Preparation method and preparation device for sample to be tested

Abstract

The invention discloses a to-be-tested sample preparation method and a preparation device. The method comprises the following steps: providing a to-be-tested chip; the to-be-tested chip comprises a front surface and a back surface deviating from each other; fixing the glass slide on a test circuit board; a through hole is formed in the center of the test circuit board; the glass slide at least covers the through hole; fixing the back surface of the to-be-tested chip at the center of one side, close to the test circuit board, of the glass slide to expose the front surface of the to-be-tested chip; the size of the to-be-tested chip is smaller than the diameter of the through hole; and performing wire bonding on the front surface of the to-be-tested chip and the test circuit board to form a to-be-tested sample. According to the method, the to-be-tested chip is fixed in the center of the through hole of the test circuit board through the glass slide to form the to-be-tested sample, so that the to-be-tested sample can be repeatedly tested, the test time is saved, and the test cost is reduced.

Description

Technical Field

[0001] This invention relates to the technical field of sample preparation in failure analysis, and more particularly to a method and apparatus for preparing a sample to be tested. Background Technology

[0002] With the development of integrated circuits, packaging forms are also changing rapidly, and the sample preparation methods for InGaAs testing are also being updated accordingly.

[0003] Before wire bonding in chip-on-package (CSP), InGaAs testing was limited to front-side pin-punch testing and testing by soldering the chip to a dedicated PCB. However, in front-side pin-punch testing, if the current is too low, the bright spots on the front side will be blocked by the wiring layer and cannot be scanned. When soldering the chip to a dedicated PCB for testing, the soldering requirements are high. If the soldering is poor or the electrical properties are incorrect, it is necessary to re-ball and re-solder. If there are few PCBs, several chips need to share a PCB, making retesting difficult. Summary of the Invention

[0004] This invention provides a method and apparatus for preparing a test sample. By fixing the chip to be tested to the center of a through hole on a test circuit board using a glass slide, the test sample can be formed, enabling repeated testing of the test sample, saving testing time and reducing testing costs.

[0005] In a first aspect, the present invention provides a method for preparing a sample to be tested, comprising:

[0006] Provide the chip to be tested; the chip to be tested includes a front and a back side that are opposite to each other;

[0007] The glass slide is fixed on the test circuit board; the test circuit board has a through hole in the center, and the glass slide at least covers the through hole;

[0008] The back side of the chip under test is fixed to the center of the glass slide near the test circuit board to expose the front side of the chip under test; the size of the chip under test is smaller than the diameter of the through hole;

[0009] The front side of the chip to be tested is wire-bonded to the test circuit board to form the test sample.

[0010] Optionally, the back of the chip under test includes a protective layer;

[0011] Before fixing the glass slide onto the test circuit board, the following steps are also included:

[0012] Remove the protective layer on the back of the chip under test to expose the back side.

[0013] Optionally, the protective layer on the back of the chip under test may be removed, including:

[0014] Using an etching reagent, the etching reagent is placed on the protective layer, and the protective layer on the back of the chip under test is removed under preset etching conditions;

[0015] Use a rinsing agent to rinse away any remaining protective layer.

[0016] Optionally, the preset corrosion conditions include placing the protective layer containing the corrosive agent in a heating device, with a heating temperature of 100℃-120℃ and a heating time of 5s-10s.

[0017] Optionally, fixing the glass slide to the test circuit board includes:

[0018] The glass slide was attached to the test circuit board using the first insulating adhesive.

[0019] The test circuit board is placed in a heating device and heated under a first heating condition to cure the first insulating adhesive.

[0020] Optionally, the first heating conditions include a heating temperature of 120℃-150℃ and a heating time of 10min-15min.

[0021] Optionally, the back side of the chip to be tested is fixed to the center of the glass slide near the test circuit board, including:

[0022] Using a second insulating adhesive, the back of the chip to be tested is attached to the center of the glass slide on the side closest to the test circuit board;

[0023] The test circuit board is placed in a heating device and heated under a second heating condition to cure the second insulating adhesive.

[0024] Optionally, the second heating conditions include a heating temperature of 120℃-150℃ and a heating time of 10min-15min.

[0025] Optionally, the front side of the chip to be tested is wire-bonded to the test circuit board, including:

[0026] Using a packaging machine, wire bonding is performed between the front side of the chip to be tested and the test circuit board under preset parameter conditions;

[0027] Confirm that the stitching is complete;

[0028] A welding machine is used to weld the wire-bonded chip and the test circuit board.

