Chip good and bare crystal grain test fixture and test method

Abstract

The invention discloses a test fixture and a test method for good and bare crystal grains of a chip. The test fixture comprises a base, a fixture body is mounted on the base through a supporting seat, heat insulation plates are arranged in an inner cavity of the fixture body, the fixture body is divided into a plurality of cavities through the heat insulation plates, and a plurality of groups of gas flow channel paths are formed in the cavities; the test method comprises the following steps: adsorbing a chip through a first normal-temperature air path, adsorbing a carrier through a second normal-temperature air path, discharging air through a normal-temperature nitrogen path, and carrying out normal-temperature dynamic and static test; a high-temperature dynamic and static test is carried out by heating through a heating rod in the jig body and heating a carrying table through a high-temperature nitrogen path. According to the invention, the carrier plate bearing the chip can be rapidly, uniformly and accurately heated, a high-temperature test environment is provided for the chip, air is discharged by releasing normal-temperature and high-pressure nitrogen, an insulation test environment can be provided, surface oxidation of the chip is prevented, high-voltage contact arc is inhibited, the compatibility is good, and multiple types of chips can be tested.

Description

Technical Field

[0001] The present invention relates to the technical field of chip test fixtures, and particularly to a test fixture and a test method for known good die (KGD) chips. Background Art

[0002] IGBT (Insulated Gate Bipolar Transistor), an insulated gate bipolar transistor, is a composite fully controlled voltage-driven power semiconductor device composed of a BJT (bipolar junction transistor) and a MOS (insulated gate field effect transistor), having the advantages of both the high input impedance of the MOSFET and the low on-state voltage drop of the GTR. Known Good Die (KGD, also known as known qualified chips) testing describes those bare chips (dies) that have passed strict tests and confirmed that their quality and reliability meet specific standards. To ensure the yield of IGBT devices, before mounting the chips on the IGBT devices, it is necessary to perform defect screening and performance testing on the used bare chips, verify the electrical parameters and functions of the bare chips, and screen out the bare chips that do not meet the requirements to ensure the quality and reliable performance of the supplied products and reduce the loss of the IGBT device output.

[0003] The thickness of the unencapsulated bare chips is relatively thin (75 - 150 μm). During KGD testing, extremely large currents (above 400 A for 2 ms continuously, 1000 A for 90 ns instantaneous current) and extremely large voltages (above 600 V) are required. The existing test fixtures have a slow heating rate. When performing high-temperature and high-voltage tests, there is air in the test environment, resulting in easy oxidation of the chips and prone to high-voltage contact arcs, leading to misjudgment of parameters such as power loss of the IGBT chips and affecting the reliability of the test results. Summary of the Invention

[0004] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0005] The purpose of the present invention is to solve the disadvantages existing in the prior art and propose a test fixture and a test method for known good die (KGD) chips.

[0006] To achieve the above purpose, in the first aspect, the present invention provides a test fixture for known good die (KGD) chips, including: a base, on which a fixture body is installed through a support base; Inside the cavity of the fixture body, a heat insulation plate is provided. The fixture body is divided into multiple cavities by the heat insulation plate. In the middle cavity, a hot runner is provided, and a heating rod and a thermocouple are inserted on both sides of the hot runner. Multiple groups of gas flow paths are opened inside the cavity. The gas flow paths are used to adsorb and heat the carrier plate carrying the chip and provide an insulation test environment.

[0007] In some embodiments, first clamping blocks are installed on both sides of the fixture body. The first clamping blocks are provided with first fixing holes, and an arc-shaped groove is arranged in the middle of the first clamping blocks.

[0008] In some embodiments, second clamping blocks are installed at the front and back of the fixture body. The second clamping blocks are provided with second fixing holes, and a gas path connector is installed on the side of the second clamping blocks.

[0009] In some embodiments, the gas path connector includes a normal temperature nitrogen inlet connector, a normal temperature nitrogen outlet connector, a first normal temperature air vacuum connector, and a second normal temperature air vacuum connector. The nitrogen inlet connector and the normal temperature nitrogen outlet connector are installed on both sides of the second clamping block, and the first normal temperature air vacuum connector and the second normal temperature air vacuum connector are installed on both sides of another second clamping block.

[0010] In some embodiments, the heat insulation plate includes a first heat insulation layer and a second heat insulation layer. The heat insulation plate divides the cavity into a top heat insulation cavity, a middle heating cavity, and a bottom heat insulation cavity. The hot runner is arranged in the middle heating cavity.

