JP2000031181A - Method and apparatus for bump forming - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bump forming apparatus, with which the temperature control different from the conventional one is performed when a bump is formed on a semiconductor wafer, and to provide the bump forming method performed on the bump forming apparatus. SOLUTION: This bump forming apparatus 101 is provided with a transfer device 140 and a control device 180, and after formation of a bump which is held by the transferring device, a wafer 202 is arranged above the bonding stage, and the temperature drop of the wafer is controlled. As a result, the generation of nonconformities such as cracks, etc., caused by thermal stresses can be prevented even for a compound semiconductor wafer which is sensitive to the change of temperature.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] 1. Field of the Invention [0002] The present invention relates to a bump forming apparatus for forming a bump on a semiconductor wafer and a bump forming method executed by the bump forming apparatus.

[0002]

2. Description of the Related Art In recent years,
For example, as devices to which electronic components are attached, such as mobile phones, have become very small, the electronic components have also become smaller. Therefore, there is a bump forming apparatus that forms a bump on an electrode portion of each of the circuit forming portions on the semiconductor wafer without cutting out individual circuit forming portions formed on the semiconductor wafer from the semiconductor wafer. Such a bump forming apparatus includes a carry-in device for taking out the pre-bump-formed wafer from the first storage container for storing the semiconductor wafer before the bump is formed, and a second storing device for storing the bump-formed wafer after the bump is formed. A container and the wafer before bump formation are placed thereon, and the semiconductor wafer is usually heated from 250 ° C. to 2 ° C. for bonding the electrode portion and the bump.
A bonding stage for heating to about 70 ° C., an unloading device for storing the wafer after the bump formation in the second storage container, and transfer of the wafer from the loading device to the bonding stage and from the bonding stage to the unloading device. And a transfer device for loading. In addition, SAW (Surface Acoustic W
ave) When the base is made of quartz instead of conventional silicon, such as a semiconductor wafer that forms a filter,
There is a so-called compound semiconductor wafer made of lithium tantalum, lithium niobium, gallium arsenide, or the like. Such a compound semiconductor wafer is also heated to a maximum of about 150 ° C. when forming the bumps, but it is necessary to slow down the heating and cooling speeds compared to a conventional silicon wafer. Especially when not cooling slowly
In some cases, a pyroelectric effect occurs on the compound semiconductor wafer to cause circuit destruction, or the wafer may be cracked due to thermal deformation of the wafer. As described above, in a bump forming apparatus for forming a bump on a compound semiconductor wafer, it is necessary to perform temperature control different from the temperature control in a conventional bump forming apparatus for forming a bump on a silicon wafer. An object of the present invention is to provide a bump forming apparatus that performs temperature control different from the conventional one before and after forming a bump on a semiconductor wafer, and a bump forming method executed by the bump forming apparatus.

[0003]

According to a first aspect of the present invention, there is provided a bump forming method for forming a bump on an electrode of a circuit formed on a semiconductor wafer. After bump bonding to the semiconductor wafer after the main heating of the semiconductor wafer, before storing the semiconductor wafer in the storage container, performing an after-cooling operation on the semiconductor wafer by controlling the temperature drop of the semiconductor wafer. Features.

According to a bump forming method of a second aspect of the present invention, in addition to the bump forming method of the first aspect, the semiconductor wafer is pre-heated before the main heating. Is also good.

According to a fifth aspect of the present invention, in addition to the bump forming method of the first aspect, the bump forming method further includes a step of heating the semiconductor wafer to a temperature for bump bonding in the main heating. Before the bump bonding is performed after the semiconductor wafer is mounted, the semiconductor wafer mounted on the bonding stage is subjected to the temperature and the temperature on the stage contact surface side of the semiconductor wafer in contact with the bonding stage. The temperature difference between the temperature on the circuit forming surface side of the semiconductor wafer opposed to the stage contact surface is controlled to be within a non-warping temperature range for suppressing the warpage of the semiconductor wafer to such an extent that bump formation is not hindered. You may.

A bump forming apparatus according to a third aspect of the present invention is arranged such that the semiconductor wafer is placed on a semiconductor wafer and the temperature of the semiconductor wafer is reduced to a bump bonding temperature necessary for forming a bump on an electrode formed on a circuit of the semiconductor wafer. A bonding stage for main heating, a bump forming head mounted on the bonding stage and forming the bumps on the electrodes of the semiconductor wafer, and a transfer device for mounting and removing the semiconductor wafer on and from the bonding stage. And after-bonding the bumps to the main heated semiconductor wafer, and after-cooling the semiconductor wafer based on a temperature drop control for the semiconductor wafer. It is characterized by having.

In the bump forming apparatus according to a fourth aspect of the present invention, in addition to the bump forming apparatus according to the third aspect, the semiconductor wafer is further mounted on the bonding stage and the semiconductor is heated to the bump bonding temperature. The semiconductor device may be configured to include a preheating device that performs a preheating operation on the semiconductor wafer before heating the wafer.

Further, in the bump forming apparatus according to a sixth aspect of the present invention, in addition to the bump forming apparatus according to the third aspect, after the semiconductor wafer is mounted on the bonding stage and before the bump bonding is performed. The temperature of the semiconductor wafer placed on the bonding stage, the temperature of the semiconductor wafer in contact with the bonding stage on the stage contact surface side, and the circuit formation surface of the semiconductor wafer facing the stage contact surface A wafer temperature control device may be provided which controls the temperature difference from the temperature on the side within a non-warping temperature range that suppresses the warpage of the semiconductor wafer to such an extent that there is no problem in bump formation.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS First Embodiment A bump forming apparatus according to an embodiment of the present invention and a bump forming method executed by the bump forming apparatus will be described below with reference to the drawings. Note that the bump forming apparatus 101 of the present embodiment shown in FIG. 1 is suitable for processing the compound semiconductor wafer, and the following description will also take the case where bumps are formed on the compound semiconductor wafer as an example. The object to be processed is not limited to the above compound semiconductor, and a conventional silicon wafer can of course be processed. In this case, the temperature of the wafer at the time of forming the bump is set to about 250 ° C.
Heat to about 270 ° C. In addition, the bump forming apparatus 101 controls the compound semiconductor wafer 2 before bump formation.
01 in a layered manner, and a second container 205 in a layered manner to accommodate the compound semiconductor wafer 202 after bump formation.
It is a so-called double magazine type provided with both storage containers 206, but is not limited to this type.
A so-called single magazine type in which the compound semiconductor wafer before bump formation 201 and the compound semiconductor wafer after bump formation 202 are housed in a single storage container may be employed.

The basic configuration of the bump forming apparatus 101 is not different from that of the conventional bump forming apparatus.
That is, the bump forming apparatus 101 is roughly divided into one bonding stage 110, one bump forming head 120, a transport device 130, and one transfer device 140.
A lifting device 150 provided for the storage containers 205 and 206 for raising and lowering the storage containers 205 and 206, respectively, and a control device 180. However, in the bump forming apparatus 101, as described in the operation description below, particularly when handling the compound semiconductor wafer, it is possible to perform temperature control that does not cause the above-described wafer cracking or the like in the compound semiconductor wafer. The point that the operation under the control of the control device 180 is executed is greatly different from the conventional bump forming apparatus. Hereinafter, each of the above components will be described.

The bonding stage 110 places a compound semiconductor wafer (hereinafter simply referred to as a “wafer before bump formation”) 201 before the bump formation, and
The pre-bump forming wafer 201 is heated to a bump bonding temperature necessary for forming a bump on an electrode in a circuit formed on the pre-bump forming wafer 201. The bump forming head 120 is a known device for forming a bump on the electrode of the wafer 201 before bump formation, which is mounted on the bonding stage 110 and heated to the bump bonding temperature, and is a material of the bump. In addition to a wire supply unit 121 for supplying a gold wire, a bump forming unit for melting the gold wire to form a ball and pressing the molten ball against the electrode, and an ultrasonic generator for applying an ultrasonic wave to the bump when pressed. Etc. are provided. The bump forming head 120 thus configured is mounted on an X, Y table 122 having a ball screw structure and movable in X and Y directions perpendicular to each other on a plane, and is fixed. X and Y tables 122 so that bumps can be formed on each of the electrodes of the wafer 201 before bump formation.
Is moved in the X and Y directions.

