JP6143684B2 - Prober - Google Patents

Description

  The present invention relates to a prober, and more particularly to a prober capable of maintaining the cleanliness of air in a chamber and supporting a low-temperature electrical property test of a wafer.

  2. Description of the Related Art Conventionally, a prober that inspects electrical characteristics of a wafer by pressing a probe against a pad formed on the wafer is known. The electrical property inspection of a wafer performed using such a prober is performed at room temperature inspection performed at room temperature or high temperature inspection performed by raising the temperature of the wafer from room temperature, as well as lowering the wafer to a low temperature (for example, −60 ° C.). Low temperature inspection.

  However, when an electrical property inspection of a wafer is performed in a low temperature environment, air in a chamber holding a wafer chuck or a probe card that holds the wafer may condense or freeze, which may adversely affect the wafer. Therefore, a chamber, a circulation duct connected to the chamber, and an FFU (Fan Filter Unit) disposed on the outlet side of the circulation duct are provided, and the FFU circulates dry air having a low dew point in the chamber and the circulation duct. What is made to be known is known (for example, refer patent document 1).

JP2003-179109A.

  However, in the prober as described above, since the probe card is connected to a device such as a tester, a slight gap tends to be generated in the chamber, and the internal pressure of the chamber is lower than the external pressure near the exhaust port of the chamber. Therefore, since the high dew point outside air may enter from the gaps described above, the dew point of the circulating air may gradually increase.

  As shown in FIG. 8, a prober 200 that forcibly circulates air in the chamber 201 and the circulation duct 202 by the FFU 203 and supplies dry air directly to the air in the chamber 201 as shown in FIG. 8 to lower the dew point of the air in the chamber. Can be considered. However, in such a prober, since the dry air diffuses into the chamber 201 along the air flow formed by the FFU 203, the dry air hardly diffuses in the upper part of the chamber 201 and tends to be unevenly distributed in the lower part of the chamber 201. It is necessary to circulate the chamber 201 and the circulation duct 202 repeatedly to stabilize the dew point of the air, and there is a problem that the waiting time is long before the electrical characteristic test is started. Further, the air and the dry air are not easily mixed efficiently, and the dew point of the air remains high, and there is a possibility that the dew condensation or icing of the air in the chamber 201 cannot be suppressed.

  Further, as shown in FIG. 9, a prober 300 that mixes dry air into the air when the air in the circulation duct 302 is sucked into the chamber 301 by the FFU 303 can be considered as a means for lowering the dew point of the air in the chamber. However, in such a prober 300, compared with the prober 200, dry air easily reaches the upper part of the chamber 301, but is difficult to uniformly diffuse into the chamber 301. Therefore, as with the prober 200, until the dew point of the air is stabilized. In addition, it takes a long time and the dew point of the air remains high, and there is a possibility that the dew condensation and icing of the air in the chamber 301 cannot be suppressed.

  Therefore, a technical problem to be solved in order to supply high cleanliness and low dew point air into the chamber arises, and the present invention aims to solve this problem.

The present invention has been proposed in order to achieve the above-mentioned object, and the invention according to claim 1 is connected to the chamber through which the wafer chuck and the probe card are accommodated, and to the chamber through an intake port and an exhaust port. A prober comprising: a circulation duct that forms a circulation path of air; and an air circulation means that circulates the air in the circulation path, wherein dry air that lowers the dew point of the air is contained in the circulation duct. Dry air supply means for supplying to the circulation duct, and stirring means provided in the circulation duct for stirring the air and the dry air, wherein the stirring means adjusts the temperature of the air flowing in the circulation duct. Based on the temperature detection unit for detecting, and the temperature of the air, a critical Reynolds number capable of stirring the air and the dry air in the circulation duct, and an empty space capable of maintaining the critical Reynolds number or more. Provided by the computing unit for deriving the turbulence can be maintained flow rate, a prober comprises a control unit for controlling the circulation flow rate of the air circulation means in accordance with the turbulent sustainable flow rate of the air.

