Electricity: measuring and testing – Fault detecting in electric circuits and of electric components – Of individual circuit component or element
Reexamination Certificate
1999-06-07
2001-02-27
Metjahic, Safet (Department: 2858)
Electricity: measuring and testing
Fault detecting in electric circuits and of electric components
Of individual circuit component or element
C324S754090, C324S627000
Reexamination Certificate
active
06194907
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to the structure of a prober, and an electric evaluation method of semiconductor devices using the prober.
2. Description of the Background Art
A prober is a device for evaluating electric characteristics of semiconductor devices formed on a wafer by contacting input/output terminals of chips with probe needles to make signal transmissions to/from a tester.
FIG. 15
is a side view schematically showing the structure of a conventional prober. A wafer
109
with semiconductor devices to be evaluated (not shown) is placed on a chuck
108
. In the upper surface of the chuck
108
, an electrode
108
a
is provided to establish electric contact with the semiconductor devices from the back surface of the wafer
109
. This electrode
108
a
is connected to a power supply
111
via a wire
110
. Also, an electric heater
107
for controlling the temperature of the wafer
109
during evaluation of the semiconductor devices is provided in the chuck
108
.
With a recent scaledown of semiconductor devices, the ability to perform an evaluation in a microcurrent region has increasingly been required of the prober. The chuck
108
is thus disposed within an electromagnetic shielding
101
to shield electromagnetic waves produced by peripheral equipment such as the power supply
111
thereby to reduce an electric noise which adversely affects evaluation.
In the electromagnetic shielding
101
, a ventilation fan
102
for ventilating the electromagnetic shielding
101
is provided. Also, a loader
106
for driving the chuck
108
in each direction X, Y, Z shown in
FIG. 15
is provided in the electromagnetic shielding
101
. The loader
106
includes an XY loader portion
106
c
for driving the chuck
108
in the directions X, Y; and a Z loader portion
106
d
for driving the chuck
108
in the direction Z. The top end of the Z loader portion
106
d
is fixed to the bottom surface of the chuck
108
. The loader
106
further includes a motor portion
106
a
for producing a driving force given to the XY loader portion
106
c
and the Z loader portion
106
d
; and a driving-force transmission portion
106
b
for transmitting the driving force to the XY loader portion
106
c and the Z loader portion
106
d.
Further on the upper surface of the electromagnetic shielding
101
, a tester head
103
is placed with a probe card
104
disposed in the bottom. Part of the upper surface of the electromagnetic shielding
101
is open, through which probe needles
105
of the probe card
104
protrude into the electromagnetic shielding
101
.
In this conventional prober, the electromagnetic shielding
101
can shield electromagnetic waves produced by the peripheral equipment, e.g., the power supply
111
, but cannot shield electromagnetic waves produced by the equipment disposed therein, e.g., the ventilation fan
102
, the motor portion
106
a
of the loader
106
, and the electric heater
107
. In the electric evaluation of semiconductor devices using such a prober, unshielded electromagnetic waves become several hundred fA levels of electric noise, interfering with the evaluation in the microcurrent region.
SUMMARY OF THE INVENTION
A first aspect of the present invention is directed to a prober comprising: a casing having a surface with a signal supply portion for supplying an electric signal for evaluation to a semiconductor device to be evaluated, the semiconductor device formed on a wafer; a table to place the wafer; and an electromagnetic shielding body having side surfaces which face a side rim of the table and which are in contact with the surface of the casing during evaluation of the semiconductor device, and a bottom surface facing a back surface of the table, the electromagnetic shielding body forming a space for surrounding the table with the surface of the casing, the side surface in contact with the surface of the casing, and the bottom surface, both the table and the electromagnetic shielding body disposed within the casing.
According to a second aspect of the present invention, the space for surrounding the table is a closed space; and the electromagnetic shielding body has a gas inlet for introducing inert gas into the closed space.
According to a third aspect of the present invention, the space for surrounding the table is a closed space; and the electromagnetic shielding body has an air outlet for evacuating the closed space by exhausting the air from the closed space.
According to a fourth aspect of the present invention, the space for surrounding the table is a closed space; and the electromagnetic shielding body has a gas inlet for introducing, into the closed space, heating/cooling gas for controlling the temperature in the closed space.
According to a fifth aspect of the present invention, the table has an electrode to establish electric contact with the semiconductor device from the back surface of the wafer; and the prober further comprising: a wire for maintaining the electromagnetic shielding body and the electrode at the same potential.
According to a sixth aspect of the present invention, the prober further comprises: a conductive plate extending from a portion of the surface of the casing in contact with the side surfaces of the electromagnetic shielding body in a direction of the space.
A seventh aspect of the present invention is directed to an electric evaluation method of semiconductor devices using a prober. The prober comprises: a casing having a surface with a signal supply portion having an electrode for supplying an electric signal for evaluation to a semiconductor device to be evaluated; a table to place the semiconductor device; a first driving portion driving the table in a normal direction of the surface of the casing, within the casing; an electromagnetic shielding body having side surfaces facing a side rim of the table and a bottom surface facing a back surface of the table, the electromagnetic shielding body forming a space for surrounding the table with the surface of the casing, the side surfaces, and the bottom surface when the side surfaces are in contact with the surface of the casing; and a second driving portion driving the electromagnetic shielding body in the normal direction within the casing, the table, the electromagnetic shielding body, and the first and second driving portions all disposed within the casing. The electric evaluation method comprises the steps of: (a) contacting the semiconductor device with the electrode by driving the table by the first driving portion; (b) contacting the side surfaces of the electromagnetic shielding body with the surface of the casing by driving the electromagnetic shielding body by the second driving portion; and (c) after the steps (a) and (b), supplying the electric signal to the semiconductor device from the signal supply portion via the electrode.
According to an eighth aspect of the present invention, the space for surrounding the table is a closed space; and the electromagnetic shielding body has a gas inlet for introducing inert gas into the closed space. The electric evaluation method further comprises the step of: (d) before the step (c), introducing the inert gas into the closed space from the gas inlet.
According to a ninth aspect of the present invention, the space for surrounding the table is a closed stage; and the electromagnetic shielding body has an air outlet for exhausting the air from the closed space. The electric evaluation method further comprises the step of: (d) before the step (c), evacuating the closed space by exhausting the air from the closed space through the air outlet.
According to a tenth aspect of the present invention, the space for surrounding the table is a closed space; and the electromagnetic shielding body has a gas inlet for introducing heating/cooling gas into the closed space. The electric evaluation method further comprises the step of: (d) before the step (c), controlling the temperature in the closed space by introducing the heating/cooling gas into the closed space from the gas
Eguchi Koji
Kanao Tsuyoshi
Yamaguchi Toru
Deb Anjan K
Metjahic Safet
Mitsubishi Denki & Kabushiki Kaisha
Oblon & Spivak, McClelland, Maier & Neustadt P.C.
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