Method and device for improving circuit board electrical test passing rate

Abstract

The invention relates to a method and device for improving the circuit board electrical test passing rate. According to the technical scheme, the method comprises the steps that a first test point and a second test point corresponding to a bonding pad of a BGA are set according to a gerber document of a circuit board; manufacturing a test panel according to the first test point and the second test point, wherein a solder ball corresponding to the second test point is arranged on the test panel; installing the test panel in a test machine, testing the conduction states of the first test point and the second test point in the to-be-tested circuit board by the test machine, and judging whether the to-be-tested circuit board is qualified or not; the circuit board has the advantages that the electrical test passing rate of the circuit board can be improved, and the needle print problem of the BGA area is relieved.

Description

Technical Field

[0001] The present invention relates to the technical field of PCB detection, and more specifically, to a method and a device for improving the passing rate of electrical testing of a circuit board. Background Art

[0002] In the process of electrical testing of circuit board production, test fixtures are commonly used detection devices. There are multiple test pins in the test fixture. The test pins contact the pads on the surface of the circuit board and conduct with the internal circuit of the tester to form a loop to measure the electrical characteristics of the tested points, that is, whether the continuity between the test points of the produced product is consistent with the design. With the advancement and development of technology, the line density of circuit boards is continuously increasing, the pad size is getting smaller, and the density is getting higher, resulting in increasing testing difficulty.

[0003] Especially for the current IC and BGA (ball grid array) positions, the pads are extremely small and the density is extremely high. In the electrical testing process, it is necessary to design the test points through software according to the pad positions, and assign the test needles to each test point to detect each test point. However, since the test points in the BGA area are too dense, the array grid points at the corresponding positions in the test fixture are difficult to meet the test points in the BGA area. Therefore, it is necessary to assign the grid points outside the BGA area to the test points in the BGA area, which will cause the test needles outside the BGA area to be in an inclined state, which is called slope in the industry. The smaller the slope, the more vertical the test needle and the better the test effect. In any case, the test effect is poor. And when the slope of the test needle exceeds a certain size, the test needles corresponding to the layer board drillings of two adjacent test points will collide, and the minimum insulation distance cannot be ensured, thus causing the test fixture body to short-circuit and the test to fail.

[0004] In addition, a small number of BGA soldering points are not actually connected to the internal circuits of the PCB. There are independent pads called independent points, which generally do not participate in the circuit logic and only play the role of fixing the soldered BGA chip and conducting heat. Such independent pads are usually tested at one test point to test whether there is a short circuit problem with the adjacent circuit. The pad is too small to set two test points to detect its open circuit. Generally, image recognition equipment is used to detect whether the pad is missing in the outer layer circuit and final inspection.

[0005] The precision of array grids is usually evaluated by density. The spacing within a unit inch is 2.54mm, which is single density. Placing twice the number of holes in this area is double density, and placing twice as many holes on this basis is quadruple density, with a spacing of 1.27mm. Conventional testing is quadruple density.

[0006] In the past, this situation generally required the use of higher density testers and test racks, which would inevitably lead to more equipment investment and test rack usage costs, and high- and low-density equipment and test racks were not interchangeable; therefore, there is still room for improvement. Summary of the invention

[0007] In view of the deficiencies in the prior art, the purpose of the present invention is to provide a method and device for improving the pass rate of electrical testing of a circuit board, so as to solve the above technical problems.

[0008] The above technical objectives of the present invention are achieved through the following technical solutions: A method for improving the pass rate of electrical testing of a circuit board, comprising: setting a first test point according to a gerber document of the circuit board, and a second test point corresponding to a pad of a BGA;

[0009] A test panel is manufactured according to the first measuring point and the second measuring point, and a solder ball corresponding to the second measuring point is arranged on the test panel;

[0010] The test panel is installed in a test machine, and the test machine tests the conduction state of the first test point and the second test point in the circuit board to be tested to determine whether the circuit board to be tested is qualified.

