JP2001025961A - Sticking method of semiconductor wafer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deterioration of flatness in one-side final finish polishing by measuring the in-plane thickness of a semiconductor wafer in the polishing of the semiconductor wafer stuck to a sticking plate, and specifying the sticking position on the basis of the measurement value. SOLUTION: In a thickness measurement part 3, the thicknesses in five points in total of the central point of a semiconductor wafer and four circumferential points are measured. In a spin coater part 5, indexing can be performed at an angle of 90 deg. from the origin position, and the rotation is stopped in a prescribed position from the thickness information from the thickness measurement part 3 and the initial set value (the information of which of the circumferential side and central side of a sticking plate 8 the thickest part is set in). When the semiconductor wafer is stopped at a specified angle in the spin coater part 5, the semiconductor wafer is baked in a baking part 5 and stuck to the sticking plate 8 by a reversing chuck part 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of attaching a semiconductor wafer to a semiconductor device when polishing the semiconductor wafer by attaching the semiconductor wafer to an attachment plate.

[0002]

2. Description of the Related Art A semiconductor wafer is completed through crystal growth, slicing, beveling, lapping, double-side polishing, and single-side finish polishing. The surface of the completed semiconductor wafer must be mirror-finished, and high flatness is required.

FIG. 3 is an explanatory view showing a conventional method of attaching a semiconductor wafer in connection with single-side finish polishing as the final step. 11 is a transfer robot, 12 is a wafer loader unit, 14 is an orientation flat (sometimes called an orientation flat) alignment unit, 15 is a spin coater unit, 16 is a baking unit, 17 is a reversing chuck unit, 18 is a sticking plate, 19 is a semiconductor wafer.

[0004] The wafer loader section 12 contains a semiconductor wafer (sometimes simply referred to as a wafer) that has been polished on both sides, and is disposed on the left and right sides of the transfer robot 11. The transfer robot 11 takes out semiconductor wafers one by one from the wafer loaders 12 arranged on the left and right.

[0005] The semiconductor wafer taken out of the wafer loader section 12 is transferred to an orientation flat alignment section 14 by a transfer robot 11. Here, the semiconductor wafer is aligned based on the orientation flat. The orientation flat (orientation flat) is a notch provided in a circular semiconductor wafer, and the orientation of the crystal axis can be determined from the orientation flat.

Thereafter, the semiconductor wafer is placed in the spin coater 1
5 and the wax is applied. Then, it is baked in the baking section 16 and is sequentially pasted on the pasting plate 18 in the reversing chuck section 17. Finally, pressure is applied by an air stamp (not shown) to complete the attachment of the semiconductor wafer.

[0007]

A semiconductor wafer that has undergone each of the lapping and double-side polishing steps has a high degree of flatness, but still has some in-plane variations. In addition, the equipment that performs single-sided polishing is
It has a peculiar characteristic due to the flatness of the surface plate and the like. That is, even in the case of a single semiconductor wafer, the direction of the outer peripheral side of the adhesive plate may be more easily polished, the direction of the central side of the adhesive plate may be more easily polished, or anywhere. In some cases, it may be polished uniformly. Usually, such a habit of the device is the device 1
It is clear for each table, and does not change each time it is used, nor does it change for each semiconductor wafer.

In the conventional method of attaching a semiconductor wafer, since the semiconductor wafer is attached to the attaching plate without taking into consideration the above-mentioned device peculiarity at all, the flattening after the double-side polishing is performed after the single-side finish polishing which is the final step. However, it was difficult to obtain a high degree of flatness, further deteriorating the degree.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a method of attaching a semiconductor wafer which solves the above-mentioned disadvantages of the prior art, prevents deterioration of flatness in final single-side polishing, and realizes high flatness. It is in.

[0010]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention measures the in-plane thickness of a semiconductor wafer in advance when polishing the semiconductor wafer by attaching the semiconductor wafer to an attaching plate, and thereafter, The attachment position was specified based on the measured value.

The thickness of the semiconductor wafer was measured using a non-contact laser length measuring device.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view showing one embodiment of a method for attaching a semiconductor wafer according to the present invention. 1 is a transfer robot, 2 is a wafer loader section, 3 is a thickness measuring section, 4 is an orientation flat alignment section, 5 is a spin coater section, 6 is a baking section, 7 is a reversing chuck section, 8 is a sticking plate, 9 is a semiconductor wafer. It is.

The wafer loader 2 accommodates semiconductor wafers that have been polished on both sides, and are disposed on the left and right sides of the transfer robot 1. The transfer robot 1 takes out semiconductor wafers one by one from the wafer loader units 2 arranged on the left and right.

