KR20170073697A - Systems and methods for conforming device testers to integrated circuit device with pressure relief valve - Google Patents

Abstract

The present invention relates to a system and method for preventing excessive pressure from occurring in a fluid management system used in an integrated circuit (IC) device tester. Preventing excessive pressure in the fluid management system is based on using a pressure relief valve coupled to the fluid management system.

Description

TECHNICAL FIELD [0001] The present invention relates to a system and a method for adapting a device tester to an integrated circuit device using a pressure relief valve,

The present invention generally relates to testing integrated circuit (IC) devices such as packaged semiconductor chips. The device tester is configured to adapt to the shape of the IC device being tested while maintaining the set point temperature in an integrated circuit device under test (IC DUT).

The tester includes a thermal control unit and a fluid management system configured to supply fluid to the thermal control unit for pneumatic actuation, cooling and condensation abating. This fluid remains pressurized within the sub-assembly of the thermal control unit. As the temperature changes, the fluid may be over-pressurized thereby causing damage to the sub-assembly of the thermal control unit.

It is therefore highly desirable to design an improved device tester that can prevent damage to the sub-assembly of the thermal control unit by relieving the pressure within the sub-assembly of the thermal control unit.

To achieve the foregoing, a system and method for testing an integrated circuit (IC) device, such as a packaged semiconductor chip, is provided in accordance with the present invention while maintaining a set point temperature in a tested IC device (IC DUT).

In one embodiment, the IC device tester comprises a thermal control unit and a fluid management system configured to supply fluid to the thermal control unit for pneumatic actuation, cooling, and condensation reduction, thereby configuring the IC DUT to maintain a setpoint temperature do. The fluid remains pressurized within the sub-assembly of the thermal control unit, i.e., the fluid management system. The fluid management system is prevented from being overpressurized by including a pressure relief valve that can prevent damage to the sub-assembly of the thermal control unit due to excessive pressurization of the fluid as the temperature changes.

It is noted that the various features of the invention described above may be implemented alone or in combination. These and other features of the present invention will be described in more detail below in the detailed description of the present invention with reference to the drawings.

In order that the invention may be more clearly understood, some embodiments will now be described by way of example with reference to the accompanying drawings.
1 is a side view of an exemplary thermal control unit including a z-axis force balancing mechanism according to an aspect of the present invention.
Figure 2 is a cross-sectional view taken along the cutting line 2-2 of Figure 1;
3 is another cross-sectional view taken along the cutting line 3-3 of FIG. 2;
4 is a bottom perspective view of a z-axis load distributor actuator block of the z-axis force distribution system of the TCU shown in Figs. 1-4; Fig.
Figure 5 is a cross-sectional view of the load distributor actuator block shown in Figure 4 along line 5-5 in combination with a spring mounted gimbal;
Figure 6 is a side view of another exemplary embodiment of a thermal control unit according to the present invention.
7A is a cross-sectional view taken along the cutting line 7A-7A of FIG.
Figure 7b is an exploded view of Figure 7a;
FIG. 8 is another cross-sectional view taken along the cutting line 8-8 of FIG. 7A; FIG.
Figure 9 is another cross-sectional view taken along section line 9-9 of Figure 7a;
10A is a bottom perspective view of an exemplary z-axis load distributor actuator block for a z-axis force distribution system of TCU 600 shown in Figs. 6-9; Fig.
Figure 10B is a bottom perspective view of an alternate embodiment of the z-axis load distributor actuator block of Figure 10A;
11 is a cross-sectional view of the load distributor actuator block shown in FIG. 10A along line 11-11 in combination with a spring loaded gimbal;
12A is a cross-sectional view of an IC device that is slightly curved prior to testing;
12B is a cross-sectional view of an IC device modified by a test;
13A and 13B are cross-sectional views illustrating embodiments of a pedestal, a substrate pusher, and a test socket according to the present invention;
Figures 13c and 13d are cross-sectional views of a further embodiment of the test socket insert;
13E is a perspective view of the test socket and test socket insert for the embodiment of FIG. 13A; FIG.
13F and 13G are cross-sectional views showing a suspension pin and a test pin for the embodiment of FIG. 13A in the rest and test states, respectively;
FIGS. 14A-14D are a front view, a top view, a perspective view, and an enlarged view illustrating a heater that is illustratively connected to a fuse in accordance with some embodiments of the present invention; FIG.
15A and 15B are perspective and exploded views of another exemplary embodiment of a thermal control unit (TCU) in accordance with the present invention;
16A and 16B are a perspective view and an exploded view of a flow management system (FMS) according to the present invention;
17A and 17B are a perspective view and an exploded view of a thermal head unit (THU);
17C and 17D are perspective views of the gimbal module;
17E is a perspective view of the heater assembly;
17F, 17G and 17H are a perspective view and an exploded view of a device kit module;
Figure 17i is a perspective view of the internal structure of a heat exchanger plate (low temperature plate);
17J and 17K are a top view of the thermal head unit THU and a cross-sectional view along line 17K-17K;
18 is a perspective view of a flexible cable chain assembly;
19A and 19B are a perspective view and an exploded view of a thermal control unit (TCU) with a dry box for condensation reduction;
Figure 20 shows a sub-assembly of a thermal control unit through which heat transfer fluid flows during use;
Figure 21 shows a sub-assembly of a thermal control unit in which no heat transfer fluid is flowing during an undocked condition;
Figure 22 illustrates a sub-assembly of a thermal control unit connected to a pressure relief valve during use;
Figure 23 shows a sub-assembly of a thermal control unit connected to a pressure relief valve during an undocked condition;
Figure 24 is a cross-sectional view of a pressure relief valve in which the inner piston is under pressure during use; And
Figure 25 is a cross-sectional view showing a pressure relief valve through which the piston can move as the fluid is expanded as the piston is not under pressure during an undocked condition.

The present invention will now be described in detail with reference to several embodiments shown in the accompanying drawings. In the following description, numerous specific details are set forth in order to provide a thorough understanding of embodiments of the invention. However, it will be understood by those skilled in the art that the embodiments may be practiced without some or all of these specific details. In other instances, well known process steps and / or structures have not been described in detail in order not to unnecessarily obscure the present invention. The features and advantages of the embodiments will be better understood with reference to the following drawings and discussion.

BRIEF DESCRIPTION OF THE DRAWINGS The aspects, features and advantages of an exemplary embodiment of the present invention may be better understood with reference to the following detailed description in conjunction with the accompanying drawings, in which: Fig. Those skilled in the art will appreciate that the described embodiments of the invention provided herein are illustrative only and not restrictive of the invention and are presented by way of example only. All features disclosed in this specification may be substituted for alternative features that perform the same or similar purposes, unless explicitly stated otherwise. Accordingly, many other modifications and variations are considered to be within the scope of the invention as defined in the following claims and their equivalents. Thus, it is to be understood that the terms absolute and / or sequential, such as "will," "will not," "do," "not," "must," " The terms "after", "after", "before", "after", "last", and "finally" It is not intended to do.

Also, as used in this specification and the appended claims, the elements and "above" include both singular and plural elements unless the context clearly indicates otherwise. Thus, for example, the phrase "piston" includes a single piston as well as a plurality of springs, and the term "outlet" includes not only one outlet but also a collection of outlets.

Before describing the present invention in detail, it should be understood that the present invention is not limited to the TCU shown herein. It is also to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

Generally, the present invention relates to a thermal control unit (TCU) that can be used to maintain a setpoint temperature on an IC device under test (IC DUT). The TCU may suitably include features common to those described in U.S. Patent No. 7,663,388, the entire content of which is incorporated herein. This feature is achieved by pumping heat from the DUT to the fluid circulation block between the thermally conductive pedestal, the fluid circulation block, and the fluid circulation block in contact with the DUT and in the z-axis stacked arrangement, Or a thermoelectric module (Peltier device) or a heater for pumping heat to the DUT. Common features also include a spring-loaded pusher mechanism for applying a compliant force to the z-axis force that holds the fluid block, the thermoelectric module (or heater) and the thermally conductive pedestal together tightly in a z- . ≪ / RTI >

The present invention also relates to a system for testing an IC device, such as a packaged semiconductor chip (also referred to as a packaged die), in particular, while preserving the original specification of the device for the physical characteristics of the IC device and ≪ / RTI >

The TCU according to the present invention can be used in a DUT having a different structure. For example, a TCU may be used with an IC device having a lidded package using an integrated heat spreader (IHS), or used with an IC device having a bare die chip package .

