Electricity: measuring and testing – Fault detecting in electric circuits and of electric components – Of individual circuit component or element
Reexamination Certificate
1997-09-22
2001-03-13
Ballato, Josie (Department: 2858)
Electricity: measuring and testing
Fault detecting in electric circuits and of electric components
Of individual circuit component or element
C324S072000, C324S1540PB
Reexamination Certificate
active
06201403
ABSTRACT:
FIELD OF THE INVENTION
The invention relates to a method and apparatus for testing integrated circuit packages for their effectiveness in shielding electromagnetic interference (EMI) emissions.
BACKGROUND OF THE INVENTION
EMI radiation from electronics mounted within a package or enclosure must be minimized in order to reduce or eliminate its potentially interfering effects on surrounding equipment such as communications receivers etc. Standards exist which stipulate the maximum EMI radiation which is permitted. These are referred to as EMC (electromagnetic compatibility) standards. Historically, the focus on reducing EMI radiation has been on enclosures or boxes which surround the electronic equipment mounted within the box. However, with new ICs (integrated circuits) and ASICs (application specific integrated circuits) being designed to operate at faster and faster speeds, individual chips are becoming significant contributors to the EMI problem and it has become important to design IC packages which are effective in reducing EMI, thereby reducing the burden of EMI reduction placed on the enclosures in which the IC packages are to be installed.
Existing methods for the EMC characterization of silicon devices were developed to measure radiation from printed circuit boards in operation inside electronic devices. These methods are not appropriate or capable of characterizing ASIC packages on their own without electronics. From a mechanical package point of view, various methods exist for measuring shielding effectiveness of metal enclosures for electronic equipment. However, these methods are not appropriate for small devices such as an ASIC package.
SUMMARY OF THE INVENTION
It is an object of the invention to obviate or mitigate one or more of the above identified disadvantages.
A new method is introduced to characterize EMI at the IC/ASIC package level. It is designed to excite the modes of radiation found in these packages in a way representative of the electronics which would normally exist inside them. In the new method, a small antenna designed on a test die is mounted inside the package under test. The package is mounted on a carrier PCB (printed circuit board) that is used to feed a test signal into the antenna on the die. Radiation is then measured from this set-up.
Preferably, the antenna is first measured in free space to obtain measurements which represent its capability to radiate without shielding. The antenna is then measured inside a package to obtain measurements representing its reduced capability to radiate with package shielding. The difference between the two measurements represents the shielding effectiveness or the EMI reduction the package offers to the die. Preferably, all measurements will be performed inside a wideband TEM (Transverse Electromagnetic Mode) cell.
According to a first broad aspect, the invention provides a method of characterizing the EMI (electromagnetic interference) emissions of a die package comprising the steps of: installing a test die in the package in place of where a normal die would be located, the test die having a first antenna thereon; injecting a test signal to the first antenna; measuring the EMI emissions produced by the first antenna at a point outside the package.
According to a second broad aspect, the invention provides a method of characterizing the EMI (electromagnetic interference) immunity of a die package comprising the steps of: installing a test die in the package in place of where a normal die would be located, the test die having a first antenna thereon; injecting a test signal to a second antenna located outside the package; measuring a resulting signal received by the first antenna.
According to a third broad aspect, the invention provides a test die for mounting within a package for performing EMI characterization of the package, the die comprising: a die with at least one antenna etched thereon; and connecting pads for connecting the antenna to connecting elements on the package.
According to a fourth broad aspect, the invention provides a test package for performing EMI characterization of a sample package, the test package comprising: a sample package with a test die installed in place of its normal die, the test die having at least one antenna etched thereon;
the test die having connecting pads connecting the antenna to connecting elements on the package.
REFERENCES:
patent: 4939446 (1990-07-01), Rogers
patent: 5006792 (1991-04-01), Malhi et al.
patent: 5053700 (1991-10-01), Parrish
patent: 5124660 (1992-06-01), Clingiroglu
patent: 5218294 (1993-06-01), Soiferman
J.P. Muccioli et al, Integrated Circuit Radiated Emissions Diagnostic Procedure 1MHz to 1000MHz, Magnetic Field-Loop Probe, Jan. 31, 19995, pp. 1-23, Electromagnetic Compatibility Measurement Procedures for Integrated Circuits.
J.P. Muccioli et al, Integrated Circuit Radiated Emission Measurement Procedure 15 kHz ro 1000 MHz, TEM Cell, Jan. 31, 1995, pp. 1-13, Electromagnetic Compatibility Measurement Procedures for Integrated Circuits.
Goulette Richard R.
Rollin Jacques J.
Wong William K.L.
Ballato Josie
Nortel Networks Limited
Tang Minh
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