ATE test method for CoW module

Abstract

The invention discloses an ATE test method for a CoW module. The method comprises the following steps: cutting a CoW module wafer; the cut single CoW module is connected with a WLCSP test socket, the WLCSP test socket is connected to a test board, and the test board provided with the CoW module and the WLCSP test socket is connected with an ATE; an ATE test program is designed according to the test requirement of a single CoW module, and corresponding CoW module tests are carried out. According to the method, the ATE test is carried out through the WLCSP test socket after the CoW module is cut, so that the problem that a probe station is difficult to carry out middle test due to overlarge warping of the CoW module is effectively solved, the wafer-level test of the CoW module is realized, the yield of packaged finished products can be favorably improved, and the requirement for high reliability in an aerospace application scene is met.

Description

Technical Field

[0001] The invention relates to an ATE testing method for a CoW module, belonging to the technical field of semiconductor testing. Background Art

[0002] With the continuous development of information technology, artificial intelligence, autonomous driving, cloud computing, etc. usually need to analyze and process massive amounts of data, which puts forward new requirements for computing power. However, as the integrated circuit process enters below 5nm, the size miniaturization is close to the physical limit. The space for improving chip performance by simply reducing the size of transistors has become smaller, and at the same time, it has brought about a rapid increase in cost and complexity. The global integrated circuit industry has entered the post-Moore era. In this context, core particles and integrated chip technology have ushered in unprecedented development opportunities and have become key technologies to solve bottlenecks such as increased complexity, longer design cycles, lower manufacturing yields, and surging costs of traditional monolithic integrated circuits. Core particles and integrated chip technology combine multiple chips into a whole through advanced integration processes, greatly improving chip performance, reducing costs, and increasing yields, becoming one of the best ways to achieve development beyond Moore's Law. As an indispensable link in the industrial chain, integrated chip testing is of great significance for monitoring design and process and improving product yields. Among them, CoW is a key process in the advanced packaging process. Since the process is not yet mature, the yield of CoW modules is low. If it is directly packaged without testing, it will lead to low yield of finished products, resulting in waste of other chips and packaging shells, and bring huge economic losses. Therefore, it is necessary to perform wafer-level testing on CoW modules. Due to the module stacking process, CoW module wafers usually have relatively large warpage, which makes it difficult for the original probe station to complete the test. There is an urgent need to develop a test method that can be applied to large-warpage CoW modules to eliminate defective modules, improve the yield of finished products, and thus reduce costs. Summary of the invention

[0003] The technical problem solved by the present invention is: to overcome the deficiencies of the prior art and provide an ATE test method for CoW modules, which is helpful to improve the yield of packaged finished products and meet the requirements of high reliability.

[0004] The technical solution of the present invention is: an ATE test method for a CoW module, comprising:

[0005] Cutting the CoW module wafer to obtain a plurality of cut CoW modules;

[0006] Connect the cut single CoW module to the WLCSP test socket, connect the WLCSP test socket to the test board, and connect the test board with the CoW module and the WLCSP test socket to the ATE;

[0007] Design ATE test program according to the test requirements of single CoW module after cutting, and perform corresponding CoW module test;

[0008] The CoW module test includes: contact test, functional test, DC parameter test and AC parameter test; specifically:

[0009] The contact test is used to test whether the connection between the CoW module under test and ATE is conductive. Other tests can be performed after the test connection is conductive;

[0010] Functional testing uses test vectors to test module functions, which are determined by the specific working conditions of the CoW module being tested;

[0011] The DC parameter test measures and judges the voltages and currents output by the CoW module under test. If the measurement results meet the index requirements of the CoW module under test, it passes.

[0012] The AC parameter test measures and judges the setup time, hold time, minimum pulse width, maximum clock frequency, and delay time of the CoW module under test. If the measurement results meet the index requirements of the CoW module under test, it passes.

[0013] Preferably, the CoW module wafer is cut from the whole wafer according to the wafer scribe lines;

[0014] The length of the CoW module after cutting is ≤60mm, the width is ≤60mm, and the module bump pitch is ≥150μm.