[0011] In some embodiments, a thermocouple is inserted on one side of the hot runner, and heating rods are symmetrically inserted on the other side of the hot runner. A gas path connector is installed between the heating rods, and the gas path connector is a high-temperature nitrogen inlet connector.

[0012] In some embodiments, the carrier plate is placed inside the border formed by the enclosure of the first clamping blocks and the second clamping blocks. The fixture body is provided with gas inlet and outlet holes, and gas circulation holes are correspondingly arranged on the carrier plate.

[0013] In some embodiments, the gas flow paths include a normal temperature nitrogen path, a first normal temperature air path, a second normal temperature air path, and a high-temperature nitrogen path. The normal temperature nitrogen path is used to discharge air during high-temperature testing. The first normal temperature air path is used to vacuum-adsorb and fix the chip. The second normal temperature air path is used to vacuum-adsorb and fix the carrier plate. The high-temperature nitrogen path is used to heat the carrier plate.

[0014] In some embodiments, the normal temperature nitrogen path is formed by the connection of the normal temperature nitrogen inlet connector, the internal flow path of the fixture body, the gas circulation holes of the carrier plate, the internal flow path of the fixture body, and the normal temperature nitrogen outlet connector. The first normal-temperature air path is formed by connecting the internal flow channel of the jig body and the first normal-temperature air vacuum joint; The second normal-temperature air path is formed by connecting the internal flow channel of the jig body and the second normal-temperature air vacuum joint; The high-temperature nitrogen path is formed by connecting the high-temperature nitrogen inlet joint, the internal flow channel of the jig body, and the gas circulation holes of the carrier plate.

[0015] In a second aspect, the present invention also provides a method for testing good and bare chip grains, which is executed via the chip good and bare chip grain testing jig as described in the first aspect. The steps of the testing method include: S100, loading the chip to be tested onto the stage, and installing a probe card on the top of the chip; S200, starting the external air source and the air extraction device connected to the air path connector, adsorbing the chip through the first normal-temperature air path, adsorbing the stage through the second normal-temperature air path, discharging air through the normal-temperature nitrogen path, and performing normal-temperature dynamic and static tests; S300, starting the external air source and the air extraction device connected to the air path connector, heating through the heating rod inside the jig body, heating the stage through the high-temperature nitrogen path, and performing high-temperature dynamic and static tests.

[0016] The present invention has the following beneficial effects: In the present invention, through the internal hot runner and heating rod, the carrier plate carrying the chip can be heated quickly, evenly, and precisely, thereby providing a high-temperature test environment for the chip. By releasing normal-temperature high-pressure nitrogen to discharge air, an insulating test environment can be provided during the high-temperature test of the chip, thereby preventing surface oxidation of the chip and suppressing high-voltage contact arcs. It has good compatibility and can test multiple chips. Description of the Drawings

[0017] Figure 1 is a schematic structural diagram of the chip good and bare chip grain testing jig proposed by the present invention; Figure 2 is a front view of the chip good and bare chip grain testing jig proposed by the present invention; Figure 3 is a side view of the chip good and bare chip grain testing jig proposed by the present invention; Figure 4 is a top view of the chip good and bare chip grain testing jig proposed by the present invention; Figure 5 is Figure 4 a cross-sectional view taken at A-A in Figure 6 is a flowchart of the method for testing good and bare chip grains proposed by the present invention.

[0018] Legend Explanation: 1. Base; 2. Fixture body; 21. Cavity; 22. Heat insulation plate; 221. First heat insulation layer; 222. Second heat insulation layer; 23. Hot runner; 24. Heating rod; 25. Thermocouple; 26. First clamping block; 261. First fixing hole; 262. Arc-shaped groove; 27. Second clamping block; 272. Gas path connector; 2721. Normal temperature nitrogen inlet connector; 2722. Normal temperature nitrogen outlet connector; 2723. First normal temperature air vacuum connector; 2724. Second normal temperature air vacuum connector; 2725. High temperature nitrogen inlet connector; 3. Gas flow path; 31. Normal temperature nitrogen path; 32. First normal temperature air path; 33. Second normal temperature air path; 34. High temperature nitrogen path; 4. Chip; 5. Carrier board. Detailed implementation manners

[0019] The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0020] The embodiments of the present application provide a chip good bare die test fixture and a test method, which solve the problems in the prior art that the existing test fixture has a slow heating speed, there is air in the test environment during high temperature and high pressure tests, resulting in easy oxidation of the chip, and there is easily a high voltage contact arc, resulting in misjudgment of parameters such as power loss of the IGBT chip and affecting the reliability of the test results. The present application can quickly, uniformly and precisely heat the carrier board carrying the chip through the internally provided hot runner and heating rod, thereby providing a high temperature test environment for the chip. By releasing normal temperature high pressure nitrogen to discharge air, an insulation test environment can be provided during the high temperature test of the chip, thereby preventing surface oxidation of the chip and suppressing high voltage contact arcs. It has good compatibility and can test multiple chips.

