JPS6346853Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to an electrostatic discharge testing device for large-scale integrated circuits, integrated circuits, general semiconductor devices, etc.

Fig. 1 is a diagram showing an example of a conventional electrostatic discharge test device, where HE is a DC high voltage generator, Rc is a series resistor for charging, Ryt is a relay switching contact, C is a capacitor, Rd is a series resistor for discharging, To is the output terminal, _l1 and _l2 are the connecting conductors, PB is the discharge rod, IC is the circuit under test, and GP is the ground plate.

Series resistance Rc for charging by DC high voltage generator HE
After charging the capacitor C through the relay switching contact Ryt and switching the relay switching contact Ryt,
A constant charge accumulated in the capacitor C is applied to a desired terminal in the circuit under test IC via the relay switching contact Ryt, the series discharge resistor Rd, the output terminal To, the connecting conductor _l1 , and the discharge rod PB.

However, the terminal spacing of integrated circuits, etc., is standardized to 2.54mm pitch for dip type circuits, for example.
In addition, among flat packages, multi-terminal types with a pitch of 0.7 mm have come into practical use in recent high-density integrated circuits, so the tip of the discharge rod PB should be made thinner than the terminal spacing. However, before the tip of the discharge rod PB contacts the desired terminal in the circuit under test, the relay switching contact must be formed so that it can contact only the desired terminal.
When switching Ryt to guide the accumulated charge in the capacitor C to the tip of the discharge rod PB via the series discharge resistor Rd, the electric field density around the tip of the discharge rod PB, which has a small radius of curvature, becomes extremely high. This causes dielectric breakdown in the air, corona discharge occurs, and part of the charge is lost.Also, in the process of bringing the tip of the discharge rod PB close to a desired terminal, a discharge path is formed between it and other terminals. There is also a high risk that the stored charge will be lost, making it impossible to apply a defined amount of charge to a desired terminal.

To prevent such a discharge phenomenon and apply a predetermined amount of charge to a desired terminal, first press the tip of the discharge rod PB into contact with the desired terminal, and then switch the relay switching contact Ryt to reduce the accumulation of capacitor C. It is necessary to apply an electric charge to the desired terminal, but when doing this, use one hand to ensure pressure contact between the tip of the discharge rod PB and the desired terminal, and use the other hand to press the relay switching contact. Not only is the handling operation relatively difficult because the switching has to be performed, but even when accumulated charge is added to a desired terminal by such an operation, conventional devices do not suffer from the following drawbacks: I can't.

That is, in an electrostatic discharge test, it is necessary to instantaneously apply a fixed amount of charge to a desired terminal in the circuit under test, but in conventional equipment, it is necessary to apply a fixed amount of charge to a desired terminal in the circuit under test. The charge transfer path consists of the capacitor C, the relay switching contact Ryt, the series discharge resistor Rd, the discharge rod PB, and the connecting conductor for these. , stray capacitance, DC resistance, degree of magnetic inductive coupling, degree of electric field inductive coupling, contact resistance between the movable contact piece and the fixed contact at the relay switching contact Ryt, and the discharge bar.
The contact resistance between the tip of the PB and the terminals of the circuit under test is distributed, and these floating components have a non-negligible effect on the electrostatic discharge test results.

Therefore, to obtain accurate test results, capacitor C, relay switching contact Ryt, and series resistor for discharge must be
Of course, it is necessary to carefully select circuit elements with good performance for all circuit elements such as Rd and discharge rod PB, but what is even more important is to be able to calculate the value of stray components distributed on the charge movement path. The only thing to do is to make it smaller.

