CN116087739A

CN116087739A - Liquid cooling test system for testing semiconductor integrated circuit chip

Info

Publication number: CN116087739A
Application number: CN202111306143.1A
Authority: CN
Inventors: 周家春; 刘德先; Q·N·阮; 梁齐海
Original assignee: Antares Advanced Test Technologies Suzhou Ltd; Smiths Interconnect Americas Inc
Current assignee: Antares Advanced Test Technologies Suzhou Ltd; Smiths Interconnect Americas Inc
Priority date: 2021-11-05
Filing date: 2021-11-05
Publication date: 2023-05-09

Abstract

A test socket for an IC chip, comprising: a retainer positioned adjacent to a load plate, the retainer defining a plurality of apertures corresponding to contact pads on the load plate; a plurality of contacts disposed in the plurality of holes, the plurality of contacts configured to electrically couple the IC chip to the contact pads; a housing defining a chamber in fluid communication with the inlet, the liquid outlet, and the vapor outlet. The housing includes a body structure defining a plurality of cavities corresponding to the plurality of apertures and configured to receive the plurality of contacts therein, and a guide structure configured to receive the IC chip and position the IC chip in a cavity when engaged with the plurality of contacts. The chamber receives a two-phase fluid coolant via the inlet to at least partially submerge the plurality of contacts in the two-phase fluid coolant.

Description

Liquid cooling test system for testing semiconductor integrated circuit chip

Technical Field

The field of the invention relates generally to a test system for testing semiconductor integrated circuit chips, and more particularly to a system including a liquid cooled test socket in which the test socket contacts are at least partially immersed in a liquid coolant.

Background

Semiconductor Integrated Circuit (IC) chips are produced in various packages or chip configurations and are mass-produced. The production of IC chips typically involves testing each IC chip package (or simply "IC chip") in a manner that simulates the end user's application of the chip. One way to test the IC chips is to connect each IC chip through a test socket to a Printed Circuit Board (PCB) or load board that performs various functions of the IC chip. And then, the IC chip is taken out from the test seat, and the production process is continued according to the test result. The test socket assembly may then be reused to test many IC chips.

IC chip testing is typically highly automated using robotic systems (e.g., "automated handlers") to move IC chips into and out of test sites. This includes disposing each IC chip in a test socket attached to a load board during testing, and removing the IC chip when testing is complete. Some robotic systems may process tens or hundreds of IC chips to tens of thousands of IC chips per hour. Thus, the accuracy and durability of the test socket is necessary. Furthermore, modern IC chips incorporate higher density semiconductor elements that operate at higher frequencies, higher current throughput, and higher power consumption. Adequate testing of such IC chips typically results in significant heating of the IC chips and the test sockets, which can degrade the test sockets over time and, if not mitigated, affect the integrity of the test itself, resulting in a reduction in the lifecycle of the test sockets. It is therefore desirable to cool the IC chip under test and the test socket through which the IC chip is coupled to the load board.

Disclosure of Invention

In one aspect, a test socket for an IC chip includes: a retainer configured to be positioned adjacent to the load plate, the retainer defining a plurality of apertures corresponding to contact pads on the load plate; a plurality of contacts disposed in the plurality of holes, the plurality of contacts configured to electrically couple the IC chip to the contact pads; a housing at least partially defining a chamber in fluid communication with the inlet, the liquid outlet, and the vapor outlet. The housing includes a guide structure configured to receive the IC chip and position the IC chip in the cavity when engaged with the plurality of contacts. The chamber is configured to receive a two-phase fluid coolant via the inlet to at least partially submerge the plurality of contacts in the two-phase fluid coolant.

In another aspect, a test system for a plurality of IC chips includes a test site, a fluid coolant system, and a handler system. The test site includes a test socket coupled to a load board. The test seat includes a housing, a plurality of contacts, and a guide structure. The housing at least partially defines a chamber. A plurality of contacts are disposed within the retainer structure within the chamber and are electrically coupled to the load board. The guide structure is configured to receive each of the plurality of IC chips and, when engaged with the plurality of contacts, position each IC chip in the chamber. The fluid coolant system includes a reservoir configured to hold a two-phase fluid coolant, an inlet path coupled between the reservoir and the test seat, an inlet path configured to deliver the two-phase fluid coolant to the test seat to at least partially fill the chamber, a liquid outlet path coupled between the reservoir and the test seat, a liquid outlet path configured to deliver heated liquid coolant away from the test seat, and a vapor outlet path coupled between the reservoir and the test seat, the test seat configured to deliver coolant vapor away from the test seat. The handler system is configured to move a plurality of IC chips from a feed container to the test site and from the test site to an output container. The handler system includes a pick-up arm configured to position each IC die into the guide structure of the test socket to engage a plurality of contacts at least partially immersed in the two-phase fluid coolant.

In yet another aspect, a method of testing an IC chip includes coupling a test socket to a load board. The test seat defines a cavity in which a plurality of contacts are disposed. The plurality of contacts are configured to electrically couple the IC chip to the load board. The method includes supplying a two-phase fluid coolant to the chamber to at least partially submerge the plurality of contacts. The method includes receiving an IC chip in a guide structure of a test socket to position the IC chip in a cavity when engaged with a plurality of contacts. The method includes performing an electrical test of the IC chip with the load board. The method includes removing heated liquid coolant via a liquid outlet defined in the test seat. The method includes removing coolant vapor via a vapor outlet defined in the test seat.