[0015] Preferably, before performing the corresponding CoW module test, corresponding instruments are connected between the ATE and the test board as required.

[0016] Preferably, the WLCSP test socket is designed according to the size of the cut single CoW module and the module bump coordinate information, and needs to meet the requirements of the single CoW module for voltage, current, signal transmission rate and test temperature.

[0017] Preferably, the WLCSP test socket is connected to the cut single CoW module by means of a vertical probe card, and the probe material is Pd alloy.

[0018] Preferably, the test board is designed according to the pin information of the single CoW module after cutting and the test specification file, and needs to meet the test requirements of the single CoW module for voltage, current and signal transmission rate.

[0019] Preferably, when the cut single CoW module is connected to the WLCSP test socket, and the WLCSP test socket is connected to the test board:

[0020] If the CoW module pin pitch is ≥200μm, the WLCSP test socket connected to the CoW module is directly connected to the test board, and then connected to the ATE test channel through the test board;

[0021] If the pin pitch of the CoW module is ≥150um and <200μm, it is necessary to transfer through the packaging substrate. Specifically, the packaging substrate is mounted on the test board, the WLCSP test socket of the CoW module is connected to the packaging substrate, and then connected to the test board through the packaging substrate, and then connected to the ATE test channel through the test board.

[0022] Preferably, the packaging substrate is any one of the following:

[0023] Ceramic substrate, plastic substrate, or customized adapter board.

[0024] Preferably, the cutting method for cutting the CoW module wafer can be any one of the following:

[0025] Grinding wheel cutting, laser cutting, diamond knife cutting.

[0026] Compared with the prior art, the present invention has the following advantages:

[0027] After the CoW module is cut, ATE testing is performed through the WLCSP test socket, which effectively solves the problem of difficulty in mid-testing using a probe station due to excessive warping of the CoW module, thereby realizing wafer-level testing of the CoW module, which can help improve the yield of finished packaging products and meet high reliability requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 This is a schematic diagram of the testing environment of the method of the present invention;

[0029] Figure 2 A schematic diagram of a CoW module structure of the present invention;

[0030] Figure 3 A schematic diagram of the ATE test program development process of the present invention. DETAILED DESCRIPTION

[0031] The purpose of the present invention is achieved through the following technical solutions:

[0032] An ATE testing method for a CoW module, the steps comprising:

[0033] Step S1: cutting the CoW module wafer to reduce warpage.

[0034] Step S2: Design a WLCSP test socket and a test board to achieve hardware connection between the CoW module and ATE.

[0035] Step S3: ATE test program development and module testing.

[0036] Furthermore, in step S1, the cutting of the CoW module wafer refers to cutting the entire CoW module wafer into individual CoW modules.

[0037] Furthermore, in step S1, the CoW module refers to a module formed by packaging a functional core particle on a silicon-based adapter board through an advanced packaging method.

[0038] Furthermore, in step S1, the cutting method includes but is not limited to grinding wheel cutting, laser cutting, diamond knife cutting, etc.

[0039] Furthermore, in step S1, the length of the cut module is ≤60 mm, the width is ≤60 mm, and the module bump pitch is ≥150 μm.

[0040] Furthermore, in step S2, designing the WLCSP test socket and the test board refers to designing the WLCSP test socket according to information such as CoW module size and bump coordinates, and designing the test board according to CoW module pin information and a test specification file.

[0041] Furthermore, in step S2, the WLCSP test socket tests the CoW module using a vertical probe card.

[0042] Furthermore, in step S2, the WLCSP test socket uses a probe made of Pd alloy.

