017] In addition, in the bonding apparatus of the present invention, each of the first bonding stage and the second bonding stage is characterized in that it is arranged on the rotary table so as to be freely rotatable around the center of the main surface of the substrate by a stage rotation mechanism.

[0018] Furthermore, a bonding method according to the present invention is a bonding method using a bonding apparatus that bonds bumps to a wafer placed on a bonding stage via a bonding head, the bonding stage comprising a first bonding stage and a second bonding stage, each having a heater and configured to be heatable, the first bonding stage and the second bonding stage being arranged opposite each other via the θ axis on a rotary table having a θ axis rotation mechanism that can rotate about the θ axis, and configured to allow the positions of the first bonding stage and the second bonding stage to be interchanged, the bonding apparatus having an XY movement mechanism that can move the rotary table in X and Y directions, and comprising a first step of heating a second wafer placed on the second bonding stage with the heater while bonding bumps to a first wafer placed on the first bonding stage and heated to a predetermined temperature by the heater, the first bonding stage on which the first wafer for which bonding has been completed is placed, a second step of rotating the rotary table to exchange the position of the second bonding stage on which the second wafer is placed; a third step of cooling the first wafer placed on the first bonding stage to the predetermined temperature by turning off the heater while bonding bumps to the second wafer that is placed on the second bonding stage and heated to a predetermined temperature by the heater; a fourth step of interrupting bonding of the second wafer placed on the second bonding stage when the first wafer placed on the first bonding stage has cooled to the predetermined temperature, moving the rotary table by the XY movement mechanism to move the first bonding stage to a wafer transfer position outside the bonding apparatus, discharging the first wafer, and carrying in a third wafer and placing it on the first bonding stage; and a fourth step of moving the rotary table by the XY movement mechanism to resume and continue bonding of the second wafer placed on the second bonding stage whileand a fifth step of heating the third wafer placed on the first bonding stage by the heater.

[0019] In addition, in the bonding method of the present invention, each of the first bonding stage and the second bonding stage is arranged on the rotary table so as to be freely rotatable around the center of the main surface of the wafer by a stage rotation mechanism, and the rotational movement expands the bondable area of ​​the wafer during bonding.

[0020] According to the present invention, the bonding stage consists of a first bonding stage and a second bonding stage, and the first bonding stage and the second bonding stage are arranged opposite each other via the θ axis on a rotary table having a θ axis rotation mechanism that can rotate about the θ axis, and is configured so that the positions of the first bonding stage and the second bonding stage can be swapped.By having an XY table that is an XY movement mechanism that can move the rotary table in the X and Y directions, it is possible to rotate the rotary table on which the two bonding stages are mounted and swap their positions, so that bonding can be performed on one bonding stage while wafer replacement is being performed on the other bonding stage, and this simple configuration makes it possible to reduce the loss of bonding operation time due to wafer replacement and increase the number of wafers produced.

[0021] According to the present invention, each of the first bonding stage and the second bonding stage is arranged on a rotary table so that it can be freely rotated around the center of the main surface of the wafer by a stage rotation mechanism, and therefore, during bonding, the rotation operation can expand the bondable area of ​​the first bonding stage or second bonding stage wafer.

[0022] According to the present invention, when the first wafer placed on the first bonding stage has cooled to a predetermined temperature, bonding to the second wafer placed on the second bonding stage is interrupted, the rotary table is moved by the XY movement mechanism to move the first bonding stage to a wafer transfer position outside the bonding apparatus, the first wafer is discharged, a third wafer is brought in and placed on the first bonding stage, the rotary table is moved by the XY movement mechanism to resume and continue bonding to the second wafer placed on the second bonding stage, and the third wafer placed on the first bonding stage is heated by a heater, so that the third wafer placed on the first bonding stage can be heated without waiting for the completion of bonding of the second wafer placed on the second bonding stage. This allows bonding of the second wafer placed on the second bonding stage and heating of the third wafer placed on the first bonding stage to be performed in parallel, thereby reducing wafer production loss due to heating time with a simple configuration.

[0023] Furthermore, if the temperature of one of the bonding stages holding a bonded wafer drops to a predetermined cooling temperature and the bonded wafer is not replaced until the other bonding stage has completed bonding, the temperature of the one bonding stage will drop further while it is waiting, and when the next wafer is replaced, the heating start temperature of the bonding stage will be lower, making it take time to heat the wafer.However, according to the present invention, it is possible to prevent the temperature of the bonded wafer from dropping while it is waiting.