[0011] In practical applications, since the structures of various circuit boards to be tested are different, the positions required for detection are also different. Therefore, it is necessary to set the first test point corresponding to the pads on the circuit board to be tested except the BGA area according to the gerber document of the circuit board, and the second test point corresponding to the pads of the BGA, and make a test panel corresponding to the circuit board to be tested according to the first test point and the second test point. Among them, a solder ball corresponding to the second test point is provided on the test panel, and the solder ball is connected to the internal circuit of the test panel, and when testing, the solder ball can contact a contact point of the BGA area on the circuit board to be tested, so as to facilitate the detection of the BGA area of ​​the circuit board to be tested. Since the detection of the BGA area is completed by the solder ball, it will not affect the detection of other peripheral circuits. Therefore, when detecting other peripheral circuits, the slope of the corresponding test needle will not be too large, thereby ensuring the accuracy during detection. When the circuit board to be tested is tested, the test machine energizes the internal circuits of the test needle and the solder ball respectively. If there is a short circuit between the test needle and the internal circuit of the solder ball, it means that there is a short circuit problem in the BGA area of ​​the circuit board to be tested, and the circuit board to be tested is unqualified. If the internal circuit between the test needle and the solder ball is open-circuited, it means that the circuit board to be tested is qualified.

[0012] Specifically, the Gerber document is a collection of file formats used by the circuit board industry software to depict the images of circuit boards (circuit layers, solder mask layers, character layers, etc.) and the drilling and milling processes. It is the standard format for image conversion in the circuit board industry.

[0013] Optionally, setting the first measuring point and the second measuring point corresponding to the pad of the BGA according to the gerber document of the circuit board includes:

[0014] Get the wiring information of the circuit layer where the BGA area is located in the gerder document of the circuit board;

[0015] Marking the BGA area as an independent measuring point according to the wiring information, and setting a second measuring point;

[0016] The end point of the same line is set as the first measuring point according to the wiring information.

[0017] In practical applications, since there is at least one circuit layer in the circuit board, it is necessary to extract the wiring information in the gerber document of the circuit layer where the BGA area is located, identify the pad point of the BGA according to the BGA area in the wiring information, and reserve a point as an independent test point of the BGA area, and set all independent test points on the circuit board to be tested as the second test point. According to the wiring information, the end point of each circuit outside the BGA area in the corresponding circuit layer is set as the first test point. Generally speaking, the first test point and the second test point are in an open circuit state.

[0018] Optionally, manufacturing a test panel according to the first measuring point and the second measuring point, and providing a solder ball corresponding to the second measuring point on the test panel, includes:

[0019] Creating a second gerber file according to the first measuring point and the second measuring point;

[0020] Make a test panel based on the second gerber document.

[0021] In practical applications, since there may be multiple second measuring points, it is necessary to connect the multiple second measuring points, and the connecting lines need to avoid the location of the first measuring point. Therefore, based on the first and second measuring points, the circuit of the second measuring point is first designed, and the corresponding second gerber file is established. Subsequently, the test panel that can meet the requirements of the first and second measuring points is produced by the second gerber file.

[0022] Optionally, making a test panel according to the second gerber document includes:

[0023] Directly electroplate the epoxy board to obtain a copper-plated panel;

[0024] Drilling the copper-plated panel according to the second measuring point position in the second gerber file and processing the target hole;

[0025] Electroplating the entire copper-plated panel after drilling;

[0026] Etch the pattern circuits on the copper-plated panel after the whole board is electroplated;

[0027] Perform solder mask treatment on the copper-plated panel after etching the graphic circuit;

[0028] Perform secondary drilling on the copper-plated panel after solder mask treatment according to the position of the first measuring point;

[0029] The ball is planted at the position corresponding to the second measuring point on the copper-plated panel after secondary drilling to obtain a test panel.

