JP2012068076A - Probe unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a probe unit capable of easily performing a probe replacement.SOLUTION: A probe unit 1 comprises a pair of a plunger holder 30 and a probe holder 40. The plunger holder 30 holds a plurality of plungers 10, and the probe holder 40 holds a plurality of probes 20 corresponding to the respective plungers 10. The probes 20 are held in the probe holder 40 so as to approach an inspection object from an inspection object facing surface 44 of the probe holder 40. The probes 20 are not fixed by screws or machine screws, etc. and are placed on a bottom surface of a probe housing recess room 45 with body parts thereof inserted into probe holding holes so that the probe unit 1 enables extremely easy replacement work of probes.

Description

  The present invention relates to a probe unit used for inspection of electrical characteristics of a semiconductor element.

  In electrical characteristic inspection of a semiconductor element in a wafer state or a chip state, a contact pin is used for electrical contact between the electrode of the semiconductor element and an external test apparatus. The contact pin is deteriorated or damaged due to heat generation or formation of an oxide film in the process of being repeatedly used for electrical characteristic inspection of a semiconductor element. Degraded or damaged contact pins cause problems such as a decrease in accuracy of electrical characteristic inspection and destruction of semiconductor elements and contact pins.

  Therefore, the contact pin may need to be replaced. In order to replace the contact pin, it is necessary to remove the wiring unit soldered to the contact pin after the probe unit is removed from the energizing device, which requires a long time.

  On the other hand, although there are some which make it easy to replace the contact pin by soldering the wiring to the sleeve, there is a case where a problem of welding at a contact portion between the sleeve and the contact pin is caused.

Therefore, there is a proposal of a probe unit in which a contact pin is separated into a probe portion and a plunger portion, and only the probe portion is replaceable (see, for example, Patent Document 1).
In addition, there is a proposal of a technique for preventing damage to the probe by inserting a resistance larger than the contact resistance in series with the probe to equalize the current flowing through each probe (for example, see Patent Document 2).

Japanese Patent Laid-Open No. 11-258295 JP-A-60-142526

  There may be several dozen or more probes provided in the probe unit, and not all of them need to be replaced. In such a case, if the probe unit is replaced one by one, the cost for the replacement is large. Further, when the deteriorated probes in the probe unit are taken out and replaced one by one, the efficiency of the probe replacement work is poor.

  The present invention has been made in view of such a point, and an object of the present invention is to provide a probe unit capable of easily exchanging probes.

  In order to solve the above problems, the probe unit includes a probe holder that holds the probe and a plunger holder that holds a plunger that is in electrical contact with the probe. The probe holder includes a probe holding hole that slidably holds the probe on the surface to be inspected. The probe includes a drop-off prevention portion, an electrode contact portion, and a plunger contact portion. The drop-off prevention unit prevents the probe from dropping from the probe holding hole. The electrode contact portion is provided at one end of the probe and contacts the inspection target electrode. The plunger contact portion is provided at the other end portion of the probe and contacts the plunger.

  The plunger holder includes a sleeve and a biasing portion. The sleeve slidably holds the plunger. The urging unit urges the plunger in the probe direction. The plunger includes a probe contact portion. The probe contact portion is provided at one end of the plunger and contacts the probe.

  According to the above probe unit, the probe can be easily replaced.

It is principal part sectional drawing of a probe unit when a probe is not contacting the semiconductor chip. It is principal part sectional drawing of a probe unit when a probe is contacting the semiconductor chip. It is principal part sectional drawing of a probe unit when a probe holder and a plunger holder are isolate | separated. It is principal part sectional drawing which shows the mode of the probe replacement | exchange of a probe holder. It is a figure which shows the relationship between a probe and a probe holding hole. It is principal part sectional drawing of a plunger holder. It is a figure which shows the modification of a probe unit.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. First, the overall configuration of the probe unit of the embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a cross-sectional view of the main part of the probe unit when the probe is not in contact with the semiconductor chip. FIG. 2 is a cross-sectional view of the main part of the probe unit when the probe is in contact with the semiconductor chip.

The probe unit 1 is connected to an external test apparatus and used for electrical characteristic inspection (including measurement of electrical characteristics) of a semiconductor element (bare chip) in a wafer state or a chip state.
The probe unit 1 brings the probe 20 into contact with the electrode portion 51 of the semiconductor chip 50 when performing an electrical characteristic inspection of the semiconductor chip 50. The probe unit 1 illustrated in FIG. 1 is in a state where the probe 20 is not in contact with the electrode unit 51.