  According to this configuration, the dry air supply means mixes the dry air into the air in the circulation duct, so that the air and the dry air are uniformly mixed when the air flows through the circulation duct. The dew point of air supplied into the chamber can be made uniform and the dew point of air can be lowered.

  In addition, by supplying dry air into the circulation duct sealed from the outside, the dry air diffuses throughout the air with a high dew point, and the dew point of the air is effectively lowered. It can be lowered in a short time to the air dew point.

Furthermore, since the supply amount of dry air is reduced by efficiently reducing the dew point of air, it is possible to achieve resource saving of dry air and high cleanness of air. By adjusting the air circulation flow rate so that the critical Reynolds number is maintained according to the temperature of the air detected by the temperature detector, the air Reynolds number is less than the critical Reynolds number due to an increase in the air temperature. To avoid turbulence in the circulation duct regardless of the temperature change of the air, and the air and dry air are agitated in the circulation duct, so that the dew point of the air supplied into the chamber is more efficiently Can be lowered.

  According to a second aspect of the present invention, in addition to the configuration of the prober according to the first aspect, the dry air supply means is configured to perform the drying at a dry air supply position disposed on the downstream side of the circulation path with respect to the exhaust port. A prober for supplying air into a circulation duct is provided.

  According to this configuration, since the dry air supply position is arranged on the downstream side of the circulation path with respect to the intake port that tends to have the highest dew point due to external air being mixed in, the entire dew point air with high dry air is arranged. Therefore, the dew point of air can be lowered efficiently.

  The present invention makes the dew point of the air supplied into the chamber through the circulation duct uniform, and suppresses the mixing of external air to effectively lower the dew point of the entire air. Low dew point air can be supplied.

The front view which shows the prober which concerns on 1st Example of this invention. The figure which shows the comparison result of the Reynolds number of the circulation duct shown in FIG. 1, and the Reynolds number of the circulation duct used for the conventional prober. The figure which shows transition of the dew point of the air which circulates in the prober. The figure which shows the time required until the dew point of the air in a prober is stabilized. The front view which shows the prober which concerns on 2nd Example of this invention. The IV section expanded sectional view of the circulation duct shown in FIG. Sectional drawing which shows the modification of the stirring means shown in FIG. The front view which shows the conventional prober which supplies dry air to the air in a chamber. The front view which shows the conventional prober which supplies dry air to the air in FFU.

In order to supply high cleanliness and low dew point air into the chamber, the present invention is connected to the chamber containing the wafer chuck and the probe card, and connected to the chamber via an intake port and an exhaust port to circulate the air. A prober comprising a circulation duct that forms a path and an air circulation means that circulates air in the circulation path, and a dry air supply means that supplies dry air that lowers the dew point of the air into the circulation duct ; A stirring means provided in the circulation duct and stirring the air and dry air, the stirring means based on the temperature of the temperature detection unit that detects the temperature of the air flowing in the circulation duct, and the temperature of the air; A calculation unit for deriving the critical Reynolds number that can agitate the air and dry air in the circulation duct and the turbulent flow sustainable flow rate that can maintain the critical Reynolds number or higher, Realized by that it comprises a control unit for controlling the circulation flow rate of the air circulating means, the Te.

  Hereinafter, a prober 1 according to a first embodiment of the present invention will be described with reference to FIG.

  The prober 1 includes a chamber 2, a circulation duct 3 that is connected to both ends of the chamber 2 to form an air circulation path R, an air circulation means 4 that circulates air in the circulation path R, and a drying that lowers the dew point of air. And a dry air supply means 5 for supplying air.

  The chamber 2 accommodates a wafer chuck 21 for holding the wafer W and a probe card 22 having a probe 22a for inspecting the electrical characteristics of the wafer W.