[0024] Furthermore, according to the present invention, by interrupting bonding on one bonding stage, placing a new wafer on the bonding stage and heating it, and then resuming bonding after placing the wafer on the other bonding stage, it is possible to heat the wafer and bond it in parallel.

[0025] 1A and 1B are diagrams showing the configuration of a bonding apparatus that performs bump bonding on a wafer or the like, where (a) is a plan view and (b) is a front view. FIG. 1B is a perspective view showing the bonding stage, rotary table, and XY table of the bonding apparatus shown in FIG. 1. FIG. 1C is a flowchart showing the process in the initial state at the start of bonding. FIG. 1D is a diagram showing the operation of the rotary table and bonding stage in the initial state at the start of bonding. FIG. 1E is a diagram showing the operation of the rotary table and bonding stage in the initial state at the start of bonding. FIG. 1F is a diagram explaining the expansion of the bonding area of ​​a wafer placed on the bonding stage by the rotation operation of the stage rotation mechanism during bonding. FIG. 1G is a flowchart showing the operation of the rotary table and bonding stage in the bonding process. FIG. 1H is a diagram explaining the movement and rotation of the rotary table and the operation of the bonding stage in the bonding process. FIG. 1I is a diagram explaining the movement and rotation of the rotary table and the operation of the bonding stage in the bonding process. FIG. 1J is a flowchart showing the movement and rotation of the rotary table and the operation of the bonding stage when a wafer is received at a bonding position without moving the XY table in the bonding process. 10A and 10B are diagrams illustrating the movement and rotation of the rotary table and the operation of the bonding stage when a wafer is received at a bonding position without moving the XY table in the bonding process.

[0026]

[0013] The following describes embodiments of a bonding apparatus and bonding method according to the present invention, with reference to the drawings. The present invention provides a bonding apparatus and bonding method for bonding bumps or wires to a substrate placed on a bonding stage via a bonding head, the bonding stage comprising a first bonding stage and a second bonding stage, the first bonding stage and the second bonding stage being configured so that their positions can be swapped by rotating a rotary table, and the rotary table is provided with an XY movement mechanism that can move in the X and Y directions, so that while wafers are being exchanged on one bonding stage, bonding can be performed on the other bonding stage, and the present invention provides a bonding apparatus and bonding method that can improve productivity in bonding substrates such as wafers with a simple configuration.

[0027] [Configuration of Bonding Apparatus] First, the configuration of a bonding apparatus for performing bump bonding on a wafer or the like will be described with reference to Figures 1 and 2. Figure 1 shows the configuration of a bonding apparatus for performing bump bonding on a wafer or the like, with (a) being a plan view and (b) being a front view. Figure 2 is a perspective view showing the bonding stage, rotary table, and XY table of the bonding apparatus shown in Figure 1.

[0028] As shown in FIGS. 1A and 1B, the bonding apparatus 1 has a bonding stage 5, a rotary table 25, an XY table 35, and a bonding head 3.

[0029] As shown in Figures 1 and 2, the bonding stage 5 of the bonding apparatus 1 consists of a first bonding stage 6 and a second bonding stage 8, and each of the first bonding stage 6 and the second bonding stage 8 is provided with a stage rotation mechanism 10, a wafer lifting mechanism, a vacuum suction mechanism, a heating mechanism, and a cooling mechanism.

[0030] The stage rotation mechanism 10 of the bonding stage 5, shown by the dotted line in Figure 1(b), is a mechanism that rotates the bonding stage 5 about the θ rotation axis, as shown by the thin arrow in Figure 1(a), with the center of the main surface of a substrate such as a wafer 51 placed on the bonding stage 5 as the rotation center. The stage rotation mechanism 10 of the bonding stage 5 can, for example, rotate 180 degrees clockwise and then rotate 180 degrees counterclockwise in that state. As a result, the half of the wafer 51 placed on the bonding stage 5, located on the front side opposite the bonding head 3, can be positioned toward the bonding head 3 by the rotation of the stage rotation mechanism 10.