One aspect of the invention relates to a TCU having different pushers used to push different portions of a chip package. In this aspect of the invention, the z-axis force applied from the top of the TCU between the different pushers is controllably distributed so that the desired balance can be achieved for the forces exerted by the different pushers, An axial load distribution system is provided. For example, when the die pusher / pedestal and the substrate pusher are used with a bare die package, the z-axis force applied to the die pusher / pedestal is adjusted for the push force exerted by the substrate pusher, Thereby balancing the load on the substrate and the die.

In yet another separate aspect of the present invention, at least one, and preferably both, of the fluid inlet and / or fluid outlet for the fluid circulation block is preferably rotated about an axis of rotation substantially perpendicular to the z- It is possible. The ability of the fluid inlet and fluid outlet to rotate serves to reduce the instability of the thermal control unit in response to the z-axis movement of the temperature control fluid block.

In a further separate aspect of the present invention, means for reducing condensation are provided. This means includes a condensation-reducing gas inlet, and a condensation-reducing gas-carrying passage in the heat control unit near the surface of the heat control unit where condensation may occur.

An exemplary embodiment of a TCU according to the present invention is shown in Figs. 1-5.

The thermal control unit 1 transfers the z-axis force indicated by arrow F in Figure 1 to the DUT contact pusher of the TCU described below, arranged in stacked relationship along the z-axis of the TCU, i. A force transmission block (10); A spring-loaded inner pusher block section (40); A fluid circulation block section (50); A thermoelectric module (hereinafter referred to as Peltier element) section 60; And a pusher end 76 that includes a temperature sensor 78 to contact and push a thermally active central portion of the IC chip, such as the die 104 of the bare die chip package 100, And a thermally conductive pedestal section (72). An external pusher structure is also provided. This pusher structure, indicated at 80, includes a rigid bottom pusher plate 81 and is suitably made of a metallic material such as aluminum for rigidity. The bottom pusher plate has a center opening so that the pusher end of the thermally conductive pedestal can protrude through the pusher plate. A second DUT contact pusher 82 extends from the bottom of the pusher plate about this center opening. This second pusher extends in the z-axis direction parallel to the pusher end of the pedestal and contacts and pushes other portions of the IC chip, such as the substrate 102 of the bare die package.

The outer pusher structure further includes a skirt 90 secured around the outer periphery of the bottom pusher plate 81 and extending upwardly in the z-axis.

Referring to FIG. 3, the fluid circulating block section 50 is shown having a bottom contact plate 58 at the bottom of the body 56 of the block. This lower contact plate is made of an excellent thermal conductor, such as copper, and is suitably provided to achieve efficient thermal conduction between the fluid circulation block section and the thermoelectric module 60. The upper compartment 56 may be formed of copper or other metals as well as a material that does not conduct heat.

The force transmission section 10 of the TCU includes a force distribution block 12 and may further include a gimbal adapter 30 above the force distribution block to form a gimbal. The gimbal adapter 30 includes an upper coupler portion 32 having upper and lower surfaces 32 and 34 and the upper surface of the coupler portion is positioned to receive the indicated z-axis force F. [ The gimbal adapter further includes a spring (36) located at a corner of the coupler portion and below the lower surface of the upper coupler portion of the gimbal adapter. The spring 36 remains compressed between the coupler portion of the adapter and the upper surface 16 of the force distribution block 12 to provide gimbals stability in preload.

As best seen in FIG. 2, the outer pusher structure is secured to the force distribution block 12 by a force transmission shaft 110. These shafts pass freely through appropriately sized holes in the spring-loaded inner pusher block section 40 and the fluid circulation block section 50. The bottom end 113 of these shafts 110 is suitably secured to the pusher plate 81 in the vicinity of the outer perimeter of the plate, for example by threaded engagement, while the upper end 112 of the shaft, Extends through an opening 20 (shown in Fig. 4) at the corners of the body 10 and is covered by a cap nut 115 or any other captive mechanism, Allowing the distribution block to remain on the shaft. As shown in Figure 2, the force distribution block includes a spring (not shown) provided on the shoulders 119 provided around the recessed portion of the shaft under the force distribution block and provided by the recessed portion of the shaft 117). The z-axis force F applied to the force transfer section 10 is thus transmitted to the pusher 82 of the outer pusher structure and is thereby transmitted in compliance with the substrate 102 of the bare die package 100 . The spring may be used to preload the force distribution block to the spring loaded inner pusher block (40).

It is noted that floor shoulders 121 are provided near the bottom end 113 of each force transmission shaft 110. These shoulders are placed in a rigid pusher plate 81 to maintain the shaft in a vertical position.

The z-axis force F comprises the stacked thermal control zones of the TCU, i.e., the spring-loaded inner pusher block segment 40, the fluid circulation block segment 50, the Peltier element 60 and the column And is transferred to the die 104 of the bare die package 100 through the conductive pedestal section 72. 2, the fluid circulation block section 50 may be pre-attached to the inner pusher block section by a suitable fastener such as a screw fastener 41. [ A pedestal retainer ring 43 may be provided at the bottom of the stacked thermal control compartments and may be provided with a screw fastener 45 and a fastener retainer ring 45 to tie the pedestal 72 and other thermal control sections 40, The same retaining fixture can be used with this retainer ring. As described generally in U.S. Patent No. 7,663,388, this is accomplished by a compliant spring (not shown) applied by a spring (such as spring 47 shown in Figure 3) captured in the inner pusher block 40 behind the pusher plate 49 of the block The z-axis force causes the stacked assembly of thermal control segments to remain in tight thermal contact with each other. 3, the pedestal 72 is installed in an upper portion of an insulation ring 73 in the retainer ring 43. As shown in Fig. This insulating ring may have a notch or passage so that the condensation reducing gas flows through the insulating ring described below.

The force transmitted to the pusher end of the pedestal 72 is actuated to change the force that is transmitted through the pedestal to the thermally active portion of the DUT relative to the force transmitted to the other portion of the DUT via the outer pusher structure portion 80, Lt; RTI ID = 0.0 > 12 < / RTI >

4 and 5, the force varying actuation means for the force distributing block comprises at least one, preferably a plurality of, nested (not shown) nested in the bottom surface 14 of the z- May be provided in the form of a piston (18). Preferably, uniformly spaced pistons 18 in a centered group at the bottom of the force distribution block 12 protrude from the piston bore 17 at the bottom of the block and the z- And can be operated in the axial direction. Fluid pressure is provided to the piston from an inlet (22) projecting from the side wall (24) of the force distribution block (12).

As shown in FIG. 5, inlet 22 is in fluid communication with piston 18 through fluid passageway 25 in force distribution block 12. The inlet may be connected to a source of pressurized gas or fluid to effect the pneumatic actuation of the piston. While pressurized air is generally used, the pressurized fluid may also be non-gaseous. For example, oil, water or an aqueous solution can be used to operate the piston. As a result, the piston produces a z-axis force that can be adjusted immediately. By adjusting the pressure behind the piston, the force transferred to the thermally conductive pedestal 72 relative to the force transmitted to the outer pusher 82 during the testing of the DUT, without unloading or disassembling the thermal control unit, Can be changed. Alternatively, the adjustable piston can be preset before use.

The z-axis force distribution block 12 can be easily mounted within the block 18 by providing an upper cover plate 13 that fits into the recess 15 in the upper surface 16 of the block. . ≪ / RTI > The upper cover plate 16 may be secured to this recess by any suitable means, such as, for example, a screw fastener. A fluid passage communicating with the piston hole 17 may be formed on the lower side of this block. The fluid inlet 22 may be, for example, a fluid line coupler attached to the fluid inlet extension 19 of the top cover plate 13 by a threaded attachment.

The fluid circulation block 50 constitutes a fluid passage through which fluids circulate through the block and can transfer heat out of the pedestal in contact with the thermally active portion of the DUT, as described in U.S. Patent No. 7,663,388. According to one aspect of the present invention, the fluid is supplied to the fluid circulation block 52 by a fluid inlet arm 52 and a fluid outlet arm 54, which are rotatably attached to the side of the TCU, typically at or near the position of the fluid circulation block. And is discharged from the fluid circulation block. Due to the external forces exerted on the TCU when the power distribution block 12 and the corner shaft 110 are mounted compliantly and the fluid inlet arm and the fluid outlet arm are rotatably attached, The biasing force exerted by the outer hose connected to the heat exchanger can reduce the instability of the thermal control unit. FIG. 1 illustrates an exemplary range of motion for rotatably attaching fluid outlet 54. As shown in FIG. The inlet and outlet arms preferably rotate about a common axis of rotation S (shown in FIG. 2), and suitably have an axis of rotation perpendicular to the z-axis of the TCU. Although the fluid inlet arm 52 and the fluid outlet arm 54 are shown attached to opposite sides of the TCU on opposite sides, this embodiment of the rotating arm of the present invention is characterized in that the rotating arm is on the opposite side It is intended to be non-existent.