[0029] In a second aspect, the present invention provides a sample preparation apparatus for testing, including a test circuit board, a glass slide, a heating device, a packaging machine, a welding machine, and a controller;

[0030] The test circuit board has a through hole in the center, and the glass slide covers at least the through hole and is fixed to the test circuit board with a first insulating adhesive; the back of the chip to be tested is fixed to the center of the glass slide near the test circuit board with a second insulating adhesive, and the size of the chip to be tested is smaller than the diameter of the through hole;

[0031] The heating device is used to heat and cure the first insulating adhesive; and to heat and cure the second insulating adhesive;

[0032] The packaging machine is used to perform wire bonding on the front side of the cured test circuit board and the chip to be tested;

[0033] The welding machine is used to weld the test circuit board and the chip to be tested after wire bonding;

[0034] The controller is electrically connected to the heating device, the packaging machine, and the welding machine respectively, and is used to control the working status of the heating device, the packaging machine, and the welding machine; to determine whether wire bonding is completed, and to control the welding machine to work after wire bonding is completed.

[0035] The technical solution of this invention involves providing a chip to be tested; the chip to be tested includes a front side and a back side that are opposite to each other; a glass slide is fixed to a test circuit board; a through-hole is provided in the center of the test circuit board, and the glass slide at least covers the through-hole; the back side of the chip to be tested is fixed to the center of the side of the glass slide closest to the test circuit board to expose the front side of the chip to be tested; the size of the chip to be tested is smaller than the diameter of the through-hole; the front side of the chip to be tested is wire-bonded to the test circuit board to form a test sample. Using the above method, by fixing the chip to be tested to the center of the through-hole of the test circuit board using a glass slide to form a test sample, repeated testing of the test sample can be achieved, providing a good foundation for accurately determining the failure location and cause of the chip to be tested, saving testing time and reducing testing costs.

[0036] It should be understood that the description in this section is not intended to identify key or essential features of the embodiments of the present invention, nor is it intended to limit the scope of the invention. Other features of the invention will become readily apparent from the following description. Attached Figure Description

[0037] To more clearly illustrate the technical solutions in the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0038] Figure 1 A flowchart illustrating a method for preparing a test sample according to an embodiment of the present invention;

[0039] Figure 2 A flowchart of another method for preparing a test sample provided in an embodiment of the present invention;

[0040] Figure 3 This is a schematic diagram of the front structure of a sample to be tested, provided in an embodiment of the present invention.

[0041] Figure 4 This is a schematic diagram of the structure of the back side of a sample to be tested, provided in an embodiment of the present invention.

[0042] Figure 5 This is a schematic diagram of the connection relationships in a sample preparation equipment provided in an embodiment of the present invention. Detailed Implementation

[0043] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the scope of protection of the present invention.

[0044] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of the invention described herein can be implemented in orders other than those illustrated or described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0045] In one embodiment, Figure 1 This is a flowchart illustrating a method for preparing a test sample according to an embodiment of the present invention. This embodiment is applicable to the preparation of a failed chip to be tested in chip failure analysis to form a test sample for indium gallium arsenide (IGaAs) testing. This method can be executed by a test sample preparation device. (Refer to...) Figure 1 As shown, the method includes:

[0046] S110 provides the chip to be tested.

[0047] The chip under test includes a front side and a back side that are opposite to each other.

[0048] S120. Fix the glass slide onto the test circuit board.

[0049] The glass slide can be a thin, transparent glass plate. The test circuit board, or PCB board, is a circuit board specifically designed for testing the chip under test.

[0050] Specifically, before fixing the chip to be tested, a glass slide needs to be prepared and fixed onto the test circuit board. The test circuit board has a through-hole in its center; therefore, when fixing the glass slide onto the test circuit board, the slide should at least cover the through-hole, that is, the glass slide should be fixed to the through-hole and its surrounding area to ensure that the chip to be tested can be placed on the glass slide.

[0051] S130. Fix the back side of the chip to be tested to the center of the side of the glass slide closest to the test circuit board to expose the front side of the chip to be tested.