In the bump forming apparatus 101, two types of transfer apparatuses 130 are provided. One of them is a carry-in apparatus 131 which takes out the pre-bump-formed wafer 201 from the first storage container 205. Is a compound semiconductor wafer after bump formation (hereinafter simply referred to as “wafer after bump formation”) 20.
2 is a device that transports and stores the second container 2 to the second storage container 206. Specifically, as shown in FIG. 2, the carry-in device 131 and the carry-out device 132 are arranged side by side along the X direction,
Rodless cylinder 134 fixed to frame 133
Move in the X direction independently of each other and while being guided by a guide member 135 fixed to the frame 133. Since the bonding stage 110 is disposed between the loading device 131 and the unloading device 132 as shown in FIG.
Reference numeral 1 denotes the first storage container 205 and the bonding stage 1
10 and the unloading device 132 moves between the bonding stage 110 and the second storage container 206.

As shown in FIG. 2, the loading device 131 has a movable holding member 1311 and a fixed holding member 1312 attached to a support member 1314, and the bumps are provided on the movable holding member 1311. Pre-formation wafer 20
1 can be placed. The movable holding member 1311 can be moved in the diameter direction of the wafer 201 before bump formation by the driving unit 1313 having an air cylinder attached to the support member 1314. The driving unit 1313 moves the movable-side holding member 1311 in a direction away from the fixed-side holding member 1312, that is, in an opening direction, and moves the movable-side holding member 1311 in a direction approaching the fixed-side holding member 1312, that is, in a closing direction. The movement of 1311 is performed by an urging force of an elastic member such as a spring. By moving the movable holding member 1311 in the opening direction, the loading device 131 configured as described above is moved by the movable portion 134a of the rodless cylinder 134 to the wafer 201 before bump formation in the first storage container 205. The movable side holding member 1311 is moved in the closing direction after the movement, whereby the positioning roller 1315 provided on the movable side holding member 1311 and the fixed side holding member 1312 are moved.
The wafer 201 before bump formation is sandwiched by the position regulating roller 1316 provided in the above. In addition, the first storage container 20
5 is a first elevating device 151 constituting the elevating device 150
The first elevating device 151 is placed on the first storage container 20 so that the wafer 201 before bump formation can be taken out by the loading device 131.
5 up and down. In addition, the first storage container 2 is
The pre-bump forming wafer 201 taken out of the wafer 05 is held by the transfer device 140. The loading device 131
The above-described operation is controlled by the control device 180.

The unloading device 132 includes a transfer device 140
A mounting member 1321 for mounting the wafer 202 after the bump formation transferred from the above is provided. A plurality of suction holes 1322 are formed in the mounting member 1321 in a row corresponding to a substantially central portion of the mounted wafer 202 after the bump is formed. The suction hole 1322 is connected to a suction device 1323 whose operation is controlled by the control device 180. Further, as one of the features of the present embodiment, a plurality of air supply holes 1324 for ejecting a gas for controlling cooling of the wafer 202 after bump formation are formed adjacent to the suction holes 1322 in the unloading device 132. ing. These air holes 1324 are connected to a blower 1325 whose operation is controlled by the controller 180. Therefore, the blower 1313
In the case of this embodiment, the mounting member 13 is formed by the temperature-controlled gas ejected from the mounting member 24 and the temperature-controlled air in the present embodiment.
The cooling of the wafer 202 after the bumps formed on the wafer 21 can be performed more slowly than in the case of natural cooling.
Further, the air ejected from the air supply hole 1324 is
21 through the exhaust groove 1326 formed in the mounting member 1
321 is discharged outside. In addition, the air supply hole 1324
Is opened in the exhaust groove 1326, while the suction hole 1322 is opened in the surface 1321a of the mounting member 1321 with which the wafer 202 contacts after bump formation. Therefore, since the air ejected from the air supply holes 1324 passes through the exhaust groove 1326, the ejected air does not cause the wafer 202 to be blown off from the mounting member 1321 after the bumps are formed. In addition, the air supply hole 1324 and the exhaust groove 132
6, and the number of suction holes 1322 are not limited to those shown. Further, the air supply hole 1324, the air blower 1325, and the exhaust groove 1326 are provided in the above-described loading device 1
A member on which the wafer 201 is placed in 31, in the case of this embodiment, a movable side holding member 1311 can further be provided.

The transfer device 140 is provided with the above-described loading device 131.
The wafer 201 before bump formation is transferred from the wafer to the bonding stage 110 and the bonding stage 1
This is an apparatus for transferring the wafer 202 after bump formation from the apparatus 10 to the unloading apparatus 132. As shown in FIG. 3, in the present embodiment, one holding section 141 for holding the wafers 201 and 202, and the holding section 141 A driving unit 142 having a ball screw structure for moving the wafers along the X direction and driven by a motor 1421, and a moving unit 143 for moving the holding unit 141 up and down in the thickness direction of the held wafers 201 and 202.
And The holding unit 141 is disposed so as to be located directly above the bonding stage 110, the movable-side holding member 1311 and the fixed-side holding member 1312 of the loading device 131, and the placement member 1321 of the unloading device 132. And moving unit 1 as described above.
43, the bonding stage 110,
The wafers 201 and 202 are transferred between the loading device 131 and the unloading device 132. The operation of the transfer device 140 thus configured is controlled by the control device 180. As shown in FIG. 3, the transfer device 140 can measure the temperature of the wafers 201 and 202 sandwiched in a non-contact state, and sends a measurement result to the control device 180 with a temperature measuring device 1419. Can also be provided.

As shown in FIG. 3 and FIG.
41 is one of the features of the present embodiment.
First clamp members 1411-1 and 14 each comprising a pair of clamp members for sandwiching the wafers 201 and 202 from two directions orthogonal to each other on the plane of the first and second substrates 01 and 202.
11-2 (sometimes collectively referred to as a first clamp member 1411) and second clamp members 1412-1 and 141
2-2 (which may be collectively referred to as a second clamp member 1412).
1-1, 1411-2 and second clamp member 1412-
A drive mechanism 1413 is provided for performing the approach / separation of 1,1412-2. In the first clamp member 1411, two pairs are provided at positions facing each other between the first clamp member 1411-1 and the first clamp member 1411-2, and in the second clamp member 1412, the second clamp member 1412-1 is provided. A pair of clamp mechanisms 1414 are provided at positions facing each other between the second clamp member 1412-2 and the second clamp member 1412-2. As shown in FIG. 6, these clamp mechanisms 1414 penetrate the housing 1415 and the first and second clamp members 1411 and 1412 in the thickness direction thereof and slidably move in the housing 1415 along the axial direction. A pin 1416 which is attached to an end of the pin 1416 so as to be rotatable around the axis of the pin 1416.
18 and the housing 14
15 and a spring 1418 for urging the pin 1416 in its axial direction. Such a clamping mechanism 1414 is provided between the first clamp member 1411 and the second clamp member 1412.
The holders 1417 hold the wafers 201 and 202 at the six locations at substantially equal intervals along the circumference of the wafers 202.

In this embodiment, by providing the second clamp member 1412 as well as the first clamp member 1411 as described above, the wafers 201 and 202 are held at the above-described six locations at substantially equal intervals as described above. Therefore, no mechanically biased stress is applied to the wafers 201 and 202, and further, a thermally biased temperature distribution is not provided. That is, the holding fitting 1417 comes into contact with the periphery of the wafers 201 and 202 and
In particular, in the case of the post-bump formation wafer 202 in a heated state, heat is transferred from the post-bump formation wafer 202 to the holding bracket 1417 because the holding member 2 is sandwiched. However,
Since the holding members 1417 are arranged at substantially equal intervals at six locations, even when the wafer 202 is sandwiched after the bumps are formed, the holding members 1417 can be attached to the wafer 20.
2 does not have a thermally biased temperature distribution. Therefore, as described above, the configuration of the present embodiment, which includes the second clamp member 1412 as well as the first clamp member 1411 and holds the wafers 201 and 202 at six locations at substantially equal intervals, is particularly suitable for bump formation. This is effective for preventing the above-described problems such as cracks from occurring in a compound semiconductor wafer that is sensitive to a temperature change, which needs to be cooled later as compared with the case of a silicon wafer.

Further, since the pin 1416 is movable in the axial direction, the holding member 1417 is also movable in the axial direction. For example, when the wafer 202 after bump formation is held from the bonding stage 110, the heated wafer 202 after bump formation may be warped by heat. When the warped wafer 202 is sandwiched by the holding fittings 1417 in this manner, the wafer 202 returns from the warped state to the original flat state as it cools after the bump formation. Since the holding bracket 1417 is also movable in the axial direction in accordance with the restoration of the wafer 202 after the formation of the bumps, the clamp mechanism 1414 does not generate a stress on the wafer 202.