Thus, according to this aspect of the invention, when any uncontrolled force is generated from the hose connected to the fluid inlet arm 52 and the fluid outlet arm 54 of the TCU during the test cycle, the fluid inlet arm 52 and the fluid outlet arm 54 are caused to rotate to alleviate this force and maintain the z-axis alignment of the portions of the TCU.

Any of a plurality of fluids can be circulated through the fluid circulation block 50. [ While the fluid is preferably provided in a liquid form, a gas phase fluid may be used from time to time. Liquids having a relatively high heat capacity are particularly useful for certain applications. In addition, the temperature control fluid may be selected according to the desired conditions. For example, water can act as a temperature control fluid to test the DUT at ambient or elevated temperatures, for example, from 20 ° C to about 65 ° C. Alternatively, testing the DUT at low temperatures at temperatures of -20 DEG C, -5 DEG C, 0 DEG C, or between them may involve the use of an aqueous solution containing methanol, ethylene glycol or propylene glycol or a non-aqueous liquid.

In another embodiment of the present invention, the thermal control unit 1 comprises a dew-reduction system. The dew condensation reduction system includes a condensation-reducing gas inlet 42 that can be suitably positioned at one edge of the spring-loaded internal pusher block section 40 of the TCU. 3, the gas inlet 42 is connected to a gas delivery passage which extends around the pedestal 72, between the pedestal and the retaining ring 43, and between the pedestal retaining ring, Extends between the pedestal and the outer pusher structure (80). The gas-carrying passages are indicated by reference numerals 44A, 44B, 44C, 44D, 46A, 46B and 47. [ This condensation-reduction system is further described below.

In use, the illustrated thermal control unit 1 may be placed on a test socket (not shown) comprising a bare die die die package 100. The z-axis force is applied to the gimbal adapter 30, for example, by a pneumatic press of an automated chip tester. The z-axis force is transmitted to the pedestal 72 by the force distribution block 12 of the self-centering gimbal 10, i. e. through the lamination of the thermal control blocks 40, 50 and 60, And transmitted to the outer pusher structure 80 through the force transmission shaft 110. [ The two pushers to which this z-axis force is transmitted are the pusher end 76 of the pedestal contacting the die 104 of the bare die package and the substrate pusher 72 of the outer pusher structure. The applied z-axis force is controllably distributed between these pushers by the force distribution block 12. The force applied to the die relative to the force applied to the substrate can be adjusted by adjusting the pressure behind the piston 18 of the force distribution block, acting as the z-axis force actuation means. Immediate power distribution can be preset or adjusted so that the die force does not exceed a desired or predetermined upper limit to ensure that the die force does not damage the die.

The pedestal pusher end 76 and the bottom substrate pusher end 82 are secured to ensure that the substrate force does not fall below a desired or predetermined lower limit to ensure proper engagement between the probe of the test socket and the electrical pad of the DUT. It should be noted that the z-axis distance between the two axes should be calibrated. For example, in bare die packaging, the manufacturer of a particular IC device may specify that a particular IC device is to be tested at a low temperature while applying a load of at least 55 pounds to the substrate. However, this designation can also prevent the die from being subjected to loads greater than 15 pounds. In this case, a total of 70 pounds of load can be applied to the DUT with the adjusted die pusher to limit the load on the die to not exceed 15 pounds.

When so engaged, the test can begin. The thermal measurement and control elements of the thermal control unit serve to monitor and maintain the set point temperature of the DUT. The DUT temperature may be monitored by a sensor 78 at pedestal pusher end 76. The desired electrical signal is supplied from an external power source to the Peltier element 60, which generates heat flow necessary to maintain the desired set point temperature in the DUT in the test socket. The heat transfer between the pedestal and the fluid circulation block 50 can be adjusted in accordance with the temperature of the DUT detected by the sensor 78 so that when the lowering of the DUT temperature is required it is circulated from the pedestal through the fluid block 50 Heat is removed from the temperature control fluid, and heat is applied from the circulating fluid to the pedestal 72 when it is necessary to raise the DUT temperature. In summary, the heat is carried or fed out by the temperature control fluid passing through the fluid passageways in the fluid circulation block 50.

A thermal interface material such as thermal grease or foil may be applied between the top surface 74 of the pedestal and the Peltier element 60 and the Peltier element 60, And is selectively provided between the element and the fluid circulation block 50.

With respect to the dew condensation aspect of the present invention, the DUT of the present invention can be used for cold testing a DUT. During this low temperature test, the temperature control fluid may be cooled to a temperature below 0 占 폚. If these tests are performed in uncontrolled ambient conditions, water or ice may accumulate on the surfaces of the TCU, DUT, and test sockets. This condensation can interfere with or short-circuit the correct functioning of the TCU, DUT and electronic components of the test socket.

A number of techniques known in the art have been used to solve condensation problems associated with low temperature testing. For example, testing IC devices at high temperatures at high-volume was performed in a controlled environment, e.g., in a room with low levels of atmospheric humidity. In low-temperature, low-temperature testing equipment, IC devices can be tested in enclosures that maintain low humidity. Additionally or alternatively, other materials in the form of plastics having a low thermal conductivity can be applied to the surface of the TCU to solve the condensation problem associated with cooling the parts of the TCU engaged in the low temperature test.

According to the condensation reduction aspect of the present invention, a TCU and a new and efficient approach to reducing condensation on the chip surface integrated into the TCU is provided. The condensation-reducing gas is introduced under pressure through the gas inlet 42 into the TCU. The condensation reducing gas is flushed through the TCU to pass over condensation-prone surfaces. 3, the gas introduced into the inlet 42 flows into the horizontal passage 44A, then flows downward through the vertical passage 44B, and from there, Is ejected through passages 44C and 44D (including openings in the pedestal insulation ring 73) and then through two exit paths, i. E., A pedestal retainer 43, preferably stainless steel, and an outer pusher structure 80 Through the passageways 46A and 46B between the outer pusher structures and the pusher end 76 of the pedestal 72 and through the passageway 47 between the substrate pusher 82 of the outer pusher structure and the pusher end 76 of the pedestal 72. [

It will be appreciated that the gas passages may be provided in a manner different from that shown. For example, passageway 44A extends generally horizontally through spring-loaded internal pusher block 40 until passageway 44A engages passageway 44B in fluid communication. The passage 44B not only extends in the z-axis direction through a part of the block 40 but also extends through the upper compartment 56 and the lower compartment 58 of the fluid circulation block 50. [ The passages 44C, 44D, 46A, 46B and 47 are shown downstream from the passageway 44B and are located between the skirt 90 and the pedestal 72. Optionally, one or more additional passageways may be formed by disposing a first surface on the second surface in which one or more channels are formed, and these surfaces may be combined to form one or more additional passageways. For example, the condensation reducing gas carrying passageway may be integrated within a module of the TCU of the present invention or disposed between the modules.

In operation, a condensation-reducing gas source (not shown) may be connected to the inlet 42. The condensation-reducing gas is introduced through the inlet 42, is ejected through the gas passage as described above, and flows over the surface where condensation may occur. Because the pedestal 72 is inevitably cold during testing at low temperatures, the skirt 90 can help the condensation reducing gas be directed over the exposed surface of the pedestal where moisture or ice is likely to be collected.

Any of a plurality of gases may be used. For example, any dry inert gas such as nitrogen, helium, argon, etc. may be used. In particular, commercially available, dry, oil-free air has been shown to reduce condensation on the TCU of the present invention. TCUs with integrated means as described above that reduce condensation do not exhibit condensation related problems during low temperature testing in uncontrolled atmospheric conditions, while the same TCU can exhibit condensation related problems during low temperature testing when no condensation reducing gas is used .

In addition to using condensation reducing gas, appropriate measures must be taken to solve the thermal conductivity problem. For example, the TCU must thermally isolate as many components of the temperature control unit from each other as possible to prevent moisture-sensitive components from cooling down. Materials with a low thermal conductivity should be used as well. For example, the use of metals in parts that do not require heat conduction should generally be avoided. As described above, a portion of the temperature control fluid block may be made of a metal such as copper for efficient thermal conduction. However, other portions of the temperature control fluid block, for example, the portions exposed to the surrounding environment, may be formed of a material that does not conduct heat, for example, plastic, to prevent condensation from being formed thereon.

To facilitate discussion, Figures 6-11 illustrate another exemplary embodiment of a thermal control unit (TCU) 600 in accordance with the present invention. The advantage of this embodiment is that it includes a fast thermal response of 40 [deg.] C / second for a tested IC device (IC DUT) having a test surface area of approximately 16 mm x 16 mm, resulting in a wattage density approaching 1000 watts per square inch do. The operation range of the TCU 600 is -60 캜 to 160 캜.

