JP3371817B2 - Pencil type probe unit - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrostatic breakdown test apparatus.
Pencil relates probe unit, in particular charged device model used (CDM: Charged Device Model) using a pencil probe unit used in the apparatus for performing the electrostatic breakdown test of IC chips mounted on a wiring board <br / > 2. Description of the Related Art Conventionally, manufacturers of semiconductor devices and manufacturers of electric equipment sets that handle LSI parts have been using ESD (Electro-static Discharge) of IC chips.
HBM (Human Body Model)
And MM (Machine Model). That is, these simulate the destruction phenomenon that occurs when a charged human body or the like contacts the IC chip and then discharges to the IC chip. However, up to now, the CDM has been modeled on a phenomenon in which the IC chip itself is charged and the charge is rapidly discharged to cause the deterioration or destruction of the IC chip.
Is becoming mainstream. The CDM is described in, for example, "Koichi Suzuki et al., Electrostatic Disruption Factor of LSI and New Measurement Method, IEICE Transactions, VOL.J80-C-2 No.10 pp335-344,1997". The electrostatic breakdown test apparatus using such a CDM is disclosed in JP-A-2-259585.
JP, JP-A-3-15773, JP-A-5-18
No. 0899 and the like. The test apparatuses and test methods described in these publications are all specific examples used for an electrostatic breakdown test of a single IC chip, and the breakdown strength of the IC chip is indicated as a breakdown voltage or a breakdown voltage. are doing. Japanese Patent Application Laid-Open No. 9-218241 discloses that in order to determine a more accurate breakdown strength than these publications, the breakdown strength is determined based on either the charge amount or the energy, and the breakdown strength of a single IC chip is measured. Without depending on
Also disclosed is a test device that can be accurately represented by a unique quantity. As described above, the CDM test of a single IC chip has been intensively studied, and many practical and reproducible test apparatuses and test methods have been provided. [0007] With the spread of personal computers (hereinafter referred to as personal computers) and game machines, parts such as printed circuit boards for personal computer function expansion, IC cards, game IC cassettes, etc. There is an increasing number of occasions in which the user himself / herself mounts the device on the main unit, and electrostatic breakdown at the time of mounting has become a problem as in the case of the single IC chip. Of course, even in such a case, it can be said that a device charging method (CDM) in which a part is charged and the charge is discharged from the part itself in a very short time can be applied as an electrostatic breakdown model. However, it is not possible to use a conventional electrostatic breakdown tester for a single IC chip by the device charging method for components such as a printed circuit board for personal computer function expansion, an IC card, and a game IC cassette. ,
There was a problem that it was difficult due to the restriction on the prober mechanism. That is, in the test of a single IC chip, since the shape is standardized, the test can be performed by fixing the IC chip on a test board (stage) and moving the probe mechanically. However, since the size and shape of the function expansion board for personal computers and the like vary, the conventional test apparatus cannot be used as it is. The present invention has been made to solve such a problem, and has a printed circuit board for personal computer function expansion and an IC.
An object of the present invention is to provide a pencil-type probe unit capable of easily performing an electrostatic breakdown test even when a card, a game IC cassette, and the like are mixed and the shapes of terminals and the like are not uniform. I do. In order to achieve the above object, the present invention provides a DC power supply for generating a predetermined DC voltage and having a negative electrode connected to the ground and a positive electrode of the DC power supply. A plurality of IC chips are mounted on a pencil-type probe unit connected via a cable to a main unit having a resistor connected to the IC chip, and a wiring having a plurality of terminals electrically connected to the IC chip A metal probe pressed against a terminal of the wiring board during an electrostatic breakdown test of the substrate, a first switch means connected via the cable between the metal probe and the resistance of the main body device, A second switch connected between the metal probe and the ground of the main unit via the cable, a third switch manually operated, and a third switch; The first switch is turned on in response to a manual operation of the switch , and after a lapse of a predetermined time, the first switch is turned on.
Switch means for turning off the switch means and the second switch means.
And control means for turning on the control signal. [0015] With this configuration, the present invention provides:
Even when the printed circuit board for personal computer function expansion, the IC card, the game IC cassette and the like are mixed and the shapes of the terminals and the like are not uniform, the electrostatic breakdown test can be easily performed. Next, one embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing one embodiment of the present invention. As shown in FIG. 1, a printed wiring board 4 on which various IC chips such as LSIs are mounted is placed on an insulator table 5. Note that the IC chip mentioned here means the following. That is, an IC chip is mounted on a board such as a personal computer or the like for expansion in a state of being housed in a package of ceramic or resin, but a bare chip is often mounted on an IC card or the like. Therefore, the IC chip in the present invention includes both a chip housed in a package and a bare chip. A plurality of terminals are formed on the edge of the printed wiring board 4, and these terminals constitute a connector 4a used for connection to a personal computer or a game machine body. Further, the insulator table 5 and the ground plane are electrically insulated from each other.