  The probe unit 1 is particularly suitable for electric characteristic inspection of power semiconductor elements. In this case, the semiconductor chip 50 corresponds to, for example, a vertical power MOSFET (Metal Oxide Semiconductor Field Effect Transistor), a vertical IGBT (Insulated Gate Bipolar Transistor), an FWD (Free Wheeling Diode), or the like.

  The probe unit 1 includes a plunger 10, a probe 20, a plunger holder 30, and a probe holder 40. Plunger 10 and probe 20 form a pair, and probe unit 1 includes a plurality of pairs of plunger 10 and probe 20. Plunger holder 30 and probe holder 40 form a pair, and probe unit 1 includes a pair of plunger holder 30 and probe holder 40. The plunger holder 30 includes a plurality of plungers 10. The probe holder 40 includes a plurality of probes 20.

  When a plurality of probes 20 are provided, the probe unit 1 may be configured such that two or more probes 20 abut on a common electrode part (inspection target electrode) 51. In this way, the probe unit 1 can suppress the amount of current flowing through each probe 20.

  The plunger 10 is connected to the electric wire (wiring) 11 through the plunger joint portion 14, the resistor 13, and the wire joint portion 12. The wire joining portion 12 may be made by joining the wire 11 and the resistor 13 by soldering, or may be a connector connection in which the plurality of wire joining portions 12 are combined for easy replacement.

  The electric wire 11 is a power line, a signal line, a ground line, or the like, and the probe unit 1 may not include the resistor 13 depending on the electric wire 11 to be connected. In addition, in order to change resistance value according to a test object, you may make it the resistor 13 accommodate in the resistor holder which connects a resistor so that replacement | exchange is possible. The resistor 13 may be a variable resistor or the like in order to change the resistance value according to the inspection target.

  The plunger 10 is connected to the resistor 13 via the plunger joint 14. The plunger joint 14 may be joined by soldering the resistor 13 and the plunger 10, or may be a connector connection in which a plurality of plunger joints 14 are combined to facilitate replacement.

  The plunger 10 electrically connects the electric wire 11 and the probe 20. The plunger 10 is inserted into the sleeve of the plunger holder 30 and held so as to slide on the sleeve portion. The plunger 10 is biased in the probe direction (inspection target direction) by the spring 16, and the sliding range is regulated by the stopper 17.

  The spring 16 may be any member that urges the plunger 10 in the probe direction. For example, the spring 16 may be a compression coil spring, but may be an urging member such as a leaf spring or an elastic member such as rubber. Good.

  The probe 20 electrically connects the plunger 10 and the electrode part 51. The probes 20 are slidably held one by one in the probe holding holes (probe insertion holes) 43 of the probe holder 40. The probe 20 is held by the probe holder 40 so as to face the semiconductor chip 50 to be inspected from the inspection object facing surface 44 of the probe holder 40.

  The plunger holder 30 has an engaging portion 31 and a guide pin 32. The probe holder 40 has a locking claw 41. The plunger holder 30 and the probe holder 40 are positioned by the guide pins 32 and are connected by engaging the engaging claws 41 with the engaging portions 31. At this time, since the plunger 10 abuts on the probe 20 and urges the probe 20 in the inspection object direction, the plunger holder 30 urges the probe holder 40 in the inspection object direction. Therefore, the engaging portion 31 and the locking claw 41 may be loosely engaged so as to prevent dropping, and play of this engagement is absorbed by the biasing force. Therefore, the plunger holder 30 and the probe holder 40 are suitable. To join.

  Thus, since the probe unit 1 connects the plunger holder 30 and the probe holder 40 without using a fixing member such as a screw, the workability related to the replacement work of the plunger 10 or the probe 20 is improved.

  In addition, the engaging part 31 and the guide pin 32 can be provided with a required number according to the magnitude | size of the plunger holder 30, and a shape. Moreover, the guide pin 32 (fitting convex part) does not necessarily need to be a pin shape, and can take any shape that fits the probe holder 40 in accordance with the size and shape of the plunger holder 30.

  The guide pin 32 may be provided in the probe holder 40, the plunger holder 30 may be provided with the locking claw 41, and the probe holder 40 may be provided with the engaging portion 31.

  When performing an electrical characteristic test, the probe unit 1 brings the probe 20 into contact with the electrode part 51 of the subject and further presses the probe 20 against the electrode part 51. The probe 20 receives a repulsive force from the spring 16, and this repulsive force becomes a pressing force of the probe 20 against the electrode portion 51.