[0052] Specifically, after fixing the glass slide onto the test circuit board, the slide is fixed to one side of the test circuit board's through-hole, while the other side is exposed. Therefore, the back side of the chip under test (DUT) can be fixed to the center of the glass slide closest to the test circuit board, i.e., fixed to the center of the exposed side of the slide. Since the size of the DUT is smaller than the diameter of the through-hole, there is a certain distance between the DUT and the test circuit board, ensuring no signal crosstalk occurs. After fixing the back side of the DUT to the glass slide, the front side of the DUT is exposed, providing a basis for subsequent wire bonding and soldering of the front side of the DUT to the test circuit board.

[0053] S140. Wire bond the front side of the chip to be tested to the test circuit board to form the test sample.

[0054] Wire bonding is a process that electrically connects the IC die to its package pins or test circuit board using thin metal wires (usually gold, copper, or aluminum wires). Soldering is the process of joining two metal surfaces, i.e., the front side of the IC die and the test circuit board, together using molten solder to form a mechanical and electrical connection.

[0055] Specifically, after wire bonding is performed between the front side of the chip to be tested and the test circuit board, soldering is required. Solder balls are used to form solder joints between the points on the test circuit board and the corresponding points on the front side of the chip to be tested. This ensures that both the solder joints on the test circuit board and the corresponding solder joints on the front side of the chip to be tested are connected to the solder bars of the wire bonding, forming the sample to be tested and enabling the transmission of electrical signals from the sample to be tested.

[0056] It should be noted that the method for forming the test sample in this embodiment is for subsequent testing of the test sample using an indium gallium arsenide lens. Specifically, the back of the test chip in the test sample is facing up, and the test sample is powered on. The test results of the test sample are then used to determine the failure location and cause of the failure of the test chip.

[0057] The technical solution of this invention involves providing a chip to be tested; the chip to be tested includes a front side and a back side that are opposite to each other; a glass slide is fixed to a test circuit board; a through-hole is provided at the center of the test circuit board, and the glass slide at least covers the through-hole; the back side of the chip to be tested is fixed to the center of the side of the glass slide closest to the test circuit board to expose the front side of the chip to be tested; the size of the chip to be tested is smaller than the diameter of the through-hole; the front side of the chip to be tested is wire-bonded to the test circuit board to form a test sample. Using the above method, by fixing the chip to be tested to the center of the through-hole of the test circuit board using a glass slide to form a test sample, repeated testing of the test sample can be achieved, providing a good foundation for accurately determining the failure location and cause of the chip to be tested, saving testing time and reducing testing costs.

[0058] In another specific embodiment, Figure 2 A flowchart of another method for preparing a test sample provided in an embodiment of the present invention is shown below. Figure 2 As shown, the method includes:

[0059] S210 provides the chip to be tested.

[0060] The chip under test includes a front and a back side that are opposite to each other.

[0061] S220. Remove the protective layer on the back of the chip under test to expose the back side.

[0062] The back of the chip to be tested includes a protective layer; the protective layer can typically be, but is not limited to, adhesive.

[0063] This step can be broken down as follows: using an etching reagent, place the etching reagent on the protective layer and remove the protective layer on the back of the chip to be tested under preset etching conditions; using a rinsing reagent, rinse the remaining protective layer to expose the back side.

[0064] Specifically, when removing the protective layer on the back of the chip to be tested, an etching agent can be used. The etching agent is applied to the surface of the protective layer using a dropper, and the protective layer is placed in a heating device. Under preset etching conditions (in this embodiment, the preset etching conditions are a heating temperature of 100℃-120℃ and a heating time of 5s-10s), the protective layer is heated to dissolve. Then, a rinsing agent, such as acetone, is used to rinse the protective layer, followed by gentle wiping with a cotton swab until the protective layer is completely removed, exposing the back of the chip to be tested. It is important to note that during the removal of the protective layer, care should be taken to ensure that the chip to be tested does not develop chips or cracks, maintaining the chip's integrity. This setup aims to allow for more accurate determination of the failure location during subsequent failure analysis, avoiding misjudgments caused by the influence of the protective layer and improving the accuracy of the failure analysis.

[0065] S230. Using the first insulating adhesive, the glass slide is attached to the test circuit board.