[0030] In practical applications, for more special circuit boards to be tested, it is usually necessary to make corresponding test panels, which are generally made using the manufacturing process of circuit boards. First, the epoxy resin board of corresponding thickness is directly electroplated by DMSE to evenly plate a layer of copper on its surface. Then, the corresponding target holes and independent holes corresponding to the second measuring point position are drilled on the electroplated copper-plated panel. Then, the copper-plated panel after drilling the target hole is electroplated on the entire board to make the thickness of the copper layer on the copper-plated panel meet the requirements and metallize the independent holes. Then, the graphic circuit is etched according to the circuit of the second measuring point designed in the second gerber document, and the circuit connection data is selectively retained on the epoxy board through lamination-film exposure-acid etching. And all the epoxy boards except the independent pads and test holes are covered with solder mask and cured. Then, the epoxy board is positioned through the target hole, and the epoxy board is poured into the CNC program to drill holes according to the position of the first measuring point. Finally, by passing solder balls on the tin net at the independent holes and independent pads corresponding to the second measuring point, a test panel with a PCB circuit attached to the panel surface, with only the end points leaking out of the circuit and the middle part covered with solder mask ink for insulation can be obtained.

[0031] Optionally, before the tester tests the conduction state of the first test point and the second test point in the circuit board to be tested, the method further includes:

[0032] Perform AOI optical scanning on the circuit board to be tested to obtain quality information of the circuit board to be tested;

[0033] It is determined whether the circuit board to be tested has any quality problem according to the quality information. If so, the detection of the circuit board to be tested is cancelled; if not, the next process is performed.

[0034] In actual applications, the BGA area and the peripheral circuit are not only disconnected when not connected, but also disconnected when there is a pad drop on the circuit board to be tested. Therefore, in order to improve the accuracy of the test results, the circuit board to be tested is first subjected to AOI optical scanning, which can identify quality problems such as pad drop and gap on the circuit board to be tested, and screen out the circuit boards without quality problems for testing.

[0035] Optionally, the testing machine tests the conduction state of the first test point and the second test point in the circuit board to be tested, including:

[0036] The circuit board to be tested is clamped by the testing machine, and a test needle is inserted into the hole corresponding to the first test point at a preset slope, and the second test point contacts the BGA of the circuit board to be tested;

[0037] Powering on the test needle and the test panel to obtain the conduction information between the solder ball corresponding to the second test point and the test needle in the first test point;

[0038] It is determined whether the BGA area of ​​the circuit board to be tested is conductive with its adjacent circuits according to the conductive information. If so, the circuit board to be tested is determined to be unqualified; if not, the circuit board to be tested is determined to be qualified.

[0039] In actual application, after the test panel is installed in the test machine, one end of the test needle in the test machine passes through the hole corresponding to the first test point on the test panel and contacts the corresponding pad on the circuit board to be tested, and the tin ball on the test panel contacts the BGA area on the circuit board to be tested. The test machine then powers on the test needle and the test panel respectively. For the first test point position detected by the test needle, the conduction state between the test needles thereon needs to be consistent with the conduction state of each circuit in the circuit layer. For the second test point position detected by the tin ball on the test panel, since the BGA area is not connected to other circuits, the tin ball cannot be connected to the test needle. Based on the above situation, by obtaining the conduction information between the tin ball and the test needle, it can be determined whether the circuit board to be tested is qualified.

[0040] Optionally, judging whether a BGA area of ​​the circuit board to be tested is conductive with its adjacent circuits according to the conductive information includes:

[0041] If the solder ball corresponding to the second measuring point is connected to the test pin in the first measuring point, it is determined that the BGA area of ​​the circuit board to be tested is connected to its adjacent circuit;

[0042] If the solder ball corresponding to the second measuring point is not connected to the test pin in the first measuring point, it is determined that the BGA area of ​​the circuit board to be tested is not connected to its adjacent circuits.

[0043] In actual applications, for the first test point detected by the test needle, the conduction state between the test needles on it needs to be consistent with the conduction state of each circuit in the circuit layer. For the second test point detected by the solder ball on the test panel, since the BGA area is not connected to other circuits, the solder ball cannot be connected to the test needle.

[0044] The present invention also provides a device for improving the pass rate of electrical testing of a circuit board, comprising: a test stand, a test needle, and a needle tray panel; at least one solder ball corresponding to and adapted to the BGA area of ​​the circuit board is arranged on the needle tray panel; at least one of the solder balls is electrically connected to the test stand; the test needle is arranged in the test stand and can pass through the needle tray panel; the test needle is electrically connected to the test stand.

