Contact type BGA packaging chip solder ball coplanarity measuring method

Abstract

The invention provides a contact-type BGA packaging chip solder ball coplanarity measurement method, which comprises the following steps: S100, fixing a sample to be measured, and leveling a ceramic substrate of the sample to be measured, so that the upper surface of the ceramic substrate is parallel to the horizontal plane; s200, the detection surface of the coplanarity detector is in contact with the top of one to-be-detected solder ball of the to-be-detected sample, the detection surface is parallel to the upper surface of the ceramic substrate, and the height of the to-be-detected solder ball can be obtained by measuring the distance between the detection surface and the ceramic substrate; s300, sequentially measuring the heights of all the to-be-measured solder balls in the to-be-measured sample by adopting the method in the S200, and fitting the highest points of all the to-be-measured solder balls to establish a to-be-measured surface; and S400, acquiring the coplanarity of the surface to be measured in the step S300. The invention provides a contact type BGA packaging chip solder ball coplanarity measuring method, and aims to solve the problem that the detection result precision is insufficient due to the fact that BGA solder ball coplanarity detection is greatly influenced by irradiation intensity, incident light angle and refraction angle in the prior art.

Description

Technical Field

[0001] The invention belongs to the technical field of electronic packaging, and more specifically, relates to a method for measuring the coplanarity of solder balls of a contact-type BGA packaging chip. Background Art

[0002] Ball-Grid-Array is the most popular packaging technology today. During the BGA packaging process, the substrate warping caused by factors such as material coefficient of thermal expansion (CTE) mismatch and the unevenness of the BGA solder balls themselves will cause the BGA solder balls on the substrate to be non-coplanar, which will induce short circuits or open circuits in the circuit, resulting in unsafe electrical connections, affecting electrical connection performance and product reliability, and even causing device failure. Therefore, it is crucial to check the coplanarity of BGA solder balls.

[0003] After the packaged device is installed on the board, its pin solder joints are hidden at the bottom of the chip, making it difficult to inspect the quality of the solder joints by direct observation. When there is a problem with the surface assembly, rework is difficult. Therefore, before surface assembly, the coplanarity of the pins needs to be inspected. At present, the commonly used methods for non-destructive inspection of the solder ball height of the pin solder joints are: manual visual inspection, X-ray inspection, and automatic optical inspection. Manual visual inspection is greatly affected by subjective factors and has low detection accuracy, while X-ray inspection and automatic optical inspection are both non-contact inspections.

[0004] Among them, automatic optical inspection is mainly based on laser scanning technology or structured light projection method. The physical scanning process of the laser beam will result in a very low measurement speed. Moreover, the traditional detection method is to achieve phase shift by mechanically moving the position of the reference grid. The movement speed is slow, and the movement brings vibration, noise and poor repetitive phase shift accuracy, which cannot meet the requirements of high-precision real-time measurement. Whether it is ray detection or automatic optical detection, it is greatly affected by the irradiation intensity, incident light angle, and refraction angle, and it is easy to have distortion points. Non-contact contour scanning of 3D contours needs to be combined with 3D cloud maps. The measurement accuracy is limited to a certain extent by the density of the scanned contour points. If the density is low, it is easy to fail to capture the highest point, so the accuracy of the detection result is affected. Summary of the invention

[0005] The purpose of the present invention is to provide a contact type BGA package chip solder ball coplanarity measurement method, aiming to solve the problem in the prior art that the BGA solder ball coplanarity detection is greatly affected by the illumination intensity, incident light angle and refraction angle, resulting in insufficient detection result accuracy.

[0006] To achieve the above object, the technical solution adopted by the present invention is: A method for measuring the coplanarity of solder balls of a contact BGA package chip is provided, comprising: S100, fixing the sample to be tested, and leveling the ceramic substrate of the sample to be tested so that the upper surface of the ceramic substrate is parallel to the horizontal plane; S200, the detection surface of the coplanarity detector is in contact with the top of one of the solder balls to be tested of the sample to be tested, and the detection surface is parallel to the upper surface of the ceramic substrate, and the distance between the detection surface and the ceramic substrate is measured to obtain the height of the solder ball to be tested; S300, using the method in S200 to sequentially measure the heights of all the solder balls to be tested in the sample to be tested, and fitting the highest points of all the solder balls to be tested to establish a test surface; S400, obtaining the coplanarity of the surface to be measured in S300.