[0066] The first insulating adhesive is an adhesive with electrical insulating properties. After curing, it effectively prevents current flow and is an adhesive material with high resistivity and voltage resistance. It not only serves as an adhesive but also prevents electrical faults such as short circuits and leakage. In this embodiment, the first insulating adhesive may include, but is not limited to, epoxy resin insulating adhesive, silicone insulating adhesive, polyurethane insulating adhesive, UV / light-cured insulating adhesive, or thermally conductive insulating adhesive, etc., which can be determined according to the actual situation and is not limited here. The size of the glass slide can be selected, but is not limited to, a glass slide of 20mm × 20mm × 0.13mm.

[0067] Specifically, when fixing the glass slide onto the test circuit board, a first insulating adhesive is used to adhere the first insulating adhesive to the outer periphery of the hollow test circuit board, i.e., the area around the through hole, and then the glass slide is adhered to the test circuit board.

[0068] S240. Place the test circuit board in a heating device and heat it under the first heating condition to cure the first insulating adhesive.

[0069] Optionally, the first heating conditions include a heating temperature of 120℃-150℃ and a heating time of 10min-15min.

[0070] Specifically, after the glass slide is attached to the test circuit board, the first insulating adhesive needs to be cured to ensure the bonding effect. In this embodiment, the attached test circuit board is placed in a heating device, and the first insulating adhesive is heated and cured under the first heating conditions of 120℃-150℃ and 10min-15min to ensure that the glass slide and the test circuit board are fixed.

[0071] S250. Using a second insulating adhesive, the back of the chip to be tested is attached to the center of the glass slide near the test circuit board.

[0072] The second insulating adhesive is an adhesive with electrical insulating properties. After curing, it effectively prevents current flow and is an adhesive material with high resistivity and voltage resistance. It not only serves as an adhesive but also prevents electrical faults such as short circuits and leakage. In this embodiment, the second insulating adhesive may include, but is not limited to, epoxy resin insulating adhesive, silicone insulating adhesive, polyurethane insulating adhesive, UV / light-cured insulating adhesive, or thermally conductive insulating adhesive, etc., which can be determined according to the actual situation and is not limited here.

[0073] Specifically, when attaching the back of the chip to be tested to the center of the glass slide near the test circuit board, a second insulating adhesive is used to adhere the second insulating adhesive to the center area of ​​the glass slide near the test circuit board, and the back of the chip to be tested is attached to the glass slide with the back facing down, so that the front of the chip to be tested is exposed facing the test circuit board.

[0074] S260. Place the test circuit board in the heating device and heat it under the second heating condition to cure the second insulating adhesive and expose the front side of the chip to be tested.

[0075] Optionally, the second heating conditions include a heating temperature of 120℃-150℃ and a heating time of 10min-15min.

[0076] Specifically, after attaching the back of the chip to be tested to the center of the side of the glass slide near the test circuit board using the second insulating adhesive, the second insulating adhesive needs to be cured to ensure the bonding effect. In this embodiment, the test circuit board is placed in a heating device, and the second insulating adhesive is heated and cured under the second heating conditions of 120℃-150℃ and 10min-15min to ensure that the glass slide and the chip to be tested are fixed.

[0077] S270: Using a packaging machine, wire bonding is performed between the front side of the chip to be tested and the test circuit board under preset parameter conditions.

[0078] Packaging is a crucial step in the semiconductor packaging process. Packaging equipment can connect fine metal wires (usually gold, aluminum, or copper wires) from the pads on the chip to the corresponding positions on the packaging substrate or lead frame with extreme precision, thereby providing physical protection, environmental isolation (such as protection against moisture and contaminants), and ensuring good electrical connection performance.

[0079] Specifically, when bonding wires to the exposed front side of the chip under test and the test circuit board, a packaging machine is used. The bonding parameters in the packaging machine are set to preset parameters. Under these preset parameters, the wire (bounding) diameter is 0.6mil-0.8mil, the current is 120mA-130mA, and the arc height formed by the bounding line is 7mil-8mil, so as to achieve bonding wires to the corresponding positions on the front side of the chip under test and the test circuit board.

[0080] S280, Confirm that the wiring is complete.

[0081] Specifically, after wire bonding, it is necessary to confirm whether the wire bonding is complete before proceeding with subsequent soldering. This confirmation can be achieved through methods such as observation using an optical microscope or by using logical algorithms to determine the wire bonding status, ultimately determining whether the wire bonding meets the expected standards; no specific method is limited here.

[0082] S290. A welding machine is used to weld the wire-bonded chip and test circuit board to form a test sample.

