Data processing: measuring – calibrating – or testing – Testing system – Of circuit
Reexamination Certificate
2000-05-08
2003-10-21
Barlow, John (Department: 2863)
Data processing: measuring, calibrating, or testing
Testing system
Of circuit
C324S754120
Reexamination Certificate
active
06636824
ABSTRACT:
TITLE OF THE INVENTION
Method of and Apparatus for Inspecting Semiconductor Device
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a method of and an apparatus for inspecting a semiconductor device, and more particularly to a method thereof and an apparatus therefor used to inspect whether or not there occurs an opening failure of a contact hole formed in a semiconductor wafer by observing a secondary electron image obtained through irradiation with a charged particle beam.
2. Description of the Background Art
Two methods has been conventionally used to inspect whether a contact hole formed in a semiconductor wafer is opened
ot-opened. One of them is shown in a conceptional view of FIG.
16
. The method uses a defect inspection device
100
and a charged-particle beam device
101
. First, the defect inspection device
100
is used for inspection. After that, the charged-particle beam device
101
inputs defect inspection data D
100
therein from the defect inspection device
100
and observes a contact hole which seems to have an opening failure.
In another method, whether a contact hole is opened
ot-opened is judged by measuring the hole diameter of the contact hole with a CD-SEM and the like.
The former method in the background art, however, has the following problems; the apparatus necessarily becomes large as a whole since the defect inspection device is needed, and moreover it takes long time to perform the inspection since the defect inspection by the defect inspection device and the observation of the defective portion by the charged-particle beam device are separately performed.
The later method in the background art has a problem of low reliability of inspection as compared with the former method since whether the contact hole is opened
ot-opened is judged only by measuring the hole diameter, not by direct inspection on whether the contact hole is actually opened or not.
SUMMARY OF THE INVENTION
The present invention is directed to a method of inspecting a semiconductor device. According to a first aspect of the present invention, in the method, one of semiconductor wafers each provided with a plurality of holes is mounted on a stage as a semiconductor wafer under inspection, and assuming that small regions obtained by sectioning a wafer surface of the semiconductor wafer under inspection into a plurality of regions are defined as inspection regions, each of the inspection regions is irradiated with charged particles from a charged-particle irradiation unit and a secondary electron image obtained by irradiation with the charged particles is observed, to inspect whether or not there occurs an opening failure in the holes inside each of the small regions, and the method of the first aspect comprises the steps of: (a) inputting positional data on at least one specified small region to a control unit, the at least one specified small region being likely to have the opening failure than the others of the small regions in the wafer surface; and (b) inspecting whether or not there occurs the opening failure in the at least one specified small region while the control unit relatively moves the charged-particle irradiation unit and the stage on the basis of the positional data so that the at least one specified small region is irradiated with the charged particles.
According to a second aspect of the present invention, in the method according to the first aspect, the step (a) includes the steps of: (a-1) inputting design data of the semiconductor wafers to an inspection-region determination unit; and (a-2) identifying the at least one specified small region on the basis of the design data by the inspection-region determination unit.
According to a third aspect of the present invention, in the method according to the first aspect, the step (a) includes the steps of: (a-1) inputting a defective distribution in the wafer surface obtained on a plurality of products already manufactured by using chips obtained from the other semiconductor wafers having the same structure as the semiconductor wafer under inspection to an inspection-region determination unit; and (a-2) identifying a specified region in the wafer surface, which is likely to have a defective, on the basis of the defective distribution by the inspection-region determination unit, to determine the small region corresponding to the specified region as the specified small region.
According to a fourth aspect of the present invention, in the method according to any one of the first to third aspects, the at least one specified small region includes a plurality of specified small regions, and the method further comprises the steps of: (c) storing inspection results obtained through the method of inspection into a database; and (d) identifying a failure high-incidence region at which occurrence of the opening failure is found in a plurality of semiconductor wafers among the plurality of specified small regions while the control unit refers to the database, and in the method of the fourth aspect, inspection on whether or not there occurs the opening failure is made only on the failure high-incidence region in the step (b).
According to a fifth aspect of the present invention, in the method of inspecting a semiconductor device, one of semiconductor wafers each provided with a plurality of holes is mounted on a stage as a semiconductor wafer under inspection, and assuming that small regions obtained by sectioning a wafer surface of the semiconductor wafer under inspection into a plurality of regions are defined as inspection regions, each of the inspection regions is irradiated with charged particles from a charged-particle irradiation unit and a secondary electron image obtained by irradiation with the charged particles is observed, to inspect whether or not there occurs an opening failure in the holes inside each of the small regions, and the method comprises the steps of: (a) storing inspection results obtained through the method of inspection into a database; (b) identifying a failure high-incidence region at which occurrence of the opening failure is found in a plurality of semiconductor wafers among the plurality of small regions while a control unit refers to the database; and (c) inspecting whether or not there occurs the opening failure in the failure high-incidence region while the control unit relatively moves the charged-particle irradiation unit and the stage so that the failure high-incidence region is irradiated with the charged particles in the semiconductor wafer under inspection.
According to a sixth aspect of the present invention, in the method according to any one of the first to fifth aspects, the plurality of holes include a plurality of the holes belonging to a first group and a plurality of the holes belonging to a second group which are different from each other in intensity of secondary electrons generated from surfaces of the holes by irradiation with the charged particles even when there occurs no opening failure, and the step (b) includes the steps of: (b-1) grouping the plurality of holes included in the at least one specified small region into the holes belonging to the first group and the holes belonging to the second group; (b-2) inspecting whether or not there occurs the opening failure in the holes belonging to the first group; and (b-3) inspecting whether or not there occurs the opening failure in the holes belonging to the second group, the step (b-3) being separately performed from the step (b-2).
The present invention is also directed to an apparatus for inspecting a semiconductor device. According to a seventh aspect of the present invention, the apparatus comprises: a stage on which one of semiconductor wafers each provided with a plurality of holes is mounted as a semiconductor wafer under inspection; a charged-particle irradiation unit for irradiating one of inspection regions with charged particles, the inspection regions being small regions obtained by sectioning a wafer surface of the semiconductor wafer under inspection into a plurality of
Ikeno Masahiko
Katayama Toshiharu
Sawai Kouetsu
Barlow John
Bhat Aditya
Mitsubishi Denki & Kabushiki Kaisha
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