[0021] Specifically, please refer to the following embodiments: Refer to Figures 1 - 5 , an embodiment of a chip good bare die test fixture provided by the present invention, the specific structure includes: a base 1, and a fixture body 2 is installed on the base 1 through a support seat.

[0022] Among them, a heat insulation board 22 is arranged inside the cavity 21 of the jig body 2, so that the jig body 2 can be divided into multiple cavities 21 by the heat insulation board 22 to realize heating the carrier plate 5 separately; specifically, a hot runner 23 is arranged in the cavity 21, and a heating rod 24 and a thermocouple 25 are inserted on both sides of the hot runner 23. When the heating rod 24 works, it acts as a continuous high-temperature heat source for heating, so that nitrogen flows through the annular flow path under the heating of the heating rod 24, so as to evenly and accurately conduct heat to the carrier plate 5, and the thermocouple 25 is used to monitor the heating process in real time and feed back the data to the control system, so that the carrier plate 5 quickly rises to the set temperature and maintains a constant temperature.

[0023] Furthermore, multiple groups of gas flow paths 3 are arranged inside the cavity 21, which can provide efficient air flow management and precise temperature control functions. Before the test, the carrier plate 5 and the chip 4 on the carrier plate 5 are adsorbed by negative pressure, and at the same time, the carrier plate 5 is heated by high-temperature nitrogen, and the air is discharged by high-pressure nitrogen to form an insulation test environment, so that the chip 4 will not have surface oxidation and high-voltage contact arcs in the high-temperature and high-pressure test environment.

[0024] Specifically, the heat insulation board 22 includes a first heat insulation layer 221 and a second heat insulation layer 222. The first heat insulation layer 221 and the second heat insulation layer 222 respectively divide the cavity 21 into a top heat insulation cavity, a middle heating cavity and a bottom heat insulation cavity, and the hot runner 23 is arranged in the middle heating cavity, so that the high-temperature nitrogen in the hot runner 23 can circulate and rise to heat the carrier plate 5 and raise its temperature to the set temperature; a thermocouple 25 is inserted on one side of the hot runner 23, and heating rods 24 are symmetrically inserted on the other side of the hot runner 23.

[0025] Please continue to refer to Figures 1 - 5 , in this embodiment, first clamping blocks 26 are installed on both sides of the jig body 2, second clamping blocks 27 are installed in the front and back of the jig body 2, and the carrier plate 5 is placed in the border formed by the enclosure of the first clamping blocks 26 and the second clamping blocks 27.

[0026] Among them, the first clamping block 26 is provided with a first fixing hole 261, and the first clamping block 26 is firmly connected to the jig body 2 through the first fixing hole 261 to ensure that there is no displacement or loosening during use. An arc-shaped groove 262 is also designed in the middle of the first clamping block 26, which can better adapt to the shape of the carrier plate 5 and then limit the carrier plate 5; correspondingly, the second clamping block 27 is provided with a second fixing hole, and the second clamping block 27 is firmly connected to the jig body 2 through the second fixing hole to ensure that there is no displacement or loosening during use, and an air path connector 272 is installed on the side of the second clamping block 27.

[0027] Furthermore, the fixture body 2 is provided with gas inlet and outlet holes, and the carrier plate 5 is correspondingly provided with gas flow holes, so that gases such as air or nitrogen can flow in and out through the gas inlet and outlet holes and the gas flow holes after flowing through the gas flow channels inside the fixture body 2 from the gas path connector 272.

[0028] Please continue to refer to Figures 1 - 5 , in this embodiment, the gas path connector 272 includes a normal-temperature nitrogen inlet connector 2721, a normal-temperature nitrogen outlet connector 2722, a first normal-temperature air vacuum connector 2723, a second normal-temperature air vacuum connector 2724, and a high-temperature nitrogen inlet connector 2725.