The drive mechanism 14 for moving the first clamp member 1411 and the second clamp member 1412 toward and away from each other.
Reference numeral 13 includes a cylinder 14131 which is a driving source, and a second clamp member moving mechanism 14132 which moves the second clamp members 1412-1 and 1412-2 in synchronization with the movement of the clamp member 1411-2. The second clamp member moving mechanism 14132 includes a first member 14133 having one end connected to the first clamp member 1411-2, and a second member 1 rotatable around a rotation center shaft 14134.
4135 is connected to the first clamp member 1411-2 in the X direction, the first member 14133 moves, and the second member 14135 rotates. The second clamp member 14
12 is moved in the Y direction.

The driving mechanism 1413 operates as follows. When the first clamp member 1411 and the second clamp member 1412 are separated from each other to hold the wafers 201 and 202, the cylinder 14131 operates and the output shaft 14137 extends in the X direction and the output shaft 1413
7 connected to the first clamp member 1411-1.
First moves in the X direction until it contacts the stopper, and the stopper stops the movement of the first clamp member 1411-1. Then, the first clamp member 1411-2 moves in the X direction. With the movement of the first clamp member 1411-2, as described above, the second clamp member moving mechanism 141
The operation of 32 moves the second clamp member 1412 in the Y direction. When the first clamp member 1411 and the second clamp member 1412 are separated from each other, the first clamp member 1411-1 moves first, and then the first clamp member 1411-2 and the second clamp member 1
412 move simultaneously. Conversely, the wafer 20
The first clamping member 1411
When approaching the second clamp member 1412 and the second clamp member 1412, first, the operation of the cylinder 14131 causes the first clamp member 1411-2 and the second clamp member 1412 to approach each other.
12 move at the same time, and then the first clamp member 1411-
1 moves. Thus, the first clamp member 1411-
By providing a time lag in the operation timing between the second and second clamp members 1412 and the first clamp member 1411-1, especially when the wafers 201 and 202 are held, The force can be prevented from acting.

In this embodiment, the bonding stage 110, the transfer device 140, and the control device 18 described above are used.
At 0, a preheating device and an aftercooling device for the wafer 201 before bump formation are configured. still,
In the present embodiment, the operation control of the preheating device and the aftercooling device is performed by one control device 180 as described above, but the operation control of these devices is performed corresponding to each of the preheating device and the aftercooling device. Second control device 180-2 and first control device 180
-1 may be provided. Furthermore, as in the present embodiment, the blower 1
Unloading device 1 from which gas whose temperature is controlled at 325 is jetted
An unloading device in which a heat insulating material is provided on a mounting member as in a modified example shown in FIGS. On the other hand, one set of each of the bonding stage 110, the transfer device 140, and the control device 180 may be provided, and each set may be configured as the preheating device and the aftercooling device. In this configuration, each control device provided in the preheating device and the aftercooling device can be integrated into one. Also in this configuration, the aftercooling device may include the above-described unloading device 132 from which the temperature-controlled gas is ejected, and an unloading device provided with a heat insulating material.

The operation of the bump forming apparatus 101 according to the present embodiment configured as described above will be described below. or,
The operation is controlled by the controller 180, and the controller 18
Numeral 0 denotes a characteristic operation in the present embodiment. As will be described in detail later, after the bumps are formed on the bonding stage 110, the temperature control is performed before the wafers 202 are stored in the second storage container 206 after the bumps are formed. While the bump 202 is formed, at least an after-cooling operation for cooling the wafer 202 is performed. In the following description, the wafer 20
Reference numeral 1202 denotes a 3-inch compound semiconductor wafer as an example, but the type and size are not limited to this.

From the first storage container 205, the loading device 13
The first lifting / lowering device 151 operates so as to move the first storage container 205 up and down so that the pre-bump-forming wafer 201 is placed at a take-out position where the wafer can be taken out in Step 1. Hereinafter, as shown in FIG. 7, in step (indicated by “S” in the figure) 1, the carry-in device 131 is moved to the first storage container 205,
The wafer 201 before bump formation is held by the movable holding member 1311 and the fixed holding member 1312 of the loading device 131. In the next step 2, the held wafer 201
Is taken out of the first storage container 205 and transported. In the next step 3, the holding unit 14 of the transfer device 140 is moved above the pre-bump-formed wafer 201 held by the loading device 131.
1 and drives the moving unit 143 of the transfer device 140 to lower the holding unit 141, and drives the cylinder 14131 of the holding unit 141 to separate the first clamp member 1411 and move the second clamp member 1412. Separate.
Next, the operation of the cylinder 14131 causes the first clamp member 1411 to approach and the second clamp member 141
2 is held close to the wafer 201 before bump formation. In the next step 4, the holding unit 141 is raised and the driving unit 142 moves the holding unit 141 above the bonding stage 110.

In this embodiment, the bonding stage 1
Before mounting the pre-bump formation wafer 201 on the pre-bump formation wafer 201 in step 5, as one of the features of the present embodiment, the pre-bump formation wafer 201 is held by the holding unit 141. Do. This is because if the pre-bump-forming wafer 201 at room temperature is immediately placed on the bonding stage 110 and heated to a maximum temperature of about 150 ° C. for bump bonding, the compound semiconductor wafer sensitive to a temperature change has the above-mentioned focus. There is a possibility that circuit breakage or the above-mentioned cracks may occur due to the electric effect, and in order to avoid this, the wafer 201 is preheated.
As a specific method of the preheating, in the present embodiment, the holding unit 141 is placed above the bonding stage 110 which has already been heated to the bump bonding temperature, in a non-contact state with the bonding stage 110, and A method is employed in which the held wafer 201 before bump formation is arranged and heated by radiation heat from the bonding stage 110. The temperature rise control of the pre-bump forming wafer 201 in such a preheating method is performed by controlling the gap size between the bonding stage 110 and the pre-bump forming wafer 201 and the position of the gap between the bonding stage 110 and the pre-bump forming wafer 201.
1 can be performed by controlling at least one of the arrangement times, and various combinations of the above-mentioned gap size and the above-mentioned arrangement times allow various kinds of the above-mentioned temperature rise control as shown in FIGS. . FIG. 8 shows a case where the gap size and the arrangement time are not changed during the preheating operation. When the temperature of the wafer 201 before bump formation is in an equilibrium state, the wafer 201 before bump formation is mounted on the bonding stage 110. 2 shows a temperature rise curve in a one-stage preheat type in which the temperature is increased to the above-mentioned temperature for bump bonding. On the other hand, FIG. 9 shows a case where the gap size and the arrangement time are changed during the preheating operation, and shows a temperature rise curve in a multi-stage preheating type. Note that t1, t shown in FIGS.
2, t3, t4, and t5 are the times used for preheating, T1, T2, T3, and T4 are the temperatures in the equilibrium state in the preheating operation, and T is the bump bonding temperature. The temperature rise curve indicated by reference numeral 1001 shows the case of the present embodiment, and the gap size is 4 mm, and the temperature rise rate takes about 90 seconds to reach 80 ° C. After holding for a minute, it was placed on the bonding stage 110.

Conditions for selecting an appropriate control from among such various temperature rise controls include, for example, a silicon wafer, a compound semiconductor wafer, the material of the semiconductor wafer such as the type of the compound, and the thickness dimension of the semiconductor wafer. Is selected based on at least one of the following. In addition, the above-described various temperature rise control patterns are stored in advance in a storage unit provided in the control device 180 as a preheating program, and the control device 180 executes the control based on at least one of the input material and the thickness of the semiconductor wafer. It is also possible to configure so as to automatically select an appropriate temperature rise control for preheating.
9 to the control device 180, the temperature rise control can also be performed based on the actual temperature information of the wafer 201 before bump formation. In the present embodiment, the preheating is performed using the heat of the bonding stage 110.
It is not limited to this, and a heating device for preheating may be separately provided. In this embodiment, step 5 is executed. However, the present invention is not limited to this, and the process may shift from step 4 to step 6 described below.

In step 6, similarly to the conventional bump forming apparatus, the transfer apparatus 140 places the wafer 201 before bump formation on the heated bonding stage 110, and the wafer 201 before bump formation is Heated to bonding temperature. Thereafter, while moving the bump forming head 120 to the respective bump forming locations on the X and Y tables 122, the bump forming head 1
At 20, bumps are formed on the wafer 201.