The semiconductor wafer taken out from the wafer loader unit 2 is transferred to the thickness measuring unit 3 by the transfer robot 1. The thickness measuring unit 3 measures a total of five thicknesses, one at the center and four at the outer periphery of the semiconductor wafer. The measurement of the thickness of the wafer was performed by a non-contact type laser measuring device, but any measurement may be made as long as it is a non-contact type.

The semiconductor wafer whose thickness has been measured is conveyed to the orientation flat alignment unit 4 and aligned based on the orientation flat. Thereafter, the wafer is transported to the spin coater unit 5 and is coated with wax while rotating at a predetermined number of rotations. In the spin coater 5, indexing is possible at an angle of 90 degrees from the origin position, and the thickness information from the previous thickness measuring unit 3 and the initial set value (the thickest part of the thickness) The rotation is stopped at a predetermined position based on the position (ie, information on whether the position is set on the outer peripheral side or the central side of the attaching plate 8).

The thickness of the semiconductor wafer may be measured at any point, but it is better to match the index from the origin position in the spin coater 5 according to the measured point. For example,
In the case of measuring a total of 9 points of 1 point at the center and 8 points at the outer periphery, the index is preferably an angle of 45 degrees.

The gist of the present invention is that the semiconductor wafer is stopped at a specific angle in the spin coater unit 5.
Even if the reversing chuck section 7 mechanically operates, the semiconductor wafer 9 is stuck to the sticking plate 8 as intended.

After that, the semiconductor wafer is baked in the baking section 6 and attached to the attaching plate 8 in the reversing chuck section 7. Then, pressure is applied by an air stamp (not shown), and the attachment is completed.

FIG. 2 shows that the semiconductor wafer 9
Is a plan view showing a state in which ten sheets are attached. Five points in the plane of the semiconductor wafer 9 were measured, and the thickest part was arranged on the outer peripheral side of the attaching plate 8. FIG. 2 is an example,
According to the method described above, the thickest portion of the semiconductor wafer can be always stuck and arranged at a location in a certain direction (the outer peripheral side or the center side of the attaching plate 8).

Gallium arsenide (Ga)
The results of the above method performed using the 4-inch wafer As) will be described below. The attachment plate 8 had a diameter of 485 mm, and ten GaAs semiconductor wafers were attached at equal intervals. After the attachment, the semiconductor wafer was subjected to single-sided polishing.

The platen used for this one-side polishing has a concave shape, and the outer peripheral side tends to be polished more frequently than the central side of the attaching plate. Therefore, the thickest GaAs wafer is provided on the outer peripheral side of the attaching plate. The parts were arranged.

The flatness of the semiconductor wafer after the double-side polishing was 1.5 μm to 2.2 μm. As a result of performing single-sided finish polishing of the final processing by using the present semiconductor wafer attaching method, the flatness is 0.9 μm to 1.6 μm.
μm.

If the center side of the sticking plate tends to be polished more by single-sided polishing, the thickest portion of the semiconductor wafer may be arranged at the center side of the sticking plate. By doing so, it is possible to improve the flatness of the semiconductor wafer after the completion of the single-sided polishing.

[0024]

According to the method of attaching a semiconductor wafer of the present invention, when attaching the semiconductor wafer to the attaching plate, the thickness of the semiconductor wafer is measured in-plane in advance, and then the thickest portion is removed. Since it is arranged at a specific position, it is possible to prevent deterioration of flatness due to single-side finish polishing and obtain a semiconductor wafer having high flatness.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing one embodiment of a method for attaching a semiconductor wafer according to the present invention.

FIG. 2 is a plan view showing a state in which the semiconductor wafer is attached to an attaching plate according to one embodiment of the method for attaching a semiconductor wafer of the present invention.

FIG. 3 is an explanatory view of a conventional method of attaching a semiconductor wafer.

[Explanation of symbols]

 1,11 Transfer robot 2,12 Wafer loader unit 3 Thickness measurement unit 4,14 Orientation flat alignment unit 5,15 Spin coater unit 6,16 Baking unit 7,17 Inversion chuck unit 8,18 Pasting plate 9,19 Semiconductor wafer

Claims (2)

[Claims] When a semiconductor wafer is attached to an attachment plate and polished, an in-plane thickness of the semiconductor wafer is measured in advance, and an attachment position is specified based on the measured value. Semiconductor wafer sticking method. 2. The method according to claim 1, wherein the thickness of the semiconductor wafer is measured by a non-contact laser length measuring device.