Various refinements exist of the features noted in relation to the above-noted aspects. Other features may also be incorporated in the above aspects as well. These refinements and additional features may exist individually or in any combination. For example, the various features discussed below with respect to any of the illustrated embodiments may be incorporated into any of the above aspects, alone or in any combination.

Drawings

FIG. 1A is a block diagram of a test system for an IC chip;

FIG. 1B is a cross-sectional view of an example test system for an IC chip;

FIGS. 2A and 2B are schematic diagrams of one embodiment of a test seat for at least partially immersing test seat contacts in a fluid coolant;

FIG. 3 is a cross-sectional view of one embodiment of a test seat for at least partially immersing test seat contacts in a fluid coolant;

FIG. 4 is a cross-sectional view of another embodiment of a test socket for at least partially immersing an IC chip in a fluid coolant;

FIG. 5 is a schematic diagram of an exemplary fluid coolant system for use with the test seat shown in FIG. 3 or FIG. 4;

FIG. 6 is a cross-sectional view of another embodiment of a test socket for at least partially immersing an IC chip in a fluid coolant;

FIG. 7 is a schematic diagram of another exemplary fluid coolant system for use with the test seat shown in FIG. 6; and

figure 8 is a flow chart of one embodiment of a method of testing an IC chip.

Although specific features of various embodiments are shown in some drawings and not in others, this is for convenience only. Any feature of any figure may be referenced and/or claimed in combination with any feature of any other figure.

The drawings provided herein are intended to illustrate features of embodiments of the present disclosure, unless otherwise indicated. These features are believed to be applicable to a variety of systems including one or more embodiments of the present disclosure. Accordingly, the drawings are not meant to include all the conventional features known to those of ordinary skill in the art as needed to practice the embodiments disclosed herein.

Detailed Description

Known systems and methods for cooling IC chips are generally limited to removing heat from the IC chip itself. For example, common cooling schemes utilize a heat sink, fan, or heat pipe to absorb heat from the package of the IC chip and release it into the surrounding environment or other substances (e.g., a coolant reservoir). Such solutions are generally not capable of cooling the contact interface of the IC chip, the contact probes in the test socket or the test socket itself.

The disclosed test socket at least partially submerges its contacts in a fluid coolant, and in some embodiments, in a liquid coolant. The test socket defines a sealed chamber that rests on a top surface of the load board, and wherein the test socket interfaces with both the load board and the IC chip when a Device Under Test (DUT) is inserted. The sealed chamber receives a fluid coolant through the inlet, and the fluid coolant fills the sealed chamber to a level that at least partially submerges a test seat contact, such as a spring probe or a rotary contact. In some embodiments, the socket contacts and the contact balls or pads of the IC chip are completely submerged. In certain embodiments, the IC die is at least partially submerged, and optionally completely submerged.

The fluid coolant is electrically insulating and has a low and stable dielectric constant. For example, the fluid coolant may include a perfluoro compound (PFC), such as perfluorohexane, perfluorohexafluoropropylene, or perfluorotripentylamine. PFCs are sometimes referred to as inert fluids ^TM (Fluorinert ^TM ) It is an example of 3M fabrication. The low conductivity of the coolant prevents the formation of shorts between the test seat contacts. The low dielectric constant maintains signal integrity through the socket pins between the IC chip and the load board. Given a fluid coolant having a dielectric constant greater than vacuum or ambient air, the properties of the test seat can be modified to compensate for the additional dielectric material surrounding the test seat contacts, i.e., the fluid coolant. For example, a cavity defined in the test socket for receiving the coaxial contact may be sized based on the dielectric constant of a fluid coolant that will flow through the cavity and the cavity between the IC chip and the load board.

That is, when introduced into the chamber, the fluid coolant may be a liquid near room temperature and, in some embodiments, has a relatively low vaporization threshold. In general, liquid coolants have a greater heat absorbing capacity than gaseous coolants. The liquid coolant is heated by the test socket, the test socket contacts, and the IC chip. In some embodiments, the liquid coolant is heated below a vaporization threshold and flows from the chamber through the liquid outlet. Such an embodiment utilizes a coolant known as a single-phase coolant, i.e., a coolant that operates only in the liquid phase. For example, the fluid coolant may have a vaporization threshold equal to or greater than about 100 degrees celsius. In other embodiments, the vaporization threshold may be higher or lower.

Alternatively, the test socket contacts, and the IC chip raise the temperature of the liquid coolant above a vaporization threshold (e.g., above about 40 to 60 degrees celsius). Such fluid coolants are sometimes referred to as two-phase coolants, i.e., at various points during cooling, they take on both gaseous and liquid states or phases. The coolant vapor rises within the chamber and flows from the chamber through the vapor outlet. Some two-phase embodiments may include a liquid outlet and a vapor outlet for the heated coolant. A seal applied between the test seat and the load plate prevents leakage of liquid or vapor coolant at the interface. Also, in embodiments having a test seat made up of two or more body structures (e.g., seat body and retainer), seals are applied between the body components to prevent leakage of liquid or vapor coolant at these interfaces. Vaporized coolant, once removed from the chamber, typically has a greater capacity to effectively release heat.