After bumps have been formed at all necessary locations,
In step 7, the transfer device 140 holds the wafer 202 after the bump formation from above the bonding stage 110. After step 7, step 8 or step 9
The after cooling, which is one of the features of the present embodiment, is performed in any one of the embodiments. This is because when the wafer 202 after the bump formation at the bump bonding temperature is immediately mounted on the mounting member 1321 of the unloading device 132 at normal temperature, the mounting member 132
In the case of a compound semiconductor wafer that is sensitive to a temperature change due to heat transfer to the wafer 1, the above-described cracks and the like may occur, and in order to avoid this, the wafer 202 is cooled by controlling the temperature drop. . In the present embodiment, the after-cooling method is executed in step 8 and, similarly to the preheating described above, the wafer 202 after bump formation is formed above the bonding stage 110 by the transfer device 140.
And the transfer device 1 executed in step 9
After the bumps are formed at 40, the wafer 202 is cooled to a cooling position other than above the bonding stage 110, for example, the unloading device 13
2 above the mounting member 1321. In any of the methods, after the bump is formed, the wafer 202 after the bump is formed is prevented from immediately coming into contact with the mounting member 1321 at room temperature, and the temperature drop of the wafer 202 after the bump is formed is delayed. Incidentally, the after-cooling method is not limited to these, and various methods as described later are conceivable.

In the after-cooling operation executed in step 8, as in the pre-heating operation in step 5 described above, at least one, preferably both, of the gap size and the arrangement time are changed, for example, as shown in FIG. As described above, the temperature drop control that draws a temperature drop curve substantially opposite to the temperature rise curves shown in FIGS. 8 and 9 is performed. Note that the temperature drop curve indicated by reference numeral 1002 is a graph when the gap size and the arrangement time are not changed during the after-cooling operation, similarly to the one-stage preheat type. Is similar to the multi-stage preheat type,
It is a graph at the time of changing the said clearance dimension and the said arrangement time during an after-cooling operation | movement. Also, t6, t7
Is the time used for aftercooling, and T5, T6
Is a temperature in an equilibrium state in the aftercooling operation, and T0 indicates a normal temperature. At the time point when the times t6 and t7 have elapsed, the wafer 202 after bump formation is transferred to the unloading device 13.
Is transferred to the second mounting member 1321. The selection of various temperature drop controls is made based on at least one of the materials and thickness dimensions of the wafers 201 and 202, as in the case of the above-described preheating operation. As in the case of the preheating operation described above, the various temperature drop control patterns described above are stored in advance in a storage unit provided in the control device 180 as an after-cooling program, and the material and thickness of the input semiconductor wafer are stored. Based on at least one of the dimensions, the controller 180 may be configured to automatically select an appropriate temperature drop control for aftercooling, or the temperature measuring device 1419 provided on the holding unit 141.
Can be performed based on the actual temperature information of the wafer 202 after the bump formation, which is supplied to the control device 180 from the controller. In the present embodiment, the after-cooling operation is performed by using the heat of the bonding stage 110. However, the present invention is not limited to this, and a separate heating device for after-cooling may be provided.

In the after-cooling operation performed in step 9, unlike the case of step 8 described above, heat radiated from the bonding stage 110 does not act. The temperature drop rate of 202 is fast. However, as compared with the case where the transfer is performed on the mounting member 1321 immediately after the formation of the bumps, there is no heat transfer to the transfer member 1321, and the cooling rate is slow. It does not occur.

Here, the relationship between the temperature rising speed and the temperature falling speed in the above-described preheating operation and after-cooling operation, and the material and thickness of the semiconductor wafer will be described. With silicon and quartz semiconductor wafers, relatively rapid heating and rapid cooling are possible as compared with the following materials. In the case of compound semiconductor wafers of lithium tantalum and lithium niobium, a rate of 50 ° C./min or less for the above cracks and a rate of 3 ° C./min or less at a level that ensures the operation of the electric circuit is ensured in both heating and cooling. preferable.
The operation of the electric circuit is sufficiently ensured even at a speed exceeding 3 ° C./min. In addition, the temperature rise rate is 50 ° C /
In some cases, a speed of about 10 seconds is sufficient, and the temperature drop control has more severe control conditions. Although it is undecided at present, gallium arsenide semiconductor wafers are considered to be in accordance with the above-described lithium tantalum and lithium niobium semiconductor wafers. Further, a clear relationship between the above-mentioned thickness and the above-mentioned temperature rising speed and temperature falling speed has not yet been confirmed. However, when being held by the holding unit of the transfer device as described above, a thinner plate is disadvantageous because warping tends to occur due to the holding force of the holding unit.

In this embodiment, step 8 or step 9 is executed, but the present invention is not limited to this. That is, steps 8 and 9 may be performed in the order of step 8 and step 9 depending on the material and the thickness of the plate. Further, in the mounting member 1321 of the present embodiment, as described above, the blower 1
Since it is possible to send out the temperature-controlled air at 325,
With the air, the temperature of the mounting member 1321 can be raised in advance to room temperature or higher, or the temperature drop of the wafer 202 after the bumps mounted on the mounting member 1321 can be delayed. Therefore, when such a structure is adopted, the process may shift from step 7 to step 10 described below depending on the material and the thickness of the semiconductor wafer. Further, the above-mentioned temperature-controlled air is supplied to the mounting member 13.
The structure of sending out from the semiconductor device 21 can also prevent the occurrence of problems such as cracks in the compound semiconductor wafer.
Further, since the temperature of the wafer 202 can be controlled by sending the air whose temperature is controlled as described above, the wafer 202 can be placed on the mounting member without waiting for the temperature of the wafer 202 to be equilibrated by the after-cooling. 1321. Therefore, when only one transfer device 140 is provided, the transfer device 140 can be released more quickly from the operation of holding the wafer 202 for the after cooling operation, and the lead time can be reduced. Can be.

In step 10 following step 8 or step 9, the wafer 202 after bump formation is transferred from the transfer device 140 to the mounting member 1321 of the unloading device 132. In step 11, the unloading device 132 transports the bumped wafer 202 to the second storage container 206, and the second lifting / lowering device 152 sets the second storage container to a height capable of storing the bumped wafer 202. Step 1 for 206
2, the unloading device 132 operates the wafer 20 after bump formation.
2 is stored. It should be noted that the above steps 10 to 1
2 is the same as the conventional operation.

As described above, according to the bump forming apparatus 101 and the bump forming method of the present embodiment, the wafer 201 before bump formation is moved from the room temperature to the bonding stage 11.
0, the wafer 201 before bump formation is heated in advance while controlling the rising temperature by the preheating operation instead of immediately heating to the above-mentioned bump bonding temperature. Even in this case, problems such as circuit destruction due to the pyroelectric effect and cracking due to thermal deformation do not occur. Further, after the bumps are formed, the post-bump forming wafer 202 is not immediately transferred onto the mounting member 1321 of the unloading device 132 at the room temperature from the bump bonding temperature, but is controlled while controlling the temperature drop by the after-cooling operation. Since the wafer 202 is cooled after the formation, even when handling the compound semiconductor wafer, there is no problem such as the above-described circuit destruction or the above-mentioned crack.

As a modification of the above-described bump forming apparatus 101, the following configuration can be adopted. In the above-described embodiment, the mounting member 1321 of the unloading device 132 is formed of a metal plate.
As shown at 51 to 253, a heat insulating material made of a resin material is provided in a contact portion with the wafer 202 after the bump is formed in the present embodiment, so that the cooling of the wafer 202 after the bump is higher than normal temperature is delayed. It is also possible to configure so that That is, in the unloading device 251 shown in FIG. 11, a heat insulating material 2512 is provided on a metal mounting member 2511 so that the wafer 202 and the mounting member 2511 do not come into direct contact with each other after the bumps are formed. The heat insulating material 2512 prevents the heat of the wafer 202 from being easily transmitted to the mounting member 2511 after the bumps are formed. Furthermore, the projections 2513 are provided on the heat insulating material 2512 so that the wafer 202 and the heat insulating material 2512 are brought into point contact with each other after the bumps are formed, so that heat transfer is more difficult. With this configuration, the temperature drop of the wafer 202 after the bump formation can be delayed as compared with the case where the wafer 202 after the bump formation is directly mounted on the metal mounting member 1321.