  The material of the plunger 10 and the probe 20 includes metals such as gold (Au), silver (Ag), platinum (Pt), tin (Sn), tungsten (W), nickel (Ni), or these metals. The main component is an alloy composed of at least two metals.

  Alternatively, the plunger 10 and the probe 20 have, for example, stainless steel, carbon steel, copper alloy (for example, beryllium copper) as a main component, and have gold (Au), silver (Ag), platinum (Pt) on the surface. Even a configuration in which a metal such as tin (Sn), tungsten (W), nickel (Ni), palladium (Pd), or an alloy composed of at least two metals including these metals is coated. Good.

Thereby, the probe unit 1 reduces the contact resistance between the plunger 10 and the probe 20 and the contact resistance between the probe 20 and the electrode portion 51.
The resistance value of the resistor 13 satisfies the upper limit value determined by the voltage applied to the electrode unit 51 and the power that can be supplied by the external test apparatus, and the lower limit value at which the plunger 10 and the probe 20 are not welded. To be determined. For example, if the total resistance value of the probe 20, the plunger 10, and the electric wire 11, and the contact portion resistance value of the probe 20 and the electrode unit 51, and the plunger 10 and the probe 20 is about 160 mΩ, the resistance value of the resistor 13. Is set to 1Ω, which is larger than 160 mΩ.

  Further, when the resistance value of the resistor 13 is increased, the external test apparatus requires more energization time to the probe unit 1 in order to increase the current value to the target value. For example, when the power supply voltage Vcc = 400 V, the test current Ic = 100 A, the circuit resistance component RL = 1Ω, the load inductance L = 50 μH, and the 14 probes, the resistance time of the resistor 13 is 0 energization time. The amount of increase is within 10% when the resistance value of the resistor 13 is 7.7Ω or less. Therefore, the resistance value of the resistor 13 is selected in consideration of how much energization time is allowed in the electrical characteristic inspection.

  When the semiconductor chip is broken during the test, if the resistor 13 is not provided, the probe unit 1 flows a current of 21 A (calculated value) per one probe 20, and it is 2 when 3000 semiconductor chips are tested. It has been experimentally confirmed that welding occurs at the contact portion of the plunger 10 and the probe 20 with a frequency of about once. When a resistor 13 having a resistance value of 1Ω is provided, a current of 5.3 A (calculated value) flows per probe 20 and the contact portion between the plunger 10 and the probe 20 is confirmed to be welded even in one million experiments. Can not.

  Thus, since the probe unit 1 including the resistor 13 is prevented from being welded at the contact portion between the plunger 10 and the probe 20, the plunger 10 held by the plunger holder 30 and the probe 20 held by the probe holder 40. Maintenance and workability are improved.

  Next, a state when the probe unit 1 of the embodiment is separated into the plunger holder 30 and the probe holder 40 will be described with reference to FIG. FIG. 3 is a cross-sectional view of the main part of the probe unit when the probe holder and the plunger holder are separated.

  The plunger 10 held by the plunger holder 30 is urged in the probe direction, and the sliding range is regulated by the stopper 17. The probe 20 held by the probe holder 40 is placed in the probe housing concave chamber 45. Thus, the probe holder 40 can separate the plunger 10 and the probe 20 easily by separating from the plunger holder 30. The probe unit 1 can easily replace the plunger 10 or the probe 20 by separating the plunger 10 and the probe 20.

  The locking claw 41 of the probe holder 40 is configured to be able to be tilted toward the outside of the probe holder 40 in order to prevent interference when the probe holder 40 and the plunger holder 30 are joined. When connecting the probe holder 40 and the plunger holder 30, the probe unit 1 can easily perform positioning for connecting the probe holder 40 and the plunger holder 30 by inserting the guide pin 32 into the fitting recess 42. it can.

  In addition, although the latching claw 41 is configured to be convertible between a holding state (standing state) and a releasing state (tilted state), the holding state and the releasing state are converted using a flexible material such as resin. It may be possible.

  Next, how the probe 20 held by the probe holder 40 of the embodiment is replaced will be described with reference to FIG. FIG. 4 is a cross-sectional view of a principal part showing a state of probe replacement of the probe holder.