[0031] The wafer lifting mechanism is a mechanism that vertically lifts the wafer 51 on the bonding stage 5. For example, as shown in Fig. 2, the wafer lifting mechanism has lift pins 13, which are rod-shaped pins, that rise from three locations on the surface of the bonding stage 5 to lift the wafer 51 while keeping it parallel to the surface of the bonding stage 5, and also has lift pins 13 that lower to lower the wafer 51.

[0032] The vacuum suction mechanism creates a vacuum state in a plurality of suction holes 16 provided on the surface of the bonding stage 5, and holds the wafer 51 on the surface of the bonding stage 5 by suction. The vacuum suction mechanism can be controlled to be in a vacuum or atmospheric state by turning it on and off.

[0033] The heating mechanism (not shown) heats the surface of the bonding stage 5 using a heater built into the bonding stage 5. The heating mechanism heats the surface of the bonding stage 5 to a predetermined temperature, and after the predetermined temperature is reached, controls the temperature to be maintained at that temperature.

[0034] The cooling mechanism (not shown) lowers the surface temperature of the bonding stage 5 by blowing air or the like, and is controlled to stop the cooling operation when the surface temperature of the bonding stage 5 reaches a predetermined temperature or lower. Note that if the surface temperature of the bonding stage 5 is lowered naturally, it is not necessary to provide a cooling mechanism.

[0035] 1 and 2 has a θ-axis rotation mechanism 26 (shown by a dotted line in FIG. 1B) that can rotate around a θ-axis 27 that is perpendicular to the horizontal plane. The first bonding stage 6 and the second bonding stage 8 are provided opposite each other via the θ-axis 27 on the turntable 25 that has the θ-axis rotation mechanism 26, and by rotating the first bonding stage 6 and the second bonding stage 8 around the θ-axis 27 by the θ-axis rotation mechanism 26 as shown by the thick arrow in FIG. 2, it is possible to swap the positions of the first bonding stage 6 and the second bonding stage 8.

[0036] For example, when the rotary table 25 is rotated 180 degrees clockwise, the positions of the first bonding stage 6 and the second bonding stage 8 are swapped, and when the rotary table 25 is rotated 180 degrees counterclockwise in this state, the first bonding stage 6 and the second bonding stage 8 return to their original positions.

[0037] The XY table 35 placed on the housing 43 of the bonding apparatus 1 shown in FIGS. 1 and 2 has an XY movement mechanism that can move the rotary table 25 in the X and Y directions, and the XY movement mechanism consists of an X-axis table 36 that moves the rotary table 25 in the X direction and a Y-axis table 40 that moves the rotary table 25 in the Y direction.

[0038] The X-axis table 36 is provided with an X-axis guide 37, and the X-axis table 36 can move the rotary table 25 along the X-axis guide 37 in the X-axis direction indicated by the solid arrow. The Y-axis table 40 is provided with a Y-axis guide 41, and the Y-axis table 40 can move the rotary table 25 along the Y-axis guide 41 in the Y-axis direction indicated by the open arrow. The X-axis table 36 is attached to the Y-axis table 40. The XY table 35 can be driven independently by the X-axis table 36 and the Y-axis table 40, but the X-axis table 36 and the Y-axis table 40 are driven simultaneously to control the bonding position. The XY table 35 may also be configured such that the Y-axis table 40 is provided on the X-axis table 36.

[0039] By driving the XY table 35, the first bonding stage 6 and the second bonding stage 8 arranged on the rotary table 25 can be moved to predetermined positions, namely, the bonding position, the wafer transfer position, and the rotary table rotation position.

[0040] As shown in Figure 1, the bonding head 3 of the bonding apparatus 1 uses a capillary 4 (see Figure 1(b)) as a bonding tool to bond bumps or wires to a wafer 51 mounted on either a first bonding stage 6 or a second bonding stage 8 located in the bonding area, and the bonding head 3 is movably attached to an XY moving table 45 which is a separate mechanism from the XY table 35. This XY moving table 45 makes it possible to bond bumps or wires to the wafer 51 located in the bonding area. Note that the bonding head of the bonding apparatus is well known, and therefore a description thereof will be omitted.

[0041] The stage rotation mechanism 10, XY movement mechanism, and θ-axis rotation mechanism 26 are each composed of a combination of a motor drive mechanism, a cam mechanism, a slide mechanism, a locking mechanism that locks the movement and rotation when stopped, and the like.