[0045] In actual applications, since there is at least one BGA area on the circuit board and the BGA areas are not connected, it is necessary to set corresponding solder balls according to the number of BGA areas on the circuit board. Each solder ball is electrically connected to the test frame, so when testing the circuit board, each BGA area is connected through the solder ball, and other areas to be tested on the circuit board are tested at the same time. Since the BGA area uses solder balls to detect whether there is a short circuit with the peripheral circuit, the array grid points of the BGA area do not need to be considered when spreading the needle. The grid points outside the BGA area only need to meet the detection of the peripheral circuit. The test needle can be detected with a smaller slope, thereby improving the test pass rate.

[0046] Optionally, at least one independent measuring point hole corresponding to at least one of the solder balls is provided on the needle disk panel; at least one of the solder balls is provided on at least one of the independent measuring point holes in a one-to-one manner; a connecting circuit layer connecting at least one of the independent measuring point holes in sequence is provided in the needle disk panel; a solder resist layer is provided on the connecting circuit layer; and the connecting circuit layer is electrically connected to the test frame.

[0047] In practical applications, since the circuits of each circuit board to be tested are different, the test points required to be tested are also different. Therefore, it is necessary to design the corresponding needle plate panel according to the circuit layer circuit of the circuit board to be tested. For circuit boards to be tested with more BGA areas, the needle plate panel can be made in the way of making circuit boards. First, the epoxy resin board of corresponding thickness is directly electroplated by DMSE to make a layer of copper evenly plated on its surface. Then, the target holes and independent test point holes are drilled on the electroplated copper-plated panel, and then the copper-plated panel after the target holes are drilled is electroplated on the whole board. The thickness of the copper layer on the copper-plated panel meets the requirements, and the independent test point holes are metallized. Then, the graphic circuit is etched according to the circuits of the pre-designed multiple independent test point holes, and the circuit connection data is selectively retained on the epoxy board through lamination-film exposure-acid etching. And all the epoxy boards except the independent pads and test holes are covered with solder mask oil and cured. Finally, the epoxy board is positioned by the target hole, and the epoxy board is poured into the CNC program to drill holes according to the positions of other areas to be tested. By passing tin balls on the tin net at the independent measuring point holes and independent pads, a connecting circuit layer attached to the surface of the panel can be obtained, with only the end points leaking out of the circuit and the middle part covered with solder mask ink insulated by the solder mask layer.

[0048] Optionally, a silver paste line layer is provided on the surface of the needle plate panel; at least one solder ball is provided on the silver paste line layer; an insulating paint layer is provided on the silver paste line layer; and the silver paste line layer is electrically connected to the test frame.

[0049] In practical applications, for relatively simple circuit boards to be tested, the existing needle plate panel can be processed. Usually, a silver paste pen is used to draw the test points corresponding to the BGA area on the needle plate panel. After connecting all the test points, extend them to the edge of the needle plate panel, and then plant solder balls on the silver paste line layer to facilitate contact with the BGA area of ​​the circuit board to be tested. Then, an insulating paint layer is applied on the silver paste line layer to insulate the middle connection part of the silver paste line layer. At this time, only the solder balls at the test points leak out of the circuit.

[0050] In summary, the present invention has the following beneficial effects:

[0051] 1) By testing the BGA area through solder balls, the test needle can test the peripheral circuit with a smaller slope, thereby improving the electrical test pass rate of the circuit board;

[0052] 2) The solder ball contacts the BGA area of ​​the circuit board to be tested, which is made of a softer material and can reduce the pin mark problem. BRIEF DESCRIPTION OF THE DRAWINGS

[0053] Figure 1 It is a method flow chart of a method for improving the passing rate of electrical testing of a circuit board according to the present invention;

[0054] Figure 2 It is a schematic diagram of the overall structure of a device for improving the passing rate of electrical testing of a circuit board according to the present invention;

[0055] Figure 3 The present invention is a schematic structural diagram of a needle plate panel in a device for improving the passing rate of electrical testing of a circuit board.