The excellent thermal performance of the TCU 600 is made possible by several key design features, such as the selection of thermally conductive materials, fluid and electrical paths, and thermal sensor locations, and these design features are described in more detail below. 6 is a side view of the thermal control unit 600. As shown in FIG. 7A is a cross-sectional view taken along the cutting line 7A-7A of FIG. 6, and FIG. 7B is a cross-sectional view taken along the line 7A-7A of FIG. 6, showing a force transfer assembly 610, a fluid circulation block (heat exchanger with heat conductive plate) 650, a heater 660, Figure 7B is an exploded view of Figure 7B showing the components of the TCU 600 including the substrate pusher 690 and the substrate pusher 690. [ Figures 8 and 9 show cross-sectional views taken along cutting lines 8-8 and 9-9, respectively, in Figure 7a. Figures 10a and 10b are bottom perspective views of two exemplary z-axis load distributor actuator blocks for a z-axis force distribution system of TCU 600, while Figure 11 is a cross-sectional view along line 11-11 of Figure 10a .

6 through 9, a thermal control unit (TCU) 600 includes the following basic compartments arranged in a stacked relationship along the z-axis of TCU 600: arrow F A force transfer assembly 610 for transferring the z-axis force, shown in Fig. 6, to a test IC device (IC DUT) contact pusher of the TCU described below; A fluid circulation block 650; Heater 660; And a thermally conductive pedestal 772 having a pusher end 776 that includes at least one pedestal temperature sensor for contacting and pushing the thermally active center portion of the IC chip, such as die 799 of the bare die chip package 797, ).

An external pusher structure 780 is also provided. Pusher 780 includes a rigid bottom pusher plate 781 and is suitably made of a metallic material such as aluminum for rigidity. The bottom pusher plate 781 has a central opening so that the pusher end of the thermally conductive pedestal can protrude through the pusher plate. A second DUT contact pusher 682 extends from the bottom of the pusher plate about this central opening. This second pusher 682 extends in the z-axis direction parallel to the pusher end of the pedestal and contacts and pushes other portions of the IC chip, such as the substrate 798 of the bare die chip package 797.

Referring to FIG. 7A, a fluid circulation block (also known as a cooler block) 650 is shown having a bottom contact plate 758 at the bottom of the body 656 of the block. This lower contact plate 758 is made of a superior thermal conductor such as copper and is suitably provided to achieve efficient thermal conduction between the fluid circulation block 650 and the heater 660. Thus, the body 656 of the block can be formed of copper or other metal as well as a material that does not conduct heat. Suitable materials for the body 656 include Peek ^™ , Ultem ^™, or Torbn ^™ , which can withstand rapid thermal shock cycles repeated during multiple rapid heating / cooling cycles of the TCU 600, And the like.

To prevent thermal runaway and thus damage to the TCU 600, the fluid circulation block 650 detects when the TCU 600 has exceeded the allowed operating range and triggers the appropriate thermal shutdown It is preferable to include at least one cooler temperature sensor.

6, the force transfer assembly 610 of the TCU 600 includes a force distribution block 612 and further includes a gimbal adapter 612 on the force distribution block 612 to form a force transfer assembly 610. [ 630). The gimbal adapter 630 includes a top surface 632 and a bottom surface 634 and the top surface 632 is positioned to receive the displayed z-axis force F. [ The gimbal adapter 630 further includes a spring 636 positioned below the lower surface 634. The spring 636 is held in compression between the gimbal adapter 630 and the upper surface 616 of the force distribution block 612 to provide gimbals stability with the preload.

7A, 7B, 9, and 10A, the outer pusher structure 780 is secured to the force distribution block 612 by a force transmission shaft 710. As shown in FIG. These shafts pass freely through holes of the appropriate size in the fluid circulation block 650. The bottom end 713 of these shafts 710 is suitably secured to the pusher plate 781 near the outer perimeter of the plate by, for example, threading engagement, while the upper end 712 of the shaft is secured to the force distribution block < (Shown in FIG. 10A) at the corners of the shaft 710 and is covered by a cap nut 715 to retain the force distribution block on the shaft 710.

The gimbal block 612 further includes an appropriately sized hole 1077 for mating with a corresponding set of alignment pins 757 projecting vertically from the upper surface of the fluid circulation block 650.

Figures 7A and 9 illustrate a spring 710 that is provided around the recessed portion of the shaft 710 under the force distribution block and on a spring 717 mounted on the shoulders 719 provided by the recessed portion of the shaft 710 Lt; / RTI > shows a power distribution block 612 that is supported in compliance. Thus, the z-axis force F applied to the force transfer assembly 610 is transmitted to the pusher 682 of the outer pusher structure and is thereby transferred to the substrate 798 of the bare die chip package 797 . The spring 717 may be used to preload the force distribution block (gimbal block) 612 into the body 656 of the fluid circulation block 650.

It is noted that floor shoulders 721 are provided near the bottom end 713 of each force transmission shaft 710. These shoulders are placed in a rigid pusher plate 781 to keep the shaft vertical.

The z-axis force F is applied to the bare die chip 600 through the stacked thermal control sections of the TCU 600, i.e., the fluid circulation block 650, the heater 660 and the thermal conductive pedestal 772, And transferred to the die 799 of the package 797. The force transmitted to the pusher end of the pedestal 772 acts to change the force that is transmitted through the pedestal to the thermally active portion of the DUT relative to the force transmitted to the other portion of the DUT via the external pusher structure portion 780, Lt; RTI ID = 0.0 > 612 < / RTI >

10A and 11, a force varying actuator for a force distribution block 612 (also known as a gimbals block) is located at the bottom surface 1014 of the gimbal block 612 to distribute the z- May be provided in the form of at least one, preferably a plurality of pistons 1018. Pistons 1018 preferably uniformly spaced in a centered group at the bottom of the force distribution block 612 protrude from the piston bore 1117 at the bottom of the gimbal block 612, It can be operated in the z-axis direction by changing the fluid pressure. Fluid pressure is provided to the piston from fluid inlet 622, which protrudes from side wall 1024 of gimbal block 612.

As shown in FIG. 11, inlet 622 is in fluid communication with piston 1018 through fluid passageway 1125 in gimbal block 612. The inlet 622 may be connected to a source of pressurized gas or fluid to effect pneumatic actuation of the piston 1018. While pressurized air is generally used, the pressurized fluid may also be non-gaseous. For example, oil, water or an aqueous solution can be used to operate the piston 1018. As a result, the piston produces a z-axis force that can be adjusted immediately. By adjusting the pressure behind the piston 1018, the force transferred to the thermally conductive pedestal 772 relative to the force transmitted to the external pusher 682, without unloading or disassembling the thermal control unit, Can be changed. Alternatively, the adjustable piston can be preset before use.

The gimbal block 612 may be configured to facilitate mounting the piston 1018 within the block by providing an upper cover plate 1113 that fits into the recess 1115 of the upper surface 1116 of the block 612 have. The upper cover plate may be secured to this recess 1115 by any suitable means such as, for example, a screw fastener. A fluid passage communicating with the piston hole 1117 may be formed on the lower side of the block 612. The fluid inlet 622 may be, for example, a fluid line coupler attached to the fluid inlet extension 1119 of the top cover plate 1113 by a threaded attachment.

10B shows an alternative embodiment of a gimbal block 1012 that locks the stacked components of the TCU 600 together without requiring a tool using a latch 1090 that is pivoted instead of a mechanical thread.

Referring to both Figures 6 and 7A, the fluid circulation block 650 is configured to transfer heat out of the pedestal in which the fluid circulates through the block and contacts the thermally active portion of the DUT, as described in U.S. Patent No. 7,663,388 Thereby forming a fluid passage. According to one aspect of the present invention, the fluid is generally supplied by a fluid inlet arm 752 and a fluid outlet arm 654, which are rotatably attached to the side of the TCU 600 at or near the position of the fluid circulation block Is introduced into the fluid circulation block and discharged from the fluid circulation block. Due to the external force exerted on the TCU 600 when the force distribution block 612 and the corner shaft 710 are complimentarily mounted and the fluid inlet arm and the fluid outlet arm are rotatably attached, And the biasing force exerted by the outer hose connected to the fluid outlet, can reduce the instability of the thermal control unit. 6 illustrates an exemplary range of motion for rotatably attaching the fluid outlet arm 654. The inlet and outlet arms 752 and 654 preferably rotate about a common axis of rotation S (shown in FIG. 7A) and suitably have an axis of rotation perpendicular to the z-axis of the TCU 600. Although the fluid inlet arm 752 and the fluid outlet arm 654 are shown attached to opposite sides on opposite sides of the TCU 600, such a swivel arm attachment embodiment of the present invention is characterized in that the swivel arm is on the opposite side But are not intended to be limiting.