In the unloading device 252 shown in FIG. 12, in addition to the structure of the unloading device 251 described above, a loading member 252 is further provided.
An air layer 2523 is formed between the first heat insulating material 1 and the heat insulating material 2522. By forming the air layer 2523 having the heat insulating effect in this manner, the metal mounting member 2
521 is easily interrupted by the heat transfer to the unloading device 2
51, the temperature drop of the wafer 202 after the bump formation can be delayed more. Note that the reason why the heat insulating material is provided on the metal mounting member as in the above-described unloading device 251 and unloading device 252 is that a smooth surface is formed by a metal mounting member that can be easily planarized. This is for smoothing the mounting surface of the heat insulating material on which the wafer 202 is mounted after the bumps are formed. When the mounting surface can be smoothed with only the heat insulating material, the unloading shown in FIG. Device 25
As shown in FIG. 3, the mounting member of the wafer 202 may be formed after the bumps are formed only by the heat insulating material 2531. When the unloading devices 251 to 253 with such a heat insulating material are provided, the cooling speed of the wafer 202 after the bump formation can be delayed as described above. However, it may be omitted.

As shown in FIG. 14, which takes the unloading device 251 as an example, the projection 2513 is provided with a gap 251 with respect to the heat insulating material 2512 and the mounting member 2511.
5 are provided. Therefore, the unloading device 25
When the wafer 202 after the bump formation moves in the direction perpendicular to the thickness direction after being mounted on the substrate 1, the projection 2513 can also move in the above-described gap in the orthogonal direction together with the wafer 202 after the bump formation. Therefore, when the wafer 202 after bump formation moves when the protrusion is fixed, the wafer 202 after bump formation may rub against the protrusion, and the protrusion may damage the wafer 202 after bump formation. However, as described above, the wafer 20
When both 2 and the projection 2513 move in the same direction, there is no possibility of causing the above-mentioned damage. Further, as shown in the figure, the projection 2513 is also provided with a gap 2515 in the thickness direction of the wafer 202 after the bumps are formed with respect to the heat insulating material 2512, so that the projection 2513 also moves in the thickness direction of the wafer 202. It is possible. Further, only the protrusion 2513 may be made of a material different from the heat insulating materials 2512, 2522, and 2531.

In order to keep the temperature of the wafer 201 before bump formation and the temperature of the wafer 202 after bump formation better than in the above-described embodiment, the transfer device 140 may be provided with a heat insulation device. FIG. 15 shows a transfer device 261 in which the heat retaining device 262 is attached to the transfer device 140 described above. The heat retaining device 262 includes a cover member 2621 and a driving unit 2624. The cover member 2621 is a member that keeps the temperature of the wafers 201 and 202, and sandwiches the first and second wafers 201 and 202 in the thickness direction of the wafers 201 and 202.
An upper cover 26 disposed over the holding portion 141 having the clamp member 1411 and the second clamp member 1412
22 and a lower shutter 2623. The lower shutter 2623 moves along the diametrical direction of the wafers 201 and 202 sandwiched between the holding portions 141, and
Two lower shutters 262 that open and close left and right with 4
3-1, 2623-2. Heat from the bonding stage 110 is applied to the lower shutters 2623-1 and 2623-2 by the wafers 201 and 20, respectively.
2 so that the lower shutter 2623 can be easily operated.
A plurality of openings 2625 penetrating -1,623-2 are provided. By providing the heat retaining device 262 configured as described above, the lower shutter 2623 is closed with the wafers 201 and 202 held therebetween, and the wafers 201 and 202 are placed above the bonding stage 110 in Steps 5 and 8 as described above. By arranging 202, the heat of bonding stage 110 enters into cover member 2621, so that wafers 201 and 202 can be kept warm.

Further, a gas for controlling the temperature of the wafers 201 and 202 and supporting the temperature of the wafers 201 and 202 is sandwiched in the cover member 2621 by the heat retaining device 262.
A heat retention support device 263 that sprays on the heaters 202 can also be provided. In this embodiment, the gas is a nitrogen gas, which is guided by a pipe 2631 and sprayed onto the wafers 201 and 202 so that the nitrogen gas flows along the surfaces of the wafers 201 and 202. By blowing gas in this manner, the entire wafers 201 and 202 can be kept at a uniform temperature. Further, by spraying a nitrogen gas or an inert gas, the oxidation of the electrodes formed on the wafers 201 and 202 can be prevented.

Further, in addition to preventing the occurrence of defects such as the cracks in the wafers 201 and 202, in order to further shorten the lead time in the bump formation process,
The following configuration can be provided in addition to the configuration of the above-described embodiment and its modified example. That is, as described above, in the present embodiment, the transfer device 140 is provided with only one holding unit 141, but the two holding units 144-1 and 144-2 are separated like the transfer device 144 shown in FIG. Having, for example, the holding unit 1
At 44-1, the wafer 201 before bump formation is transferred and
Each of the holding units 144-2 may be independently driven so that the wafers 202 are transferred after the bumps are formed. The temperature measuring device 1419 is also provided in each of the holders 144-1 and 144-2. With this configuration, the wafer before bump formation 201
And the transfer operation of the wafer 202 after the bump formation can be shared by the respective holding portions, and the lead time can be reduced.

When one transfer device 140 is provided, at least one of the carry-in device 131 and the carry-out device 132 has a temporary holding member 27 as shown in FIG.
1 can be provided. The temporary holding member 271 provided on the loading device 131 side is a first temporary holding member 271-1, and the temporary holding member 271 provided on the unloading device 132 side is a second temporary holding member 271-2. For example, when the loading device 131 is used as an example, the first temporary holding member 271-1 is
1 and is moved up and down by a drive unit 272 that is operationally controlled by the control unit 180 along the thickness direction of the wafer 202 mounted on the mounting member 1321. By providing the first temporary holding member 271-1 in this manner, the placing member 1321 and the first temporary holding member 271 are described.
-1 can be transferred between the wafer 201 and the mounting member 1321.
You can go get out. Thus, the lead time can be reduced. Such operations and effects are the same in the case of the second temporary holding member 271-2.

Further, as shown in FIG.
In the so-called single-magazine type bump forming apparatus 301 having only one storage container 302 for the first and second containers 202, 202, the temporary holding member 303 with a heater further provided with a heater in addition to the temporary holding member described above, 304
And the wafers 201 and 202 with respect to the storage container 302.
For example, by providing a transfer device 305 for loading and unloading, and a transfer device 306, the wafer 201 before bump formation taken out by the transfer device 305 is placed on the temporary holding member 303 with a heater, and the preheating is performed. Meanwhile, it is also possible to go to take out the next wafer 201 before bump formation by the empty transfer device 305 and transfer the wafer 202 after bump formation from the bonding stage 110 to the temporary holding member 304 by the transfer device 306. The provision of the temporary holding member enables each operation to be performed in parallel, so that the lead time can be reduced even in the single magazine type. In such a configuration, the heater-equipped temporary holding member 303 needs to be cooled to almost room temperature after the preheating and before the next pre-bump-forming wafer 201 is mounted. Preferably, it is provided.

Second Embodiment In the above description, the compound semiconductor wafer mainly used as an example is considered to cause little problem. For example, a semiconductor wafer in which a semiconductor circuit is formed on a quartz substrate (hereinafter, referred to as a semiconductor wafer). , "Quartz semiconductor wafer"
) Further has the following problem.
The quartz semiconductor wafer described here has a diameter of 3 inches and a thickness of 0.3 to 0.35 mm as an example.
Of course, it is not limited to this. From the viewpoint of facilitating the formation of bumps on a semiconductor wafer as described above, the bump bonding temperature is, for example, about 250 to about 270 ° C. for a silicon wafer and about 150 ° C. for a lithium tantalum wafer as described above. As such, the highest possible temperature is preferred. The case of the quartz semiconductor wafer is not an exception, but the quartz semiconductor wafer that has been subjected to the preheating described above is placed on the bonding stage set at various temperatures and heated to the bump bonding temperature. According to experiments performed by the applicant, the following phenomena were observed. Even when the bonding stage is gradually heated at a heating rate of 5 ° C./minute, the bonding stage is at about 250 degrees, that is, the stage of the quartz semiconductor wafer 211 that contacts the bonding stage as shown in FIG. When the contact surface side 211b reaches about 250 degrees of the bonding stage, the quartz semiconductor wafer 211 warps as shown in FIG. If the temperature difference between the temperature of the bonding stage and the temperature of the quartz semiconductor wafer 211 immediately before mounting is about 50 ° C.,
As shown in FIG. 9, the quartz semiconductor wafer 211 warps. Further, even if the temperature difference is 50 ° C. or less, the above-described warpage occurs when the material is rapidly heated, for example, at a rate of 20 ° C./min. The specific value of the warpage is about 2 mm in the dimension I shown in FIG.