[0056] In the figure: 1. Test stand; 2. Test needle; 3. Needle plate panel; 4. Solder ball; 5. Independent test point hole; 6. Connection circuit layer; 7. Circuit board to be tested. DETAILED DESCRIPTION

[0057] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the specific implementation methods of the present invention are described in detail below in conjunction with the accompanying drawings. Several embodiments of the present invention are shown in the accompanying drawings. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein.

[0058] In the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal connection of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances. The terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features.

[0059] In the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may include the first and second features being in direct contact, or may include the first and second features being in contact not directly but through another feature between them. Moreover, the first feature being "above", "above" and "above" the second feature includes the first feature being directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature includes the first feature being directly below and obliquely below the second feature, or simply indicates that the first feature is lower in level than the second feature. The terms "vertical", "horizontal", "left", "right", "above", "below" and similar expressions are for illustrative purposes only, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be understood as limiting the present invention.

[0060] The present invention is described in detail below in conjunction with the accompanying drawings and embodiments.

[0061] Embodiment 1

[0062] This embodiment provides a method for improving the pass rate of circuit board electrical testing, such as Figure 1 As shown, including:

[0063] Step 100, setting a first measuring point and a second measuring point corresponding to a pad of a BGA according to a gerber file of the circuit board;

[0064] Step 200: manufacturing a test panel according to the first test point and the second test point, and providing a solder ball corresponding to the second test point on the test panel;

[0065] Step 300: Install the test panel in a test machine, and let the test machine test the conduction state of the first test point and the second test point in the circuit board to be tested to determine whether the circuit board to be tested is qualified.

[0066] Optionally, setting the first measuring point and the second measuring point corresponding to the pad of the BGA according to the gerber document of the circuit board includes:

[0067] Get the wiring information of the circuit layer where the BGA area is located in the gerder document of the circuit board;

[0068] Marking the BGA area as an independent measuring point according to the wiring information, and setting a second measuring point;

[0069] The end point of the same line is set as the first measuring point according to the wiring information.

[0070] Optionally, manufacturing a test panel according to the first measuring point and the second measuring point, and providing a solder ball corresponding to the second measuring point on the test panel, includes:

[0071] Creating a second gerber file according to the first measuring point and the second measuring point;

[0072] Make a test panel based on the second gerber document.

[0073] Optionally, making a test panel according to the second gerber document includes:

[0074] Directly electroplate the epoxy board to obtain a copper-plated panel;

[0075] Drilling the copper-plated panel according to the second measuring point position in the second gerber file and processing the target hole;

[0076] Electroplating the entire copper-plated panel after drilling;

[0077] Etch the pattern circuits on the copper-plated panel after the whole board is electroplated;

[0078] Perform solder mask treatment on the copper-plated panel after etching the graphic circuit;

[0079] Perform secondary drilling on the copper-plated panel after solder mask treatment according to the position of the first measuring point;

[0080] The ball is planted at the position corresponding to the second measuring point on the copper-plated panel after secondary drilling to obtain a test panel.

[0081] The production of the test panel mainly includes the following steps:

[0082] 1. Data Processing

[0083] Organize the gerber data of the circuit board to be tested;

[0084] Definition: Import data to define the layer, such as solder mask, circuit, drilling, text, molding, to facilitate software recognition;

[0085] Convert to pad: Convert the circuit under the solder mask window to pad attribute, so that the software can automatically add test points when running test points;

[0086] Run the network: Run the processed data on the network. The software will automatically select the end points of the same network as test points according to the layer attributes to facilitate testing;

[0087] Select test points: Check the test points that are automatically generated to see if there are any omissions or multiple selections, and manually add or reduce them. Pay special attention to this step to keep only one independent test point for BGA; edit the second gerber data and connect this independent point with the regional independent point;

[0088] Needle Spreading: Import the selected measuring point data, select the test structure, connect the measuring points and grid points with the test needles, and manually fine-tune the points where the slope exceeds the standard;

[0089] Place the support: Place the PCB board without test points in the support position to ensure the stability of the test fixture to ensure the test effect and prevent it from collapsing;

[0090] Export CNC data: The software automatically exports CNC processing data of each layer;

[0091] Export test data and maintenance data: The software exports test data for the test machine and maintenance data for the maintenance machine;