  The wafer chuck 21 holds the wafer W by vacuum suction on the mounting surface 21a. The wafer chuck 21 is connected to a temperature adjustment mechanism (not shown). Using this temperature adjustment mechanism, the temperature of the wafer chuck 21 is raised or lowered, and the temperature of the wafer W is arbitrarily set according to the inspection conditions. can do.

  The probe card 22 is supported on the periphery of the probe card 22 and fixed to the upper portion of the chamber 2.

  The probe 22a is attached to the approximate center of the probe card 22, and inspects the electrical characteristics of the wafer by connecting a pad of the wafer W and a tester (not shown). The probe 22a inspects the wafer pressed against the wafer chuck 21.

  Further, the chamber 2 includes an X-axis moving stage 23 that can move the wafer chuck 21 in the X-axis direction that coincides with the left-right direction of FIG. 1 and the Y-axis direction that matches the wafer chuck 21 with the vertical direction of FIG. And a Z-axis moving stage 25 capable of moving the wafer chuck 21 in the Z-axis direction coinciding with the vertical direction of the drawing in FIG.

  The X-axis moving stage 23 is connected to the slide table 23a on which the Y-axis moving stage 24 is placed, the guide rail 23b laid along the X-axis direction on the base 26 below the slide table 23a, and the slide table 23a. A slide 23c that is screwed into a ball screw (not shown) that extends along the X-axis direction between the guide rails 23b and an X-direction drive motor (not shown) that rotates the ball screw are provided. A linear motor may be adopted instead of the ball screw.

  When the X-direction drive motor rotates the ball screw, the slider 23c screwed to the ball screw 23c moves in the X-axis direction, and the slide table 23a moves relative to the Y-axis stage 24 in the X-axis direction. It is supposed to be.

  The Y-axis moving stage 24 includes a slide table 24a on which the Z-axis moving stage 25 is placed, a pair of guide rails 24b and 24b extending along the Y-axis direction below the slide table 24a, and a pair of guide rails A ball screw (not shown) extending along the Y-axis direction between 24b and 24b, a slider connected to the slide table 24a and screwed to the ball screw, and a Y-direction drive motor (not shown) for rotating the ball screw. Yes. A linear motor may be adopted instead of the ball screw.

  When the Y-direction drive motor rotates the ball screw, the slider screwed to the ball screw moves in the Y-axis direction, and the slide table 23a moves in the Y-axis direction relative to the X-axis moving stage 23. It is like that.

  The Z-axis moving stage 25 has the wafer chuck 21 mounted thereon. The Z-axis moving stage 25 rotates the wafer chuck 21 around a rotation axis extending in the Z-axis direction through the center of the wafer chuck 21 and a Z-direction drive motor (not shown) that moves the wafer chuck 21 up and down in the Z-axis direction. And a Θ direction drive motor.

  The X axis movement stage 23, the Y axis movement stage 24, and the Z axis movement stage 25 are driven and controlled by a control device (not shown). The control device sends drive signals to the X direction drive motor, the Y direction drive motor, the Z direction drive motor, and the Θ direction drive motor, and positions the wafer chuck 2 at a desired position in accordance with the drive amount of each drive motor.

  The circulation duct 3 is a circular pipe having a circular cross section, and one end is connected to the air inlet 2 a of the chamber 2 and the other end is connected to the air outlet 2 b of the chamber 2. In the vicinity of the exhaust port 2b, since the air flow path is narrowed and the flow velocity is increased, the internal pressure of the air is small, and the dew point of the air is the highest in the circulation path R.

  The air circulation means 4 includes an FFU 42 having a suction fan 41 attached to the intake port 2a of the chamber 2 and a filter (not shown) that passes the air sucked by the suction fan 41 and prevents dust, and an exhaust port 2b of the chamber 2 And an exhaust fan 43 provided so as to be closed. The suction fan 41 and the exhaust fan 43 form an air circulation path R counterclockwise in FIG. Hereinafter, “upstream side” and “downstream side” correspond to the upstream side and the downstream side in the circulation path R, respectively.

