JPS6265433A - Inspection device for warpage of semiconductor wafer - Google Patents

Abstract

PURPOSE:To inspect warpage precisely by projecting laser beams or ultrasonic waves onto a dicing line for a semiconductor wafer and reflecting or projecting them in a direction that coincide with the direction of the dicing line. CONSTITUTION:A wafer 10 is irradiated by laser beams while being monitored by a microscope 24. The position and direction of the wafer are adjusted by the revolution and movement in the X-Y directions of a stage 21, dicing lines monitored in left and right visual fields are conformed as shown in the figure (B), and the dicing lines and laser beams 3 are made to coincide. Consequently, laser beams can be reflected positively on the flat dicing lines, thus accurately detecting the warpage of the wafer even when stepped sections by wirings, etc. are formed in chip regions 11. When above-mentioned inspection is conducted on the dicing lines of each row by pitch-feed in the X-Y directions of a stage 21, the whole warpage in the wafer can be inspected.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to an apparatus for detecting warpage of a semiconductor wafer used in the manufacture of semiconductor devices such as ICs, particularly warpage during or after the so-called "unicornering" process.

[Technical background of the invention]

A device conventionally used to inspect warpage of semiconductor wafers irradiates the surface of a semiconductor wafer 1 to be inspected with laser light 3 from a laser light source 2 and detects the reflected light, as shown in FIG. The warpage is detected by a device 4, and the state of warpage is investigated from the detected amount and angle.

Additionally, inspection devices that use ultrasonic waves instead of laser light have also been conventionally used.

[Problems with background technology]

With the conventional inspection equipment mentioned above, it is possible to inspect the warpage of unprocessed semiconductor wafers before they are introduced into the uni-hanni process, but there is a problem in that it is not possible to accurately detect the warpage state of wafers that have been introduced into the uni-hani-hani process. be. That is, in the process of manufacturing a semiconductor device, there are steps on the wafer surface due to various patterns such as wiring formed on the wafer surface, and the reflection state changes.

For this reason, conventional warpage inspection equipment can only inspect warpage on test wafers (mirror wafers with no steps).
Warpage of the wafer on which elements are actually formed cannot be investigated. As a result, for example, even if mask alignment misalignment occurs in one lithography process and wafer warpage is confirmed by visual observation, conventional equipment cannot accurately measure the warpage.

[Purpose of the invention]

The present invention has been made in view of the above-mentioned circumstances, and it is an object of the present invention to provide an apparatus that can accurately inspect the warpage of semiconductor wafers even in a state where a step is formed on the surface due to a wiring layer or an insulating film.

[Summary of the invention]

The present invention focuses on the fact that even when a semiconductor wafer is subjected to various processing, the dicing line portion between each chip area remains flat until the end. That is, as shown in FIG. 4, each chip region 1 of the semiconductor wafer lO
The dicing line 12 existing between the dicing lines 12 remains flat until the end in a normal sea urchin process. Therefore, by irradiating the laser beam 3 in the same direction as the dicing line 12, it is possible to inspect the wafer 10 for warpage even if there is a step in the chip area 11.

However, since the conventional device cannot adjust the irradiation position of the laser beam, if the irradiation position of the laser beam does not match the dicing line 12 as shown in FIGS. 5(A) and 5(B), can't be fixed like this. Therefore, in the present invention, a mechanism is provided to adjust the irradiation position and direction of the laser beam or the like from the state shown in FIGS. 5(A) and 4(B) to the state shown in FIG. 4.

The semiconductor wafer warpage inspection apparatus according to the present invention is an apparatus for detecting warpage of a wafer by irradiating the surface of a conductive wafer with laser light or ultrasonic waves and detecting the reflected light or reflected sound waves, which comprises: a step movement adjustment mechanism in the X-Y direction on the stage on which the semiconductor wafer is placed so that laser light or ultrasonic waves are irradiated onto the dicing line of the semiconductor wafer and are irradiated and reflected in the same direction as the dicing line; and a rotational movement adjustment mechanism.

[Embodiments of the invention]

FIG. 1 is an explanatory diagram showing a semiconductor device warpage inspection apparatus according to an embodiment of the present invention. In the same figure, 21 is X-Y
A semiconductor wafer 10 to be inspected for warpage is placed on a stage provided with a directional movement adjustment mechanism. A rotation adjustment mechanism 22.23 is coupled to the stage;
E-alignment of the wafers 10 is now performed.

Furthermore, a microscope m24 is installed on the stage 21 to confirm the alignment of sea urchins/1-10. As shown, the microscope 24 is adapted to monitor fields of view of the left and right portions of the wafer 10 simultaneously.

In order to inspect the warpage of the wafer 10 using the apparatus of the above embodiment, the wafer 10 is irradiated with laser light while being monitored by the microscope 24. At that time, the dicing lines 12 in the left and right fields of view are monitored as shown in FIG. 2(A).
If they do not match, the laser beam 3 will be directed to the dicing line 1.
2, and there is a high possibility that it is not reflected at the dicing line L. Therefore,
In such a case, the position and direction of the wafer are adjusted by rotating the stage 21 and moving in the X-Y directions, so that the dicing lines monitored in the left and right fields of view are aligned, as shown in FIG. 2(B). Moreover, the dicing line and the laser beam 3 are made to coincide. In this way, the laser beam can be reliably reflected on a flat dicing line, and therefore, even if a step is formed in the chip region 11 due to wiring or the like, warpage of the wafer can be accurately detected.

Further, by performing the same inspection as above on each row of dicing lines by pitch-feeding the stage 21 in the X-Y direction, it is possible to inspect the entire warpage within the wafer.

Note that the same applies when ultrasonic waves are used instead of laser light.

〔Effect of the invention〕

As detailed above, according to the warpage inspection device of the present invention,
It is possible to obtain remarkable effects such as being able to accurately inspect the warpage of a semiconductor wafer even if the semiconductor wafer has a step formed on the surface due to a wiring layer or an insulating film.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing a semiconductor wafer warp inspection device according to an embodiment of the present invention, FIGS. 2(A) and (B) are explanatory diagrams showing its operation, and FIG. FIGS. 4 and 5 (A) and 5(B) are explanatory diagrams showing the principle of a semiconductor wafer warpage inspection apparatus that is used in the present invention. 3... Laser light, 10... Semiconductor wafer, 11.
...Chip area, 12...Dicing line, 21.
...Stage, 22.23...Rotation adjustment mechanism, 24.
...Monitor Microscope Applicant Representative Patent Attorney Takehiko Suzue Figure 1 Figure 2

Claims (1)

[Claims] A device for detecting warpage of a wafer by irradiating a laser beam or an ultrasonic wave onto the surface of a semiconductor wafer and detecting the reflected light or reflected sound wave, the apparatus comprising: The stage on which the semiconductor wafer is placed is provided with a step movement adjustment mechanism in the X-Y direction and a rotational movement adjustment mechanism so that the semiconductor wafer is irradiated and reflected in the same direction as the dicing line. Semiconductor wafer warpage inspection equipment.