JPS62257742A - Measuring method for thickness of semiconductor substrate - Google Patents

Abstract

PURPOSE:To enable correction at every wafer, to stop the movement of a fixed angular table and to prevent abrasion due to the continuous contact of a probe and wafers by correcting the zero point of a measuring instrument by using the surface of the fixed angular table. CONSTITUTION:A semiconductor substrate 3 is set onto the disk surface 1a of a fixed angular table 1 shifted and fed in the horizontal direction of a semiconductor-substrate back grinding attachment, directing the back 3a of the substrate 3 upward, and the back of the substrate 3 is ground. Shifting and feeding are stopped temporarily on the grinding, a probe 2a for a measuring instrument 2 is lowered from an upper section and brought into contact with the disk surface 1a of the table 1, the zero point of the measuring instrument 2 is corrected, using the height of the disk surface 1a as a reference, and the probe 2a is pulled up to height where the probe is not brought into contact with the substrate 3. The table 1 is moved again, which is stopped when the back 3a of the substrate 3 reaches just under the probe 2a, and the probe 2a is lowered and brought into contact with the back 3a. The thickness of the substrate 3 is measured by the difference of the hight of a position at that time and the table 1, thus preventing the abrasion due to the continuous contact of the probe 2a and the substrate 3.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for measuring the thickness of a wafer in a back grinding step of grinding the back surface of a semiconductor substrate (hereinafter referred to as a wafer).

[Prior Art] Conventionally, this type of back grinding equipment prepares a reference wafer to measure the thickness of the wafer after grinding, inputs the thickness of the reference wafer as initial data, and then measures the thickness of the wafer on a fixed table that moves. The conventional method was to bring a probe into contact with the wafer and measure the thickness of the wafer.

[Problems to be Solved by the Invention] For this reason, it is necessary to periodically change the initial data using the reference wafer again in order to prevent accumulation of measurement errors due to wear and the like caused by constant contact between the probe and the wafer. Not only is it necessary to stop the device periodically for correction and replacement of the probe, but the reliability of the measured values is often low due to the accumulation of errors.

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for measuring the thickness of a wafer, which eliminates measurement errors caused by wear of the probe and enables accurate measurement.

[Means for Solving the Problems] The present invention is a semiconductor substrate back grinding device for grinding the back surface of a semiconductor substrate. The measuring device is temporarily stopped, and the probe of the measuring device is lowered from above for each semiconductor board and brought into contact with the surface of the fixed table.The zero point of the measuring device is corrected using the height of the surface of the fixed table as a reference. is lifted up, the fixed table is fed and lowered again just above the semiconductor substrate, and the thickness of the semiconductor substrate is measured by the difference between the height of the position where it contacts the semiconductor substrate and the height of the surface of the fixed table. This is a method for measuring the thickness of a semiconductor substrate.

[Example] Hereinafter, one embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, the semiconductor substrate back grinding device sets a substrate 3 with the back surface 3a of the semiconductor substrate (wafer) 3 facing up on the board surface 1a of a fixed table 1 which is given horizontal movement and feed. Grind the back side of wafer 3.

The present invention temporarily stops the moving feed of the fixed table 1 on which the wafer 3 whose back side has been ground is mounted, and the measuring device 2
The measuring stylus 2a is lowered from above and brought into contact with the plate surface 1a of the fixed table 1, and the zero point correction of the measuring instrument 2 is performed using the height position of the plate surface 1a of the fixed table 1 as a reference.
is raised to a height where it does not come into contact with the wafer 3.

Next, the fixed table 1 is given moving feed again, and the measuring stylus 2a
When the back surface 3a of the wafer 3 comes to a position directly below , the fixed table 1 is stopped, the probe 2a is lowered and brought into contact with the back surface 3a of the wafer 3, and the height of the contact point of the probe 2a with the wafer 3 is The thickness of the wafer 3 is measured based on the difference from the plate surface 1a of the fixed table 1.

The above operation is repeated for each wafer 3, and the thickness of the wafer after grinding is measured.

[Effects of the Invention] As explained above, the present invention uses the fixed table surface to perform zero point correction of a measuring instrument, thereby making it possible to perform zero point correction for each ever, and also to automatically stop the movement of the fixed table. Since the probe is brought into contact with the wafer on the surface of the board, there is no wear caused by constant contact between the probe and the wafer, and wear on the probe can be eliminated. This not only makes work more efficient by eliminating the need to stop the device for replacement, but also has the effect of eliminating measurement errors when measuring thickness.

[Brief explanation of drawings]

FIGS. 1 and 2 are process diagrams showing one embodiment of the present invention. 1...Fixed table 2...Measuring instrument 2a...
・Measurement element 3... Semiconductor substrate patent applicant Kyushu NEC Co., Ltd. tlj”” Agent Patent attorney Kanno Offer □'t', <
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Claims (1)

[Claims] (1) In a semiconductor substrate back grinding device that grinds the back side of a semiconductor substrate, the movement and feed of a fixed table fixed with the back side of the semiconductor substrate facing upward during grinding is temporarily stopped;
For each semiconductor substrate, the probe of the measuring device is lowered from above and brought into contact with the surface of the fixed table, the zero point of the measuring device is corrected using the height of the surface of the fixed table as a reference, and then the probe is pulled up. A semiconductor device characterized in that the fixed table is fed and lowered again just above the semiconductor substrate, and the thickness of the semiconductor substrate is measured by the difference between the height of the position where the probe contacts the semiconductor substrate and the height of the fixed table. This is a method for measuring the thickness of a substrate.