JPH06331339A - Method and device for measuring deformation of thin plate - Google Patents

Abstract

PURPOSE:To accurately measure only the original deformation of a thin plate by dipping the thin plate to be measured in a liquid with nearly a same specific gravity as that of the thin plate or up to the liquid interface and then measuring the deformation of the thin plate. CONSTITUTION:A thin plate 3 to be measured is dipped until its upper side surface is level with the liquid interface inside a liquid container 1 and is placed on support rods 4 by suppressing the influence due to its own weight of the plate 3 itself. The deformation such as the warpage of the plate 3 is measured in this state by a measuring instrument 5. A liquid with nearly the same specific gravity as that of the plate 3 is used as a liquid 2 inside the container 1 but actually the specific gravity of the liquid is slightly smaller than that of the plate 3. In this manner, when the plate 3 is dipped in the liquid 2, buoyancy acts on the plate 3 to reduce the influence of gravity relatively, thus minimizing the influence of the deformation, etc., due to the own weight of the plate 3. It can be applied to a thin plate which is easily subjected to deformation such as warpage and deflection such as a ceramic substrate. For example, electrical and optical measuring instruments can be used for the measuring instrument 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides an original deformation of a thin plate such as a ceramic substrate or a semiconductor wafer which is apt to be deformed by warping or bending due to its own weight, that is, an original deformation of the thin plate in which the influence of the own weight of the thin plate is suppressed as much as possible. The present invention relates to a thin plate deformation measuring method and apparatus.

[0002]

2. Description of the Related Art Conventionally, in the case of measuring the deformation of a thin plate such as a ceramic substrate, it has been general to set an object to be measured in the atmosphere.

As a specific method for setting a thin plate, a thin plate to be measured is fixed on a flat surface in the atmosphere by vacuum suction, an electrolytic chuck, a mechanical chuck, or a thin plate is stood and fixed by vacuum suction or the like. A method, a method of setting it on a flat surface in a free state, a method of supporting a thin plate at three points, and the like have been adopted.

For the measurement, a mechanical, electrical, optical, or other measuring device is used to measure the amount of displacement of the surface of the thin plate (the amount of deformation such as warpage).

[0005]

However, when the thin plate is set in the atmosphere as described above, the thin plate is deformed by its own weight as well as the original deformation of the thin plate. Further, there is a problem in that even if the thin plates are set, the measured values vary, and the original deformation of the thin plates cannot be accurately measured.

The present invention has been made in view of the above problems, and an object thereof is to provide a thin plate deformation measuring method and apparatus capable of more accurately measuring only the original deformation of the thin plate.

[0007]

In order to solve the above-mentioned problems, the method of the present invention comprises submerging a thin plate to be measured in a liquid having a specific gravity substantially the same as that of the thin plate or to its liquid interface,
It is characterized in that the deformation is measured while suppressing the influence of the weight of the thin plate.

The apparatus of the present invention has a liquid having substantially the same specific gravity as the thin plate to be measured and supporting the thin plate while suppressing the influence of its own weight and a thin plate supported by the liquid. It is characterized by being configured with a measuring device for measuring deformation.

[0009]

By submerging the thin plate in a liquid having substantially the same specific gravity as the thin plate, the influence of the weight of the thin plate can be suppressed. Thereby, the original deformation of the thin plate can be accurately measured.

[0010]

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

Reference numeral 1 in FIG. 1 denotes a liquid container.
Liquid 2 is injected into the. As the liquid 2, a liquid having substantially the same specific gravity as the thin plate 3 which is the object to be measured is used. To be precise, the specific gravity of the liquid 2 is set to be slightly lighter than that of the thin plate 3. As described above, when the specific gravity of the liquid 2 is made substantially the same as that of the thin plate 3, by immersing the thin plate 3 in the liquid 2, buoyancy acts on the thin plate 3 and the influence of gravity can be relatively reduced. Therefore, the influence of deformation of the thin plate 3 due to its own weight can be minimized. It should be noted that the thin plate 3 can be applied to a thin plate such as a ceramic substrate or a semiconductor wafer which is easily deformed such as warped or bent. At this time, the liquid 2
Is appropriately selected according to the specific gravity of the material of the thin plate 3 to be measured.