In such a warped state, the quartz semiconductor wafer 211 cannot be attracted onto the bonding stage, and it is of course impossible to form bumps on the quartz semiconductor wafer 211. On the other hand, when the warped quartz semiconductor wafer 211 is forcibly attracted to the bonding stage, the quartz semiconductor wafer 2
11 breaks. The cause of the warpage is considered to be essentially due to the physical properties of the quartz semiconductor wafer 211. However, directly, the temperature of the quartz semiconductor wafer 211 is non-uniform in its thickness direction. In other words, the quartz semiconductor wafer 211 is placed on the bonding stage, so that the quartz semiconductor wafer 2
11, the stage contact surface side 211b is rapidly heated, but the temperature rise rate of the circuit forming surface side 211a of the quartz semiconductor wafer 211 facing the stage contact surface side 211b is lower than that of the stage contact surface side 211b. slow. Therefore, a temperature difference occurs between the stage contact surface side 211b and the circuit formation surface side 211a, and the temperature difference causes the warpage.

Therefore, in this embodiment, the temperature difference between the circuit forming surface 211a and the stage contact surface 211b of the quartz semiconductor wafer 211 mounted on the bonding stage 110 is determined. Wafer temperature control device 160 for controlling the amount of wafer warpage that does not cause a problem when bumps are formed on semiconductor wafer 211, in the present embodiment, to be within a non-warping temperature range that suppresses warpage of quartz semiconductor wafer 211 to 50 μm. Was provided as shown in FIG. 1 or FIG. The above-mentioned wafer warpage amount is
When the quartz semiconductor wafer 211 is warped convexly,
Quartz semiconductor wafer 211 on bonding stage 110
Is an amount corresponding to the dimension indicated by “I” shown in FIG. 19 in a state before is adsorbed. When the bumps are actually formed, the above-mentioned suction operation is performed, so that the value of 50 μm becomes about 20 μm or less. Wafer temperature control device 16
0 indicates that the temperature difference is within the non-warping temperature range and the quartz-crystal semiconductor wafer 211 mounted on the bonding stage 110 is on the circuit forming surface side 211.
a) or cool the stage contact surface side 211b. Here, the above-mentioned non-warping temperature range is within about 20 ° C. based on the above experimental results.

In the wafer temperature control device 160, as a form for heating the circuit forming surface side 211a, a heated air blowing device 161 is provided as shown in detail in FIG. The hot air blowing device 161 is installed at a position behind the bonding stage 110 that does not interfere with the operation of the bump forming head 120.
Heating air having a temperature such that the temperature difference falls within the non-warping temperature range is blown to the entire area or almost the entire area of the circuit forming surface 211a of the quartz semiconductor wafer 211 mounted on the zero. For example, the bonding stage 11
0 is set to 200 ° C. and the hot air blowing device 1
A heated air at 61 to 200 ° C. is sent out for about 30 seconds.
The installation location of the hot air blowing device 161 is not limited to the above location, and may be, for example, on the front side of the bonding stage 110 or the like. The hot air blowing device 161 is connected to the control device 180 and controls the temperature, the blowing time, the flow rate, the wind speed and the like of the hot air based on the relationship with the temperature of the bonding stage 110.

On the other hand, in the wafer temperature control device 160, as a form for cooling the stage contact surface side 211b, a cooling air supply device 162 can be provided as shown in detail in FIG. Conventionally, a plurality of suction holes 111 are provided on a bonding stage for sucking a semiconductor wafer, and these are connected to a suction device 113 via an air passage 112. The cooling air supply device 1
62 is connected to the air passage 122
The cooling air is supplied to the entire area or almost the entire area of the stage contact surface 211b through the interface. Incidentally, since the projection 114 for positioning and supporting the mounted semiconductor wafer is conventionally provided on the bonding stage 110, the quartz semiconductor wafer 211 is bonded by the supply of the cooling air by the cooling air supply device 162. Stage 11
It will not fall off from above zero. The cooling air supply device 162 is connected to the control device 180 and controls the temperature, the supply time, the flow rate, the wind speed, and the like of the cooling air based on the relationship with the temperature of the bonding stage 110. In the case of the present embodiment, when the temperature of the bonding stage 110 is set to 200 ° C., the cooling air supply device 162
From about 20 seconds. At this time, the temperature of the cooling air immediately after being sent from the cooling air supply device 162 and before reaching the stage contact surface side 211b is 185.
° C. As a method of correcting the warpage, it is originally preferable to provide the heating air blowing device 161 for heating the circuit forming surface side 211a having a lower temperature than the stage contact surface side 211b. Compared with the case where the heated air blowing device 161 is provided, the cooling air supply device 162 is more convenient because the existing air passage 112 can be used and the installation location can be freely selected.

The operation of wafer temperature control device 160 configured as described above will be described with reference to FIG. FIG.
The operation indicated by 0 is an operation when heating and bonding of the quartz semiconductor wafer 211 in Step 6 shown in FIG. In the present embodiment, the case of the cooling air supply device 162 is taken as an example of the wafer temperature control device 160. In the present embodiment, the temperature of the bonding stage 110 is set to 200 ° C. As described above, the temperature of the bonding stage 110 and the bonding stage 1
Since the temperature difference between the quartz semiconductor wafer 211 and the quartz semiconductor wafer 211 placed on the wafer 10 must be within about 50 ° C., the quartz semiconductor wafer 211 is subjected to the above-described preheating in step 5 described above. In this embodiment, the preheating is performed in two stages as described with reference to FIG.
The temperature of the quartz semiconductor wafer 211 is increased to 150 ° C. At the end of the preheating, the quartz semiconductor wafer 211 has the same temperature on both the circuit forming surface side 211a and the stage contact surface side 211b.

Next, in step 61, the transfer device 1
The quartz semiconductor wafer 211 is placed on the bonding stage 110 by the holding part 141 of the forty, and the main heating of the quartz semiconductor wafer 211 is performed in step 62. Since the stage contact surface side 211b is rapidly heated by the above-described placement, the warpage starts to occur in the quartz semiconductor wafer 211, but step 63 is executed simultaneously with execution of step 62. That is, the cooling air is supplied from the cooling air supply device 162 to the crystal semiconductor wafer 21.
1 is supplied to the entire or almost the entire area of the stage contact surface 211b for about 20 seconds.
The temperature rise rate of b is suppressed. Therefore, the temperature difference between the circuit forming surface side 211a and the stage contact surface side 211b is reduced by the wafer warpage amount which does not hinder the formation of bumps on the mounted crystal semiconductor wafer 211. Within the non-warping temperature range for suppressing warpage. Therefore, even if the warpage occurs once, it is corrected and the warp of the quartz semiconductor wafer 211 falls within the wafer warpage amount. Thus, the quartz semiconductor wafer 21
Reference numeral 1 denotes a bonding stage 11 in this embodiment.
It is heated to the above-mentioned bonding temperature of 200 ° C., which is the set temperature of 0. In step 64, after the heating to the bonding temperature, the quartz semiconductor wafer 211 is sucked onto the bonding stage 110 by the operation of the suction device 113, and a bump is formed on the circuit forming portion by the bump forming head 120. . Thereafter, the operations after step 7 described above are performed.

As described above, according to the present embodiment, the warpage of the quartz semiconductor wafer 211 at the time of the main heating can be suppressed within a wafer warpage amount that does not cause a problem when forming bumps. Quartz semiconductor wafer 2 up to a high temperature such as 250 ° C. within the above wafer warpage amount
11 can be heated and the quartz semiconductor wafer 2
11 can be formed with bumps.

As described above, the cooling air supply device 162
Although the cooling air is uniformly supplied to the entire area or almost the entire area of the stage contact surface 211b, from the viewpoint of more effectively preventing the occurrence of the warpage, the temperature, the supply amount, and the like are changed depending on the location. Is also good. For example, a cooling air supply device that supplies the cooling air to the central portion of the quartz semiconductor wafer 211 and a cooling air supply device that supplies the cooling air to other portions are provided. Thus, the temperature of the cooling air to the central portion can be lowered or the amount of air can be increased.

In the above description, the quartz semiconductor wafer 211
However, the present invention is not limited to this, and the second embodiment is effective for a semiconductor wafer using a material that has a poor heat transfer and a coefficient of thermal expansion that greatly differs depending on the temperature.

[0052]

As described above in detail, according to the bump forming method of the first aspect and the bump forming apparatus of the third aspect of the present invention, an after-cooling device is provided. Since the after-cooling operation is controlled by controlling the temperature drop, even when handling compound semiconductor wafers that are sensitive to temperature changes, problems such as circuit breakdown due to the pyroelectric effect and cracks due to thermal deformation may occur. There is no.