The fluid coolant is supplied from the reservoir using an inflow pump, gravity, or other suitable power. Unheated or fresh fluid coolant flows into the chamber until a desired fill level is reached. For example, the fill level may be detected by one or more sensors located on the test seat. The sensor may comprise, for example, a pressure transducer or an optical sensor. In certain embodiments, one or more additional sensors may be positioned in the chamber, for example, to measure the coolant temperature within the chamber. From the chamber, the heated coolant flows through the outlet into the same reservoir for cooling and recirculation, or a second reservoir for cooling and recirculation or for treatment. The heated coolant exiting the chamber may include a liquid coolant, coolant vapor, or both. For example, in one embodiment, the heated coolant flows from the chamber in the liquid phase only. In an alternative embodiment, the heated coolant flows from the chamber in both liquid and gas phases.

The heated coolant must be cooled to enable recirculation, which can be achieved, for example, by a refrigerant cooling system. The heated coolant may flow from the chamber under pressure from the inlet, or alternatively, may move by an outflow pump, gravity, or other suitable motive force. The pressure of the heated fluid coolant may be measured using one or more pressure sensors disposed in the return coolant flow path. In certain embodiments, the heated coolant is filtered to remove particulates or other contaminants before it reaches the pump, cooler, or reservoir. The flow of fluid coolant through the chamber may be regulated according to a flow algorithm based on measured temperature, pressure, flow rate, or other operating parameters. The flow algorithm may include a constant flow set point that is determined by a look-up table or programmed by the user according to IC chip size and power requirements. Alternatively, for example, the flow algorithm may dynamically adjust the outflow to achieve a desired coolant outlet temperature set point or a desired coolant pressure set point.

The fluid coolant system may be incorporated into a test system known as an automated handler system or provided separately. In certain embodiments, the fluid coolant system serves multiple test seats or test sites within the automated handler system, thereby achieving greater efficiency in the scale of the fluid coolant system. The test system or automated handler may include additional venting devices to vent coolant vapors escaping from the test seats. Also, in certain embodiments, additional sealants or seals may be incorporated into the test system housing to ensure that coolant vapors do not escape the test system.

Fig. 1A is a block diagram of a test system 100 for an IC chip 102. FIG. 1B is a schematic cross-sectional view of test system 100. Test system 100 is sometimes more generally referred to as an "automated handler" or "automated test equipment. The test system 100 is an automated system for electrically testing thousands of IC chips 102 over a given period of time. The test system 100 includes a handler system 104 that moves IC chips from an input or feed container 106 to one or more test sites 108 and then to an output container 110. The feed container 106 may include, for example, a molded tray for precisely orienting and securing each IC chip 102 as it moves through the processor system 104. Likewise, output receptacle 110 may include, for example, one or more output trays or bins for collecting IC chips that "pass" or "fail" electrical tests. In some embodiments, the feed container 106 and the output container 110 may be a single container as shown in fig. 1B. The handler system 104 also includes a pick arm 112 or pick system that retrieves the IC chips 102 from the feed container 106 and disposes the IC chips 102 into test seats 114 at a given test site 108. In some embodiments, the pick-up arm 112 may continue to apply force to the IC chip 102 under test in the direction of the test socket (e.g., downward) during electrical testing. Alternatively, the pick arm 112 may release the IC chip 102 under test during testing. When the electrical test is completed, the pick arm 112 removes the IC chip 102 from the test socket 114 and disposes the IC chip 102 in the output container 110, which may include, for example, a pass box and a fail box. Pick arm 112 then retrieves another IC chip 102 from feed container 106 for another electrical test cycle.

The test system 100 may include one or more test sites 108 and a processor system 104. In addition, each handler system 104 may supply IC chips 102 to a plurality of test sites 108 and a plurality of test seats 114. For clarity only, FIG. 1 shows a single handler system 104 for a single test site 108 and a single test seat 114.

Each test seat 114 is mounted or coupled to a surface of a load board 116. Load board 116 is a Printed Circuit Board (PCB) configured to perform automated electrical testing on a given IC chip, such as IC chip 102. The load board 116 may house one or more test sockets 114 for electrically testing a plurality of IC chips 102 substantially simultaneously. For example, a given test site 108 may include one or more load boards 116, each having one or more test seats 114 mounted thereon.

The test system 100 includes a fluid coolant system 118. The fluid coolant system 118 includes a reservoir 120 of fluid coolant, and in some embodiments, the coolant is liquid at a temperature near room temperature (e.g., near 20-25 degrees celsius), and in some embodiments has a relatively low vaporization threshold, such as in the range of about 40 to 60 degrees celsius. Such a coolant is called a two-phase coolant. In alternative embodiments, the vaporization threshold may be higher, for example, about 60 to 70 degrees celsius, about 70 to 80 degrees celsius, about 80 to 90 degrees celsius, about 90 to 100 degrees celsius, or any other suitable threshold temperature for the particular test seat and test system. The fluid coolant is electrically insulating or non-conductive and has a low dielectric constant. Fluid coolant is supplied from reservoir 120 through inflow path 122 to one or more test sites 108, each having one or more test seats 114. The fluid coolant may be supplied by means of inflow pump 124, gravity, or any other suitable power. The liquid coolant is heated by the test socket 114, the test socket contacts, and the IC chip 102. In some embodiments, the liquid coolant is heated below a vaporization threshold and flows from the chamber through the liquid outlet. Such embodiments utilize a coolant referred to as a single-phase coolant (i.e., a coolant that operates only in the liquid phase). For example, the fluid coolant may have a vaporization threshold at about 100 degrees celsius or above.