Thus, in accordance with this aspect of the present invention, when any uncontrolled force is generated from the hose connected to fluid inlet arm 752 and fluid outlet arm 654 of TCU 600 during a test cycle, The fluid inlet arm 752 and the fluid outlet arm 654 rotate about the axis of rotation to alleviate this force and maintain the z-axis alignment of the portions of the TCU.

Any of a number of fluids can be circulated through the fluid circulation block 650. [ While the fluid is preferably provided in a liquid form, a gas phase fluid may be used from time to time. Liquids having a relatively high heat capacity are particularly useful for certain applications. Also, the temperature control fluid can be selected according to the desired conditions. For example, at ambient or elevated temperatures, for example. To test the DUT at 20 ° C to about 65 ° C, water can act as a temperature control fluid. Alternatively, testing the DUT at low temperatures at temperatures of -20 DEG C, -5 DEG C, 0 DEG C, or between them may involve the use of an aqueous solution containing methanol, ethylene glycol or propylene glycol or a non-aqueous liquid.

In another aspect of the invention, the thermal control unit (TCU) 600 includes a dew-reduction system. During testing at low temperatures, the temperature control fluid can be cooled to a temperature below 0 ° C. If these tests are performed in uncontrolled ambient conditions, water or ice may accumulate on the surfaces of the TCU, DUT, and test sockets. This condensation can interfere with or short-circuit the correct functioning of the TCU, DUT and electronic components of the test socket.

Thus, the condensation-reduction system includes a condensation-reducing gas inlet 668 that can be suitably positioned at one edge of the fluid circulation block 650. 6 and 7A, the gas inlet 668 is connected to a gas delivery passage extending around the pedestal 772 in a manner similar to that of another embodiment of the TCU 1 described above, whereby the TCU 1, the TCU and the approach for reducing condensation on the chip surface, as described above, can be incorporated into the TCU 600.

In addition to using condensation reducing gas, appropriate measures must be taken to solve the heat conduction problem. For example, the TCU must thermally isolate as many components of the temperature control unit from each other as possible to prevent moisture-sensitive components from cooling down. Materials with a low thermal conductivity should be used as well. For example, the use of metals in parts that do not need to conduct heat should generally be avoided. As described above, a portion of the temperature control fluid block may be made of a metal such as copper for efficient thermal conduction. However, other portions of the temperature control fluid block, for example, the portions exposed to the surrounding environment, may be formed of a material that does not conduct heat, for example, plastic, to prevent condensation from being formed thereon.

In use, the illustrated thermal control unit 600 may be disposed on a test socket (not shown) that includes a bare die chip package 797. The z-axis force is applied to the gimbal adapter 630 by, for example, a pneumatic press of an automatic chip tester. The z-axis force is transmitted to the thermally conductive pedestal 772 by the force distribution block 612 of the self-centering gimbals 610 to the pedestal 772, i. e. through the lamination of the thermal control sub-assemblies 650 and 660 And through the force transmission shaft 710 to the outer pusher structure 780. The two pushers to which this z-axis force is transmitted are the pusher end 776 of the pedestal contacting the die 798 of the bare die package 799 and the substrate pusher 690 of the outer pusher structure.

The applied z-axis force is controllably distributed between these pushers by a force distribution block 612. The force applied to the die 799 relative to the force applied to the substrate 798 can be adjusted by adjusting the pressure behind the piston 1018 of the force distribution block, acting as the z-axis force actuation means. The instant force distribution can be preset or adjusted so that the die force does not exceed the desired or predetermined upper limit to ensure that the die force does not damage the die 799. [ In other words, the total z-axis force exerted by the force distribution block 612 is equal to the sum of the force exerted on the substrate 798 and the force exerted on the die 799. This force distribution between the substrate 798 and the die 799 is such that excessive internal structural stresses caused by the harmful bending forces are applied to the TCU 600 while maintaining effective thermal conductivity between the TCU 600 and the DUT during testing. Lt; RTI ID = 0.0 > DUT. ≪ / RTI >

Between the pedestal pusher end 776 and the bottom substrate pusher end 682 to ensure that the substrate force does not fall below a desired or predetermined lower limit to ensure proper engagement between the probe of the test socket and the electrical pad of the DUT. - It is noted that the shaft distance has to be corrected. For example, in a bare die packaging, the manufacturer of a particular IC device may specify that a particular IC device is tested at a low temperature with a load of at least 55 pounds applied to the substrate 798. However, this designation can also prevent the die 799 from being subjected to a load of 15 pounds or more. In this case, a total of 70 pounds of load may be applied to the DUT with the adjusted die pusher 776 to limit the load applied to the die to not exceed 15 pounds.

When so engaged, the test can begin. The thermal measurement and control elements of the thermal control unit serve to monitor and maintain the set point temperature of the DUT. The DUT temperature can be monitored by a pedestal thermal sensor at pedestal pusher end 776. [

The desired electric current is supplied to the heater 660 from an external power source, from which heat flow is generated to maintain the desired set point temperature in the DUT in the test socket. Heat transfer between the pedestal 772 and the fluid circulation block 650 can be adjusted according to the temperature of the DUT detected by the thermal sensor so that fluid block 650 can be removed from pedestal 772 when it is desired to lower the DUT temperature. The heat can be removed by the temperature control fluid circulated through the heat exchanger. It is also possible to add supplemental heat generated by the heater 660 to the pedestal 772 with additional heat from the circulating fluid if the DUT temperature needs to be raised quickly. In summary, the heat is carried or fed out by the temperature control fluid passing through the fluid passageways in the fluid circulation block 650.

As discussed above, the fluid circulation block 650 can be made of a suitable thermoplastic to reduce condensation, but the thermally conductive plate 758 can be made of a relatively thin (low-melting) material, such as nickel plated copper Mass) is made of high conductivity material. Similarly, the electrically resistive heater 660 may be made of any suitable material including a ceramic material such as AlN (aluminum nitride) having suitable thermal conductivity.

Between to further enhance the variety of thermal interface efficiency, thermal grease or foil, for example, Artic-Silver ^TM heat the top surface of a suitable thermal interface material base, such as Compound 774 with the heater 660 and the fluid May be provided between the heat conductive plate 758 located at the bottom of the circulation block 650 and the heater 660. These thermal interface materials, typically about 1 mil thick, fill small imperfections and voids, thereby improving the thermal conductivity and efficiency of each interface. The thermal interface material also accommodates different coefficients of expansion of the different materials made up of different materials, such as plate 758, heater 660, and pedestal 772 during the fast heating cycle and the cooling cycle.

In some embodiments, a suitable liquid thermal interface material (LTIM), e.g., water and glycerin, is applied to the pedestal tip 760 to improve the thermal efficiency of the interface between the pedestal pusher end 776 and the die 799. In some embodiments, Is injected under pressure from the at least one perforation located at the bottom of the pusher end 776 into the pedestal / die interface. Thereafter, after testing the DUT, the residual LTIM is removed from the same bottom hole of the pedestal pusher end 776 under suction. The LTIM is supplied to and removed from pedestal pusher end 776 via a corresponding set of LTIM inputs and outputs 669 shown in Figs.

As described above, a typical device tester is designed on the assumption that the device under test (DUT) is flat. As a result, due to the flat profile of the pedestal, the substrate pusher and the test socket, excessive pressure is applied to the DUT curved during the test, especially by the pedestal on the die. In addition, the pedestal and the substrate pusher apply pressure to selected surface areas of the substrate. Thus, after testing, the surface of the device becomes somewhat flat due to excessive pressure from the pedestal and the pusher and is often uneven due to uneven pressure between the support surface and the non-support surface of the DUT.

The problem of uneven pressure on the DUT can be partially alleviated by introducing adjustable touchdown coverage attempting to increase the supported upper surface area of the DUT. This is accomplished by providing additional surface support, e.g., on resistors, capacitors, and I / O drivers, on peripheral components surrounding the die on the substrate, i.e. between the pedestal and the substrate pusher. The adjustable touchdown range, however, does not address the more severe and undesirable and unintended device flattening problems.

The device planarization problem becomes more pronounced as the substrate thickness decreases. For today's portable devices, the device substrate thickness has steadily decreased from about 800 microns to about 100-200 microns. Unlike thicker, for example, 800 micron devices, which can recover their original curvature after being planarized by the device tester, today thinner devices are much smaller, as illustrated by device 1280B of FIG. 12B There is a possibility that it will be transformed more permanently.