[0007] In a possible implementation, the S100 specifically includes: S110, fixing the sample to be tested on an adjustment device; S120, controlling the adjusting device to level the ceramic substrate so that the upper surface of the ceramic substrate is parallel to a horizontal plane.

[0008] In a possible implementation manner, the S120 specifically includes: S121, placing a level detector on the ceramic substrate; S122, adjusting the ceramic substrate so that the upper surface of the ceramic substrate is parallel to a horizontal plane.

[0009] In a possible implementation, in S200, the detection surface is parallel to a horizontal plane, the coplanarity detector moves freely in an X direction and a Y direction in a plane parallel to the upper surface of the ceramic substrate, and the coplanarity detector moves freely in a Z direction, which is perpendicular to the horizontal plane.

[0010] In a possible implementation, in S200, the coplanarity detector further includes a contact sensing module, and when the detection surface contacts the solder ball to be detected, the contact sensing module generates a stop signal, and the coplanarity detector stops moving in the Z direction.

[0011] In a possible implementation, the S200 specifically includes: S210, fixing the sample to be tested; S220, the image recognizer detects the position of the solder ball to be tested in the sample to be tested, and sends the position information of the solder ball to the coplanarity detector; S230, the coplanarity detector moves to the top of the solder ball to be tested according to the position information of the solder ball to be tested, and then moves downward until the detection surface contacts the top of the solder ball to be tested; S240, measuring the distance between the detection surface and the ceramic substrate.

[0012] In a possible implementation manner, in S240, a measuring ruler is used to measure the distance between the detection surface and the ceramic substrate.

[0013] In a possible implementation, in S240, the coplanarity detector includes a distance sensing module, and the distance sensing module measures the distance between the detection surface and the ceramic substrate.

[0014] In a possible implementation, S400 specifically includes calculating the maximum height difference among all the solder balls to be tested, and obtaining the coplanarity of the surface to be tested.

[0015] In a possible implementation, in S200, the coplanarity detector includes a distance sensing module and a control module communicatively connected to the distance sensing module, and also includes a display module communicatively connected to the control module, the distance sensing module detects the height of the solder ball to be measured, and the display module outputs the height of the solder ball to be measured.

[0016] The beneficial effect of the contact-type BGA package chip solder ball coplanarity measurement method provided by the present invention is that: compared with the prior art, the contact-type BGA package chip solder ball coplanarity measurement method of the present invention first fixes the sample to be tested, then levels the ceramic substrate of the sample to be tested, so that the upper surface of the ceramic substrate is parallel to the horizontal plane, and then directly contacts the detection surface parallel to the working surface with the solder ball to be tested, and then the height of the solder ball to be tested can be obtained by measuring the distance between the detection surface and the ceramic substrate. In the present invention, the height of the solder ball to be tested is detected by direct contact, and the detection surface is parallel to the upper surface of the ceramic substrate to ensure contact with the highest point of the solder ball to be tested. Compared with non-contact detection methods such as ray detection and light detection in the prior art, it is not affected by the incident light angle, irradiation intensity, etc., and has a higher detection accuracy. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 A schematic diagram of the contact type BGA package chip solder ball coplanarity measurement method provided in an embodiment of the present invention during measurement.

[0019] In the figure: 1, coplanarity detector; 101, detection surface; 2, sample to be tested; 201, solder ball to be tested; 202, ceramic substrate. DETAILED DESCRIPTION

[0020] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0021] In the claims, specification and the above drawings of the present invention, unless otherwise clearly defined, the terms "first", "second" or "third" are used to distinguish different objects, rather than to describe a specific order. Unless otherwise specified, other directional words, such as "vertical", "clockwise", "counterclockwise", etc., indicating directions or positional relationships are based on the directions and positional relationships shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific direction or be constructed and operated in a specific direction, so it cannot be understood as limiting the specific protection scope of the present invention. In the claims, specification and the above drawings of the present invention, unless otherwise clearly defined, the terms "fixed connection" or "fixed connection" should be understood in a broad sense, that is, any connection method without a displacement relationship and relative rotation relationship between the two, that is, including non-detachable fixed connection, detachable fixed connection, integrated connection and fixed connection through other devices or elements. In the claims, specification and the above drawings of the present invention, the terms "including", "having" and their variations are used, and the intention is to "include but not limited to".