Alternatively, the test socket 114, the test socket contacts, and the IC chip 102 raise the temperature of the liquid coolant above a vaporization threshold (e.g., above about 40 to 60 degrees celsius). Such fluid coolants are sometimes referred to as two-phase coolants, i.e., at various points during cooling, they take on both gaseous and liquid states or phases. The coolant vapor rises within the chamber formed by the test seat 114 and flows out of the chamber through the vapor outlet. Some two-phase embodiments may include both a liquid outlet and a vapor outlet for the heated coolant.

Once heated at the test site 108, the fluid coolant is removed through the outflow path 126 and returned to the reservoir 120 to be cooled and recycled. The heated coolant exiting the chamber may include a liquid coolant, coolant vapor, or both. For example, in one embodiment, the heated coolant flows from the test site 108 only in the liquid phase. In an alternative embodiment, the heated coolant flows from the test site 108 in both liquid and gas phases.

The heated coolant must be cooled to enable recirculation, which can be achieved, for example, by a refrigerant cooling system. The heated coolant may flow from the chamber under pressure from the inlet, or alternatively, may move by an outflow pump, gravity, or other suitable motive force. The pressure of the heated fluid coolant may be measured using one or more pressure sensors disposed in the return coolant flow path. In certain embodiments, the heated coolant is filtered to remove particulates or other contaminants before it reaches the pump, cooler, or reservoir.

In alternative embodiments, the heated fluid coolant may be returned to a second reservoir (not shown) for cooling via outflow path 126, and in certain embodiments, recirculated to reservoir 120. Inflow path 122 and outflow path 126 each comprise a suitable fluid conduit or duct, including, for example, metal or plastic tubing. The fluid coolant may flow to the reservoir 120 through the outflow path 126 with the aid of the outflow pump 128, gravity, or any other suitable motive force.

In certain embodiments, the fluid coolant system 118 includes a pump controller (not shown) having one or more processing devices and a memory configured to operate (i.e., control) the torque or speed output of the inflow pump 124, the outflow pump 128, or both. In certain embodiments, the pump controller operates the inflow pump 124 to fill the test seat 114 to a predetermined fill level. Alternatively, the pump controller may operate the inflow pump 124 until a desired fill level is detected, for example, by one or more sensors (such as pressure sensors or optical sensors). Similarly, once the desired fill level is detected, the pump controller may operate the outflow pump 128 to remove heated coolant at a selected rate. The rate may be programmed into the memory or, alternatively, the user may select. In alternative embodiments, the pump controller may execute a control algorithm for dynamically adjusting outflow from the test seat 114 based on one or more parameters or set points. For example, the pump controller may operate the outflow pump 128 to remove heated coolant at a selected rate to achieve a desired temperature of the heated coolant.

The test system 100 includes a housing 130 in which the test site 108 and the handler system 104 are disposed. The housing 130 provides a controlled environment for testing the IC chip, including, for example, ambient temperature, humidity, or ambient air composition. In at least some embodiments, the fluid coolant system 118 can introduce at least some amount of coolant vapor that escapes from the test site 108. Accordingly, the test system 100 includes a ventilation subsystem 132 to vent steam from the interior of the enclosure 130 or to exchange ambient air within the enclosure 130 with another volume. Additionally, in certain embodiments, the test system 100 may include one or more seals 134, for example, to help trap coolant vapor within the enclosure 130 and avoid undesired leakage through doors, hatches, or other openings in the enclosure 130.

Fig. 2A is a perspective schematic view of a test socket 200 for at least partially immersing a plurality of test socket contacts (not shown) in a fluid coolant. Fig. 2B is a perspective cross-sectional view of the test socket 200. The test seat 200 includes a housing 202 at least partially defining a chamber 204, one or more inlets 206, and one or more outlets 208. The test socket 200 also includes a guide structure 210 configured to receive the IC chip and position the IC chip in the cavity 204 when engaged with the plurality of test socket contacts. The test socket 200 includes a body structure 212 that holds a holder cartridge 214 defining a plurality of cavities (not shown) configured to receive a plurality of test socket contacts. The chamber 204 is configured to receive a fluid coolant via one or more inlets 206 to at least partially submerge the plurality of test seat contacts in the fluid coolant. In certain embodiments, the filling level of the fluid coolant is sufficient to at least partially submerge the IC die itself. The inlet 206 and the outlet 208 are fluidly coupled to a fluid coolant system, such as the fluid coolant system 118 shown in fig. 1, more specifically, for example, the inlet 206 is in fluid communication with the inflow path 122; and the outlet 208 is in fluid communication with the outflow path 126.