To minimize this undesirable planarization problem, in some embodiments of the device tester as shown in Figure 13a (not to scale), the sockets of the pedestal 1360, the substrate pusher 1370, and the test socket 1390 The insert 1392 is configured to receive the curved device 1380. The pusher end 1366 of the pedestal 1360 is slightly recessed to substantially match the curvature of the surface of the die 1384 of the device 1380. [ Similarly, the top surface of the socket insert 1392 is slightly convex so as to substantially coincide with the curvature of the bottom of the substrate 1380 of the device 1380.

13B illustrates the curved profile of each of pedestal pusher end 1366, die 1384, substrate pusher ends 1372, 1374, substrate 1382, and socket insert 1392 in more detail Is a simplified and exaggerated cross-section.

Thus, depending on the size and thickness of the DUT, various variations of the curved shape for the socket insert and / or pusher end, such as circular, elliptical, spherical, faceted (such as cut jewel) ) And compound forms, and combinations thereof, may be considered, alone or in combination. It should also be appreciated that irregularities such as depressions and / or bumps may also be intentionally introduced into the selected portion (s) of the socket insert and / or the pusher end depending on the particular DUT profile and structure.

13E is a perspective view of a test socket 1390 and a test socket insert 1392 showing a plurality of suspension support pins 1396 while FIGS. 13F and 13G are cross-sectional views respectively showing a rest state and a test state. In this embodiment, there are four support pins 1396 (16 total support pins in total) along each of the four sides of the insert 1392 to support and stabilize the socket insert 1396.

The suspension support pin 1396 supports the socket insert 1392 in an elevated position (see FIG. 13F) above the recessed surface of the test socket 1390, while one or more spring-loaded test pins 1398 are in a rest state And does not protrude above the top surface of the socket insert 1392. As a result, the top surface of the socket insert 1392 is substantially smooth and there are no protrusions that are disturbed, thereby facilitating proper alignment and placement of the device 1380 relative to the test socket 1390 and socket insert 1392 .

Thereafter, as shown in FIG. 13G, the test pin (s) 1398 are placed on the substrate bottom device (s) 1380 after the device 1380 has been properly seated against the socket insert 1392 and the test socket 1390 during the test state (S) located on the pad (s) 1380 and contacts the pad.

It is noted that a typical DUT includes a square DUT ranging from about 14 mm square to 50 mm square and a rectangular DUT ranging from about 22 mm x 25 mm to 24 mm x 42 mm. The curvature of a typical DUT depends on factors such as substrate and die size, thickness, and / or aspect ratio. For example, a 50 mm square substrate has a profile about 250 mil higher in the middle of the substrate than a side of the substrate. In this example, the corresponding socket insert should have a profile about 120 mils higher in the middle than the side, thereby allowing the test pin to function within the compression and expansion range that it operates during the test while substantially reducing the planarization problem have.

Many modifications and additions to the device tester described above are also possible. For example, the thickness and / or profile of the different portions of the test socket insert may be varied such that the socket insert flexes and adapts (e.g., differentially across the socket insert), resulting in significantly less total stress on the DUT, I. E., Produce less planarization effects (see the exaggerated cross-sectional views of Figures 13c and 13d). The test socket insert may also be made of a material having varying stiffness and / or flexibility depending on the DUT.

It may also be possible to reduce the overall stress on the DUT by fabricating the socket insert using two or more bonded materials that substantially match the temperature-related profile changes of the DUT in a manner similar to the bimetallic strip. In addition, the test socket can be heated and / or cooled to minimize temperature differences.

Referring now to FIGS. 14A-14D, there is shown a front view, a top view, a perspective, and an enlarged view illustrating an exemplary heater 1460 for some embodiments of the device tester described above. The heater 1460 is configured to be operatively coupled to the pedestal of the device tester. The heater 1460 may be thermally and / or electrically connected to the fuse. 14B, the heater elements 1464 and 1466 are connected by a fuse 1468 to electrically connect the conductive leads 1461, the heater element 1466, the fuse 1468, the heater element 1464, And a conductive lead 1462. The fuse circuit of Fig. Fuse 1468 is positioned along the open edge of heater body 1469 and can be easily accessed during assembly, reconfiguration and / or maintenance. The exemplary fuse 1468 can be made of a material having a suitable melting point of about 300 DEG C, which can significantly reduce the risk of fire, such as tester damage and / or spontaneous combustion.

In summary, the above embodiments illustrate a system and method for testing an IC device, such as a packaged semiconductor chip, while preserving the original specifications of the device. These advantages include reducing physical damage during subsequent assembly with the motherboard and / or loss due to poor contact alignment by minimizing deformation of the IC device under test (IC DUT).

It will be understood by those skilled in the art that the present invention may be embodied in various forms. Those skilled in the art will be able to review the teachings contained herein to determine the components of a thermal control unit, for example, to ensure that the components function properly under the force and temperature required for IC device testing Lt; RTI ID = 0.0 > materials. ≪ / RTI > Similarly, those of ordinary skill in the art will be able, upon reviewing the disclosure contained herein and through routine experimentation, to distinguish between optional and critical elements in the present invention in different contexts will be. For example, one of ordinary skill in the art will appreciate that the present invention may require only one pusher in some cases, but may require a plurality of pushers in other cases.

It is to be understood that the foregoing description is intended to illustrate and not limit the scope of the invention. For example, while the above description has focused on TCUs for IC devices with bare die packaging, the present invention is not limited to such packaging. Thus, the above-described piston, rotatable inlet and outlet arms, and the aforementioned condensation reducing means can be used in a TCU configured to test a bare die package as well as a die package with a lid. Further, the present invention is not limited to the force providing means having the structure as shown in the drawings. Those of ordinary skill in the art will appreciate that when reviewing the disclosure contained herein, it will be appreciated that one skilled in the art will appreciate that when receiving the total z-axis force and controllably distributing the total z-axis force to different parts of the IC package It will be possible to devise a variety of different means of providing force. In either case, aspects of the different embodiments of the invention may be included in other embodiments or excluded from the other embodiments. Other aspects, advantages, and modifications within the scope of the invention will be apparent to those skilled in the art to which the invention pertains.

An exemplary embodiment of a thermal control unit (TCU) 1500 according to the present invention is shown in Figures 15A and 15B. The advantages of this embodiment include a fast thermal response of about 40 占 폚 / sec for a tested IC device (IC DUT) that can be tested at a test surface area of about 30 mm x 30 mm and a temperature range of about -60 占 폚 to 160 占 폚 do.

Another important feature of this embodiment is to use a feedback mechanism to control the temperature of the device under test (DUT) and to maintain this temperature at a substantially stable temperature throughout the test period using the TCU.

15A and 15B, the thermal control unit (TCU) 1500 includes three main subsystems: a fluid management system (FMS) 1600, a thermal head unit (THU) 1700 ), And a flexible cable chain assembly 1800. A fluid management system (FMS) 1600 provides support and connection to a thermal head unit (THU) 1700 to which fluid for pneumatic actuation, cooling and temperature control and condensation reduction ). The flexible cable chain assembly 1800 incorporates a cable that provides an electrical connection to the thermal head unit 1700 with the required cable contained in the flexible chain. The sub-systems 1600, 1700 and 1800 are described in detail below.

Fluid management subsystem 1600 is shown in Figures 16A and 16B. The fluid management subsystem comprises an internal manifold 1610 and an external manifold 1620. Mounting tower 1611 provides a mount for thermal head unit 1700. Each of the mounting towers is supported on three support columns 1612 rigidly secured to the TCU base 1613. The U-shaped hose 1614 is formed in a U-shape to convey the cooled cooling fluid and prevent the thermal head unit (THU) 1700 from becoming unstable during testing. The tube 1615 carries the liquid thermal interface material (LTIM) to the thermal head unit 1700. The function of the LTIM will be discussed later when details of the thermal head unit 1700 are given. Tubes 1616 and 1617 are hooked to external manifold 1620. The cooled fluid enters through 1616, leaves internal manifold 1610 and exits through tube 1617 to external manifold 1620. The connector 1618 provides a secondary inlet port that provides drying gas to reduce condensation. Connector 1619 provides a secondary outlet port for dry gas.

In external manifold 1620, port 1621 is the inlet for the cooled fluid and port 1622 is the outlet for the cooled fluid. Port 1623 is hooked to tube 1616 to provide a flow of cooling fluid to the internal manifold. Port 1624 is hooked into tube 1617 to allow cooled fluid to flow from the inner manifold to the outer manifold 1620 from the outside. The flow in the external manifold 1620 is controlled by the solenoid valve 1625. The tube 1626 provides an inlet-outlet bypass that allows cooling fluid to flow directly from the inlet port to the outlet port to avoid stagnation of flow in the internal manifold.