  The probe holder 40 separated from the plunger holder 30 is opened above the probe housing concave chamber 45. The inspection object facing surface 44 is a surface facing the semiconductor chip 50 to be inspected. The inspection object facing surface 44 is a bottom surface of the probe housing concave chamber 45 and has a probe holding hole 43 for holding the probe 20. The probe holding hole 43 holds the probe 20 slidably. The probe 20 includes a drop prevention part 22 for preventing the probe 20 from dropping from the probe holding hole 43. The probe 20 has a substantially cylindrical shape, and the dropout prevention portion 22 has a disk shape that interferes with the probe holding hole 43. The drop prevention part 22 is not limited to a disk shape as long as it interferes with the probe holding hole 43 and prevents the probe 20 from falling off, and may be a tongue piece or the like so as to be easily grasped.

  In this way, the probe 20 is mounted on the bottom surface of the probe housing concave chamber 45 with the main body portion being inserted into the probe holding hole 43 without being fixed with screws, screws or the like. This makes it possible to change the probe very easily.

  In addition, the probe 20 can be easily inserted into the probe holding hole 43 by making one end (the end opposite to the drop-off preventing portion 22) U-shaped in cross section. The tip of the probe 20 may have a diameter sufficiently smaller than that of the probe holding hole 43 so that the main body of the probe 20 is guided to the probe holding hole 43, and may have a wedge shape.

Next, the relationship between the probe 20 of the embodiment and the probe holding hole 43 will be described with reference to FIG. FIG. 5 is a diagram showing the relationship between the probe and the probe holding hole.
The probe 20 includes a plunger abutting portion 21 that abuts the plunger at one end of a substantially cylindrical main body portion. The plunger abutting portion 21 has a disk shape with a diameter d1 and abuts against the plunger 10 at the central portion. The disc-shaped plunger abutting portion 21 is larger than the diameter d2 of the main body portion and the diameter d3 of the probe holding hole 43, and also serves as a dropout prevention portion 22 that prevents the probe 20 from dropping out of the probe holding hole 43.

  The probe 20 includes a tip electrode contact portion 23 that contacts the electrode portion 51 at the other end of the substantially cylindrical main body portion. The tip electrode contact portion 23 has a U-shaped cross section and has a sharpened tip. Even if a natural oxide film is formed on the electrode part 51, the sharpened tip easily breaks through the natural oxide film and improves the contact between the tip electrode contact part 23 and the electrode part 51. The tip electrode abutting portion 23 having a sharp tip is illustrated, but the tip shape is not limited to this as long as the electrical contact with the electrode portion 51 is good. It can be crowned or planar.

The main body portion of the probe 20 is d2 slightly smaller than the diameter d3 of the probe holding hole 43, and the probe 20 can slide in the probe holding hole 43.
The probe holding hole 43 is formed in the bottom surface (plate thickness d5) of the probe housing recess 45, and the main body of the probe 20 has a length d4 that is sufficiently larger than the plate thickness d5. Accordingly, the probe 20 held in the probe holding hole 43 is favorably held by the probe holder 40 even when the probe holder 40 and the plunger holder 30 are separated. Such a probe 20 contributes to cost reduction of the probe unit 1 because of its simple configuration.

Next, how the plunger 10 is held by the plunger holder 30 according to the embodiment will be described with reference to FIG. FIG. 6 is a cross-sectional view of the main part of the plunger holder.
Plunger holder 30 holds one plunger 10 slidably with a pair of sleeve 33 and sleeve 34. The plunger 10 has a shape in which three cylinders having different diameters are connected in series. The side above the stopper 17 of the plunger 10 (the electric wire 11) is inserted into the spring 16, so that the spring 16 can expand and contract around the plunger 10. The upper portion of the plunger 10 is inserted into the sleeve 33. The diameter of the sleeve 33 is smaller than the outer diameter of the spring 16 and larger than the diameter of the upper portion of the plunger 10.

  A side portion (probe 20) below the stopper 17 of the plunger 10 is inserted into the sleeve 34. The diameter of the sleeve 34 is smaller than the outer diameter of the stopper 17 and larger than the diameter of the lower side portion of the plunger 10.

  The lowermost portion of the plunger 10 includes a probe contact portion 18 that contacts the plunger contact portion 21 of the probe 20. The probe contact portion 18 has a U-shaped cross section with a sharpened tip. Even if a natural oxide film is formed on the electrode portion 51, the sharpened tip easily breaks through the natural oxide film and improves the contact between the probe contact portion 18 and the plunger contact portion 21. Although the probe contact portion 18 having a sharp tip is illustrated, the shape of the tip is not limited to this as long as the electrical contact with the plunger contact portion 21 is good. , Can be crowned or planar.