The housing 202 also defines one or more channels to receive seals for retaining the fluid coolant within the chamber 204. For example, the housing 202 defines a channel facing the retainer cartridge 214 to receive the cartridge seal 216. The cartridge seal 216 prevents leakage of fluid coolant at the interface between the housing 202 and the retention cartridge 214. The retainer tube 214 defines an additional channel configured to face the load plate. The additional channel receives PCB seal 218. The PCB seal 218 prevents leakage of the fluid coolant at the interface between the test seat 200 and the load plate as the fluid coolant flows around the test seat contacts through the chamber defined in the holder cartridge 214.

Fig. 3 is a cross-sectional view of a test socket 300 for at least partially immersing test socket contacts 302 in a fluid coolant 304. Fig. 4 is a cross-sectional view of another embodiment of the test socket 300 shown in fig. 3 for at least partially immersing an IC die 306 in a liquid coolant 304. FIG. 5 is a schematic diagram of an exemplary fluid coolant system for use with a test seat, such as the test seat 300 shown in FIG. 3 or FIG. 4. Referring to fig. 3 or 4, the test seat 300 includes a housing 305 at least partially defining a chamber 310. The test socket includes a body structure 308 defining a plurality of cavities in which the test socket contacts 302 are disposed to electrically connect the IC chip 306 and the load board 314. The cavity is sized to receive the socket contact 302 and allow fluid to flow within the chamber 310 and, more specifically, between the interface between the IC chip 306 and the socket contact 302 and the interface between the socket contact 302 and the load plate 314. The test seat 300 includes a retainer 312 positioned adjacent to the load plate 314, for example, mounted to a top surface of the load plate 314. The load plate 314 includes a plurality of contact pads 316. The retainer 312 defines a plurality of apertures corresponding to the contact pads 316 on the load plate 314 and corresponding to the cavities in the body structure 308. The test socket contacts 302 are disposed in the holes of the holder 312 and the cavity of the body structure 308 and electrically couple the IC chip 306 to contact pads 316 on the load board 314 for electrical testing on the IC chip 306.

The test socket 300 includes a guide structure 318 configured to receive the IC chip 306 and to position the IC chip 306 in the chamber 310 when engaged with the test socket contacts 302. The guide structure 318 enables the IC chip 306 to be precisely inserted into the chamber 310, for example, by an automated handler system such as that shown in fig. 1. The housing 305 also defines one or more inlets 322 and one or more outlets 324. Inlet 322 and outlet 324 are in fluid communication with a fluid coolant system (e.g., fluid coolant system 118 shown in fig. 1). Inlet 322 is capable of introducing fluid coolant 304 (e.g., liquid coolant) into chamber 310. Fluid coolant fills around the test seat contacts 302, through the retainers 312 to the top surface of the load plate 314. One or more PCB seals 326 are positioned between the holder 312 and the load plate 314 to prevent fluid coolant from escaping between the test seat 300 and the load plate 314. An additional cartridge seal 327 is also located between the retainer 312 and the guide structure 318 of the test seat 300, or alternatively between the retainer 312 and the body structure 308. In alternative embodiments, the body structure 308, the guide structure 318, and the retainer 312 may be combined into a single unitary structure, thereby eliminating the need for a seal between the retainer 312 and the guide structure 318, for example. The body structure 308, the guide structure 318, and the retainer 312 may be made of metal, metal alloy, or plastic. For example, the body structure 308, the guide structure 318, and the retainer 312 may be made of aluminum, magnesium, titanium, zirconium, copper, iron, or any alloy thereof (e.g., aluminum 5053). Alternatively, body structure 308, guide structure 318, and retainer 312 may be made of, for example, polyetheretherketone (PEEK), ceramic PEEK, MDS100, SCP 5000, or other suitable materials.

The fluid coolant fills the chamber 310 until a desired fill level is reached. For example, the body structure 308 includes a sensor 328 configured to detect a fill level within the chamber 310. In the embodiment of fig. 3, sensor 328 is located at the same level as IC chip 306. Thus, the fluid coolant 304 submerges the test seat contacts 302. Similarly, in the embodiment of fig. 4, sensor 328 is located at a level above the top surface of IC chip 306. Thus, the fluid coolant 304 submerges at least a portion of the test socket contacts 302 and the IC chip 306. In certain embodiments, one or more additional sensors may be positioned in the chamber, for example, to measure the coolant temperature within the chamber.

FIG. 5 illustrates the fluid coolant system 118 of FIG. 1 in use with a test seat 300. The fluid coolant system 118 includes a reservoir 120 fluidly coupled to an inflow pump 124. In certain embodiments, one or more sensors 140 may be included within the reservoir 120 to measure the fill level of the fluid coolant within the reservoir 120. The inflow pump 124 moves fluid coolant from the reservoir 120 through the inflow path 122 to the inlet 322 of the test seat 300. The heated coolant exits the test seat 300 through the outlet 324 and flows back to the fluid coolant system 118 via the outflow path 126. The outflow path 126 is fluidly coupled to an outflow pump 128 to help move the heated coolant back to the reservoir 120 for recirculation. The outflow path 126 may include a pressure sensor 136 for measuring the fluid pressure of the heated coolant flowing from the outlet 324. The outflow path 126 may include a filtration system 138 for capturing particulates or other contaminants from the heated coolant before the heated coolant is returned to the reservoir 120.