[0043] Furthermore, in step S2, the hardware connection between the CoW module and the ATE is divided into two cases:

[0044] 1) When the CoW module pin pitch is ≥200μm, the CoW module is directly connected to the test board through the test socket, and then connected to the ATE test channel through the test board;

[0045] 2) When the CoW module pin pitch is ≥150μm and <200μm, due to manufacturing process limitations, the spacing between the test board pins cannot meet the test socket pin spacing requirements. At this time, it is necessary to transfer through the package substrate. The package substrate is mounted on the test board, and the CoW module is connected to the package substrate through the test socket, and then connected to the test board through the package substrate, and then connected to the ATE test channel through the test board.

[0046] Furthermore, in step S2, the packaging substrate may be a ceramic substrate, a plastic package substrate, or a customized adapter board.

[0047] Furthermore, in step S3, the ATE test program development and module testing completion refer to writing the ATE test program according to the CoW module testing specification to complete the testing of the CoW module.

[0048] Further, in step S3, the module test includes contact test, functional test, DC parameter test and AC parameter test. The contact test is mainly open circuit and short circuit test. The functional test mainly uses test vectors to test the module function. The DC parameter test includes but is not limited to output high / low level voltage, input high / low level voltage, input high / low level current, output high / low level current, power supply current, etc. The AC parameter test includes but is not limited to setup / hold time, minimum pulse width, maximum clock frequency, delay time, etc.

[0049] The meanings of the English abbreviations involved in the present invention are as follows:

[0050] CoW: Chip-on-Wafer, a semiconductor packaging technology that directly packages the chip on a silicon interposer;

[0051] WLCSP: Wafer Level Chip Scale Package, a chip packaging technology;

[0052] ATE: Automatic Test Equipment, automatic test equipment.

[0053] Example:

[0054] Exemplary embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0055] Figure 1 It is a schematic diagram of the overall framework of the method of the present invention. Figure 1 The overall framework includes a CoW module, a WLCSP test socket, a package substrate, a test board, instruments and ATE. Figure 1 The arrows in the figure represent signal transmission, and their specific meanings are as follows:

[0056] ①: ATE's transmission path to the test board, including power / ground and data signals;

[0057] ②: ATE receiving path to the test board, including various test signals;

[0058] ③: Information sent by ATE to instruments;

[0059] ④: ATE reads the information of instruments;

[0060] ⑤: Information provided by instruments to the test board;

[0061] ⑥: Information obtained by instruments from the test board.

[0062] By testing the CoW module after cutting, the impact of warping is avoided, and the problem of being unable to be tested due to excessive warping of the CoW module is solved; the hardware connection between the CoW module and ATE is realized through the WLCSP test socket and test board, and the connection of power / ground and signal channels is realized; by writing the ATE test program, the test of the CoW module is realized.

[0063] An ATE testing method for a CoW module, the steps comprising:

[0064] Step S1: Before testing, the CoW module wafer is cut into independent CoW modules, thereby eliminating the problem that the CoW module wafer is too warped to be tested.

[0065] Figure 2 This is a schematic diagram of the structure of a CoW module, including the functional core and the adapter board. Due to process problems, the CoW module wafer will have a large warpage of about 1000μm-1500μm, and ordinary probe stations cannot test this warped wafer. After the CoW module is cut, the warpage of a single module is 35μm-60μm. The corresponding advantage is that the warpage of a single module is small, which meets the warpage requirements for testing with a socket.

[0066] In this embodiment, the size of a single CoW module after cutting is 38.6 mm in length, 30.6 mm in width, 910 μm in thickness, and the module bump pitch is 180 μm, which meets the application scope of the method of the present invention.

[0067] Step S2: Design a WLCSP test socket according to the CoW module size information, bump coordinate information, etc., and bring out the fine-pitch pins of the CoW module. The WLCSP test socket uses a vertical probe card to connect to the module, and the probe material is Pd alloy. The corresponding benefit is that a higher probe density can be achieved. Design a test board according to the CoW module pin information and test specification documents to connect the test socket to the ATE test channel. In this embodiment, the CoW module pin pitch is less than 200μm, and the socket and the test board are connected through a ceramic packaging substrate.