The thermal head unit (THU) 1700 is shown in a perspective view in Figure 17A. An exploded view of the thermal head unit (THU) 1700 is shown in Fig. 17B. The THU is composed of a connector kit 1701, a fluid circulation block 1703, a gimbal module 1710, a heater assembly 1720, and a device kit module 1730 composed of a pedestal assembly 1740 and a pusher assembly 1750 .

The connector unit 1701 is attached to the fluid circulation block 1703. The connector unit transmits an electric signal from the connector terminal 1702 and transmits an electric signal propagated to the connector terminal 1702.

In some embodiments, the fluid enters the fluid circulation block 1703 and is discharged from the fluid circulation block 1703 by the fluid inlet connector 1704 and the fluid outlet connector 1705. In operation, fluid connectors 1704 and 1705 are fixedly coupled to a U-shaped hose 1614 (FIG. 16B), which carries the cooled cooling fluid to the thermal head unit (THU) 1700 during testing.

The gimbal module 1710 (also referred to as a gimbals) is shown in Figures 17c (top view) and Figure 17d (bottom view), which provides a z-axis force indicated by arrow F, To the pedestal assembly (1740) and the pusher assembly (1750). The gimbal adapter 1711 is mounted on the force distribution block 1712 and can be rotated without using any tool by using a rotary coupler 1713 provided with a quick-release clip 1714 It easily fits in place. Inlet 1715 provides pressurized fluid to perform pneumatic actuation in gimbal module 1710. This inlet must be connected to a source of pressurized fluid. Generally, pressurized air is used, but the pressurized fluid may be air or a non-liquid gas. For example, a suitable oil, water or aqueous solution known to those skilled in the art can be used for pneumatic operation. The pin 1716 ensures that the gimbal adapter 1711 is correctly aligned with respect to the force distribution block 1712. The quick release clip 1717 facilitates mounting and dismounting of the pusher assembly 1750 in a short period of time and without the need to use any tools.

Referring to Figures 17c and 17d, the force varying actuator for the force distribution block includes at least one, preferably a plurality of pistons 1718, located at the bottom surface 1719 of the z-axis force distribution block 1712, As shown in FIG. The pistons 1718, which are uniformly spaced, preferably in a group centered on the bottom of the force distribution block 1712, can be operated in the z-axis direction by changing the fluid pressure behind the piston. Fluid pressure is provided from the inlet 1715 to the piston.

The heater assembly 1720 is shown in Figure 17e. The heater 1721 is supported in an isolator plate 1722. A heater is an electrothermal heater in which electric current flows to generate heat through a resistor implemented in a suitable material including ceramics such as aluminum nitride (AlN) having an appropriate thermal conductivity. The electric current is supplied through the heater electrical lead 1723. A fuse 1724 is inserted in the resistor circuit. The fuse may be made of a material having a melting point of a relatively low temperature such as lead. This fuse prevents temperature runaway. The pin 1725 ensures that the heater assembly is aligned within the thermal head unit 1700. The insulator plate 1722 may be made of a material with low thermal conductivity, such as plastic. The groove 1726 is a portion for aligning with the device kit module 1730.

Figs. 17g, 17f and 17h show the device kit module 1730 and its two parts, pedestal assembly 1740 and substrate pusher assembly 1750. Fig. Pedestal assembly 1740 includes a thermally conductive pedestal 1741 having a bottom end configured to contact a die of the DUT. The upper surface of the pedestal is in direct contact with the heat exchange plate, known as cold plate 1742, which is a thin plate made of copper with a good thermal conductivity. The copper of the low temperature plate 1742 is plated with nickel for durability and oxidation prevention. The low temperature plate 1742 includes a channel (not shown) that carries a liquid thermal interface material (LTIM) to improve the thermal conductivity between the low temperature plate 1742 and the heater 1721 and between the low temperature plate 1742 and the thermally conductive pedestal 1741 1743). The LTIM is fluidly communicated to the channel 1743 through port 1744.

In operation, the low temperature plate 1742 is configured to be in direct contact with the heater 1721 on one side and in direct contact with the thermally conductive pedestal 1741 on the other side. A resistive thermal device (RTD) 1745 is a temperature sensor that detects the temperature of the low temperature plate 1742 and feeds the detected temperature back to an external temperature control system (not shown).

The substrate pusher assembly 1750 is configured to contact the substrate of the DUT. This pusher assembly 1750 includes a rigid pusher plate 1751 and is suitably made of a metallic material such as aluminum for rigidity. The bottom pusher plate has a central opening 1752 so that the pusher end of the thermally conductive pedestal 1741 can protrude through the pusher plate. The pusher assembly 1750 is spring loaded to apply a force F conforming to the z-axis to the die of the DUT via the thermal conductive pedestal 1741 and to the substrate of the DUT by a rigid pusher plate 1751 do. The pins 1753 hold the substrate pusher assembly 1750, the pedestal assembly 1740 and the heater assembly 1720 together tightly using a preloaded spring 1754 that is kept in a generally compressed state. The pins 1753 are aligned with the holes 1746 of the pedestal assembly 1740 to ensure that the device kit module 1730 is properly aligned. In operation, pin 1755 aligns the device kit module 1730 with the socket assembly that supports the DUT.

Figure 17I shows two different configurations for the internal structure of the low temperature plate 1742. To improve the heat exchange efficiency of the low temperature plate 1742, in structure 1747, the internal structure follows a spiral pattern of parallel channels. In an arrangement 1748, the internal structure consists of an array of microchannels.

17K is a perspective view of a 17K-17K (not shown) cut through parts including a thermal head unit (THU) 1700 in a stacked relationship along the z-axis with a socket assembly 1760 and a socket insert 1770 supporting the DUT. (Fig. 17J). A gimbal adapter 1711 follows the protruding portion of the cable connector unit 1701. The pin 1716 ensures that the gimbal adapter 1711 is aligned with the rotatable coupler 1713. The gimbal adapter 1711 is mounted on the force distribution block 1712 and can be easily and uniquely fitted into place without the need to use any tools by using the rotatable coupler 1713 provided with the quick release clip 1714 . The pin 1706 provides for the gimbal adapter 1711 to hard-stop the rotary coupler 1713. The force distribution block 1712 has an upper cover 1707 that fits into the recess 1708. [ The channel 1709 is a passageway for the pressurized fluid to perform a pneumatic actuation on the piston 1718. The piston 1718 is located at the center of the bottom of the force distribution block 1712. The connector 1704 and the connector 1705 are the inlet and the outlet of the fluid circulation block 1703. The cooled fluid is deformed through the fluid passage 1719 embedded in the fluid circulation block 1703. The heater 1721 directly contacts the top of the low temperature plate 1742 which is solidly stacked on the thermally conductive pedestal 1741. The bottom pusher plate should be such that the pusher end of the thermally conductive pedestal 1741 can protrude through the central opening 1752 of the pusher plate 1751. The pusher assembly 1750 is spring loaded to bias the force F conforming to the z-axis into a thermally conductive pedestal 1741 that contacts and pushes the thermally active center portion of the IC chip, such as the die of the DUT 1781, To the die of the DUT, and to the substrate of the DUT 1782 by the pusher plate 1751 of rigidity.

In operation, the temperature of the DUT is maintained at the value specified in the test using the temperature feedback mechanism. The RTD sensor 1745 in the thermal control unit (TCU) 1500 sends the value of the detected temperature to the external controller which controls both the temperature of the heater 1721 and the flow of the cooled fluid. The temperature of the heater 1721 is changed by adjusting the electric current flowing to the heater 1721 through the heater electrical lead 1723. [ The flow of the cooled fluid is controlled by varying the electric current flowing to the solenoid valve 1625.

18 shows a flexible cable chain assembly 1800 that connects an electrical cable to a thermal head unit (THU) 1700 via an electrical connector 1810 with quick release characteristics for connection to a connector 1702 without the use of a tool ). Thus, the chain may be an assembly of individual segments 1812 attached to provide flexibility to the chain to substantially improve the stability of the thermal head unit (THU) 1700 during testing.

In yet another embodiment, a method for reducing condensation is provided. This method includes a condensation-reducing gas inlet, and a condensation-reducing gas carrying passage in a thermal head unit (THU) 1700 near the surface of a thermal control unit (TCU) 1500 where condensation may occur. Other means 1900 for reducing condensation are shown in Figures 19A and 19B. A thermal control unit (TCU) 1500 is surrounded by two drying boxes 1910 and 1920, which provide a dry environment filled with dew condensation-reducing gas. The small box 1910 covers the thermal head unit (THU) 1700 and the large box 1920 includes a drying environment around the fluid management system 1600.

