JP2587746Y2 - CDM simulator - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a CDM simulator for simulating a high-speed discharge phenomenon in order to test an electrostatic discharge of an IC circuit.

[0002]

BACKGROUND ART CDM simulator, as shown in FIG. 1, the charging side for the IC which is connected to ground by the DC power supply circuit and, to connect the terminals of the IC to the ground, and have a stray inductance and resistance R ₂ The mercury reed switch is used in recent years in the discharge side circuit to prevent an arc phenomenon or the like, as shown in FIG.

When the mercury reed switch is connected to the ground and the terminal of the IC via the lead wire, the value of the stray inductance in the discharge circuit becomes very large.

[0004] Incidentally has a circular cross-section radius is a, linear self-inductance of the lead wire of length l _{is, L ≒ μ o l / 2μ} (log2l / a-1) (μ o: airborne through permeability ), And since l << a, it can be sufficiently understood that the inductance L due to the mercury reed switch and the surrounding lead wires has a considerably large value.

On the other hand, in general, in a series circuit of a resistor R, a capacitor C, and an inductance L, In the case of, the discharge current is Decay at the rate of It vibrates at the size of.

Therefore, when the inductance L is large, it means that rapid decay is performed, that is, discharge is not performed at once.

Moreover, it is difficult to obtain a discharge waveform conforming to the required standard of the CDM simulator simply by actually connecting the mercury reed switch to the ground and the terminal of the IC via the lead wire.

[0008]

In view of the drawbacks of the prior art, the present invention reduces the inductance due to the lead wires on both sides of the mercury reed switch and reduces the inductance on the discharge circuit side of the IC to a very small value. It is an object of the present invention to provide a CDM simulator that can be set as follows.

[0009]

As means for solving the above-mentioned problems, as shown in FIG. 2, the structure of the present invention is to connect an IC connected to the ground via a DC power supply circuit and a charging switch as shown in FIG. A CDM in which a mercury reed switch is provided between the ground and an IC terminal to discharge the charged charge
In a simulator, a mercury reed switch is housed in a cylindrical conductor, and a side opposite to a connection side of the mercury reed switch to an IC terminal is connected to the cylindrical conductor, and an IC of the cylindrical conductor
It consists of a CDM simulator based on connecting the terminal side to ground.

[0010]

Generally, radii r ₀ and r ₀ as shown in FIG.
The self-inductance when the same cylindrical conductor of ₁ , r ₂ and length l forms a reciprocating circuit is: Where μ: magnetic permeability of the conductor.

In the above, r ₀ is set to a value close to r ₁ ,
Moreover set meat pressure outside the cylinder as appropriate, in the case of setting the difference of a predetermined size between r ₁ and r _2, the inductance L is found to be not very large value.

This is because the direction of the current flowing through the inner conductor and the direction of the current flowing through the surrounding cylinder are opposite to each other, so that the magnetic fluxes generated in the two cancel each other out, and as a result, the energy ( 1/2) Li
² (i is the magnitude of the conducting current) is considerably smaller than the case where only the inner conductor is used.

The basic principle of the present invention is that, when the conductor and its surroundings are surrounded by a conductor and currents in opposite directions are conducted, magnetic fluxes generated in the conductors cancel each other.

[0014]

[Embodiment 1] Normally, a conductor surrounding a mercury reed switch 3 and its surrounding lead wires is often cylindrical, but in Embodiment 1, as shown in FIG. 4, a hexagonal cylindrical conductor 5 is used. And the lead wire 31 in the mercury reed switch 3 was arranged at a position corresponding to a substantially central axis of the cylindrical conductor 5 and connected to the cylindrical conductor 5 and the IC.

With such an arrangement and connection state, the magnetic flux generated from the mercury reed switch 3 and the lead wires before and after the mercury switch can be canceled by the magnetic flux generated by the outer conductor, and the inductance as a whole can be set small. is there. Although the hexagonal cylindrical conductor 5 is used in FIG. 4, the configuration is not necessarily limited to the hexagonal shape, and the configuration of the first embodiment may be generally applied to an equilateral cylindrical conductor. Can be.