However, in the conventional device, the output terminal To
Connecting conductor L ₁ and output terminal between one side of the discharge rod PB and the output terminal
Since it is necessary to lengthen the connecting conductor _l2 between the other To and the ground to facilitate handling of the discharge rod PB, (1) the stray inductance in each of the connecting conductors _l1 and _l2 becomes large; (2) Stray capacitance between each connecting conductor _L1 and _L2 and between each connecting conductor and the ground becomes large. (3) Unnecessary radiation of high frequency energy occurs from the connecting conductors l ₁ and l ₂ and the discharge rod PB as the relay switching contact Ryt switches open and close. (4) The relationship between the connecting conductors l ₁ , l ₂ and the discharge bar PB and the electric and magnetic fields around them is uncertain, depending on the distance to the ground or other conductive object, the shape of the conductive object, etc. The electromagnetic environment changes and the stray capacitance changes. or,
(5) The discharge energy applied to the desired terminal of the circuit under test is attenuated due to reasons such as the relatively large stray capacitance between the discharge rod PB and the hand when the discharge rod PB is held by the hand. With this, the amount of attenuation becomes indeterminate,
Furthermore, since the waveform is irregularly deformed, the quantitative and qualitative properties of the applied energy are lost, making it impossible to conduct an accurate test.

The present invention incorporates a part of the movement path of accumulated charges in an electromagnetic shielding holder to exclude some of the various stray components from the energy conversion circuit and the energy transmission circuit, and also eliminates the energy transmission path outside the electromagnetic shielding holder. By forming it extremely short and minimizing various floating components in this part to a level that causes almost no errors in practice, it is possible to ensure the quantitative and qualitative nature of the applied energy, and also to reduce static electricity that is easy to handle. The purpose is to realize a discharge test device.

FIG. 2 is a cross-sectional view showing an example of a discharge energy application probe according to the present invention, in which 1 is a front holder made of a cylindrical insulator, 2 is a rear holder made of a cylindrical conductor, and 3 is an insulating support. The front end of the tube is fixed to the front end of the front holder 1, and the rear end is fixed to the inner wall of the front holder 1 via a ring-shaped support 4, so that the insulating support tube 3 is attached to the front holder. It is installed coaxially with 1. 5 is a movable metal rod, and the insulating support tube 3
It is slidably inserted into the inner end, and its outer end is formed narrower than the terminal spacing in the circuit under test, and a movable metal ball 6 is attached to the inner end. A spring 7 is interposed between the rear end wall of the insulating support cylinder 3 and a protrusion 8 provided on the movable metal rod 5, and normally presses the movable metal rod 5 to keep it in the forward state. A fixed metal rod 9 is fixed to the rear end wall of the front holder 1 and the front end wall of the rear holder 2 via an insulating support 10. Its front end is inserted into the front holder 1, and the rear end is inserted into the front holder 1. It is inserted into the rear holder 2. 11 and 12 are ring-shaped insulating supports, and 13 is a fixed metal ball, which is attached to the front end of the fixed metal rod 9 and is normally opposed to the movable metal ball 6 at an appropriate distance. Reference numeral 14 denotes a series resistor for discharging, which is interposed in the middle portion of the fixed metal rod 9 in the front holder 1 as shown in the figure, or interposed between the front end of the fixed metal rod 9 and the fixed metal ball 13. 15 is a DC high voltage input terminal, and the insulating support 1
It is attached to the rear holder 2 via 6. Reference numeral 17 denotes a series resistor for charging, which is interposed between the rear end of the fixed metal rod 9 and the input terminal 15. Reference numeral 18 denotes a grounding conductor, which is attached to the rear holder 2.

FIG. 3 is a diagram showing the entire configuration of the present device, where S is a power supply section, P is a probe shown in FIG. 2, and shows an equivalent circuit of the electric circuit portion thereof. In the power supply section S, HE is a DC high voltage generator, which has the same configuration as the conventional one shown in FIG. Rys is a switching contact, such as a switching contact of a relay. Rb is a buffer resistor for limiting charging current and preventing unnecessary radiation, and To is an output terminal. In the probe P, 15 is an input terminal, 2 is a ground side input terminal formed from the side wall of the rear holder, and 17 is a series resistor for charging, which limits the charging current and prevents unnecessary radiation. _{C9.2 ​}
is the distributed capacity between the fixed metal rod 9 and the rear holder 2, 1
4 is a series resistor for discharging, G is a gap between the metal balls 6 and 13, CE is a contact electrode formed at the outer end of the movable metal rod 5, and 18 is a grounding conductor. l ₃ and l ₄ are connection conductors between the power supply section S and the probe P.