[0083] A welding machine is an automated or semi-automated equipment platform used to perform welding processes. Welding machines may include, but are not limited to, reflow soldering machines, wave soldering machines, selective welding machines, laser welding machines, ultrasonic welding machines, or resistance welding machines, etc., and the specific type can be determined according to actual circumstances; no restrictions are imposed here.

[0084] Specifically, after the wire bonding is completed, a soldering machine is used to solder the front side of the chip to be tested to the test circuit board. The soldering parameters can be determined according to the actual situation and are not limited here. After soldering, the test sample is prepared. Failure testing is then performed on the test sample by powering it on and testing it with the back side facing up using an InGaAs lens. Based on the test results, the failure location and cause of the chip under test are finally determined.

[0085] The technical solution of this invention involves removing the protective layer on the back of the chip under test to expose the back side; using a first insulating adhesive to attach a glass slide to a test circuit board; placing the test circuit board in a heating device and heating it under a first heating condition to cure the first insulating adhesive; using a second insulating adhesive to attach the back side of the chip under test to the center of the side of the glass slide closest to the test circuit board; placing the test circuit board in a heating device and heating it under a second heating condition to cure the second insulating adhesive, thus exposing the front side of the chip under test; using a packaging machine under preset parameter conditions to perform wire bonding between the front side of the chip under test and the test circuit board; confirming the wire bonding is complete; and using a soldering machine to solder the wire-bonded chip under test and the test circuit board. This method ensures the rapid and complete removal of the protective layer on the back of the chip under test, providing a foundation for the accurate determination of the failure location and cause. Simultaneously, the use of insulating adhesive to bond the glass slide and test circuit board, and the glass slide and chip under test together, ensures the strength and stability of the bonding, and is low-cost and easy to operate.

[0086] Based on the same inventive concept Figure 3 This is a schematic diagram of the front structure of a sample to be tested, provided in an embodiment of the present invention. Figure 4 This is a schematic diagram of the structure of the back side of a sample to be tested, provided in an embodiment of the present invention. Figure 5 This is a schematic diagram of the connection relationships in a sample preparation apparatus provided by an embodiment of the present invention, with reference to... Figures 3 to 5 As shown, the fabrication apparatus includes a test circuit board 1, a glass slide 2, a heating device 3, a packaging machine 4, a welding machine 5, and a controller 6. The test circuit board 1 has a through-hole 11 at its center. The glass slide 2 at least covers the through-hole 11 and is fixed to the test circuit board 1 with a first insulating adhesive. The back side of the chip 7 to be tested is fixed to the center of the side of the glass slide 2 near the test circuit board 1 with a second insulating adhesive, and the size of the chip 7 to be tested is smaller than the diameter of the through-hole 11. The heating device 3 is used to heat and cure the first insulating adhesive and the second insulating adhesive. The packaging machine 4 is used to wire bond the cured test circuit board 1 and the front side of the chip 7 to be tested. The welding machine 5 is used to weld the wire-bonded test circuit board 1 and the chip 7 to be tested. The controller 6 is electrically connected to the heating device 3, the packaging machine 4, and the welding machine 5 respectively, and is used to control the working status of the heating device 3, the packaging machine 4, and the welding machine 5; determine whether the wire bonding is complete, and control the welding machine 5 to work after the wire bonding is completed.

[0087] The glass slide 2 can be a thin, transparent glass plate. The test circuit board 1, or PCB board, is a circuit board specifically designed for testing the chip 7 under test. The heating device 3 is used to heat and cure the insulating adhesive under preset conditions. The packaging machine 4 can precisely connect fine metal wires (usually gold, aluminum, or copper wires) from the pads on the chip to the corresponding positions on the packaging substrate or lead frame, thereby providing physical protection, environmental isolation (such as protection against moisture and contaminants), and ensuring good electrical connection performance. The welding machine 5 is an automated or semi-automated equipment platform for implementing the welding process. The welding machine may include, but is not limited to, reflow soldering machines, wave soldering machines, selective soldering machines, laser soldering machines, ultrasonic soldering machines, or resistance soldering machines, etc., depending on the actual situation, and is not limited here. The controller 6 is the core control structure of this embodiment. It is used to control the heating device 3 to start working before the heating device 3 starts heating; to control the packaging machine 4 to start working before the packaging machine 4 starts wire bonding; and to control the welding machine 5 to start working after the fiber bonding is completed and the preset wire bonding result is achieved.