Suppose that exists. On the other hand, an electrostatic breakdown test device is installed beside the insulator table 5, and is composed of a main unit 3, a cable 3 a and a probe unit 2. The main unit 3 includes a power supply for generating a DC voltage, a charge measuring device, an oscilloscope, and the like. The probe unit 2 has a metal probe 1 at its tip for making contact with the connector 4a, and button switches BSW1 and BSW2, which are mechanical switches for controlling charging and discharging, on its side. The probe unit 2 has a pencil shape and can be used by an operator in a manner of holding the pen. Of course, button switch BSW
1, BSW2 is also provided at a position where it can be operated while holding the probe unit 2, and can be easily operated by pressing it with the index finger. Therefore, the operator presses the metal probe 1 against the connector 4a of the printed wiring board 4 to be tested and then presses the button switch BSW1 to apply the DC voltage generated by the main unit 3 to the cable 3a. The voltage is applied to the connector 4a via the metal probe 1 to perform charging. After that, when the charging is completed after a predetermined time, the connection of the switch in the probe unit 2 is automatically switched to disconnect the connection between the metal probe 1 and the DC power supply. Connected.
As a result, the electric charge charged in the wiring board 4 on the contrary this time is
Discharge is discharged to the ground surface via the connector 4a, the metal probe 1, and the cable 3a. At this time, by appropriately pressing the button switch BSW2, the charge amount and the discharge voltage can be measured, and the results can be displayed on the main unit 3. Next, details of the electrostatic breakdown test apparatus according to FIG. 1 will be described. FIG. 2 is a block diagram showing details of the electrostatic breakdown test apparatus according to FIG. As shown in the figure,
Switches SW1 and SW2 are connected to the metal probe 1. Each of the switches SW1 and SW2 is desirably constituted by a mercury relay or the like in order to prevent chattering at the time of discharging or the like. The switches SW1 and SW2 are turned on and off by a control signal from the control means 2a, and a button switch BSW1 is connected to the control means 2a. When the BSW1 is pressed, the control unit 2a switches the connection between the switches SW1 and SW2. The operation will be described later. The switch SW1 has a value of 100 k to 10 k.
A resistor R1 of MΩ is connected to prevent rapid movement of electric charge during charging, and a DC power supply of 1000 V or more is connected between the resistor R1 and the switch SW2. The GND line in the probe unit 2 (that is, the wiring connected between the switch SW2 and the ground) is made of a conductor as large as possible in order to generate an ideal high-speed discharge. There is a need to. For example, a metal plate or a metal rod may be installed in the probe unit 2, a metal may be printed on the back surface of the mounting board in the probe unit 2, or a metal of the probe unit 2 may be plated. It is desirable that the metal used at this time has low impedance and low inductance by increasing the area and thickness as much as possible, and it is desirable that the metal be connected to a position as close to the tip of the metal probe 1 as possible. Here, the operation of the present embodiment will be described. First, the printed wiring board 4 to be tested is placed on the insulator table 5 on the ground plane. Next, both the switches SW1 and SW2 are turned off, and the metal probe 1 is brought into contact with the terminal of the connector 4a of the printed wiring board 4. At this time, in order to prevent the IC chip from being broken by the movement of the electric charge at the time of the contact, the switch SW1 may be brought into contact with the ON state. Next, after setting the DC power supply V to 1000 V DC, the switch SW1 is turned on, this state is maintained until charging is completed, and then turned off. Next, by turning on the switch SW2, the electric charge is discharged in an extremely short time. A series of these charging and discharging operations are performed by pressing the button switch BSW1 by the operator.