[0042] A transfer robot (not shown) for transferring the wafer 51 to the bonding stage 5 is installed on the left side of the bonding apparatus 1 shown in FIG.

[0043] The rotary table 25 described above has the first bonding stage 6 and the second bonding stage 8 arranged opposite each other around the θ-axis 27, but the number of bonding stages on the rotary table 25 is not limited to two; it is also possible to arrange three or more bonding stages. For example, it is possible to arrange three bonding stages in a triangular shape every 120 degrees around the θ-axis 27.

[0044] [Processes in the Initial State at the Start of Bonding] Next, the processes of loading a wafer onto the first bonding stage 6 and the second bonding stage 8 in the initial state at the start of bonding in the bonding apparatus 1, and the processes from when the wafer on the first bonding stage 6 rises to a predetermined temperature until bonding is started, will be described with reference to the drawings. Fig. 3 is a flowchart showing the processes in the initial state at the start of bonding. Figs. 4 to 6 are diagrams showing the operation of the rotary table and bonding stage in the initial state at the start of bonding. Fig. 7 is a diagram explaining the expansion of the bonding area of ​​a wafer placed on the bonding stage by the rotational operation of the stage rotation mechanism during bonding.

[0045] As shown in FIG. 4A, in the initial state when bonding begins in the bonding apparatus 1, the first bonding stage 6 is positioned on the bonding head 3 side, and the second bonding stage 8 is positioned on the wafer transfer position side.

[0046] Furthermore, the wafer transfer position, bonding position, and turntable rotation position indicating the positions of the turntable 25 described below indicate positions from the origin of the XY table, and when the turntable 25 is located at the wafer transfer position, the symbol a is used on the θ-axis 27 of the turntable 25 in the drawing, when the turntable 25 is located at the bonding position, the symbol b is used, and when the turntable 25 is located at the turntable rotation position, the symbol c is used to indicate each position of the turntable 25. Note that the turntable rotation position c is a rotational operation performed by the turntable 25 to exchange the positions of the first bonding stage 6 and the second bonding stage 8, and is the position to which the turntable 25 moves to prevent interference between the turntable 25 and the XY moving table 45 on which the bonding head 3 is mounted due to rotation, as shown by the dotted circle in Figure 4(c).

[0047] First, as shown in FIG. 4(b), the XY table 35 carrying the rotary table 25 moves from the bonding position b shown in FIG. 4(a) to the rotary table rotation position c (step S1 shown in FIG. 3). After the rotary table 25 moves to the rotary table rotation position c, the rotary table 25 carrying the first bonding stage 6 and the second bonding stage 8 rotates 180 degrees, and the first bonding stage 6 moves to the wafer transfer position a as shown by the arrow in FIG. 4(c) (step S2).

[0048] 4(d), after the rotary table 25 moves to the wafer transfer position a, the lift pins 13 (shown in FIG. 2), which are the wafer lifting mechanism of the first bonding stage 6, rise and receive the wafer 51 from the transfer robot (step S3). Note that the transfer of the wafer 51 on the bonding stage 5 is not limited to the transfer robot, and may be performed by other wafer exchange mechanisms, such as an elevator mechanism having a magazine for discharging and storing wafers.

[0049] As shown in Figure 5(a), after receiving the wafer 51, the bonding apparatus 1 turns on the vacuum suction mechanism of the first bonding stage 6, lowers the lift pins 13, and adsorbs the wafer 51 to fix it on the first bonding stage 6 (step S4).

[0050] After the wafer 51 is fixed, the heater of the heating mechanism in the first bonding stage 6 is turned on to heat the wafer 51 (step S5).

[0051] As shown by the arrow in Fig. 5(a), the turntable 25 moves to the turntable rotation position c (step S6), and as shown in Fig. 5(b), after the turntable 25 moves to the turntable rotation position c, the turntable 25 rotates 180 degrees, and as shown by the arrow in Fig. 5(c), the second bonding stage 8 moves to the wafer transfer position side (step S7). After the turntable 25 has rotated, the first bonding stage 6 is positioned on the bonding head 3 side.

[0052] As shown in FIG. 5D, after the rotary table 25 moves to the wafer transfer position a, the lift pins 13, which are the wafer lifting mechanism of the second bonding stage 8, rise to receive the wafer 51 from the transfer robot (step S8).