[0029] Among them, the normal-temperature nitrogen inlet connector 2721 and the normal-temperature nitrogen outlet connector 2722 are installed on both sides of the second clamping block 27, and are used to supply normal-temperature high-pressure nitrogen through an external gas source (such as a nitrogen storage tank, etc.), and then discharge the air in the upper space of the carrier plate 5 to form an air-insulated test environment, which can effectively prevent oxidation on the surface of the chip 4 and inhibit high-voltage contact arcs; while the first normal-temperature air vacuum connector 2723 and the second normal-temperature air vacuum connector 2724 are respectively installed on both sides of another second clamping block 27, and are used to extract air through an external air extraction device (such as an air extraction pump, etc.), so that the chip 4 and the carrier plate 5 are adsorbed and fixed under the action of negative pressure; a high-temperature nitrogen inlet connector 2725 is installed between the heating rods 24, and is used to supply high-temperature nitrogen through an external gas source (such as a nitrogen storage tank, etc.), and after circulating in the hot runner 23, quickly, evenly and precisely heat the carrier plate 5.

[0030] Please continue to refer to Figures 1 - 5 , in this embodiment, the gas flow path 3 includes a normal-temperature nitrogen path 31, a first normal-temperature air path 32, a second normal-temperature air path 33, and a high-temperature nitrogen path 34. Among them, the normal-temperature nitrogen path 31 is used to discharge air during high-temperature testing, the first normal-temperature air path 32 is used for vacuum adsorption and fixation of the chip 4, the second normal-temperature air path 33 is used for vacuum adsorption and fixation of the carrier plate 5, and the high-temperature nitrogen path 34 is used for heating the carrier plate 5; specifically: (1) The normal-temperature nitrogen path 31 is formed by connecting the normal-temperature nitrogen inlet connector 2721 - the internal flow channel of the fixture body 2 - the gas inlet and outlet holes of the fixture body 2 - the gas flow holes of the carrier plate 5 - the internal flow channel of the fixture body 2 - the normal-temperature nitrogen outlet connector 2722. It is used to supply normal-temperature high-pressure nitrogen through an external gas source (such as a nitrogen storage tank, etc.), and then discharge the air in the upper space of the carrier plate 5 to form an air-insulated test environment (positive pressure ≥ 0.4 Mpa), which can effectively prevent the surface of the chip 4 from contacting with oxygen in the air, thereby preventing oxidation reaction on the surface of the chip 4; at the same time, it can inhibit the high-voltage contact arcs that occur during the test, prevent electrical damage or destruction caused by the arcs, and thus ensure the safety during the test and the accuracy of the test results; (2) The first normal-temperature air path 32 is formed by connecting the gas inlet / outlet hole of the fixture body 2 - the internal flow channel of the fixture body 2 - the first normal-temperature air vacuum joint 2723, and is used to extract air through an external air extraction device (such as an air extraction pump, etc.), so that the chip 4 is adsorbed and fixed under the action of negative pressure (negative pressure ≤ -80 Kpa); (3) The second normal-temperature air path 33 is formed by connecting the gas inlet / outlet hole of the fixture body 2 - the internal flow channel of the fixture body 2 - the second normal-temperature air vacuum joint 2724, and is used to extract air through an external air extraction device (such as an air extraction pump, etc.), so that the carrier plate 5 is adsorbed and fixed under the action of negative pressure (negative pressure ≤ -80 Kpa); (4) The high-temperature nitrogen path 34 is formed by connecting the high-temperature nitrogen inlet joint 2725 - the internal flow channel of the fixture body 2 - the gas inlet / outlet hole of the fixture body 2 - the gas circulation hole of the carrier plate 5, and is used to supply high-temperature nitrogen through an external gas source (such as a nitrogen storage tank, etc.), and after circulating in the hot runner 23, quickly, evenly and precisely heat the carrier plate 5 to a preset temperature (temperature ≤ 175°C ± 2°C).

[0031] Refer to Figure 6 , the present invention also provides an embodiment of a method for testing good bare chips of a chip 4, which is executed via the chip good bare chip testing fixture in the above embodiment, and the steps of the testing method include: S100, place the chip 4 to be tested on the stage, and install a probe card on the top of the chip 4; S200, start the external gas source and the air extraction device connected to the gas path connector 272, adsorb the chip 4 through the first normal-temperature air path 32, adsorb the stage through the second normal-temperature air path 33, and discharge air through the normal-temperature nitrogen path 31 to perform normal-temperature dynamic and static tests; S300, start the external gas source and the air extraction device connected to the gas path connector 272, heat through the internal heating rod 24 of the fixture body 2, and heat the stage through the high-temperature nitrogen path 34 to perform high-temperature dynamic and static tests.