[0092] 2. BGA surface test panel processing:

[0093] Direct electroplating: Take the epoxy board and pass it through DMSE to evenly plate a layer of copper;

[0094] Drilling: Drill the only independent measuring point of the BGA and process the target hole for subsequent alignment;

[0095] Full-plate plating: metalize this hole;

[0096] Graphic circuit: The circuit connection data of this step is selectively retained on the epoxy board through lamination-film exposure-acid etching;

[0097] Solder mask: Cover the epoxy board with circuits in the previous step except for independent pads and test holes with solder mask oil and cure;

[0098] Drilling of test stand: import this board into CNC program for drilling, locate through target hole, and skip independent test point holes;

[0099] Tinning: Put solder balls on all the leaked independent pad test points on the test panel through the solder net.

[0100] Among them, the gerber document is a collection of file formats for the circuit board industry software to depict the circuit board (circuit layer, solder mask layer, character layer, etc.) image and drilling and milling. It is the standard format for image conversion in the circuit board industry. Pad is a soldering pad, which is mainly used to solder component pins to achieve electrical connection and mechanical fixation. There are two types of soldering pads: pin soldering pads and surface mount soldering pads. Pin soldering pads usually have solder holes for soldering pin components; while surface mount soldering pads have no solder holes and are suitable for soldering surface mount components.

[0101] Optionally, the testing machine tests the conduction state of the first test point and the second test point in the circuit board to be tested, including:

[0102] The circuit board to be tested is clamped by a testing machine, and a test needle is inserted into the hole corresponding to the first test point at a preset slope, and the second test point contacts the BGA of the circuit board to be tested;

[0103] Powering on the test needle and the test panel to obtain the conduction information between the solder ball corresponding to the second test point and the test needle in the first test point;

[0104] It is determined whether the BGA area of ​​the circuit board to be tested is conductive with its adjacent circuits according to the conductive information. If so, the circuit board to be tested is determined to be unqualified; if not, the circuit board to be tested is determined to be qualified.

[0105] Optionally, judging whether a BGA area of ​​the circuit board to be tested is conductive with its adjacent circuits according to the conductive information includes:

[0106] If the solder ball corresponding to the second measuring point is connected to the test pin in the first measuring point, it is determined that the BGA area of ​​the circuit board to be tested is connected to its adjacent circuit;

[0107] If the solder ball corresponding to the second measuring point is not connected to the test pin in the first measuring point, it is determined that the BGA area of ​​the circuit board to be tested is not connected to its adjacent circuits.

[0108] This embodiment sets a second test point corresponding to the pad of the BGA according to the wiring information of the circuit board to be tested, makes a test panel with the wiring information of the circuit board to be tested, and plants a solder ball in the area where the second test point is located on the test panel. The test panel has a PCB circuit connecting all the solder balls, and the test panel has a through hole corresponding to the first test point. After the test panel is placed in the test frame, the PCB circuit on the test panel is energized, the solder ball contacts a point in the BGA area of ​​the circuit board to be tested, one end of the test needle in the test frame is connected to the test frame, and the other end contacts the first test point on the circuit board to be tested, so that it can be determined whether the first test point is connected to the BGA area of ​​the circuit board to be tested, and the detection of the circuit board to be tested can be completed. Since the test needle does not need to detect the BGA area of ​​the circuit board to be tested, the grid points outside the BGA area only need to meet the detection of the peripheral circuit, and the test needle can be detected with a smaller slope, thereby improving the test pass rate; and the material of the solder ball that contacts the BGA area of ​​the circuit board to be tested is softer, which can reduce the problem of needle printing.

[0109] Embodiment 2

[0110] like Figure 2-3 As shown, this embodiment provides a device for improving the pass rate of electrical testing of a circuit board, comprising: a test frame 1, a test needle 2, and a needle tray panel 3; at least one solder ball 4 corresponding to and adapted to the BGA area of ​​the circuit board is arranged on the needle tray panel 3; at least one of the solder balls 4 is electrically connected to the test frame 1; the test needle 2 is arranged in the test frame 1 and can pass through the needle tray panel 3; the test needle 2 is electrically connected to the test frame 1.