Connect the grounding conductor 18 to the grounding terminal of the circuit under test, close the relay switching contact Rys, and use the output of the DC high voltage generator HE to connect the buffer resistor Rb and the connecting conductor.
l ₃ and l ₄ , distributed capacitance via charging series resistor 17
After charging C _{9. 2} , open the relay switching contact Rys, hold the probe P in your hand, and touch the tip CE of the movable metal rod 5.
When the probe P is pressed and moved forward against the elasticity of the spring 7 after contacting the desired terminal in the circuit under test, the movable metal rod 5 and the movable metal ball 6 move back relatively, and the movable metal ball 6 When the gap G between the fixed metal ball 13 and the fixed metal ball 13 is shortened and reaches the gap length determined by Patsien's law, an air discharge occurs between the metal balls 6 and 13, and the accumulated charge of the distributed capacitance _{C 9.2 is} suddenly discharged under test. released to the desired terminal in the circuit. If the charging voltage of _the distributed capacitance _C9.2 is approximately 350 volts or less, the metal balls 6 and 1 will be charged under 1 atm.
However, in this case, the probe P is further pushed forward to press the metal ball 6 to the metal ball 13, and when a completely conductive state is reached, a contact discharge occurs. The accumulated charge _of distributed capacitance C _9.2 is released all at once.

In the probe of the present device, the discharge circuit for the charge accumulated in the distributed capacitance C _9.2 is normally open by the gap G between the metal balls 6 and 13, so that the distributed capacitance C _9.2 is _not charged _. Since there is no possibility that corona discharge will occur from the tip of the movable metal rod 5 later on, even if the terminal spacing of the circuit under test is extremely small, the tip of the movable metal rod 5 can be made thin in accordance with this spacing.

Furthermore, after bringing the tip of the movable metal rod 5 into contact with a desired terminal, the probe P is pushed forward to shorten the gap length between the metal balls 6 and 13 and discharge the discharge energy, which is different from the conventional device. In contrast to devices where one hand is used to secure contact between the desired terminal and the discharge rod and the other hand is used to switch the relay switching contact, the proposed device can achieve its purpose with one-handed operation and is easy to handle. It is capacity.

In the probe of the proposed device, _the distributed capacitance _C9.2
A part of the fixed metal rod 9 forming the battery and the charging series resistor 17 are placed inside the rear holder 2 made of a cylindrical conductor to electromagnetically shield the fixed metal rod 9 in the front holder 1 forming a discharge circuit. , series resistance for discharge 1
4. By making the total length of the metal balls 13 and 6 and the movable metal rod 5 as short as possible, various floating components in this discharge circuit can be minimized to the extent that practically no errors are caused in the test results. In addition, since the discharge circuit is mechanically held by the insulating support tube 3, the ring-shaped insulating support 11, and the insulating support 10 to prevent irregular positional fluctuations, fluctuations in various floating components can be prevented. In addition, the stray capacitance between the discharge circuit and the hand when the probe is held in the hand can be made extremely small, and the buffer resistor prevents unnecessary radiation of high frequency energy when the relay switching contact Rys is opened and closed.
Since this can be prevented by Rb, it is possible to ensure the quantitative and qualitative nature of the discharge energy applied to the circuit under test, and furthermore, the distance between the discharge source and the terminals of the circuit under test can be kept extremely close. It has the advantage of being able to perform electrostatic discharge tests under conditions similar to those in which the circuit under test actually suffers from damage due to discharge energy.

For example, the metal balls 6 and 13 are attached to each end of the movable metal rod 5 and the fixed metal rod 9 by screws, and each metal ball is rotated to change the gap length between the two metal balls. By forming this structure, the discharge voltage can be freely selected, and by filling a suitable dielectric material between the fixed metal rod 9 and the rear holder 2, the distributed capacitance _C9.2 can be increased, and the fixed metal rod 9 and the rear holder ₂ can be The mechanical support strength of the metal rod 9 can be increased.

