Electricity: measuring and testing – Fault detecting in electric circuits and of electric components – Of individual circuit component or element
Reexamination Certificate
2002-02-25
2003-12-23
Cuneo, Kamand (Department: 2829)
Electricity: measuring and testing
Fault detecting in electric circuits and of electric components
Of individual circuit component or element
C324S757020
Reexamination Certificate
active
06667626
ABSTRACT:
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a probe card for performing electrical properties confirmation tests (wafer test) for semiconductor integrated circuits, display tests for display devices, operation test for electronic circuit boards, and other such test for semiconductor integrated circuits, and for performing circuit adjustments. The present invention also relates to a test apparatus having the probe card.
2. Description of the Related Art
Conventionally, in the field of semiconductor manufacturing, electrical operation testing of multiple circuit devices in a semiconductor wafer state is performed using measurement equipment called a probe card.
FIG. 7
is a plan view illustrating a conventional probe card. With conventional probe cards, electrode pads
12
are disposed at set intervals on the perimeter of the upper face of circuit devices
11
(semiconductor integrated circuits) which are unit blocks of a semiconductor wafer, and multiple probe needles
1
through
10
of the probe card are arrayed such that the tops thereof come into contact with each of the electrode pads
12
. Further, the probe card comprises a circuit board
101
with the center portion thereof opened, with the rear ends of the multiple probe needles
1
through
10
to come into contact with the electrode pads
12
of the circuit device
11
attached thereto. A testing apparatus (not shown) is connected to the probe card, so that the test results can be recorded, displayed, etc. Also, arrangements are made wherein a metal resistor is provided in the circuit device
11
beforehand, and an electrical current is applied from the probe card so as to melt the metal resistor and change the resistance value thereof, or wherein a redundant circuit is provided in the circuit device
11
beforehand with a diode, and voltage is applied from the probe card to cause a short-out and make a detour to adjust the semiconductor integrated circuit.
With such probe cards, performing tests by bringing the probe needles
1
through
10
into contact with the electrode pads
12
of the semiconductor integrated circuit may meet instances wherein an insulating film (oxidized film) exists between the electrode pads
12
and the probe needles
1
through
10
, which raises the contact resistance, leading to the problem of erroneous measurements. This problem is being dealt with by pressing the probe needles against the electrode pads so as to break through the oxidized film on the surface of the electrode pad and realize contact with a newly-formed surface, but this causes a problem in that the oxidized film that has been scraped off accumulates between the electrode pads
12
and the probe needles
1
through
10
, so prolonged use is not possible.
An example of a probe guard for solving the above problems, invented by the present assignee, is disclosed in Japanese Unexamined Patent Application Publication No. 11-148947. This takes advantage of the fact that the electrode pads
12
exhibit shearing deformation only in a particular crystal orientation at the time of pressing the probe needles against the electrode pads
12
of the circuit device
11
, such that causing shearing deformation always keeps a newly-formed surface of the electrode pads in contact with the tips of the probe needles, so that testing can be performed for prolonged periods in a stable manner, without raising contact resistance. This probe needle takes into consideration the angle of contact between the probe needle and electrode pad to effect the shearing deformation, so the shape of the tip of the probe needle has been changed from the conventional flat form to a spherical form, and the radius of curvature r of the surface of the spherical form is set with regard to the thickness t of the electrode pad such that the expression 9t ≦r ≦35t holds.
Also,
FIG. 8
is a cross-sectional diagram illustrating another conventional probe card disclosed in Japanese Unexamined Patent Application Publication No. 6-18560. This probe card has the rear end of a probe needle
1
which comes into contact with an electrode pad
12
on the surface of a circuit device
11
attached to a circuit board
101
, with the probe needle
1
further provided with an ultrasonic vibrator
21
, coil
22
, and ultrasonic oscillator
23
, so as to break through the oxidized film by applying vibrations to the probe needle
1
and thus secure stable electrical contact.
Also, maintenance processing has been performed for scrubbing (sliding sideways on the electrode faces on the semiconductor integrated circuit) adhered aluminum in a state of being mechanically engaged with the tip of the probe needle
1
so as to eliminate the adhered aluminum.
However, with the above-described conventional probe card, in the event of applying a great current, such as 1 A or greater, the electrical resistance between the probe needle
1
and the electronic pad
12
is great at the plane of contact, so there has been the problem of heat thereat. For example, in the event that the tip of the probe needle
1
oxidizes and the contact resistance at the electrode pad reaches several ohms or more, the temperature reaches or exceeds the melting point of aluminum (approximately 660° C.), of which the electrode pad
12
is composed, due to the Joule heat thereat, so the aluminum melts and adheres to the tip of the probe needle
1
. The aluminum which has adhered by the above-described melting cannot be eliminated by ultrasonic vibration or scrubbing processing, and once the melding and adhesions of aluminum occurs, the surface thereof oxidizes and the contact resistance thereof becomes high, to the extend that heat is readily generated a current values under 1 A as well. Repeating such testing unavoidably results in accumulation of aluminum on the tip of the probe needle, to the point that finally all conductivity is lost.
Also, attempts to reduce the contact resistance and suppress generation of heat by applying a weight load to the probe needle
1
so as to secure area of contact with the electrode pad
12
, but this resulted in a problem in that cracks occur in the circuit device
11
due to the load in the event that the tip form of the probe needle
1
changes due to adhesion of aluminum in particular.
Also, in the event that the area of contact becomes to great due to increasing the diameter of the tip of the probe needle
1
, the heat generated can be decreased, but the contact resistance becomes great after repeated tests, leading to the problem of accelerated increase in the amount of heat generated, causing the problem of melting and adhesion of aluminum.
SUMMARY OF THE INVENTION
The present invention has been made to solve the above problems, and accordingly, it is an object thereof to provide a probe card capable of suppressing adhesion of melded material to the probe needle while recovering from increasing in contact resistance due to oxidation of molten adhered material, and a testing apparatus using the same.
The probe card according to a first aspect of the present invention comprises: a circuit board for sending and receiving electrical signals to test the operation of semiconductor integrated circuits; and a plurality of probe needles with one end connected to the circuit board and the other end coming into contact with electrodes connected to the semiconductor integrated circuit; wherein at least two of the probe needles are of the same potential at the time of testing the semiconductor integrated circuit, and wherein the probe needles of the same potential are situated at the same electrode on the semiconductor integrated circuit.
The tip of the probe needles may be of a generally spherical shape.
The probe card according to a second aspect of the present invention comprises: a circuit board for sending and receiving electrical signals to test the operation of semiconductor integrated circuits; a probe needle with one end connected to the circuit board and the other end coming into contact with electrodes connected to the semiconductor
Kashiba Yoshihiro
Maekawa Shigeki
Takemoto Megumi
Watanabe Yuetsu
Burns Doane , Swecker, Mathis LLP
Cuneo Kamand
Mitsubishi Denki & Kabushiki Kaisha
Nguyen Trung
LandOfFree
Probe card, and testing apparatus having the same does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Probe card, and testing apparatus having the same, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Probe card, and testing apparatus having the same will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-3151979