[0111] Optionally, at least one independent measuring point hole 5 corresponding to at least one of the solder balls 4 is provided on the needle disk panel 3; at least one of the solder balls 4 is provided on at least one of the independent measuring point holes 5 in a one-to-one manner; a connecting circuit layer 6 connecting at least one of the independent measuring point holes 5 in sequence is provided in the needle disk panel 3; a solder resist layer is provided on the connecting circuit layer 6; and the connecting circuit layer 6 is electrically connected to the test frame 1.

[0112] In this embodiment, independent measuring point holes 5 are opened on the needle plate panel 3, and each independent measuring point hole 5 is connected through a connecting circuit layer 6, and the solder ball 4 is soldered to the independent measuring point hole 5. Therefore, when the circuit board 7 to be tested is tested, the solder ball 4 contacts the BGA area of ​​the circuit board 7 to be tested, and is powered by the test frame 1. At the same time, one end of the test needle 2 is connected to the test frame 1, and the other end contacts the corresponding measuring point on the circuit board 7 to be tested, so as to detect the circuit board 7 to be tested. And because the test needle 2 does not need to detect the BGA area of ​​the circuit board 7 to be tested, the grid points outside the BGA area only need to meet the detection of the peripheral circuit, and the test needle 2 can be detected with a smaller slope, thereby improving the test pass rate. By contacting the BGA area of ​​the circuit board 7 to be tested with the solder ball 4, its material is softer, which can reduce the problem of needle printing.

[0113] Embodiment 3

[0114] like Figure 2-3 As shown, this embodiment provides a device for improving the pass rate of electrical testing of a circuit board, comprising: a test frame 1, a test needle 2, and a needle tray panel 3; at least one solder ball 4 corresponding to and adapted to the BGA area of ​​the circuit board is arranged on the needle tray panel 3; at least one of the solder balls 4 is electrically connected to the test frame 1; the test needle 2 is arranged in the test frame 1 and can pass through the needle tray panel 3; the test needle 2 is electrically connected to the test frame 1.

[0115] Optionally, a silver paste line layer is provided on the surface of the needle plate panel 3; at least one solder ball 4 is provided on the silver paste line layer; an insulating paint layer is provided on the silver paste line layer; and the silver paste line layer is electrically connected to the test frame 1.

[0116] In this embodiment, for the circuit board 7 to be tested with a relatively simple structure, a silver paste pen is directly used to draw a silver paste line on the surface of the needle plate panel 3, and a solder ball 4 is planted on the silver paste line at a position corresponding to the BGA area, and an insulating paint is applied to the silver paste line to insulate the middle connection part of the silver paste line layer. At this time, the test stand 1 can supply power to the solder ball 4 through the silver paste line layer, because the test needle 2 does not need to detect the BGA area of ​​the circuit board 7 to be tested. Therefore, the grid points outside the BGA area only need to meet the detection of the peripheral circuit, and the test needle 2 can be detected with a smaller slope, thereby improving the test pass rate; and the solder ball 4 contacts the BGA area of ​​the circuit board 7 to be tested, and its material is softer, which can reduce the needle printing problem.

[0117] A method and device for improving the electrical test pass rate of a circuit board of the present invention can improve the electrical test pass rate of the circuit board and alleviate the pin printing problem in the BGA area.

[0118] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A method for improving the pass rate of electrical testing of circuit boards, characterized in that: include: According to the gerber file of the circuit board, a first measuring point and a second measuring point corresponding to the pad of the BGA are set; A test panel is manufactured according to the first measuring point and the second measuring point, and a solder ball corresponding to the second measuring point is arranged on the test panel; The test panel is installed in a test machine, and the test machine tests the conduction state of the first test point and the second test point in the circuit board to be tested to determine whether the circuit board to be tested is qualified.

2. A method for improving the pass rate of electrical testing of a circuit board according to claim 1, characterized in that: The step of setting the first measuring point and the second measuring point corresponding to the pad of the BGA according to the gerber document of the circuit board includes: Get the wiring information of the circuit layer where the BGA area is located in the gerder document of the circuit board; Marking the BGA area as an independent measuring point according to the wiring information, and setting a second measuring point; The end point of the same line is set as the first measuring point according to the wiring information.