[0053] As shown in FIG. 6A, after receiving the wafer 51, the lift pins are lowered while the vacuum suction mechanism of the second bonding stage 8 is turned on, and the wafer 51 is suctioned and fixed onto the second bonding stage 8 (step S9).

[0054] After the wafer 51 is fixed, the heater of the second bonding stage 8 is turned on to heat the wafer 51 (step S10).

[0055] 6A, the rotary table 25 then moves to the bonding position b (step S11), as shown in FIG. 6B, whereby the wafer 51 on the first bonding stage 6 is positioned in the bonding area 50 shown in FIG.

[0056] After the rotary table 25 has moved to the bonding area 50, bonding begins when the first bonding stage 6 reaches a predetermined bonding start temperature (step S12). Also, while the first bonding stage 6 is bonding, the temperature of the second bonding stage 8 is monitored.

[0057] Also, as shown in Figure 7, if the bonding area 50 indicated by the dotted line during bonding does not cover the entire wafer 51, each of the first bonding stage 6 and the second bonding stage 8 can be rotated around the center of the main surface of the wafer 51 by the stage rotation mechanism 10, so that after bonding half the area of ​​the wafer 51, the bonding stage 5 can be rotated 180 degrees to bond the remaining half of the area of ​​the wafer.

[0058] This allows the bonding area 50 of the wafer placed on the first bonding stage 6 and the second bonding stage 8 to be enlarged by the rotational operation of the stage rotation mechanism 10 during bonding.

[0059] As a result of the above, the wafer 51 is loaded onto the first bonding stage 6 and the second bonding stage 8 in the initial state at the start of bonding in the bonding apparatus 1, and bonding begins after the wafer 51 on the first bonding stage 6 has risen to a predetermined temperature.

[0060] [Bonding Process] Next, a wafer is mounted on the first bonding stage 6 and the second bonding stage 8, and the bonding process on the first bonding stage 6 and the second bonding stage 8 will be described with reference to FIGS.

[0061] Fig. 8 is a flowchart showing the operation of the turntable and bonding stage in the bonding process, and Figs. 9 and 10 are diagrams explaining the movement and rotation of the turntable and the operation of the bonding stage in the bonding process.

[0062] 8, bonding of the wafer 51 on the first bonding stage 6 is completed (step S20), and after the bonding is completed, the heater of the first bonding stage 6 is turned OFF (step S21). Also, if a cooling function is being used, the cooling mechanism of the first bonding stage 6 is turned ON.

[0063] As shown by the arrow in Fig. 9(a), the turntable 25 moves from bonding position b to turntable rotation position c (step S22), and after the turntable 25 moves to turntable rotation position c, the turntable 25 rotates 180 degrees, and as shown in Fig. 9(b), the positions of the first bonding stage 6 and the second bonding stage 8 are swapped (step S23). That is, after the turntable 25 rotates, the second bonding stage 8 is positioned on the bonding head 3 side.

[0064] 9(c), the turntable 25 moves to the bonding position b (step S24), and once the second bonding stage 8 has risen to a predetermined bonding start temperature after the turntable 25 has moved to the bonding position b, bonding begins (step S25). Also, while the second bonding stage 8 is bonding, the temperature of the first bonding stage 6 is being cooled and monitored.

[0065] If the temperature of the first bonding stage 6 drops to a predetermined temperature while bonding is being performed on the second bonding stage 8, the bonding operation on the second bonding stage 8 is temporarily interrupted (step S26), and the first bonding stage 6 is moved to the wafer transfer position a by the rotary table 25 (step S27), as shown by the arrow in Figure 9(d). Also, if a cooling function is being used, the cooling mechanism of the first bonding stage 6 is turned off.

[0066] As shown in FIG. 10A, the first bonding stage 6 moves to the wafer transfer position a, the vacuum suction mechanism of the first bonding stage 6 is turned off, and then the lift pins of the first bonding stage 6 are raised (step S28).

[0067] As shown by the arrow in FIG. 10B, the bonded wafer 51 is removed from the first bonding stage 6 by the transfer robot (step S29).

[0068] After the bonded wafer 51 is discharged, the next wafer 51 is received by the first bonding stage 6 as shown by the arrow in FIG. 10(c) (step S30).

[0069] The lift pins are lowered while the vacuum suction mechanism of the first bonding stage 6 is turned on, and the wafer 51 is suctioned onto the first bonding stage 6, thereby fixing the wafer 51 onto the first bonding stage 6 (step S31).

