JPS59201435A - Etching pattern inspecting method - Google Patents

Abstract

PURPOSE:To facilitate a secure and simple resolution test of a formed pattern by a method wherein light energy such as laser beam is applied to a semiconductor chip to be tested and a wave signal corresponding to an etching pattern is obtained by a reflected signal and this wave signal is compared with a reference wave signal. CONSTITUTION:Light energy such as laser beam 13 is applied to a mask chip 12 in a photomask on which a reference etching patten 11 is formed and the pattern 11 is scanned to the direction expressed by an arrow (a). Then an etching pattern 11a, which corresponds to the etching pattern 11 and is formed on a semiconductor chip 14 to be imspected, is scanned in the same way. After that, reflected signals from the chips 12 and 14 are converted into respective pulse wave signals and their shapes are compared and difference between them is detected. If their wave shapes are identical, it is judged that the photoetching is performed accurately and if they are not, it is judged that the pattern is defective.

Description

[Detailed Description of the Invention] [Technical Field of the Invention] The present invention relates to etching of a semiconductor wafer that is photo-etched in accordance with a photomask on which a predetermined etching pattern is formed, for example, in a photo-etching process of a semiconductor device manufacturing process. This invention relates to an etching pattern inspection method for automatically inspecting patterns.

[Technical background of the invention]

For example, the Ueno-X automatic inspection apparatus is used to inspect a semiconductor wafer on which a noso turn has been formed in a photoetching process of a semiconductor device manufacturing process. This inspection device irradiates each of a plurality of semiconductor chips with light energy such as a laser beam, detects the strength of the reflected light, and inspects for dust and scratches on the surface of the semiconductor chips. This inspection device is also used in the same way when inspecting the surface of a photomask for dust, scratches, etc.

Here, this inspection apparatus is mainly used to inspect dust, scratches, etc. on the surface of a semiconductor wafer or a photomask, and cannot inspect etching or turns formed on the wafer or photomask itself. That is,
Multiple chips on a photomask or semiconductor wafer [Problems in background technology] However, if the etching pattern formed on a semiconductor wafer or photomask is inspected by human eyes in this way, for example, the semiconductor after photoetching cannot be inspected. When inspecting a wafer, the following four items must be inspected.

(1) Peeling condition of resist film.

(2) Presence or absence of foreign matter, scratches, etc. on the wafer surface.

(3) Resolution of etching turns.

(4) Sea urchin eight serial number.

In other words, for such a large number of items, if each photo-etched image was inspected one by one, an extremely large amount of inspection time would be consumed, and especially in the resolution calibration of item (3) above, Inspection is highly difficult and causes significant eye fatigue, resulting in inconveniences such as often overlooking wafers with pattern defects.

[Object of the invention] This invention was made in view of the above problems.
To provide an etching pattern inspection method that enables reliable and easy inspection without spending a lot of inspection time, for example, when inspecting the resolution of an etching pattern formed on each of a plurality of chips of a semiconductor wafer. With the goal.

[Summary of the invention]

That is, the etching pattern inspection method according to the present invention irradiates a chip to be inspected with light energy such as a laser beam, and processes a waveform signal corresponding to the etching pattern of the chip to be inspected, which is obtained from a reflected signal, by a predetermined etching process. By comparing the waveform signals corresponding to the patterns, the differences between the respective patterns can be recognized.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows the calibration process when inspecting, for example, a freshly etched pattern formed on a semiconductor chip using this inspection method. First, a predetermined etched pattern 11 is formed as shown in FIG. For example, a mask chip 12 in a photomask is irradiated with light energy such as a laser beam 13 as shown by a broken line arrow, and is scanned in parallel as shown by a diagonal arrow a. Next, as shown in FIG. 1CB), the test target 14 in the semiconductor wafer, which has been photoetched and patterned in correspondence with the predetermined pattern 11 of the mask chip 12, is laser-etched in the same manner as above. light 13
to scan in parallel.

Then, the reflected signals from the mask chip 12 and the test boot 14 obtained by parallel scanning with the laser beam 13 are converted into pulse waveform signals as shown in FIGS. 2(A) and 2(B), respectively. Convert to In this case, the waveform signals are transmitted to the two chips 12, respectively.
The pulse waveforms correspond precisely to the etching patterns 11 and 11a formed in the mask step 12. By comparing the shapes of the respective waveform signals in FIG. The difference between this and the etching marks and turns lla formed on the chip 14 to be inspected is determined.

That is, for the waveform signal corresponding to the predetermined etching pattern 11 of the mask chip 12 shown in FIG. If the waveforms are the same, it can be determined that the pattern lla of the chip 14 to be inspected has been accurately photoetched, and if the waveforms are not the same, it can be determined that the pattern lla of the chip 14 to be inspected is
It can be determined that an abnormality has occurred in pattern llH of No. 4. Therefore, in this embodiment, it is possible to determine that the /set turn lla formed by photoetching on the chip 14 to be inspected is a defective turn.

In the above embodiment, the mask chip 12 was used as the model chip on which the predetermined etching pattern 11 was formed, but it is also possible to use a semiconductor chip determined to be a good product/base turn as the model chip. good.

〔Effect of the invention〕

As described above, according to the present invention, even when inspecting the resolution of etching patterns formed on each of a plurality of chips of 1,000 semiconductor wafers within a predetermined time of 8 hours, visual inspection can It becomes possible to perform an inspection accurately and easily without spending time, and it becomes possible to prevent the occurrence of inspection errors.

[Brief explanation of drawings]

FIG. 1 explains the etching and turn inspection process according to an embodiment of the present invention (AJ is a mask chip,
fB) is an enlarged view of the chip to be tested, Figure 2 (A)
and (B) are diagrams showing waveform signals corresponding to the mask chip and the test amount chip, respectively. 11, lla... Etching pattern, 12... Mask chip, 13 peak laser beam, 14... Chip to be inspected.

Claims (1)

[Claims] Etch puffer formed on a mask chip or a semiconductor chip in a photoetching process in a semiconductor device manufacturing process/4
In the turn inspection, means for irradiating optical energy onto the IE chip to be tested; means for converting a reflected signal corresponding to the etching pattern of the chip to be tested reflected by the irradiation means into a waveform signal; An etching pattern inspection method comprising means for comparing and recognizing the converted waveform signal of the chip to be inspected with a waveform signal corresponding to a predetermined etching pattern.