The control means 2a is driven and is automatically implemented by its operation. [Second Embodiment] FIG. 3 is a block diagram showing a second embodiment of the present invention. 1, the same reference numerals as those in FIG. 1 denote the same or equivalent parts, and in this embodiment, a charge amount measuring device 6 is further provided so that the charge amount of the printed wiring board 4 can be measured. It is characterized by The charge amount measuring device 6 is disclosed in, for example,
It is preferable to use an excessive dynamic charge amount measuring device disclosed in JP-A-325119. That is, in the probe unit 2, the switch SW3 connected to the metal probe 1, the resistor R2 connected to the switch SW3, and the resistor R
2 and an operational amplifier OP connected to the
A capacitor C2 is connected between the two input terminals of P. Further, the main body device 3 is provided with a charge amount measuring device 6, which is supplied with an output from the operational amplifier OP and measures the charge amount. Next, the operation of this embodiment will be described. The procedure from when the metal probe 1 is brought into contact with the terminal 4a of the connector, when the button switch BSW1 is depressed and charging is performed is the same as in the first embodiment. Next, the control means 2a is driven by depressing the button switch BSW2, and the switch SW3 is turned on by the control. As a result, the resistance R
2, the capacitor C2, the operational amplifier OP and the charge measuring device 6 measure the excess dynamic charge Q [nC], and the result is displayed on the display unit of the charge measuring device 6.
Thereafter, if the charged charge is discharged by pressing the button switch BSW1 again, the resistance to electrostatic damage by the device charging method can be displayed by the charge amount. Third Embodiment FIG. 4 is a block diagram showing a third embodiment of the present invention. In the figure, the same or equivalent parts as those in FIG. 1 are denoted by the same reference numerals, and in the present embodiment, a current probe 7a (for example, CT-2) is provided in the probe unit 2.
), The main unit 3 is provided with an oscilloscope 7 connected to the current probe 7a. That is, with such a configuration, the waveform at the time of discharge can be displayed on the oscilloscope 7. Here, the operation of the present embodiment will be described. First, charging is performed by bringing the metal probe 1 into contact with the terminal of the connector 4a and pressing the button switch BSW1. Thereafter, the switch SW1 is turned off and the switch SW2 is turned on, and the electric charge is discharged in a very short time. The current discharged at this time is detected by the current probe 7a, and the discharge waveform is displayed on the oscilloscope 7. The metal probe 1 of each of the above embodiments
Can be replaced with a specially made needle probe to make electrical contact with the semiconductor wafer,
The present invention is also applicable to the case of testing a semiconductor wafer . Also,
The probe unit 2 is so compact that an operator can hold it by hand, so that the probe unit 2 can be held mechanically and can be easily converted to an automatic machine. As described above, according to the present invention, the pencil type probe unit is connected to the main unit via a cable, and the pencil type probe unit is connected to the first switch means, the second switch means, and the second switch means. A third switch means and a control means, and the first switch means is turned on via the control means in response to a manual operation of the third switch means ;
After the lapse of a fixed time, the first switch is turned off.
By turning on the second switch means , the operator can select a desired terminal on the wiring board and perform an electrostatic breakdown test. Therefore, a single I
It can be used for testing not only C chips but also electrical components having any structure.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing one embodiment of the present invention. FIG. 2 is a block diagram showing the electrostatic breakdown test apparatus according to FIG. FIG. 3 is a block diagram showing another embodiment of the present invention. FIG. 4 is a block diagram showing another embodiment of the present invention. [Description of Signs] 1 ... Metal probe, 2 ... Probe unit, 2a ... Control means, 3 ... Main unit, 4 ... Printed wiring board, 5 ... Insulator table, 6 ... Charge amount measuring instrument, 7 ... Oscilloscope,
3a: Cable, 4a: Connector, 7a: Current probe, SW1, SW2: Switch, BSW1, BSW2 ...
Button switch, R1, R2: resistance, C1: floating capacitance,
C2: capacitor, V: DC power supply.

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-231458 (JP, A) JP-A-1-312479 (JP, A) JP-A-5-180899 (JP, A) 99694 (JP, U) Jiko 38-27977 (JP, Y1) (58) Field surveyed (Int. Cl. ⁷ , DB name) G01R 31/26-31/30

Claims (1)

(57) [Claim 1] A main unit having a DC power supply for generating a predetermined DC voltage and having a negative electrode connected to the ground and a resistor connected to the positive electrode of the DC power supply. A pencil-type probe unit connected via a cable, said plurality of IC chips being mounted on said wiring board having a plurality of terminals electrically connected to said IC chip. A metal probe pressed against a terminal of a substrate, first switch means connected via the cable between the metal probe and the resistance of the main unit, and a metal probe connected to a ground of the main unit. A second switch connected between the second switch via the cable, a third switch manually operated, and a first switch corresponding to a manual operation of the third switch. The switching means is turned on, after a predetermined time has elapsed, the first
Turning off the switch means and the second switch
And a control means for turning on the means.