[0070] The heater of the first bonding stage 6 is turned on (step S32).

[0071] As shown by the arrow in FIG. 10C, the rotary table 25 moves to the bonding position b, and as shown in FIG. 10D, bonding of the wafer 51 on the second bonding stage 8 is resumed (step S33).

[0072] After bonding of the wafer 51 on the second bonding stage 8 is completed, the heater of the second bonding stage 8 is turned OFF (step S34). If a cooling function is being used, the cooling mechanism of the second bonding stage 8 is turned ON.

[0073] Thereafter, the process proceeds to step S22. Note that the sequence from step S22 to step S34 is such that the first bonding stage 6 and the second bonding stage 8 are swapped each time step S34 is completed, and the first bonding stage 6 is replaced (read) as the second bonding stage 8, and the second bonding stage 8 is replaced (read) as the first bonding stage 6.

[0074] As a result of the above, bonding on the first bonding stage 6 is completed, bonding on the second bonding stage 8 is started and interrupted, the wafer 51 is ejected and loaded onto the first bonding stage 6, bonding on the second bonding stage 8 is resumed, bonding on the second bonding stage 8 is completed, and the wafer 51 is ejected and loaded.

[0075] In this way, in the present invention, the bonding stage consists of a first bonding stage and a second bonding stage, and by rotating the rotary table on which the two bonding stages are mounted and exchanging their positions, it becomes possible to perform bonding on one bonding stage while exchanging wafers on the other bonding stage, thereby reducing the loss of bonding operation time due to wafer exchange with a simple configuration and increasing production volume.

[0076] Furthermore, in the present invention, when the first wafer placed on the first bonding stage has cooled to a predetermined temperature, bonding to the second wafer placed on the second bonding stage is interrupted, the first bonding stage is moved to a wafer transfer position outside the bonding apparatus, the first wafer is discharged, a third wafer is brought in and placed on the first bonding stage, and then bonding to the second wafer placed on the second bonding stage is resumed and continued while the third wafer placed on the first bonding stage is heated by a heater, thereby allowing bonding of the second wafer placed on the second bonding stage and heating of the third wafer placed on the first bonding stage to be performed in parallel, thereby reducing wafer production loss due to heating time with a simple configuration.

[0077] Furthermore, if the temperature of one of the bonding stages holding a bonded wafer drops to a predetermined cooling temperature and the bonded wafer is not replaced until the other bonding stage has completed bonding, the temperature of the one bonding stage will drop further while it is waiting, and when the next wafer is replaced, the heating start temperature of the bonding stage will be lower, making it take time to heat the wafer.However, according to the present invention, it is possible to prevent the temperature of the bonded wafer from dropping while it is waiting.

[0078] [Mode for Wafer Exchange at the Bonding Position of the Rotary Table] Next, an embodiment for wafer exchange at the bonding position of the rotary table will be described with reference to Figures 11 and 12, in which a wafer can be received at the bonding position without moving the XY table 35 and the rotary table 25 is simultaneously positioned at the wafer transfer position and the bonding position. Figure 11 is a flowchart showing the movement and rotation of the rotary table and the operation of the bonding stage when a wafer is received at the bonding position without moving the XY table during the bonding process. Figure 12 is a diagram explaining the movement and rotation of the rotary table and the operation of the bonding stage when a wafer is received at the bonding position without moving the XY table during the bonding process.

[0079] In the bonding operation and wafer exchange operation shown in Figure 8, when the turntable 25 moves from bonding position b to wafer transfer position a, or when it moves from wafer transfer position a to bonding position b, the turntable 25 needs to move. However, for example, if the transfer arm of the transport robot is long, wafer exchange can be performed at bonding position b on the turntable 25, and the turntable 25 does not need to move between bonding position b and wafer transfer position a.

[0080] In the following explanation, it is assumed that the process has been completed in the initial state at the start of bonding shown in Fig. 3. As shown in Fig. 11, after bonding of the wafer 51 on the first bonding stage 6 is completed (step S50), the heater of the first bonding stage 6 is turned OFF. Furthermore, if a cooling function is being used, the cooling mechanism of the first bonding stage 6 is turned ON (step S51).