Further, according to the bump forming method of the second aspect and the bump forming apparatus of the fourth aspect of the present invention, a pre-heating device is further provided in addition to the after-cooling device, and before the bump is formed on the wafer, Since the wafer is heated while controlling the temperature rise of the wafer, even when a compound semiconductor wafer sensitive to temperature change is handled, problems such as circuit destruction due to the pyroelectric effect and cracking due to thermal deformation occur. Can be further prevented.

The bump forming method according to the fifth aspect of the present invention,
According to the bump forming apparatus of the sixth aspect, the semiconductor device further includes a wafer temperature control device, which suppresses the warpage of the semiconductor wafer mounted on the bonding stage to such an extent that the semiconductor wafer mounted on the bonding stage does not hinder the bump formation. Therefore, the semiconductor wafer can be maintained in a substantially flat state even at a high temperature of, for example, 200 to 250 ° C., so that bumps can be formed on the semiconductor wafer at the high temperature.

[Brief description of the drawings]

FIG. 1 is a perspective view showing a bump forming apparatus according to an embodiment of the present invention.

FIG. 2 is a perspective view showing the transport device shown in FIG.

FIG. 3 is a perspective view showing the transfer device shown in FIG. 1;

FIG. 4 is a perspective view showing a modified example of the transfer device shown in FIG.

5 is a plan view of the transfer device shown in FIG.

FIG. 6 is a cross-sectional view showing a clamp mechanism of the transfer device shown in FIG.

FIG. 7 is a flowchart showing an operation in a bump forming method executed by the bump forming apparatus shown in FIG. 1;

FIG. 8 is a graph showing various temperature rise curves in preheating in step 5 shown in FIG.

9 is a graph showing various temperature rise curves in the preheating in step 5 shown in FIG.

FIG. 10 is a graph showing a temperature drop curve in step 8 or step 9 shown in FIG. 7;

11 is a cross-sectional view showing a modification of the unloading device shown in FIG.

FIG. 12 is a sectional view showing a modified example of the unloading device shown in FIG.

FIG. 13 is a sectional view showing a modified example of the unloading device shown in FIG.

FIG. 14 is a cross-sectional view of a protrusion provided on the unloading device shown in FIGS. 11 to 13.

FIG. 15 is a view showing a modification of the transfer device shown in FIG. 1;

FIG. 16 is a perspective view showing a temporary holding member provided in a modification of the bump forming apparatus shown in FIG.

FIG. 17 is a block diagram showing a modification of the bump forming apparatus shown in FIG.

18 is a perspective view showing a state in which the bump forming apparatus shown in FIG. 1 is provided with a heated air blowing device constituting a wafer temperature control device.

FIG. 19 is a view showing a state in which the quartz semiconductor wafer is warped on the bonding stage.

20 is a flowchart showing an operation in step 6 in FIG. 7 when the bump forming apparatus shown in FIG. 1 is provided with a wafer temperature control device.

[Explanation of symbols]

101: Bump forming device, 110: Bonding stage, 120: Bump forming head, 130: Transport device, 1
31: Loading device, 132: Unloading device, 140: Transfer device, 144-1, 144-2: Transfer device, 160: Wafer temperature control device, 180: Control device, 205: First storage container, 206: No. 2 storage container, 211: quartz semiconductor wafer, 211a: circuit forming surface side, 211b: stage contact surface side, 263: heat retention support device, 271: temporary holding member, 1
325: blower, 1411, 1412: clamp member, 1414: clamp mechanism, 1419: temperature measuring device,
2511, 2521 ... Placement member, 2512, 2522 ...
Insulation material, 2621 ... cover member, 2625 ... opening.

Continued on the front page (72) Inventor Masahiko Ikeya 1006 Kazuma Kadoma, Osaka Prefecture Matsushita Electric Industrial Co., Ltd. Matsumae Electric Industrial Co., Ltd.

Claims (57)