The fluid cooling system 118 includes a chiller 130 that receives the heated coolant from the outflow path 126 and cools the fluid coolant to a temperature suitable for re-circulation to the test seat 300. In certain embodiments, the cooler 130 also condenses the fluid coolant back to a liquid state in the event that the fluid coolant exits the test seat 300 as a vapor. Once the fluid coolant is cooled and condensed, it flows back to the reservoir 120 for recirculation.

Fig. 6 is a cross-sectional view of a test socket 600 for at least partially immersing the test socket contacts 302 in a fluid coolant 304. More specifically, the test socket 600 is configured for a two-phase coolant, i.e., a coolant that operates in both liquid and gas phases during cooling. To the extent that similar components of the test socket 300 shown in fig. 3 and 4 are included in the test socket 600, a common part number is used in the description of the test socket 600. FIG. 7 is a schematic diagram of an exemplary fluid coolant system 118 for use with a test socket, such as the test socket 600 shown in FIG. 6. Referring to FIG. 6, a test seat 600 includes a housing 305 at least partially defining a chamber 310. The test socket 600 includes a body structure 308 defining a plurality of cavities in which the test socket contacts 302 are disposed to electrically connect the IC chip 306 and the load board 314. The cavity is sized to receive the socket contact 302 and allow fluid to flow within the chamber 310 and, more specifically, between the interface between the IC chip 306 and the socket contact 302 and the interface between the socket contact 302 and the load plate 314. The test seat 600 includes a retainer 312 positioned adjacent to the load plate 314, for example, mounted to a top surface of the load plate 314. The load plate 314 includes a plurality of contact pads 316. The retainer 312 defines a plurality of apertures corresponding to the contact pads 316 on the load plate 314 and corresponding to the cavities in the body structure 308. The test socket contacts 302 are disposed in the holes of the holder 312 and the cavity of the body structure 308 and electrically couple the IC chip 306 to contact pads 316 on the load board 314 for electrical testing on the IC chip 306.

The test socket 600 includes a guide structure 318 configured to receive the IC chip 306 and position the IC chip 306 in the chamber 310 when engaged with the test socket contacts 302. The guide structure 318 enables the IC chip 306 to be precisely inserted into the chamber 310, for example, by an automated handler system such as that shown in fig. 1. The housing 305 also defines one or more inlets 322, one or more liquid outlets 324, and one or more vapor outlets 330. The inlet 322, liquid outlet 3330, and vapor outlet 332 are in fluid communication with a two-phase fluid coolant system (e.g., fluid coolant system 118 shown in fig. 1 or 7). Inlet 322 is capable of introducing fluid coolant 304 (e.g., liquid coolant) into chamber 310. Fluid coolant fills around the test seat contacts 302, through the retainers 312 to the top surface of the load plate 314. One or more PCB seals 326 are positioned between the holder 312 and the load plate 314 to prevent fluid coolant from escaping between the test seat 600 and the load plate 314. An additional cartridge seal 327 is also positioned between the retainer 312 and the guide structure 318 of the test seat 600, or alternatively between the retainer 312 and the body structure 308. In alternative embodiments, the body structure 308, the guide structure 318, and the retainer 312 may be combined into a single unitary structure, thereby eliminating the need for a seal between the retainer 312 and the guide structure 318, for example. The body structure 308, the guide structure 318, and the retainer 312 may be made of metal, metal alloy, or plastic. For example, the body structure 308, the guide structure 318, and the retainer 312 may be made of aluminum, magnesium, titanium, zirconium, copper, iron, or any alloy thereof (e.g., aluminum 5053). Alternatively, body structure 308, guide structure 318, and retainer 312 may be made of, for example, polyetheretherketone (PEEK), ceramic PEEK, MDS100, SCP 5000, or other suitable materials.

The fluid coolant fills the chamber 310 until a desired fill level is reached. For example, the body structure 308 includes a sensor 328 configured to detect a fill level within the chamber 310. In the embodiment of fig. 6, sensor 328 is located at a level above the top surface of IC chip 306. Thus, the fluid coolant 304 submerges at least a portion of the test socket contacts 302 and the IC chip 306. In certain embodiments, one or more additional sensors 334 may be positioned in the chamber, for example, to measure the coolant temperature within the chamber.

Fig. 7 illustrates the fluid coolant system 118 of fig. 1 used with a two-phase coolant and test seat 600. The fluid coolant system 118 includes a reservoir 120 fluidly coupled to an inflow pump 124. In certain embodiments, one or more sensors 140 may be included within the reservoir 120 to measure the fill level of the fluid coolant within the reservoir 120. The inflow pump 124 moves fluid coolant from the reservoir 120 through the inflow path 122 to the inlet 322 of the test seat 600. The heated liquid coolant exits the test seat 600 through the liquid outlet 330 and flows back to the fluid coolant system 118 via the outflow path 126. The outflow path 126 is fluidly coupled to an outflow pump 128 to help move the heated coolant reservoir back to the reservoir 120 for recirculation. The outflow path 126 may include a pressure sensor 136 for measuring the fluid pressure of the heated coolant flowing from the liquid outlet 330. The outflow path 126 may include a filtration system 138 for capturing particulates or other contaminants from the heated coolant before the heated coolant is returned to the reservoir 120. Likewise, some of the heated coolant evaporates, and the coolant vapor 336 exits the test seat 600 through the vapor outlet 332 and flows back to the fluid coolant system 118 via the vapor passage 142. The vapor passage 142 is fluidly coupled to a vapor pump 144 to assist in moving coolant vapor back to the cooler 130 for condensation and ultimately to the reservoir 120 for recirculation.