[0088] Specifically, when preparing the test sample, first use a dropper to apply the etching reagent to the protective layer on the back of the chip 7 to be tested. Then place the chip 7 in the heating device 3 and heat it for 5-10 seconds at a temperature of 100℃-120℃. Next, rinse with a rinsing agent, such as acetone, and then gently wipe the protective layer with a cotton swab until the protective layer is completely removed and the back of the chip 7 is clean. Note: Avoid chipping or cracking during the removal of the protective layer.

[0089] After removing the protective layer, the glass slide 2 and the test circuit board (PCB) 1 are attached. In this embodiment, a glass slide 2 with dimensions of 20mm × 20mm × 0.13mm is attached to the periphery of the through hole in the center of the test circuit board 1 using a first insulating adhesive, and only the joint between the glass slide 2 and the test circuit board 1 is adhered, so that the glass slide 2 covers the area of ​​the through hole 11, providing a basis for the subsequent placement of the chip to be tested 7 on the glass slide 2. The test circuit board 1 is placed in the heating device 3 and heated on a heating table at a heating temperature of 120℃-150℃ for 10-15 minutes, then removed to cure the first insulating adhesive, fixing the glass slide 2 and the test circuit board 1. Next, the back side of the chip to be tested 7 is attached to the glass slide 2 using a second insulating adhesive, placing it in the center of the glass slide 2, so that the front side of the chip to be tested 7 is in the same direction as the test circuit board 1, providing a basis for subsequent wire bonding and soldering. Next, place the test circuit board 1 in the heating device 3 and heat it on a heating platform at a temperature of 120℃-150℃ for 10-15 minutes. Then remove it to cure the second insulating adhesive, thus fixing the glass slide 2 and the chip to be tested 7. Because the size of the chip to be tested 7 is smaller than the diameter of the through hole 11, the chip to be tested 7 will not contact the test circuit board 1. During this process, care should be taken to avoid air bubbles or other issues when the back of the chip to be tested 7 is bonded to the glass slide 2. After bonding, place the chip to be tested 7 on the packaging machine 4, set the packaging machine parameters: bonding wire diameter: 0.6-0.8mil, bonding current: 120-130mA, arc height: 7-8mil, and perform wire bonding between the chip to be tested 7 and the test circuit board 1. After wire bonding is completed, the controller 6 will determine whether the wire bonding is complete. Once the wire bonding is confirmed, the controller will start the welding machine 5 to weld the test circuit board 1 and the chip to be tested 7, thus forming the test sample. Finally, the test sample is powered on as required, and the back of the chip to be tested 7 is placed face up. The test sample is then tested using an InGaAs lens to determine the failure location and cause of failure.

[0090] In addition, by electrically connecting the controller 6 to the heating device 3, the packaging machine 4 and the welding machine 5 respectively, the controller 6 will first control the heating device 3 and the packaging machine 4 to start working before the heating device 3 starts heating and before the packaging machine 4 starts wire bonding.

[0091] The technical solution of this invention involves first attaching a glass slide to the periphery of a through-hole in the center of a test circuit board using a first insulating adhesive, applying the adhesive only to the junction of the glass slide and the test circuit board. The test circuit board is then placed in a heating device and heated on a heating platform at 120℃-150℃ for 10-15 minutes to cure the first insulating adhesive, thus fixing the glass slide and the test circuit board. Next, the back of the chip to be tested is attached to the glass slide using a second insulating adhesive, placing it in the center of the glass slide. The test circuit board is then placed back in the heating device and heated on a heating platform at 120℃-150℃ for 10-15 minutes to cure the second insulating adhesive, thus fixing the glass slide and the chip to be tested. Because the size of the chip to be tested is smaller than the diameter of the through-hole, the chip will not contact the test circuit board. After pasting, the chip to be tested is placed on the packaging machine. The packaging machine parameters are set, and wire bonding is performed between the chip to be tested and the test circuit board. After wire bonding is completed, the controller will determine whether the wire bonding is complete. If so, it will control the soldering machine to start, so that the test circuit board and the chip to be tested can be soldered, thus preparing the test sample. Finally, the test sample is powered on as required, and the back side of the chip to be tested is placed face up. An InGaAs lens is used to test the sample to determine the failure location and cause. Using the above structure, the test sample can be prepared, and only one chip to be tested is set on each test circuit board, enabling repeated testing of the chip to be tested. It is easy to operate and has low cost.