3. A method for improving the passing rate of electrical testing of circuit boards according to claim 2, characterized in that: The test panel is manufactured according to the first test point and the second test point, and a solder ball corresponding to the second test point is arranged on the test panel, including: Creating a second gerber document according to the first measuring point and the second measuring point; Make a test panel based on the second gerber document.

4. A method for improving the passing rate of electrical testing of circuit boards according to claim 3, characterized in that: The manufacturing of the test panel according to the second gerber document comprises: Directly electroplate the epoxy board to obtain a copper-plated panel; Drilling the copper-plated panel according to the second measuring point position in the second gerber file and processing the target hole; Electroplating the entire copper-plated panel after drilling; Etch the pattern circuits on the copper-plated panel after the whole board is electroplated; Perform solder mask treatment on the copper-plated panel after etching the graphic circuit; Perform secondary drilling on the copper-plated panel after solder mask treatment according to the position of the first measuring point; The ball is planted at the position corresponding to the second measuring point on the copper-plated panel after secondary drilling to obtain a test panel.

5. A method for improving the passing rate of electrical testing of circuit boards according to claim 1, characterized in that: Before the tester tests the conduction state of the first test point and the second test point in the circuit board to be tested, the method further includes: Perform AOI optical scanning on the circuit board to be tested to obtain quality information of the circuit board to be tested; It is determined whether the circuit board to be tested has any quality problem according to the quality information. If so, the detection of the circuit board to be tested is cancelled; if not, the next process is performed.

6. A method for improving the passing rate of electrical testing of circuit boards according to claim 1, characterized in that: The testing machine tests the conduction state of the first test point and the second test point in the circuit board to be tested, including: The circuit board to be tested is clamped by the testing machine, and a test needle is inserted into the hole corresponding to the first test point at a preset slope, and the second test point contacts the BGA of the circuit board to be tested; Powering on the test needle and the test panel to obtain the conduction information between the solder ball corresponding to the second test point and the test needle in the first test point; It is determined whether the BGA area of ​​the circuit board to be tested is conductive with its adjacent circuits according to the conductive information. If so, the circuit board to be tested is determined to be unqualified; if not, the circuit board to be tested is determined to be qualified.

7. A method for improving the passing rate of electrical testing of circuit boards according to claim 6, characterized in that: The step of judging whether the BGA area of ​​the circuit board to be tested and its adjacent circuits are conductive according to the conductive information includes: If the solder ball corresponding to the second measuring point is connected to the test pin in the first measuring point, it is determined that the BGA area of ​​the circuit board to be tested is connected to its adjacent circuit; If the solder ball corresponding to the second measuring point is not connected to the test pin in the first measuring point, it is determined that the BGA area of ​​the circuit board to be tested is not connected to its adjacent circuits.

8. A device for improving the passing rate of electrical testing of circuit boards, characterized in that: include: A test stand, a test needle, and a needle tray panel; at least one solder ball corresponding to the BGA area of ​​the circuit board is arranged on the needle tray panel; At least one of the solder balls is electrically connected to the test stand; the test needle is arranged in the test stand and can pass through the needle tray panel; the test needle is electrically connected to the test stand.

9. A device for improving the passing rate of electrical testing of circuit boards according to claim 8, characterized in that: At least one independent measuring point hole corresponding to at least one of the solder balls is arranged on the needle disk panel; at least one of the solder balls is arranged on at least one of the independent measuring point holes in a one-to-one manner; a connecting circuit layer connecting at least one of the independent measuring point holes in sequence is arranged in the needle disk panel; a solder resist layer is arranged on the connecting circuit layer; and the connecting circuit layer is electrically connected to the test frame.

10. The device for improving the passing rate of electrical testing of a circuit board according to claim 8, characterized in that: A silver paste line layer is arranged on the surface of the needle plate panel; at least one solder ball is arranged on the silver paste line layer; an insulating paint layer is arranged on the silver paste line layer; and the silver paste line layer is electrically connected to the test frame.

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