Fig. 8 is a flow chart of one embodiment of a method 800 of testing an IC chip (e.g., IC chip 306 shown in fig. 6) using a test socket (e.g., test socket 600 shown in fig. 6). The test socket 600 is coupled 802 to the load board 314. The test socket 600 defines a chamber 310 with the test socket contacts 302 disposed within the chamber 310. The test socket contacts 302 are configured to electrically couple the IC chip 306 to a load board 314. A two-phase fluid coolant is supplied 804 to the chamber 310 to at least partially submerge the plurality of test seat contacts 302. In some embodiments, a two-phase fluid coolant is supplied to chamber 310 to at least partially submerge IC die 306 in addition to test seat contacts 302. The guide structure 318 receives 806 the IC chip 306 and guides it precisely into the chamber 310, and more specifically, into engagement with the test socket contacts 302.

Once IC chip 306 is in place within test socket 600, load board 314 is used to perform 808 electrical testing of IC chip 306. Electrical testing typically results in the IC chip 306 consuming a large amount of power, and current being conducted through at least some of the socket contacts 302, resulting in substantial heating of the socket 600 (and more specifically the socket contacts 302, the housing 305, and the IC chip 306). At least the two-phase fluid coolant in which the test seat contacts 302 are at least partially immersed circulates within the chamber 310 and is removed from the chamber 310 once sufficiently heated. The heated liquid coolant is removed 810 via the liquid outlet 330 defined in the test seat 600. When the heated liquid coolant is heated to a vaporization threshold, coolant vapor is removed 612 through vapor outlet 332.

The liquid and vapor coolant returns to the chiller for cooling and condensing, and then flows to the reservoir 120 for recirculation to the test seat 600. When the electrical test is completed, the IC chip 306 is removed from the test socket 600 and transferred into the output receptacle. The test socket 600 may then be used to perform electrical testing on the next IC chip 306.

Example technical effects of the methods, systems, and apparatus described herein include at least one of: (a) At least partially immersing at least a test socket contact in a fluid coolant to directly cool the test socket contact, the interface between the test socket contact and the load plate, and the interface between the test socket contact and the IC chip; (b) At least partially immersing an IC chip under test in a fluid coolant to directly cool the IC chip and a test socket housing in addition to the test socket contacts; (c) Signal integrity is maintained by the test seat contacts being immersed in a non-conductive and low dielectric constant fluid coolant; (d) Increasing the heat absorbing and releasing capacities of the fluid coolant by using the fluid coolant which is liquid at about room temperature and has a low vaporization threshold; (e) Improving the heat absorption and release capabilities of the single-phase coolant by increasing the flow rate through the test seat; (f) Controlling the flow of fluid coolant supplied to and removed from the test seat to achieve a desired coolant temperature, test seat contact temperature, IC chip temperature, or other suitable parameter; (g) improving the service life of the test socket contacts; and (h) reducing downtime for the test system to replace the test socket contacts.

The systems and methods described herein are not limited to the specific embodiments described herein, but rather, components of the systems and/or steps of the methods may be utilized independently and separately from other components and/or steps described herein.

Although specific features of various embodiments of the disclosure may be shown in some drawings and not in others, this is for convenience only. Any feature of the drawings may be referenced and/or claimed in combination with any feature of any other drawings in accordance with the principles of the present disclosure.

As used herein, an element or step recited in the singular and proceeded with the word "a" or "an" should be understood as not excluding plural elements or steps, unless such exclusion is explicitly recited. Furthermore, references to "one embodiment" or "an example embodiment" of the present disclosure are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.

Unless specifically stated otherwise, a separate language such as the phrase "at least one of X, Y or Z" is generally understood in the context that the term, etc., may be X, Y or Z or any combination thereof (e.g., X, Y and/or Z). Thus, such a separable language is not generally intended and should not imply that certain embodiments require at least one of X, at least one of Y, or at least one of Z to each be present. In addition, unless explicitly stated otherwise, a connection language such as the phrase "at least one of X, Y and Z" should also be understood to mean X, Y, Z or any combination thereof (including "X, Y and/or Z").

This written description uses examples to disclose various embodiments, including the best mode, to enable any person skilled in the art to practice those embodiments, including making and using any devices or systems and performing any incorporated methods. The patentable scope is defined by the claims, and may include other examples that occur to those skilled in the art. These other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.