[0022] See also Figure 1 The contact type BGA package chip solder ball coplanarity measurement method provided by the present invention is now described. The contact type BGA package chip solder ball coplanarity measurement method comprises:

[0023] Compared with the prior art, the contact-type BGA package chip solder ball coplanarity measurement method provided by the present invention first fixes the sample 2 to be tested, then levels the ceramic substrate 202 of the sample 2 to be tested, so that the upper surface of the ceramic substrate 202 is parallel to the horizontal plane, and then directly contacts the solder ball 201 to be tested with the detection surface 101 parallel to the working surface, and then obtains the height of the solder ball 201 to be tested by measuring the distance between the detection surface 101 and the ceramic substrate 202. In the present invention, the height of the solder ball 201 to be tested is detected by direct contact, and the detection surface 101 is parallel to the upper surface of the ceramic substrate 202 to ensure contact with the highest point of the solder ball 201 to be tested. Compared with the non-contact detection methods such as ray detection and light detection in the prior art, it is not affected by the incident light angle, irradiation intensity, etc., and has a higher detection accuracy.

[0024] It should be noted that the test sample 2 includes a ceramic substrate 202 and a plurality of test solder balls 201 disposed on the upper surface of the ceramic substrate 202. Detecting the height of the test solder balls 201 means detecting the distance between the detection surface 101 and the ceramic substrate 202 (the upper surface of the ceramic substrate 202).

[0025] In some embodiments, see Figure 1 , S100 specifically includes: S110, fixing the sample 2 to be tested on the adjustment device; S120 , controlling the adjusting device to level the ceramic substrate 202 so that the upper surface of the ceramic substrate 202 is parallel to the horizontal plane.

[0026] The sample 2 to be tested is first fixed to prevent the sample 2 from moving during the measurement process, which may lead to inaccurate measurement results. The position of the ceramic substrate 202 is changed by the adjustment device to achieve that the upper surface of the ceramic substrate 202 is parallel to the horizontal plane. The solution in this embodiment increases the stability of the sample 2 to be tested during the measurement process and improves the detection accuracy.

[0027] Optionally, a clamp may be used to fix the sample 2 to be tested, and the clamp applies a clamping force to the side wall of the sample 2 to be tested to avoid interference with the coplanarity detector 1, and can be adapted to samples 2 to be tested of different sizes and specifications.

[0028] In some embodiments, see Figure 1 , S120 specifically includes: S121, placing a level detector on the ceramic substrate 202; S122 , adjusting the ceramic substrate 202 so that the upper surface of the ceramic substrate 202 is parallel to the horizontal plane.

[0029] In this embodiment, a level detector is used to detect the levelness of the upper surface of the ceramic substrate 202, and the ceramic substrate 202 is adjusted until the upper surface of the ceramic substrate 202 is parallel to the horizontal plane. The level detector can be a laser level detector or a bubble level.

[0030] In some embodiments, see Figure 1 In S200, the detection surface 101 is parallel to the horizontal plane, the coplanarity detector 1 is free to move in the X and Y directions in a plane parallel to the upper surface of the ceramic substrate 202, and the coplanarity detector 1 is free to move in the Z direction, which is perpendicular to the horizontal plane.

[0031] The coplanarity detector 1 is controlled by a driving component, and the driving component controls the coplanarity detector 1 to move along the X, Y, and Z directions respectively until the detection surface 101 contacts the solder ball 201 to be tested. The solution in this embodiment does not need to manually move the coplanarity detector 1, which not only ensures that the detection surface 101 is parallel to the upper surface of the ceramic substrate 202, but also ensures the stability of the coplanarity detector 1 during the measurement process, thereby improving the detection accuracy.