[0081] The turntable 25 moves to the turntable rotation position c (step S52), and after the moving table 25 moves to the turntable rotation position c, the turntable 25 is rotated, and the positions of the first bonding stage 6 and the second bonding stage 8 are swapped by the rotation (step S53). That is, after the turntable 25 rotates, the second bonding stage 8 is positioned on the bonding head side.

[0082] The turntable 25 moves to the bonding position b (step S54), and when the second bonding stage 8 reaches the bonding start temperature after the turntable 25 moves to the bonding position b, bonding starts (step S55). Also, the temperature of the first bonding stage 6 is monitored while the second bonding stage 8 is bonding.

[0083] When the temperature of the first bonding stage 6 drops to a predetermined temperature while bonding is being performed on the second bonding stage 8, if a cooling function is being used, the cooling mechanism of the first bonding stage 6 is turned off. Also, the vacuum suction mechanism of the first bonding stage 6 is turned off, and then the lift pins 13 of the first bonding stage 6 are raised (step S56).

[0084] Even if the temperature of the first bonding stage 6 drops to the target temperature in step S56, the bonding operation of the second bonding stage 8 continues without interruption.

[0085] As shown by the arrow in FIG. 12A, the bonded wafer 51 is removed from the first bonding stage 6 by the transfer robot (step S57).

[0086] After the bonded wafer 51 is discharged, the next wafer 51 is received by the first bonding stage 6 as shown by the arrow in FIG. 12(b) (step S58).

[0087] The lift pins are lowered while the vacuum suction mechanism of the first bonding stage 6 is turned on, and the wafer 51 is suctioned onto the first bonding stage 6 (step S59).

[0088] The heater of the first bonding stage 6 is turned on (step S60).

[0089] After bonding of the wafer 51 on the second bonding stage 8 is completed, the heater of the second bonding stage 8 is turned off. If a cooling mechanism is used, the cooling mechanism of the second bonding stage 8 is turned on (step S61).

[0090] It should be noted that, when the temperature of the first bonding stage 6 drops to the target temperature while bonding is being performed on the second bonding stage 8 in step S56, it is also possible to temporarily halt the bonding operation on the second bonding stage 8, eject the bonded wafer 51, and continue the bonding operation on the second bonding stage 8 after the next wafer 51 is received by the first bonding stage 6. For example, in order to avoid any adverse effects associated with the replacement of the wafer 51, the bonding operation may be stopped while the wafer 51 is being replaced.

[0091] Thereafter, the process proceeds to step S52. Note that the sequence from step S52 to step S61 is such that the first bonding stage 6 and the second bonding stage 8 are swapped each time step S61 is completed, and the first bonding stage 6 is replaced (read) as the second bonding stage 8, and the second bonding stage 8 is replaced (read) as the first bonding stage 6.

[0092] In this way, when the rotary table 25 is simultaneously positioned at the wafer transfer position a and the bonding position b, the transfer robot can receive the wafer from one of the bonding stages at the bonding position without moving the moving table 25, so there is no need to interrupt bonding on the other bonding stage, making it possible to increase the number of wafers produced.

[0093] As described above, according to the present invention, the bonding stage comprises a first bonding stage and a second bonding stage, and the first bonding stage and the second bonding stage are arranged opposite each other via the θ axis on a rotary table having a θ axis rotation mechanism that can rotate about the θ axis, and the positions of the first bonding stage and the second bonding stage can be swapped. By having an XY table that is an XY movement mechanism that can move the rotary table in the X and Y directions, it is possible to rotate the rotary table on which the two bonding stages are mounted and swap their positions, so that bonding can be performed on one bonding stage while wafer exchange is being performed on the other bonding stage. This simple configuration reduces the loss of bonding operation time due to wafer exchange and makes it possible to increase the number of wafers produced.

[0094] Furthermore, according to the present invention, each of the first bonding stage and the second bonding stage is arranged on a rotary table so that it can be freely rotated around the center of the main surface of the wafer by a stage rotation mechanism, and therefore, the rotation operation during bonding can expand the bondable area of ​​the first bonding stage or second bonding stage wafer.