  The dry air supply means 5 includes a nozzle 51 that supplies dry air into the circulation duct 3 and a dry air supply source (not shown) connected to the nozzle 51. The flow rate of the dry air supplied from the nozzle 51 can be arbitrarily adjusted.

  The nozzle 51 is disposed at the dry air supply position D on the downstream side of the exhaust fan 43. The nozzle 51 may be provided anywhere as long as it is blocked from the outside, that is, in the sealed circulation duct 3.

  The prober 1 includes stirring means 6 for stirring the air flowing in the circulation duct 3 and the dry air supplied into the circulation duct 3 through the nozzle 51. The stirring means 6 includes a temperature detection unit 61, a flow velocity detection unit 62, a calculation unit 63, and a control unit 64.

  The temperature detector 61 detects the temperature of the air flowing through the circulation duct 3. The temperature detector 61 is attached to the circulation duct 3 on the downstream side of the dry air supply position D.

  The flow velocity detector 62 detects the flow velocity of the air flowing through the circulation duct 3. The flow velocity detector 62 is attached to the circulation duct 3 so as to face the temperature detector 61 on the downstream side of the dry air supply position D.

  Based on the temperature of the air detected by the temperature detector 61, the calculation unit 63 calculates the critical Reynolds number Rec of the air flowing in the circulation duct 3 and the turbulent flow maintainable flow rate that can maintain the critical Reynolds number Rec or more. To derive. In the present embodiment, the critical Reynolds number Rec of the circular circulation duct 3 is 2300 to 4000. Further, when deriving the turbulent flow maintaining flow rate, the calculation unit 63 calls the kinematic viscosity coefficient of air stored in a storage unit (not shown) based on the air temperature detected by the temperature detection unit 61, The critical velocity of air corresponding to the Reynolds number Rec is derived, and the turbulent flow maintaining flow rate is derived.

  Here, “the critical velocity of the air” varies depending on the temperature of the air, and the product of the critical Reynolds number Rec and the kinematic viscosity coefficient is expressed by the inner diameter of the circulation duct 3 and the cross-sectional area of the circulation duct 3. Divided. The critical velocity of air in this embodiment is 0.34845 to 0.60600 m / s. The “flow rate capable of maintaining turbulent air flow” is obtained by multiplying the critical velocity of air by the cross-sectional area of the circulation duct 3. The air turbulent flow rate that can be maintained in this embodiment is 0.00266 to 0.00462 m ^ 3 / s.

  The control unit 64 adjusts the number of rotations of the suction fan 41 so as to maintain the Reynolds number Re of the air to be equal to or higher than the critical Reynolds number Rec based on the turbulent flow maintainable flow rate derived by the calculation unit 63. Adjust the circulation flow rate. Further, it is preferable that the air flow rate is feedback-controlled by detecting the air flow rate in the circulation duct 3 by the flow rate detection unit 62. In this embodiment, the air circulation flow rate is set to 0.008333 m ^ 3 / s, the air Reynolds number Re reaches about 7103, and the air Reynolds number Re is greater than or equal to the critical Reynolds number Rec. Turbulence can be generated in the duct 3.

  In this way, as shown in FIG. 2, in the conventional prober, the kinematic viscosity coefficient increases as the temperature of the air rises, and the Reynolds number of the air decreases, and there is a possibility that the turbulence cannot be maintained. In 1, the air Reynolds number Re can be maintained at or above the critical Reynolds number Rec regardless of the air temperature by adjusting the air circulation flow rate according to the temperature change of the air. Stirring in the duct 3 is possible.