Reference numeral 4 denotes a support rod for supporting the thin plate 3 from the inside of the liquid 2. The upper surface of the thin plate 3 is attached to the liquid interface which is the upper surface of the liquid 2.
The thin plate 3 is supported in a state where the other surface is sunk while leaving the measurement surface).

Reference numeral 5 is a measuring device for measuring the amount of deformation of the thin plate 3 submerged in and supported by the liquid 2, and is provided at a position above the liquid container 1.

The method for measuring the deformation of a thin plate using the above apparatus is as follows.

The thin plate 3 to be measured is sunk until its upper surface becomes flush with the liquid interface in the liquid container 1 and placed on the support rod 4 while suppressing the influence of the own weight of the thin plate 3 itself. In this state, the warp or other deformation of the thin plate 3 is measured by the measuring device 5.

Next, description will be made using specific numerical values.

The measuring device 5 is of an optical type. Φ3 inch, thickness 800 cut from GaAs ingot with specific gravity 5.316
The processing strain layer is removed from the wafer having a thickness of μm, and the wafer is submerged in the liquid 2 and placed on the support rod 4. Specific gravity of liquid 4.9
HCO ₃ Tl + C ₃ H ₂ O ₂ Tl ₂ + H ₂ O are used. Then, the deformation (warpage) of the surface of the wafer was measured by the measuring device 5.

On the other hand, the deformation (warpage) of the wafer set by three-point support was measured even in the atmosphere having a small specific gravity with respect to the wafer.

As a result, when the warp value of the ingot cut section which is considered to be almost equal to the warp shape excluding the influence of the weight of the wafer itself and each measurement result are compared, the warp value at the ingot cut end face is compared. Is 4 μm and the value measured in the atmosphere is 2.5 μm, whereas HCO ₃ Tl + C ₃ H
_The value measured in ₂ O ₂ Tl ₂ + H ₂ O was 3.8 μm. That is, HCO ₃ Tl + C ₃ H ₂ O ₂ Tl ₂ + H ₂
The measured value in O showed the value of the warp of the ingot cut section, that is, the value close to the original shape of the warp.

As described above, by immersing the thin plate 3 in the liquid 2 and measuring the warpage and the like, buoyancy acts on the thin plate 3 and the thin plate 3
It is possible to suppress deformation due to its own weight as much as possible,
Only the original deformation of the thin plate 3 itself can be accurately measured.

In the above-described embodiment, the object to be measured is floated on the upper surface of the liquid for measurement, but a measuring instrument that can be immersed in the liquid for measurement or an object to be measured immersed in the liquid is used. By using a measuring device that can measure from the outside of the liquid, the object to be measured can be completely submerged in the liquid, and the measurement can be performed without being more affected by its own weight.

As the measuring device 5, various types of measuring devices such as mechanical type, electric type and optical type can be used.

Although the specific gravity of the liquid 2 is set to be slightly lighter than the specific gravity of the thin plate 3, it may be set to some other weight, such as slightly heavier or more accurately.

The liquid 2 is HCO ₃ having a specific gravity of 4.9.
Tl + C ₃ H ₂ O ₂ Tl ₂ + H ₂ O was used, and particularly in silicon (specific gravity 2.33), measurement in CH ₃ I (specific gravity 2.28) shows a good value.

[0025]

As described above in detail, according to the thin plate deformation measuring method and apparatus of the present invention, the thin plate is submerged in the liquid and the warpage and the like are measured, so that the deformation of the thin plate itself due to its own weight is suppressed as much as possible. Therefore, it is possible to accurately measure only the original deformation of the thin plate itself.

[Brief description of drawings]

FIG. 1 is a schematic configuration diagram showing a thin plate deformation measuring apparatus according to the present invention.

[Explanation of symbols]

 1 Liquid container 2 Liquid 3 Thin plate 4 Support rod 5 Measuring instrument

Claims (2)

[Claims] 1. A thin plate, characterized in that a thin plate to be measured is immersed in a liquid having substantially the same specific gravity as that of the thin plate or to the liquid interface thereof to measure the deformation while suppressing the influence of the own weight of the thin plate. Deformation measurement method. 2. A liquid having a specific gravity substantially the same as that of a thin plate to be measured and supporting the thin plate while suppressing the influence of its own weight and a deformation of the thin plate supported by the liquid. An apparatus for measuring deformation of a thin plate, characterized by being configured with a container.