[0095] Furthermore, according to the present invention, when the first wafer placed on the first bonding stage has cooled to a predetermined temperature, bonding to the second wafer placed on the second bonding stage is interrupted, the rotary table is moved by the XY movement mechanism to move the first bonding stage to a wafer transfer position outside the bonding apparatus, the first wafer is discharged, a third wafer is brought in and placed on the first bonding stage, the rotary table is moved by the XY movement mechanism to resume and continue bonding to the second wafer placed on the second bonding stage, and the third wafer placed on the first bonding stage is heated by a heater, so that the third wafer placed on the first bonding stage can be heated without waiting for the completion of bonding of the second wafer placed on the second bonding stage. This allows bonding of the second wafer placed on the second bonding stage and heating of the third wafer placed on the first bonding stage to be performed in parallel, thereby reducing wafer production loss due to heating time with a simple configuration.

[0096] Furthermore, if the temperature of one of the bonding stages holding a bonded wafer drops to a predetermined cooling temperature and the bonded wafer is not replaced until the other bonding stage has completed bonding, the temperature of the one bonding stage will drop further while it is waiting, and when the next wafer is replaced, the heating start temperature of the bonding stage will be lower, making it take time to heat the wafer.However, according to the present invention, it is possible to prevent the temperature of the bonded wafer from dropping while it is waiting.

[0097] Furthermore, according to the present invention, by interrupting bonding on one bonding stage, placing a new wafer on the bonding stage and heating it, and then resuming bonding after placing the wafer on the other bonding stage, it is possible to heat the wafer and bond it in parallel.

[0098] Furthermore, in the present invention, when the rotary table is simultaneously positioned at the wafer transfer position and the bonding position, it is possible to receive the wafer on one of the bonding stages at the bonding position without moving the movable table, which eliminates the need to interrupt bonding on the other bonding stage, thereby enabling an increase in the number of wafers produced.

[0099] The present invention can be embodied in many different forms without departing from its essential characteristics, and it should be understood that the above-described embodiments are merely illustrative and are not intended to limit the present invention.

[0100] REFERENCE SIGNS LIST 1 Bonding device 3 Bonding head 4 Bonding tool (capillary) 5 Bonding stage 6 First bonding stage 8 Second bonding stage 10 Stage rotation mechanism 13 Lift pin (wafer lifting mechanism) 16 Suction hole (vacuum suction mechanism) 25 Rotary table 26 θ-axis rotation mechanism 27 θ-axis 35 XY table (XY movement mechanism) 36 X-axis table 37 X-axis guide 40 Y-axis table 41 Y-axis guide 43 Housing 45 XY movement table 50 Bonding area 51 Wafer a Wafer transfer position b Bonding position c Rotary table rotation position

Claims

1. A bonding method using a bonding apparatus that bonds bumps to a wafer placed on a bonding stage via a bonding head, comprising the steps of: the bonding stage includes a first bonding stage and a second bonding stage each having a heater and configured to be heatable; the first bonding stage and the second bonding stage are disposed opposite each other via the θ axis on a rotary table having a θ axis rotation mechanism rotatable around the θ axis, and the positions of the first bonding stage and the second bonding stage are configured to be interchangeable; the bonding apparatus has an XY movement mechanism capable of moving the rotary table in X and Y directions; a first step of heating a second wafer placed on the second bonding stage by the heater while bonding bumps to a first wafer placed on the first bonding stage and heated to a predetermined temperature by the heater; a second step of exchanging positions of the first bonding stage on which the first wafer, which has been bonded, is placed and the second bonding stage on which the second wafer is placed by rotating the rotary table; a third step of bonding bumps to the second wafer, which is placed on the second bonding stage and heated to a predetermined temperature by the heater, while cooling the first wafer, which is placed on the first bonding stage, to a predetermined temperature with the heater turned off; a fourth step of interrupting bonding of the second wafer placed on the second bonding stage when the first wafer placed on the first bonding stage has cooled to a predetermined temperature, moving the rotary table by the XY movement mechanism to move the first bonding stage to a wafer transfer position outside the bonding apparatus, discharging the first wafer, and carrying in and placing a third wafer on the first bonding stage; a fifth step of moving the rotary table by the XY movement mechanism to resume and continue bonding of the second wafer placed on the second bonding stage while heating the third wafer placed on the first bonding stage by the heater; A bonding method comprising the steps of:

2. The bonding method according to claim 1, characterized in that each of the first bonding stage and the second bonding stage is arranged on the rotating table so as to be freely rotatable around the center of the main surface of the wafer by a stage rotation mechanism, and the rotational movement during bonding expands the bondable area of ​​the wafer.