  In addition, the air circulation flow rate is preferably adjusted to a value close to the turbulent flow maintainable flow rate, that is, the air circulation flow rate is preferably reduced within a range in which the turbulent flow in the circulation duct 3 can be maintained. As a result, the turbulence of the airflow in the vicinity of the wafer chuck 2 is reduced, so that the wafer W can be accurately inspected without locally lowering the temperature of the wafer chuck 2 during the electrical characteristic inspection. Further, by restricting the air circulation flow rate within a range in which the turbulent flow in the circulation duct 3 can be maintained, it becomes easier to secure the dew point of the air by suppressing the inflow of outside air having a high dew point, and a small current such as a parametric test. Leakage current during measurement can be reduced.

  FIG. 3 shows a comparison of the dew point of the air in the prober according to the present example and the comparative example with respect to the prober in which the place for supplying the dry air is changed as a comparative example with the present example. In Comparative Example 1, as shown in FIG. 8, dry air is directly supplied into the chamber. In Comparative Example 2, as shown in FIG. To supply dry air.

  In FIG. 3, A, B, and C indicate measurement locations of the air dew point, respectively, A is one end of the circulation duct 3 near the air inlet 2 a of the chamber 2, and B is in the chamber 2 Yes, C is the other end of the circulation duct 3 in the vicinity of the air inlet 2 b of the chamber 2. Comparing the dew point of the air in the chamber of the prober according to the present example and each comparative example, as shown in FIG. 3, it is −28 ° C. in Comparative Example 1 and −34 ° C. in Comparative Example 2, whereas It turns out that it is -55 degreeC in a present Example.

  FIG. 4 shows a comparison of the time required to reach the dew point of air in the probers according to the present example and each comparative example. According to FIG. 4, it can be seen that the comparative example 1 requires 70 minutes and the comparative example 2 requires 50 minutes, whereas the present example requires 30 minutes.

  In this manner, the prober 1 according to this embodiment is configured so that the dry air supply means 5 mixes dry air into the air in the circulation duct 3, so that when the air flows in the circulation duct 3, Are uniformly mixed, so that the dew point of the air supplied into the chamber 2 through the circulation duct 3 can be made uniform and the dew point of the air can be lowered.

  Further, by supplying dry air into the circulation duct 3 sealed from the outside, the dry air diffuses throughout the air having a high dew point, and the dew point of the air is effectively lowered. It can be lowered in a short time to the air dew point.

  Furthermore, since the supply amount of dry air is reduced by efficiently reducing the dew point of air, it is possible to achieve resource saving of dry air and high cleanness of air.

  In addition, in order to suppress a decrease in the Reynolds number due to the temperature change of the air by adjusting the circulating flow rate of the air so that the Reynolds number of the air maintains the critical Reynolds number or more according to the temperature change of the air, The dew point of the air supplied into the chamber 2 can be made uniform by stirring the air and the dry air in the circulation duct 3.

  Next, a prober according to a second embodiment of the present invention will be described with reference to the drawings. The prober according to the second embodiment of the present invention differs from the prober according to the first embodiment described above in the specific configuration of the stirring means, and the other configurations are basically different. Therefore, the same members as those of the above-described prober of the first embodiment are denoted by the same reference numerals, and redundant description thereof is omitted.

  That is, as shown in FIG. 6, the stirring means 6 is a stirring groove 65 formed on the inner peripheral surface of the circulation duct 3 on the downstream side from the dry air supply position D. The stirring groove 65 is provided in the circumferential direction of the circulation duct 3, and a plurality of the agitation grooves 65 are provided in parallel along the longitudinal direction of the circulation duct 3. As shown by the arrows in FIG. 6, the stirring groove 65 stirs the air and the dry air by disturbing the flow of the air and the dry air flowing through the circulation duct 3. The specific shape of the stirring groove 65 may be any shape as long as air is disturbed.

  As shown in FIG. 7, the stirring means 6 may be a stirring wall 66 erected from the inner peripheral surface of the circulation duct 3 on the downstream side from the dry air supply position D. The stirring wall 66 is formed in a substantially circular arc shape, and alternately extends from above and below the circulation duct 3 so as to form a labyrinth structure that prevents the flow of air, as indicated by arrows in FIG. It is installed. The specific shape of the stirring wall 66 may be any shape as long as it prevents air flow.