[0032] Optionally, the driving assembly includes a lifting mechanism arranged along the Z direction, an X-direction moving mechanism connected to the lifting mechanism, and a Y-direction moving mechanism connected to the X-direction moving mechanism. The lifting mechanism, the X-direction moving mechanism and the Y-direction moving mechanism may be telescopic parts, such as pneumatic telescopes or hydraulic telescopes, or may be lead screw structures. The coplanarity detector 1 is connected to the Y-direction moving mechanism.

[0033] In some embodiments, see Figure 1 In S200, the coplanarity detector 1 further includes a contact sensing module. When the detection surface 101 contacts the solder ball 201 to be detected, the contact sensing module generates a stop signal, and the coplanarity detector 1 stops moving in the Z direction. The contact sensor can be a laser, ultrasonic or infrared sensor, which detects whether the detection surface 101 is in contact with the solder ball 201 to be tested, which can prevent the detection surface 101 from stopping above the solder ball 201 to be tested, resulting in the detected height of the solder ball 201 being greater than the actual height; it can also prevent the detection surface 101 from being in too close contact with the solder ball 201 to be tested, which will produce a squeezing force on the solder ball 201 to be tested, thereby causing the solder ball to deform, and deriving the detected height of the solder ball 201 to be less than the actual height. The solution in this embodiment can ensure the accuracy of the measurement result and facilitate the control of the stop position of the coplanarity detector 1 in the Z direction.

[0034] In some embodiments, see Figure 1 , S200 specifically includes: S210, fixing the sample 2 to be tested; S220, the image recognizer detects the position of the solder ball 201 to be tested in the sample 2 to be tested, and sends the position information of the solder ball 201 to the coplanarity detector 1; S230, the coplanarity detector 1 moves to the top of the solder ball 201 to be tested according to the position information of the solder ball 201 to be tested, and then moves downward until the detection surface 101 contacts the top of the solder ball 201 to be tested; S240 , measuring the distance between the detection surface 101 and the ceramic substrate 202 .

[0035] The image recognizer can detect the position of the solder ball 201 to be tested, and the coplanarity detector 1 moves along the X and Y directions according to the position information until the coplanarity detector 1 moves to the top of the solder ball 201 to be tested, and then controls the coplanarity detector 1 to move along the Z direction. The solution in this embodiment can accurately control the position of the coplanarity detector 1, and at the same time avoid the problem of the coplanarity detector 1 moving along the Z direction and causing the solder ball 201 to be tested to collide.

[0036] In some embodiments, see Figure 1 In S240, a measuring ruler is used to measure the distance between the detection surface 101 and the ceramic substrate 202.

[0037] The measuring ruler measures the distance between the detection surface 101 and the ceramic substrate 202. The measuring ruler is low-cost and easy to obtain, which saves the detection cost. During the measurement, ensure that the measuring ruler is perpendicular to the working surface.

[0038] In some embodiments, see Figure 1 In S240 , the coplanarity detector 1 includes a distance sensing module, and the distance sensing module measures the distance between the detection surface 101 and the ceramic substrate 202 .

[0039] After the detection surface 101 contacts the solder ball 201 to be detected, the distance sensing module automatically measures the distance between the detection surface 101 and the solder ball 201 to be detected, and the detection efficiency is high. The coplanarity detector 1 can also include a voice module or a display module. After the distance sensing module measures the height of the solder ball 201 to be detected, it outputs it to the outside through the voice module or the display module.

[0040] In some embodiments, see Figure 1 S240 specifically includes calculating the maximum height difference among all solder balls 201 to be tested, and obtaining the coplanarity of the surface to be tested.

[0041] After detecting the height of each solder ball 201 to be tested, the heights of all solder balls 201 to be tested are compared to determine the coplanarity of the solder balls 201 to be tested. The coplanarity of each solder ball 201 to be tested is detected separately to avoid short circuit or breakage of the circuit caused by non-coplanarity of the BGA solder balls on the substrate, thereby improving the electrical connection performance and product reliability.