[0092] It should be understood that the various forms of processes shown above can be used, with steps reordered, added, or deleted. For example, the steps described in this invention can be executed in parallel, sequentially, or in different orders, as long as the desired result of the technical solution of this invention can be achieved, and this is not limited herein.

[0093] The specific embodiments described above do not constitute a limitation on the scope of protection of this invention. Those skilled in the art should understand that various modifications, combinations, sub-combinations, and substitutions can be made according to design requirements and other factors. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this invention should be included within the scope of protection of this invention.

Claims

1. A method for preparing a sample to be tested, characterized in that, include: A chip to be tested is provided; the chip to be tested includes a front side and a back side that are opposite to each other; Fix the glass slide onto the test circuit board; The test circuit board has a through hole at its center, and the glass slide at least covers the through hole. The back side of the chip under test is fixed to the center of the glass slide near the test circuit board to expose the front side of the chip under test; the size of the chip under test is smaller than the diameter of the through hole; The front side of the chip to be tested is wire-bonded to the test circuit board to form the sample to be tested.

2. The method for preparing the sample to be tested according to claim 1, characterized in that, The back of the chip under test includes a protective layer; Before fixing the glass slide onto the test circuit board, the following steps are also included: Remove the protective layer on the back of the chip under test to expose the back side.

3. The method for preparing the sample to be tested according to claim 2, characterized in that, Removing the protective layer on the back of the chip under test includes: Using an etching reagent, the etching reagent is placed on the protective layer, and the protective layer on the back of the chip to be tested is removed under preset etching conditions; The remaining protective layer is rinsed off using a rinsing agent.

4. The method for preparing the sample to be tested according to claim 3, characterized in that, The preset corrosion conditions include placing the protective layer containing the corrosive agent in a heating device, with a heating temperature of 100℃-120℃ and a heating time of 5s-10s.

5. The method for preparing the sample to be tested according to claim 1, characterized in that, Fixing the glass slide onto the test circuit board includes: The glass slide is attached to the test circuit board using a first insulating adhesive. The test circuit board is placed in a heating device and heated under a first heating condition to cure the first insulating adhesive.

6. The method for preparing the sample to be tested according to claim 5, characterized in that, The first heating conditions include a heating temperature of 120℃-150℃ and a heating time of 10min-15min.

7. The method for preparing the sample to be tested according to claim 1, characterized in that, Fixing the back side of the chip to be tested to the center of the glass slide near the test circuit board includes: Using a second insulating adhesive, the back side of the chip to be tested is attached to the center of the glass slide near the test circuit board. The test circuit board is placed in a heating device and heated under a second heating condition to cure the second insulating adhesive.

8. The method for preparing the sample to be tested according to claim 7, characterized in that, The second heating conditions include a heating temperature of 120℃-150℃ and a heating time of 10min-15min.

9. The method for preparing the sample to be tested according to claim 1, characterized in that, The front side of the chip to be tested is wire-bonded to the test circuit board, including: Using a packaging machine, wire bonding is performed between the front side of the chip to be tested and the test circuit board under preset parameter conditions; Confirm that the stitching is complete; A welding machine is used to weld the chip to be tested and the test circuit board after the wire bonding is completed.

10. A sample preparation apparatus, characterized in that, This includes test circuit boards, glass slides, heating devices, packaging machines, welding machines, and controllers; The test circuit board has a through hole at its center. The glass slide at least covers the through hole and is fixed to the test circuit board by a first insulating adhesive. The back of the chip to be tested is fixed to the center of the side of the glass slide near the test circuit board by a second insulating adhesive, and the size of the chip to be tested is smaller than the diameter of the through hole. The heating device is used to heat and cure the first insulating adhesive; and to heat and cure the second insulating adhesive; The packaging machine is used to perform wire bonding on the front side of the cured test circuit board and the chip to be tested; The welding machine is used to weld the test circuit board and the chip to be tested after wire bonding; The controller is electrically connected to the heating device, the packaging machine, and the welding machine, respectively, and is used to control the working status of the heating device, the packaging machine, and the welding machine; determine whether wire bonding is completed, and control the welding machine to work after wire bonding is completed.

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