One embodiment of the present invention is directed to a method of controlling the temperature of a fluid in a sub-assembly of a thermal control unit that houses a heat transfer fluid when the sub-assembly is not docked and separated, Solve the problem.

Figure 20 illustrates a configuration 2000 that includes a sub-assembly 2010 in which heat transfer fluid is flowing through sub-assembly 2010 during use. During use, heat transfer fluid flows from inlet port 2020 through sub-assembly 2010 and fluid transmission line 2040 to outlet port 2030. In this state, both the flow valve 2025 (at the inlet port 2020) and the flow valve 2035 (at the outlet port 2030) are both open and there is no pressure rise due to thermal expansion of the heat transfer fluid .

Figure 21 illustrates a configuration 2100 in which flow valve 2025 and flow valve 2035 are closed such that heat transfer fluid does not flow through sub-assembly 2010 during an undocked condition. In this state, the heat transfer fluid is trapped in the sub-assembly 2010 and the fluid transmission line 2040. As the temperature rises from low to room temperature, the heat transfer fluid expands due to thermal expansion and the pressure of the heat transfer fluid rises. As a result, excessive pressure can occur and damage the sub-assembly 2010.

An example of a heat transfer fluid in sub-assembly 2010 is 3M ^TM Novec ^TM Engineered Fluid HFE-7500. The thermal expansion coefficient of HFE-7500 fluid is 0.00129 / K. As the temperature rises from low to room temperature, the HFE-7500 fluid expands due to thermal expansion and the pressure of the HFE-7500 fluid rises. As a result, excessive pressure can occur and damage the sub-assembly 2010. Therefore, it is necessary to reduce the pressure as the temperature rises.

One embodiment of the present invention solves the above-mentioned problem of excessive pressure on the sub-assembly 2010. [ As shown in configuration 2200 of FIG. 22, pressure relief valve 2260 is attached to fluid transmission line 2040. Assembly 2010 and fluid delivery line 2040 to outlet port 2030. The heat transfer fluid flows from inlet port 2020 to sub- In this state, both the flow valve 2025 (at the inlet port 2020) and the flow valve 2035 (at the outlet port 2030) are both open so that the pressure rise due to the thermal expansion of the heat transfer fluid none. The pressure of the heat transfer fluid at the inlet port 2020 is about 90 psi. The pressure of the heat transfer fluid at the outlet port 2030 is approximately 10 psi to 20 psi. The pressurized air is fed into the pressure relief valve 2260 through the valve inlet port 2261 at a pressure of about 80 psi to 100 psi or at some other pressure value that is higher than the operating pressure of the heat transfer fluid. Thus, the air pressure in the pressure relief valve 2260 is sufficient to keep the piston or diaphragm (not shown) in the pressure relief valve 2260 in the lower position 2263.

The advantage of adding a pressure relief valve to prevent excessive pressure from occurring in the sub-assembly of the thermal control unit is better illustrated with reference to Fig. In configuration 2300, both the flow valve 2025 (at the inlet port 2020) and the flow valve 2035 (at the outlet port 2030) are closed. The sub-assemblies are not docked (they are all separate at the inlet port 2020 and the outlet port 2030). As the temperature of the sub-assembly 2010 rises, the heat transfer fluid expands. However, pressure relief valve 2260 is operatively connected to fluid transmission line 2040 via engagement port 2262. In this state, the air supplied to the pressure relief valve 2260 at its input port 2261 is almost zero. Thus, the piston or diaphragm (not shown) in the pressure relief valve 2260 moves to the upper position 2363 under the pressure of the expanded heat transfer fluid. Thus, according to one embodiment of the present invention, the pressure relief valve 2260 prevents excessive pressure from being created in the sub-assembly of the thermal control unit and, due to the occurrence of excessive pressure in the sub-assembly, To prevent damage.

To describe the pressure relief valve 2260 in more detail, FIGS. 24 and 25 are used. Figure 24 shows a cross-sectional view of the pressure relief valve 2260 along axis A-A during use. Pressure relief valve 2260 is comprised of a cylindrical body 2265 and a piston 2264 movable within a cylindrical cover 2266. The piston 2264 has two recessed grooves for receiving two sets of O-ring seals 2267. Two additional sets of O-ring seals are included in the pressure relief valve 2260. There are an upper O-ring sealing material 2268 and a lower O-ring sealing material 2269. The piston 2264 is configured such that the air pressure inside the cylindrical body 2265 is greater than the pressure of the heat transfer fluid at the connection port 2262 of the pressure relief valve 2260 because the configuration 2400 of FIG. It is understood that it is in the lower position because it is possibly larger.

25 shows a cross-sectional view of pressure relief valve 2260 along axis B-B during an undocked condition. In this state, the air supplied from the input port 2261 to the pressure relief valve 2260 is almost zero. Thus, the piston 2264 is free to move upward under the pressure of the heat transfer fluid at the connection port 2262 of the pressure relief valve 2260. Accordingly, pressure relief valve 2260 serves to prevent pressure build-up within the sub-assembly of the thermal control unit. Thus, the pressure relief valve 2260 is effective in preventing excessive pressure from occurring and preventing any damage to the sealed chamber and its seal due to any thermal expansion and excessive pressure of the sub-assembly.

25, the piston 2264 may be replaced by a diaphragm (not shown), which is similar to a piston, such that the pressure relief valve 2260 is in fluid communication with the pressure relief valve 2260. In an alternative embodiment of the present invention, Is understood to be free to move upwardly under the pressure of the heat transfer fluid at the coupling port 2262. [ Thus, the pressure relief valve with the diaphragm serves to prevent pressure build-up within the sub-assembly of the thermal control unit. Thus, a pressure relief valve with a diaphragm is effective to prevent excessive pressure from occurring and prevent any damage to the sealed chamber and its seal due to any thermal expansion and excessive pressure of the sub-assembly.

Thus, while this invention has been described in terms of some embodiments, there may be many variations, modifications, permutations, and equivalents that fall within the scope of the invention. It should also be noted that there are many alternative ways of implementing the method and apparatus of the present invention. Accordingly, it is intended that the appended claims be interpreted as including all such alterations, modifications, permutations, and equivalents as fall within the true spirit and scope of the present invention.

Claims (5)

1. An integrated circuit (IC) device tester configured to maintain a set point temperature in a device under test (DUT) having a die attached to the substrate,
The tester comprising a thermal control unit,
The thermal control unit includes:
A pedestal assembly including a thermally conductive pedestal configured to contact the die of the DUT;
A heat exchange plate having a thermally conductive pedestal and a temperature sensor attached thereto for facilitating thermal conduction from the thermally conductive pedestal and monitoring the temperature;
A temperature-controlled fluid circulation block having a fluid inlet and a fluid outlet configured to circulate the fluid, the fluid circulation block being in a stacked relationship with the thermally conductive pedestal along the z-axis;
A thermally conductive heater configured to provide heat to the pedestal through the heat exchange plate;
A substrate pusher configured to contact the substrate of the DUT;
a controllable force distributor configured to receive a z-axis force and to controllably distribute the z-axis force between the pedestal assembly and the substrate pusher;
A fluid management system configured to supply fluid to the thermal control unit for pneumatic actuation, cooling, and condensation reduction; And
And a pressure relief valve configured to relieve the pressure of the fluid in the thermal control unit. The pressure reducing valve according to claim 1,
A cylindrical body covered with a cylindrical cover;
A piston movable within the cylindrical body and having two recessed grooves for receiving two sets of O-ring seals;
Inlet port; And
And a coupling port configured to couple the pressure relief valve to the fluid management system. The pressure reducing valve according to claim 1,
A cylindrical body covered with a cylindrical cover;
A diaphragm movable within the cylindrical body;
Inlet port; And
And a coupling port configured to couple the pressure relief valve to the fluid management system. A method for preventing excessive pressure from occurring in a fluid management system due to thermal expansion of the fluid,
Coupling a pressure relief valve through the coupling port to the fluid management system;
Supplying pressurized air to the pressure relief valve through the inlet port at a pressure greater than the operating pressure of the heat transfer fluid; And
Wherein the piston in the pressure relief valve is free to move under the pressure of the pressurized air supplied to the pressure relief valve through the inlet port and the pressure of the fluid in the fluid management system. A method for preventing excessive pressure from occurring in a fluid management system due to thermal expansion of the fluid,
Coupling a pressure relief valve through the coupling port to the fluid management system;
Supplying pressurized air to the pressure relief valve through the inlet port at a pressure greater than the operating pressure of the heat transfer fluid; And
Wherein the diaphragm in the pressure relief valve is free to move under the pressure of the pressurized air supplied to the pressure relief valve through the inlet port and the pressure of the fluid in the fluid management system.

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