[0042] In some embodiments, see Figure 1 In S400, the coplanarity detector 1 includes a distance sensing module and a control module connected to the distance sensing module in communication, and also includes a display module connected to the control module in communication. The distance sensing module detects the height of the solder ball 201 to be tested, and the display module outputs the height of the solder ball 201 to be tested. After the detection surface 101 contacts the solder ball 201 to be tested, the distance sensor module measures the distance between the detection surface 101 and the ceramic substrate 202 to obtain the height of the solder ball 201 to be tested, and the display module outputs the height value of the solder ball 201 to be tested to the outside, and the data can be directly obtained through the display module. The solution in this embodiment does not require manual measurement of the height of the solder ball 201 to be tested, and the height of the solder ball 201 to be tested can be quickly obtained.

[0043] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for measuring the coplanarity of solder balls of contact BGA package chips, characterized in that: include: S100, fixing the sample to be tested, and leveling the ceramic substrate of the sample to be tested so that the upper surface of the ceramic substrate is parallel to the horizontal plane; S200, the detection surface of the coplanarity detector is in contact with the top of one of the solder balls to be tested of the sample to be tested, and the detection surface is parallel to the upper surface of the ceramic substrate, and the distance between the detection surface and the ceramic substrate is measured to obtain the height of the solder ball to be tested; S300, using the method in S200 to sequentially measure the heights of all the solder balls to be tested in the sample to be tested, and fitting the highest points of all the solder balls to be tested to establish a test surface; S400, obtaining the coplanarity of the surface to be measured in S300.

2. The contact BGA package chip solder ball coplanarity measurement method according to claim 1, characterized in that: The S100 specifically includes: S110, fixing the sample to be tested on an adjustment device; S120, controlling the adjusting device to level the ceramic substrate so that the upper surface of the ceramic substrate is parallel to a horizontal plane.

3. The contact BGA package chip solder ball coplanarity measurement method according to claim 2, characterized in that: The S120 specifically includes: S121, placing a level detector on the ceramic substrate; S122, adjusting the ceramic substrate so that the upper surface of the ceramic substrate is parallel to a horizontal plane.

4. The contact BGA package chip solder ball coplanarity measurement method according to claim 1, characterized in that: In S200, the detection surface is parallel to the horizontal plane, the coplanarity detector is free to move in the X and Y directions in a plane parallel to the upper surface of the ceramic substrate, and the coplanarity detector is free to move in the Z direction, which is perpendicular to the horizontal plane.

5. The contact BGA package chip solder ball coplanarity measurement method according to claim 4, characterized in that: In the step S200, the coplanarity detector further includes a contact sensing module. When the detection surface contacts the solder ball to be detected, the contact sensing module generates a stop signal, and the coplanarity detector stops moving in the Z direction.

6. The contact BGA package chip solder ball coplanarity measurement method according to claim 1, characterized in that: The S200 specifically includes: S210, fixing the sample to be tested; S220, the image recognizer detects the position of the solder ball to be tested in the sample to be tested, and sends the position information of the solder ball to the coplanarity detector; S230, the coplanarity detector moves to the top of the solder ball to be tested according to the position information of the solder ball to be tested, and then moves downward until the detection surface contacts the top of the solder ball to be tested; S240, measuring the distance between the detection surface and the ceramic substrate.

7. The contact BGA package chip solder ball coplanarity measurement method according to claim 6, characterized in that: In S240, a measuring ruler is used to measure the distance between the detection surface and the ceramic substrate.

8. The method for measuring the coplanarity of solder balls of a contact BGA package chip according to claim 1, characterized in that: In S240, the coplanarity detector includes a distance sensing module, and the distance sensing module measures the distance between the detection surface and the ceramic substrate.

9. The contact BGA package chip solder ball coplanarity measurement method according to claim 1, wherein S400 specifically comprises calculating the maximum height difference among all the solder balls to be measured to obtain the coplanarity of the surface to be measured.

10. The contact BGA package chip solder ball coplanarity measurement method according to claim 1, characterized in that: In S200, the coplanarity detector includes a distance sensing module and a control module communicatively connected to the distance sensing module, and also includes a display module communicatively connected to the control module. The distance sensing module detects the height of the solder ball to be measured, and the display module outputs the height of the solder ball to be measured.

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