  In this way, the prober 1 according to the present embodiment can easily stir air and dry air simply by providing the stirring groove 65 or the stirring wall 66 in the circulation duct 3.

  Further, since the stirring groove 65 or the stirring wall 66 is disposed on the downstream side from the dry air supply position D, the air and the dry air are reliably stirred in a state where the dry air is mixed in the air, and the chamber The dew point of the air supplied into 2 can be lowered more efficiently.

  In addition, although the stirring groove 65 or the stirring wall 66 which concerns on a present Example demonstrated what is arrange | positioned downstream from the dry air supply position D, the stirring groove 65 or the stirring wall 66 is upstream from the dry air supply position D. Alternatively, the dry air may be supplied in a state where the air in the circulation duct 3 is turbulent in advance to diffuse the dry air into the air.

  As described above, according to the present invention, the dry air supply means 5 mixes dry air into the air in the circulation duct 3, so that the air and the dry air are made uniform when the air flows in the circulation duct 3. Since they are mixed, the dew point of the air supplied into the chamber 2 through the circulation duct 3 can be made uniform and the dew point of the air can be lowered.

  Also, by supplying dry air into the circulation duct 3 sealed from the outside, the dry air diffuses throughout the high dew point air, and the dew point of the air can be lowered efficiently.

  Furthermore, since the supply amount of dry air is reduced by efficiently reducing the dew point of air, it is possible to achieve resource saving of dry air and high cleanness of air.

  In each of the above-described embodiments, the prober to which the present invention is applied has been described. However, the present invention is not limited to the prober, and may be applied to, for example, a loader provided adjacent to the prober. Absent.

  The present invention can be variously modified without departing from the spirit of the present invention, and the present invention naturally extends to the modified ones.

DESCRIPTION OF SYMBOLS 1 ... Probe 2 ... Chamber 2a ... Intake port 2b ... Exhaust port 21 ... Wafer chuck 22 ... Probe card 22a ... Probe 23 ... X-axis moving stage 23a ...・ Slide table 23b ・ ・ ・ Guide rail 23c ・ ・ ・ Slide 24 ・ ・ ・ Y axis movement stage 24a ・ ・ ・ Slide table 24b ・ ・ ・ Guide rail 25 ・ ・ ・ Z axis movement stage 26 ・ ・ ・ Base 3 ・ ・・ Circulation duct 4 ... Air circulation means 41 ... Suction fan 42 ... FFU
43 ... Exhaust fan 5 ... Dry air supply means 51 ... Nozzle 6 ... Stirring means 61 ... Temperature detection part 62 ... Speed detection part 63 ... Calculation part 64 ... Control Portion 65 ... Stirring groove 66 ... Stirring wall D ... Dry air supply position R ... Circulation path W ... Wafer

Claims (2)

A chamber for accommodating the wafer chuck and the probe card, a circulation duct connected to the chamber via an intake port and an exhaust port to form an air circulation path, and air circulation for circulating the air in the circulation path A prober comprising means,
Dry air supply means for supplying dry air for reducing the dew point of the air into the circulation duct ;
Agitating means provided in the circulation duct for agitating the air and the dry air;
With
The stirring means includes
A temperature detector for detecting the temperature of air flowing in the circulation duct;
A calculation unit for deriving a critical Reynolds number capable of stirring the air and the dry air in the circulation duct and a turbulent flow maintainable flow rate of air capable of maintaining the critical Reynolds number or more based on the temperature of the air; ,
A control unit for controlling the circulation flow rate of the air circulation means according to the flow rate capable of maintaining the turbulent flow of air;
Prober, characterized in that it comprises. 2. The prober according to claim 1, wherein the dry air supply means supplies the dry air into the circulation duct at a dry air supply position disposed on the downstream side of the circulation path with respect to the exhaust port.

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