[Claims] 1. A bump forming method for forming a bump on an electrode of a circuit formed on a semiconductor wafer, the method comprising: after the main heating of the semiconductor wafer for bump formation, after the bump bonding to the semiconductor wafer; A method of forming a bump, comprising: performing an after-cooling operation on the semiconductor wafer by controlling a temperature drop of the semiconductor wafer before storing the semiconductor wafer in a storage container. 2. The after-cooling operation, wherein after the completion of the bump bonding, the temperature of the semiconductor is reduced to a bump bonding temperature in the main heating required to form a bump on an electrode formed on a circuit on the semiconductor wafer. 2. The bump forming method according to claim 1, wherein the semiconductor wafer is arranged above the bonding stage for heating the wafer in a non-contact state with the bonding stage. 3. The bump forming method according to claim 1, wherein the after-cooling operation is performed by disposing the semiconductor wafer at a cooling position deviated from above the bonding stage after the completion of the bump bonding. 4. The bump forming method according to claim 1, wherein the after-cooling operation is performed according to a preset after-cooling program. 5. The bump forming method according to claim 1, wherein the after-cooling operation is performed while actually measuring the temperature of the semiconductor wafer. 6. The temperature drop in the after-cooling operation is caused by a gap between the bonding stage and the semiconductor wafer, and an arrangement in which the semiconductor wafer is arranged above the bonding stage in a non-contact state with the bonding stage. The bump forming method according to claim 2, wherein the method is controlled by changing at least one of time. 7. The bump forming method according to claim 6, wherein the temperature drop in the after-cooling operation is performed by controlling at least one of the gap size and the arrangement time to change a plurality of times. 8. The bump forming method according to claim 1, wherein said after cooling operation is controlled based on at least one of a material and a thickness of said semiconductor wafer. 9. The bump forming method according to claim 1, wherein a preheating operation is performed on the semiconductor wafer before performing the main heating. 10. When the semiconductor wafer is mounted on the bonding stage for heating the semiconductor wafer to the bump bonding temperature and the main heating is performed, the preheating operation is performed above the bonding stage. 10. The bump forming method according to claim 9, wherein the method is performed by disposing the semiconductor wafer in a non-contact state with a bonding stage. 11. The preheating operation is performed according to a preheating program set in advance.
Or the bump forming method according to 10. 12. The preheating operation is performed while actually measuring the temperature of the semiconductor wafer.
Or the bump forming method according to 10. 13. The temperature rise in the preheating operation is controlled by changing at least one of a gap size between the bonding stage and the semiconductor wafer and an arrangement time for disposing the semiconductor wafer above the bonding stage. Claims 10 to 12
The bump forming method according to any one of the above. 14. The bump forming method according to claim 13, wherein the temperature increase in said preheating operation is executed by control for changing at least one of said gap size and said arrangement time a plurality of times. 15. The bump forming method according to claim 9, wherein the preheating operation is controlled based on at least one of a material and a thickness of the semiconductor wafer. 16. When both the preheating operation and the aftercooling operation are performed, the rate of temperature change per unit time in the temperature drop control in the aftercooling operation is lower than that in the temperature rise control in the preheating operation. 9. The method according to claim 9, wherein the setting is fine.
5. The bump forming method according to any one of 5. 17. The bump forming method according to claim 1, wherein said semiconductor wafer is a compound semiconductor wafer. 18. After the semiconductor wafer is mounted on a bonding stage for heating the semiconductor wafer to the temperature for bump bonding in the main heating, before the bump bonding is performed, the semiconductor wafer is mounted on the bonding stage. With respect to the semiconductor wafer, the temperature at the stage contact surface side (211b) of the semiconductor wafer in contact with the bonding stage and the circuit formation surface side (211b) of the semiconductor wafer facing the stage contact surface
18. The bump forming method according to claim 1, wherein a temperature difference from the temperature in a) is controlled within a temperature range in which warpage of the semiconductor wafer is suppressed so as not to cause a problem in bump formation. . 19. The bump according to claim 18, wherein the control within the non-warping temperature range is achieved by heating the circuit forming surface side of the semiconductor wafer mounted on the bonding stage. Forming method. 20. The circuit forming surface according to claim 19, wherein the heating of the circuit forming surface is performed by blowing heated air having a temperature at which the temperature difference falls within the non-warping temperature range to the circuit forming surface. Bump formation method. 21. The bump according to claim 18, wherein the control within the non-warping temperature range is achieved by cooling the stage contact surface side of the semiconductor wafer mounted on the bonding stage. Forming method. 22. The cooling device according to claim 21, wherein the cooling of the stage contact surface is performed by blowing cooling air having a temperature at which the temperature difference falls within the non-warping temperature range to the stage contact surface. Bump formation method. 23. The non-warping temperature range is 20 ° C.
23. The bump forming method according to claim 18, wherein 24. The bump forming method according to claim 18, wherein said semiconductor wafer is a wafer based on quartz. 25. A bonding stage (110) for mounting a semiconductor wafer and fully heating the semiconductor wafer to a bump bonding temperature necessary for forming a bump on an electrode formed on a circuit of the semiconductor wafer.
A bump forming head (120) mounted on the bonding stage and forming the bump on the electrode of the semiconductor wafer; and a transfer device (140) for mounting and removing the semiconductor wafer on and from the bonding stage.
And an after-cooling apparatus that cools the semiconductor wafer based on temperature drop control on the semiconductor wafer after bonding the bump to the heated semiconductor wafer. (110, 140, 180). A bump forming apparatus comprising: 26. The after-cooling device includes the bonding stage, the transfer device, and a first control device (180-1), and after-cooling the semiconductor wafer by using heat of the bonding stage. An apparatus for performing an operation, wherein the first control device holds the semiconductor wafer at a position where the semiconductor wafer is not in contact with the bonding stage above the bonding stage heated to the bump bonding temperature. 26. The bump forming apparatus according to claim 25, wherein a transfer apparatus is arranged. 27. The semiconductor device according to claim 27, wherein the first control device changes at least one of a gap size between the bonding stage and the semiconductor wafer and an arrangement time for disposing the semiconductor wafer above the bonding stage. The bump forming apparatus according to claim 26, wherein a temperature drop in the after-cooling operation is controlled. 28. The bump formation according to claim 27, wherein the control of the temperature drop in the after-cooling operation by the first control device is performed by a control that changes at least one of the gap size and the arrangement time a plurality of times. apparatus. 29. The bump forming apparatus according to claim 26, wherein the first control device executes the after-cooling operation according to a preset after-cooling program. 30. A first temperature measuring device (14) for measuring a temperature of a semiconductor wafer on which the after-cooling operation is performed.
27) The first control device controls the after-cooling operation based on the temperature of the semiconductor wafer actually measured by the first temperature measuring device.
29. The bump forming apparatus according to any one of items 28 to 28. 31. The bump forming apparatus according to claim 26, wherein the first control device controls the after-cooling operation based on at least one of a material and a thickness of the semiconductor wafer. 32. A preheating device (110, 140, 140) for performing a preheating operation of the semiconductor wafer before placing the semiconductor wafer on the bonding stage and heating the semiconductor wafer to the bump bonding temperature.
The bump forming apparatus according to any one of claims 25 to 31, further comprising (180). 33. The preheating device, wherein the bonding stage, the transfer device, and a second control device (18)
0-2), wherein the pre-heating operation of the semiconductor wafer is performed using the heat of the bonding stage, wherein the second control device is configured to heat the bonding stage heated to the bump bonding temperature. 33. The bump forming apparatus according to claim 32, wherein the transfer device holding the semiconductor wafer is disposed at a position where the semiconductor wafer is not in contact with the bonding stage above the bonding stage. 34. The semiconductor device according to claim 34, wherein the second control device changes at least one of a gap size between the bonding stage and the semiconductor wafer and an arrangement time for disposing the semiconductor wafer above the bonding stage. The bump forming apparatus according to claim 33, wherein a temperature rise in said preheating operation is controlled. 35. The bump forming apparatus according to claim 34, wherein the control of the temperature rise in the preheating operation by the second control device is executed by a control for changing at least one of the gap size and the arrangement time a plurality of times. . 36. The bump forming apparatus according to claim 33, wherein the second control device executes the preheating operation according to a preset preheating program. 37. A semiconductor device comprising a second temperature measuring device (1419) for measuring a temperature of the semiconductor wafer to be preheated, wherein the second control device controls the semiconductor wafer actually measured by the second temperature measuring device. 36. The bump forming apparatus according to claim 33, wherein the preheating operation is controlled based on the temperature of the bump. 38. The bump forming apparatus according to claim 33, wherein the second control device controls the preheating operation based on at least one of a material and a thickness of the semiconductor wafer. 39. A storage container (205, 206) for storing the semiconductor wafer, and a transfer for transferring the semiconductor wafer to and from the transfer container while transferring the semiconductor wafer to and from the storage container. A bump forming apparatus according to any of claims 25 to 38, further comprising an apparatus (130). 40. A first temporary holding member (27) for holding the semiconductor wafer (201) before bump formation taken out of the storage container and transferring it to the transfer device by the transfer device.
1-1) and at least one of a second temporary holding member (271-2) for holding the semiconductor wafer (202) after bump formation held by the transfer device from the bonding stage and transferring the semiconductor wafer (202) to the transfer device. The bump forming apparatus according to claim 39, further comprising: 41. A clamping mechanism, wherein the transfer device is disposed at substantially equal intervals around the semiconductor wafer and does not mechanically apply stress to the semiconductor wafer and does not generate a thermal temperature gradient. 1414).
41. The bump forming apparatus according to any one of 6 to 31, 33 to 40. 42. The storage container includes a first storage container (205) for storing a semiconductor wafer (201) before bump formation before bump formation, and a second storage container for storing a semiconductor wafer (202) after bump formation after bump formation. 42. The bump forming apparatus according to claim 39, further comprising a two-storage device (206). 43. The transfer device includes a mounting member (2511, 2521) for mounting the semiconductor wafer, and at least a portion of the mounting member that contacts the semiconductor wafer delays a temperature drop of the semiconductor wafer. 39. The heat insulating material (2512, 2522) to be provided.
3. The bump forming apparatus according to any one of 2. 44. A transfer device (131) for taking out the semiconductor wafer before bump formation from the first storage container, and a carry-out device (132) for transferring the semiconductor wafer after bump formation to the second storage container. ) And
The bump forming apparatus according to claim 42 or 43. 45. The unloading device is included in the aftercooling device, and the unloading device blows a gas whose temperature is controlled by the first control device onto the mounted semiconductor wafer after the bumps are formed. 45. The bump forming apparatus according to claim 44, further comprising a blower (1325) that performs the blowing. 46. The bump forming apparatus according to claim 45, wherein the gas is an inert gas. 47. The gas of claim 4, wherein the gas is nitrogen gas.
6. The bump forming apparatus according to 5. 48. The transfer apparatus, which is openable and closable for covering the semiconductor wafer held when performing at least one of the pre-heating operation and the after-cooling operation of the semiconductor wafer and keeping the semiconductor wafer warm. 48. The bump formation according to any one of claims 33 to 47, further comprising a cover member (2621), wherein the cover member is provided with an opening (2625) so that heat from the bonding stage enters. apparatus. 49. The transfer apparatus further includes a heat retention assisting device (263) for blowing a gas which is temperature-controlled to the semiconductor wafer covered with the cover member and which assists the temperature retention of the semiconductor wafer. The bump forming apparatus according to claim 48. 50. The transfer device for transferring the semiconductor wafer held by the loading device or the first temporary holding member to the bonding stage.
1) and a second transfer device (14) for transferring the semiconductor wafer from the bonding stage to the second temporary holding member.
50. The bump forming apparatus according to claim 40, comprising: 4-2). 51. After mounting the semiconductor wafer on the bonding stage and before performing the bump bonding, the semiconductor wafer mounted on the bonding stage is in contact with the bonding stage. The stage contact surface side (211) of the semiconductor wafer
The temperature difference between the temperature in b) and the temperature on the circuit forming surface side (211a) of the semiconductor wafer opposed to the stage contact surface is set such that no warpage of the semiconductor wafer is suppressed to such an extent that no bump formation is hindered. A wafer temperature control device (160) for controlling the temperature within the temperature range;
The bump forming apparatus according to any one of claims 25 to 50. 52. The wafer temperature control device achieves the above-mentioned control within the non-warping temperature range by heating the circuit forming surface side of the semiconductor wafer mounted on the bonding stage. The bump forming apparatus according to claim 51. 53. The wafer temperature control device heats the circuit forming surface by blowing a heating air having a temperature at which the temperature difference falls within the non-warping temperature range to the circuit forming surface. The bump forming apparatus according to claim 52. 54. The wafer temperature control device achieves the control within the non-warping temperature range by cooling the stage contact surface side of the semiconductor wafer mounted on the bonding stage. The bump forming apparatus according to claim 51. 55. The wafer temperature controller cools the stage contact surface by blowing a cooling air having a temperature at which the temperature difference falls within the non-warping temperature range to the stage contact surface. The bump forming apparatus according to claim 54. 56. The non-warping temperature range is 20 ° C.
The bump forming apparatus according to any one of claims 51 to 55, wherein: 57. The bump forming apparatus according to claim 51, wherein said semiconductor wafer is a wafer based on quartz.