[0016]

Embodiment 2 In a CMD simulator, a resistor may be inserted in order to increase the degree of attenuation of a discharge current.

In this case, the resistance wire itself often has a fixed inductance.

As shown in FIG. 5, in the second embodiment,
The shape of the cylindrical conductor 5 is cylindrical or equilateral polygonal (FIG. 5 shows a cylindrical conductor as the cylindrical conductor).
A resistor 6 is radially provided from the outside of the cylindrical conductor at the IC-side end of the cylindrical conductor with reference to a position corresponding to the center axis of the cylindrical conductor, and is connected to the ground.

As a result, the magnetic flux generated from the resistor 6 cancels each other, and the influence of the inductance of the resistor 6 itself can be set small.

[0020]

[Effect of the Invention] With the configuration of the present invention as described above, CM
Since the inductance of the D simulator is designed to be small, it is possible to discharge the discharge current at a stroke and simulate a high-speed discharge phenomenon.

FIG. 6 (a) shows a discharge current waveform when a conventional mercury reed switch is used in which a voltage of 500 volts is applied, an IC terminal has a capacity of 4PF, and a conventional mercury reed switch is used. In this case,
A peak current _{i p} 6.2 amperes and the time of the half value width is 680Psec hand, FIG. 6 (b) is
In case of installing a tubular outer conductor is the peak current _{i p} 8.4 amps, the time of the half value width is 380Psec
However, the present invention is found to be far superior to the prior art in terms of the magnitude of the peak current and rapid discharge.

In addition, in the case of the present invention, since the inductance L is small, it is possible to arbitrarily set a necessary waveform by appropriately adding the capacitance C.

As described above, according to the present invention, the CDM simulator has been improved in the points described above.
Its value is enormous.

[Brief description of the drawings]

FIG. 1 shows a circuit of a conventional CDM simulator.

FIG. 2 shows a circuit of a CDM simulator according to the present invention.

FIG. 3 is a cross-sectional view of a coaxial cylindrical conductor for illustrating a basic principle of the present invention.

FIG. 4 is a cross-sectional view showing an arrangement relationship between a lead wire of a mercury reed switch and a cylindrical conductor in Example 1.

FIG. 5 is a plan view of Example 2 in which resistance wires are provided radially.

FIGS. 6A and 6B show the state of the discharge current according to the related art and the state of the discharge current according to the present invention.

[Description of sign]

 1: IC 2: Power supply voltage 3: Mercury reed switch 31: Lead wire of mercury reed switch 5: Cylindrical conductor 6: Resistance 7: Coaxial cable connected to oscilloscope

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kenichi Sengo 689-3 Ogakiuchi, Wakayama City, Wakayama Prefecture Inside Hanwa Electronics Industry Co., Ltd. 231458 (JP, A) (58) Field surveyed (Int. Cl. ⁶ , DB name) G01R 31/26 G01R 31/30 H01L 21/66 G01R 31/12

Claims (3)

(57) [Scope of request for utility model registration] In a CDM simulator provided with a mercury reed switch between a ground and an IC terminal for discharging an electric charge charged to an IC connected to the ground via a DC power supply circuit and a charging switch, the mercury reed switch is provided. The switch is housed in a cylindrical conductor and the mercury reed switch IC
CDM based on connecting the side opposite to the terminal connection side to the cylindrical conductor and connecting the IC terminal side of the cylindrical conductor to ground.
Simulator 2. The method according to claim 1, wherein the tubular conductor is cylindrical or equilateral polygonal, and the lead wire in the mercury reed switch is arranged at the center axis position of the tubular conductor. 2. The CDM simulator according to claim 1, wherein the CDM simulator is connected to the cylindrical conductor and an IC. 3. The shape of the cylindrical conductor is a cylindrical state or an equilateral polygonal cylindrical state, and at the tip of the cylindrical conductor on the IC side, from the outside of the cylindrical conductor with reference to the center axis position of the cylindrical conductor. 2. The CDM simulator according to claim 1, wherein the resistance wires are provided radially and connected to the ground.