[0032] Through the above technical solutions, the present application can quickly, evenly and precisely heat the carrier plate 5 carrying the chip 4 through the internally provided hot runner 23 and heating rod 24, thereby providing a stable high-temperature test environment for the chip 4; by releasing normal-temperature high-pressure nitrogen to discharge the air in the test area, an air-insulated test environment is formed, which can effectively prevent the surface of the chip 4 from contacting with oxygen in the air and undergoing an oxidation reaction, and at the same time effectively suppress the high-voltage contact arc that appears during the high-temperature test and reduce the risk of electrical damage, ensuring the safety during the test; it has good compatibility and can adapt to multiple different models and specifications of chips 4 for testing.

[0033] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A chip good bare die test fixture, characterized in that: include: A base, on which a fixture body is mounted via a support seat; The internal cavity of the fixture body is provided with a heat insulation board, and the fixture body is divided into multiple cavities by the heat insulation board. The middle cavity is provided with a hot runner, and heating rods and thermocouples are inserted on both sides of the hot runner; The cavity has multiple gas flow paths formed inside, and the gas flow paths are used to adsorb and heat the carrier board carrying the chip and provide an insulating test environment; The gas flow path includes a normal temperature nitrogen path, a first normal temperature air path, a second normal temperature air path and a high temperature nitrogen path. The normal temperature nitrogen path is used to exhaust air during high temperature testing. The first normal temperature air path is used to vacuum adsorb and fix the chip. The second normal temperature air path is used to vacuum adsorb and fix the carrier. The high temperature nitrogen path is used to heat the carrier. The normal temperature nitrogen path is formed by connecting the normal temperature nitrogen inlet joint, the internal flow channel of the fixture body, the gas flow hole of the carrier plate, the internal flow channel of the fixture body and the normal temperature nitrogen outlet joint; the first normal temperature air path is formed by connecting the internal flow channel of the fixture body and the first normal temperature air vacuum joint; the second normal temperature air path is formed by connecting the internal flow channel of the fixture body and the second normal temperature air vacuum joint; the high temperature nitrogen path is formed by connecting the high temperature nitrogen inlet joint, the internal flow channel of the fixture body and the gas flow hole of the carrier plate.

2. The chip good bare die test fixture according to claim 1, characterized in that: First clamping blocks are installed on both sides of the fixture body, the first clamping blocks are provided with first fixing holes, and the middle part of the first clamping blocks is provided with an arc groove.

3. The chip good bare die test fixture according to claim 1, characterized in that: The second clamping blocks are installed at the front and rear of the fixture body, the second clamping block is provided with a second fixing hole, and the side of the second clamping block is installed with an air circuit connector.

4. The chip good bare die test fixture according to claim 3, characterized in that: The gas circuit connector includes a normal temperature nitrogen inlet connector, a normal temperature nitrogen outlet connector, a first normal temperature air vacuum connector and a second normal temperature air vacuum connector. The nitrogen inlet connector and the normal temperature nitrogen outlet connector are installed on both sides of the second clamping block, and the first normal temperature air vacuum connector and the second normal temperature air vacuum connector are installed on both sides of another second clamping block.

5. The chip good bare die test fixture according to claim 1, characterized in that: The heat insulation board comprises a first heat insulation layer and a second heat insulation layer. The heat insulation board divides the cavity into a top heat insulation cavity, a middle heating cavity and a bottom heat insulation cavity. The hot runner is arranged in the middle heating cavity.

6. The chip good bare die test fixture according to claim 1, characterized in that: A thermocouple is inserted on one side of the hot runner, and heating rods are symmetrically inserted on the other side of the hot runner. A gas circuit connector is installed between the heating rods, and the gas circuit connector is a high-temperature nitrogen inlet connector.

7. The chip good bare die test fixture according to claim 1, characterized in that: The carrier plate is placed in the surrounding edge formed by the first clamping block and the second clamping block. The fixture body is provided with gas inlet and outlet holes, and the carrier plate is correspondingly provided with gas flow holes.

8. A chip good bare die testing method, characterized in that: The testing method is performed by a chip good bare die testing fixture according to any one of claims 1 to 7, and the testing method comprises: S100, the chip to be tested is loaded on the stage, and a probe card is installed on the top of the chip; S200, starting the external air source and the air extraction device connected to the air path connector, adsorbing the chip through the first normal temperature air path, adsorbing the carrier through the second normal temperature air path, exhausting the air through the normal temperature nitrogen path, and performing a normal temperature dynamic and static test; S300, start the external gas source and the exhaust device connected to the gas path connector, heat the fixture body through the internal heating rod, heat the carrier through the high-temperature nitrogen path, and perform high-temperature dynamic and static tests.

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