Furthermore, by providing an electromagnetic shielding cylinder on the outer surface or inner surface of the side wall of the front holder 1 corresponding to an appropriate axial length from the rear end wall of the front holder 1, for example, to the fixed metal ball 13. Stray capacitance between the hand and the discharge circuit when the probe is held by hand can be reduced.

The above is an example of a configuration in which the charge in the stray capacitance between the rear end of the fixed metal rod 9 and the rear holder 2 is discharged via the discharge circuit. The central axis electrode of a capacitor (with a dielectric interposed between it and the provided cylindrical electrode) is replaced with the entire length or part of the fixed metal rod 9 in the rear holder 2, and the rear holder 2 is attached to the outer surface of the cylindrical electrode. The side walls of the
The present invention can also be implemented by configuring the cylindrical electrode and the rear holder 2 to be connected by a connecting conductor.

[Brief explanation of the drawing]

Fig. 1 is a diagram showing a conventional device, Fig. 2 is a diagram showing a probe in an embodiment of the present invention, and Fig. 3 is a wiring diagram showing an embodiment of the present invention. Device, Rc, Rb and 17: Series resistance for charging, Ryt: Relay switching contact, C: Capacitor,
Rd and 14: series resistance for discharge, To: output terminal,
PB: discharge rod, GP: ground plate, IC: circuit under test, l ₁
or l ₄ : Connection conductor, 1: Front holder, 2: Rear holder, 3: Insulated support tube, 4, 10, 11, 12
and 16: support body, 5: movable metal rod, 6: movable metal ball, 7: spring, 8: protrusion, 9: fixed metal rod, 13: fixed metal ball, 15: input terminal, 18:
Grounding conductor, Rys: Switching contact, G: Gap, CE:
Contact electrode, _C9.2 : Distributed _capacitance .

Claims (1)

[Claims for Utility Model Registration] (1) A front holder made of a cylindrical insulator, a rear holder made of a cylindrical conductor integrally connected to the rear end of this front holder, and a front end portion of which is connected to the front holder. a fixed metal rod inserted into the rear holder, the rear end of which is inserted into the rear holder and fixed to the front end wall of the rear holder via an insulating support; a fixed metal ball inserted in series with the fixed metal rod in the front holder; a series resistor for discharging inserted in the front holder so as to be slidable back and forth; A movable metal rod is provided inside the front holder, and is normally moved forward to move the movable metal ball between the fixed metal ball and the movable metal ball. a DC high voltage input terminal attached to the rear holder via an insulating support, and a spring inserted between the rear end of the fixed metal rod and the DC high voltage input terminal. A probe consisting of a series resistance for charging and a grounding conductor attached to the rear holder, and a power supply unit that applies the output of a DC high voltage generator to the DC high voltage input terminal of the probe via a switching contact. An electrostatic discharge test device characterized by: (2) The electrostatic discharge test device according to claim 1, which is a utility model and has a variable constant gap length between a movable metal ball and a fixed metal ball housed in the front holder of the probe. (3) The electrostatic discharge test device according to claim 1, wherein a series resistor for discharging built into the front holder of the probe is inserted into the middle of the fixed metal rod. (4) The electrostatic discharge test device according to claim 1, wherein a series resistor for discharge built into the front holder of the probe is inserted between the front end of the fixed metal rod and the fixed metal sphere. (5) The electrostatic discharge testing device according to claim 1, wherein a dielectric material is interposed between the fixed metal rod in the rear holder of the probe and the side wall of the rear holder. (6) Utility model registration claim 1, in which the entire length or part of the fixed metal rod in the rear holder of the probe is replaced with a central axis electrode of a feedthrough capacitor, and the cylindrical electrode of the feedthrough capacitor is connected to the rear holder. The electrostatic discharge test device described in Section 1.