  The plunger holder 30 has a biasing portion storage space 35 between the sleeve 33 and the sleeve 34. The plunger holder 30 holds the plunger 10 so that the spring 16 and the stopper 17 of the plunger 10 are accommodated in the urging portion storage space 35.

  The spring 16 urges the plunger 10 toward the probe 20 by bringing both ends into contact with the ceiling portion of the urging portion storage space 35 and the stopper 17. The floor portion of the urging portion storage space 35 is in contact with the stopper 17 to restrict the sliding range of the plunger 10.

  Thus, the plunger 10 is suitably held by the plunger holder 30. Further, the probe unit 1 improves the maintenance and workability of the plunger 10 held by the plunger holder 30. Moreover, since such a plunger 10 has a simple configuration, it contributes to cost reduction of the probe unit 1.

Next, a probe unit which is a modification of the embodiment will be described with reference to FIG. FIG. 7 is a view showing a modification of the probe unit.
The probe unit 61 connects the resistor 63 and the plunger 66 via the electric wire 64.

The probe unit 61 includes a resistor 63 and an electric wire 64.
The plunger 66 is connected to the electric wire 64 at the plunger joint 65. The resistor 63 includes electric wire joining portions 62 at both ends, and is connected to the electric wire 64 through one electric wire joining portion 62 and connected to the electric wire 11 through the other electric wire joining portion 62. The wire joint portion 62 and the plunger joint portion 65 may be joined to the wire 11 or the wire 64 by soldering. Moreover, it is good also as connector connection which put together the some electric wire junction part 62 or the plunger junction part 65 in order to make replacement | exchange easy.

  By connecting the resistor 63 and the plunger 66 via the electric wire 64 in this way, the probe unit 61 can easily replace the plunger 66 or the resistor 63.

  The probe unit 61 may be configured not to include the electric wire 64 or the resistor 63 and the electric wire 64. In that case, the electric wire 64 or the resistor 63 and the electric wire 64 can be components on the external test apparatus side.

The above-described embodiment can be variously modified within a range not departing from the gist of the embodiment.
Further, the above-described embodiments can be modified and changed in many ways by those skilled in the art, and are not limited to the exact configurations and application examples described.

DESCRIPTION OF SYMBOLS 1,61 Probe unit 10,66 Plunger 11,64 Electric wire 12,62 Electric wire joint part 13,63 Resistor 14,65 Plunger joint part 16 Spring 17 Stopper 18 Probe contact part 20 Probe 21 Plunger contact part 22 Falling prevention part 23 Tip electrode contact portion 30 Plunger holder 31 Engagement portion 32 Guide pin 33, 34 Sleeve 35 Energizing portion storage space 40 Probe holder 41 Locking claw 42 Fitting recess 43 Probe holding hole 44 Inspection object facing surface 45 Probe storage recess Chamber 50 Semiconductor chip 51 Electrode section

Claims (8)

A probe unit comprising: a probe holder for holding a probe; and a plunger holder for holding a plunger in electrical contact with the probe,
The probe holder includes a probe holding hole for slidably holding the probe on a surface to be inspected,
The probe includes a drop-off preventing portion that prevents the probe from dropping out from the probe holding hole, an electrode abutting portion that abuts the inspection target electrode at one end, and a plunger abutting portion that abuts the plunger at the other end.
The plunger holder includes a sleeve that slidably holds the plunger, and an urging portion that urges the plunger in the probe direction,
The plunger includes a probe abutting portion that abuts the probe at one end.   The probe unit according to claim 1, wherein the probe holder includes a storage concave chamber in which the probe holding hole is disposed on a bottom surface.   The probe unit according to claim 2, wherein the probe holder includes a locking portion that engages with the plunger holder.   The probe unit according to claim 3, wherein the locking portion is displaced in a direction of expanding an open area of the storage concave chamber.   The probe unit according to claim 4, wherein the probe holder includes a fitting recess that fits into a guide portion of the plunger holder.   The probe unit according to any one of claims 1 to 5, wherein the probe has a substantially cylindrical shape, and the drop-off prevention portion is a tongue piece provided at an end portion on the electrode contact portion side.   The probe unit according to claim 6, wherein the plunger is connected to the wiring via a resistor. The probe and the plunger are provided with a plurality of pairs,
The probe unit according to claim 7, wherein two or more of the probes are in contact with the common electrode to be inspected.

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