Claims

1. A test socket for an Integrated Circuit (IC) chip, the test socket comprising:

a retainer configured to be positioned adjacent to a load plate, the retainer defining a plurality of apertures corresponding to contact pads on the load plate;

a plurality of contacts disposed in the plurality of holes, the plurality of contacts configured to electrically couple the IC chip to the contact pads; and

a housing at least partially defining a chamber in fluid communication with an inlet, a liquid outlet, and a vapor outlet, the housing comprising:

A guide structure configured to receive the IC chip and position the IC chip in the chamber when engaged with the plurality of contacts;

wherein the chamber is configured to receive a two-phase fluid coolant via the inlet to at least partially submerge the plurality of contacts in the two-phase fluid coolant.

2. The test socket of claim 1, wherein the plurality of contacts comprises a plurality of coaxial contact probes.

3. The test socket of claim 1, wherein the plurality of contacts comprises a plurality of rotating contacts.

4. The test seat of claim 1, wherein the chamber is further configured to receive a perfluorinated compound as the two-phase fluid coolant.

5. The test seat of claim 1, further comprising a sensor disposed on the housing and configured to detect a temperature of the two-phase fluid coolant within the chamber.

6. The test seat of claim 1, further comprising a sensor disposed on the housing and configured to detect a fill level of the two-phase fluid coolant within the chamber, wherein the sensor is positioned to detect the fill level such that the plurality of contacts are at least partially submerged in the two-phase fluid coolant.

7. The test seat of claim 1, further comprising a sensor disposed on the housing and configured to detect a fill level of the two-phase fluid coolant within the chamber, wherein the sensor is positioned to detect the fill level such that the IC chip is at least partially immersed in the two-phase fluid coolant.

8. The test seat of claim 1, wherein the chamber is further configured to receive the two-phase fluid coolant in a liquid state at room temperature, and wherein the fluid coolant has a vaporization threshold of no more than 60 degrees celsius.

9. A test system for a plurality of Integrated Circuit (IC) chips, comprising:

a test site, comprising:

a test socket coupled to a load board, the test socket comprising:

a housing at least partially defining a chamber;

a plurality of contacts disposed within a retainer structure within the chamber and electrically coupled to the load board; and

a guide structure configured to receive each of the plurality of IC chips and position each IC chip in the chamber when engaged with the plurality of contacts;

a fluid coolant system comprising:

A reservoir configured to hold a two-phase fluid coolant;

an inlet path coupled between the reservoir and the test seat, the inlet path configured to carry the two-phase fluid coolant to the test seat to at least partially fill the chamber; and

a liquid outlet path coupled between the reservoir and the test seat, the liquid outlet path configured to carry heated liquid coolant away from the test seat;

a vapor outlet path coupled between the reservoir and the test seat, the vapor outlet path configured to carry coolant vapor away from the test seat; and

a handler system configured to move the plurality of IC chips from a feed container to the test site and from the test site to an output container, the handler system comprising a pick arm configured to dispose each IC chip into the guide structure of the test socket to engage the plurality of contacts at least partially submerged in the two-phase fluid coolant.

10. The test system defined in claim 9, wherein the test site further comprises a load board configured to conduct an electrical test on the IC chip.

11. The test system of claim 9, wherein the test site comprises a plurality of test seats coupled to the fluid coolant system.

12. The test system defined in claim 9, wherein the fluid coolant system comprises an inflow pump coupled to the reservoir and the inlet path, the inflow pump configured to move the two-phase fluid coolant through the inlet path into the chamber of the test seat until a fill level is reached.

13. The test system defined in claim 9, wherein the fluid coolant system comprises an outflow pump coupled to the reservoir and the liquid outlet path, the outflow pump configured to move heated liquid coolant from the chamber of the test seat through the liquid outlet path at a selected flow rate.

14. The test system defined in claim 13, wherein the fluid coolant system further comprises a vapor pump coupled to the reservoir and the vapor outlet path, the vapor pump configured to move heated coolant vapor from the chamber of the test seat through the vapor outlet path at a selected flow rate.

15. The test system of claim 9, wherein the fluid coolant system further comprises a filtration system fluidly coupled in the liquid outlet path to remove contaminants from the heated liquid coolant.

16. The test system defined in claim 9, wherein the fluid coolant system further comprises a sensor coupled in the liquid outlet path and configured to measure a pressure of heated liquid coolant flowing from the test seat.

17. The test system of claim 9, further comprising a housing within which the test site and the handler system are arranged, wherein the housing includes a ventilation system configured to vent coolant vapor emanating from the test site.

18. A method of testing an Integrated Circuit (IC) chip, the method comprising:

coupling a test socket to a load board, the test socket defining a cavity within which a plurality of contacts are arranged, the plurality of contacts configured to electrically couple the IC chip to the load board;

supplying a two-phase fluid coolant to the chamber to at least partially submerge the plurality of contacts;

Receiving the IC chip in a guide structure of the test socket to position the IC chip in the cavity when engaged with the plurality of contacts;

performing an electrical test of the IC chip using the load board; and

removing heated fluid coolant from the chamber, comprising:

removing heated liquid coolant via a liquid outlet defined in the test seat; and

coolant vapor is removed via a vapor outlet defined in the test seat.

19. The method of claim 18, further comprising removing the IC chip from the test socket once the electrical test is completed.

20. The method of claim 18, further comprising supplying the fluid coolant to the chamber to at least partially submerge the IC die.