[0068] Step S3: According to the CoW module test specification and the corresponding information of the test board pins, write the ATE test program to complete the module test. The corresponding benefit of using ATE for module testing is that it can improve the test efficiency and ensure the reliability of the test.

[0069] Figure 3 A flow chart for ATE test program development is provided, which includes four stages: contact test, functional test, DC parameter test, and AC parameter test.

[0070] The connectivity test is used to test the connectivity between the CoW module and the ATE channel, mainly open circuit and short circuit tests. The functional test tests the module functions based on relevant test vectors. The DC parameter test includes output high / low level voltage, input high / low level voltage, input high / low level current, output high / low level current, and power supply current. The AC parameter test includes setup / hold time, minimum pulse width, maximum clock frequency, and delay time.

[0071] The contents not described in detail in the specification of the present invention belong to the prior art known to the professional and technical personnel in this field.

Claims

1. An ATE test method for a CoW module, characterized in that include: Cutting the CoW module wafer to obtain a plurality of cut CoW modules; Connect the cut single CoW module to the WLCSP test socket, connect the WLCSP test socket to the test board, and connect the test board with the CoW module and the WLCSP test socket to the ATE; Design ATE test program according to the test requirements of single CoW module after cutting, and perform corresponding CoW module test; The CoW module test includes: contact test, functional test, DC parameter test and AC parameter test; specifically: The contact test is used to test whether the connection between the CoW module under test and ATE is conductive. Other tests can be performed after the test connection is conductive; Functional testing uses test vectors to test module functions, which are determined by the specific working conditions of the CoW module being tested; The DC parameter test measures and judges the voltages and currents output by the CoW module under test. If the measurement results meet the index requirements of the CoW module under test, it passes. The AC parameter test measures and judges the setup time, hold time, minimum pulse width, maximum clock frequency, and delay time of the CoW module under test. If the measurement results meet the index requirements of the CoW module under test, it passes.

2. The ATE testing method for a CoW module according to claim 1, characterized in that: Cut the CoW module wafer from the whole wafer according to the wafer dicing lanes; The length of the CoW module after cutting is ≤60mm, the width is ≤60mm, and the module bump pitch is ≥150μm.

3. The ATE testing method for a CoW module according to claim 1, characterized in that: Before performing the corresponding CoW module test, connect the corresponding instruments between the ATE and the test board as required.

4. The ATE testing method for a CoW module according to claim 1, characterized in that: The WLCSP test socket is designed based on the size of the cut single CoW module and the module bump coordinate information, and needs to meet the requirements of the single CoW module for voltage, current, signal transmission rate and test temperature.

5. The ATE testing method for a CoW module according to claim 1, characterized in that: The WLCSP test socket uses a vertical probe card to connect to the cut single CoW module, and the probe material is Pd alloy.

6. The ATE testing method for a CoW module according to claim 1, characterized in that: The test board is designed based on the pin information of the single CoW module after cutting and the test specification file, and needs to meet the test requirements of the single CoW module for voltage, current and signal transmission rate.

7. The ATE testing method for a CoW module according to claim 1, characterized in that: When connecting the cut single CoW module to the WLCSP test socket and connecting the WLCSP test socket to the test board: If the CoW module pin pitch is ≥200μm, the WLCSP test socket connected to the CoW module is directly connected to the test board, and then connected to the ATE test channel through the test board; If the pin pitch of the CoW module is ≥150um and <200μm, it is necessary to transfer through the packaging substrate. Specifically, the packaging substrate is mounted on the test board, the WLCSP test socket of the CoW module is connected to the packaging substrate, and then connected to the test board through the packaging substrate, and then connected to the ATE test channel through the test board.

8. The ATE testing method for a CoW module according to claim 7, characterized in that: The package substrate can be selected from any of the following: Ceramic substrate, plastic substrate, or customized adapter board.

9. The ATE testing method for a CoW module according to claim 1, characterized in that: The CoW module wafer can be cut in any of the following ways: Grinding wheel cutting, laser cutting, diamond knife cutting.

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