CN1472800A - Operation method for reworking and saving integrated circuit assembly - Google Patents

Abstract

The invention relates to a method for recovering an integrated circuit assembly by reworking, wherein the integrated circuit assembly is packaged in a Ball Grid Array (BGA) mode, and the method comprises the following steps: (a) the method comprises the steps of firstly, checking by a preliminary inspection step to screen out damaged and failed integrated circuit components, (b) baking target integrated circuit components at a preset temperature within a preset time, (c) removing at least one solder ball of the integrated circuit components, and (d) re-soldering the solder on the solder-removed parts of the integrated circuit components.

Description

A working method for rework and salvage of integrated circuit components

technical field

The invention relates to a method for reworking and rescuing integrated circuit components, in particular to a method for selecting whether to re-solder soldered integrated circuit components packaged in a ball grid array, so as to save the integrated circuit components for the next step of testing. Methods of operation of circuit assemblies.

Background technique

Generally speaking, when the customer finds substandard integrated circuit components, they will return these integrated circuit components to the manufacturer, hoping to conduct quality analysis or replace them. At this time, the manufacturer will try to determine whether these returned IC components are really unqualified IC components as the customer said, and if they are really unqualified IC components, they can understand which pins are faulty and why. The unqualified analysis will help IC component manufacturers to refer to the next batch of IC components to avoid the occurrence of the same failure. Of course, some IC components returned by customers may be found to be normal IC components after unqualified analysis. In this way, these IC components returned by customers can be retained and returned to customers for re-use. Verify or reuse.

The ball grid array (BGA) packaging method has been widely used in the packaging of integrated circuit components. When the integrated circuit components using the ball grid array packaging method are returned because they are judged as substandard products by the client, the integrated circuit component manufacturer will conduct failure analysis on these substandard products returned by the customer. The unqualified analysis method of common technology is to remove these so-called faulty integrated circuit components from the circuit carrier board (motherboard), remove all the solder on it, and then re-solder it with solder, so that Carry out the next step of unqualified analysis.

These defective integrated circuit components may be exposed to air for a period of time before waiting to be re-soldered with solder, causing the interior to absorb moisture from the air. In this way, the instantaneous high temperature (for example, about 180 to 260 degrees Celsius) that comes with re-soldering will cause the moisture inside the integrated circuit component to expand rapidly due to thermal shock, causing bursting or delamination, etc. Popcorn failure will make it difficult to obtain correct results for the unqualified analysis that will be carried out later, and also waste the materials and time required for re-soldering.

In addition, the whole process from re-soldering, to checking whether the re-soldered solder is complete, to cleaning the entire integrated circuit assembly will consume five to six minutes. When a large number of IC components need to be re-soldered for IC component pin function testing, it still takes quite a lot of time overall. In the case that some customers need to know the analysis results as soon as possible, how to speed up the verification and analysis is an urgent problem.

Contents of the invention

The main purpose of the present invention is to provide a working method for reworking and salvaging integrated circuit components. This operation method is to bake the target integrated circuit assembly at a predetermined temperature for a predetermined time before re-soldering to remove the ambient moisture that may be absorbed inside the target integrated circuit assembly, so that when the re-soldering action is performed, no The volume of these water (moisture) gases will expand rapidly due to instantaneous high heat, resulting in popcorn-like bulges at the bottom of integrated circuit components or damage to the internal structure, so that subsequent unqualified analysis cannot obtain correct results.

In addition, the operation method of the present invention can be applied to integrated circuit components packaged in a grid array of ball pins using POGO Pin test sockets. After removing all the solder of the so-called unqualified integrated circuit components, the target is not first The integrated circuit component is re-soldered, so that the target integrated circuit component is completely in electrical contact with the POGO Pin test slot with the conductive pad. First, judge whether it is a qualified product. If it is a failed product, no re-soldering action will be performed. , and only re-soldering is performed for some integrated circuit components that are judged as qualified products and have a chance to be rescued, so as to save the time required for re-soldering. It should be noted that this action of not re-soldering at all is only applied to the POGO Pin test socket. For integrated circuit components packaged with ball-pin grid arrays that use other general test sockets, the re-soldering Action is still required.

In order to achieve the above-mentioned purpose, the operation method for reworking the integrated circuit component of the ball grid array package of the present invention includes an inspection step for checking whether the bottom of the target integrated circuit component has a bulge or an open and short circuit failure, and then Bake the target integrated circuit device at a predetermined temperature for a predetermined time, remove at least one solder of the target integrated circuit device, and resolder the removed solder of the target integrated circuit device. Among them, for general test slots and POGO Pin test slots, the operation method of the present invention can choose whether to solder the target integrated circuit component after removing the solder, and the correct defect of the pin position of the target integrated circuit component can be obtained. In addition to analyzing the results, it saves the time spent on re-soldering.

In order to further understand the features and technical content of the present invention, please refer to the following detailed description and accompanying drawings of the present invention. However, the accompanying drawings are provided for reference and illustration only, and are not intended to limit the present invention.

Description of drawings

Fig. 1 is the flowchart of the first preferred embodiment of working method of the present invention;

Fig. 2 is a flowchart of another preferred embodiment of the working method of the present invention.

Detailed ways

Please refer to FIG. 1 . FIG. 1 is a flowchart of a working method 100 according to a first preferred embodiment of the present invention. Working method 100 of the present invention comprises the following steps:

Step 101: start;

Step 102: remove the unqualified integrated circuit assembly from the main board, which is the target integrated circuit assembly to be inspected;

Step 103: Execute the initial inspection step to inspect the target integrated circuit component, if it is unqualified, go to step 104, if it is qualified, go to step 105;

Step 104, the integrated circuit component is judged as defective and discarded;

Step 105: Bake the target IC device at a predetermined temperature for a predetermined time;

Step 106: removing solder;

Step 107: cleaning the integrated circuit assembly;

Step 108: re-soldering the integrated circuit component with solder;

Step 109: Execute the re-inspection step to check whether the solder of the target integrated circuit component is qualified, if qualified, go to step 110, and if unqualified, go back to step 108;

Step 110: cleaning the integrated circuit assembly again;

Step 111: install the integrated circuit component into the test slot for functional verification test, if not qualified, go to step 112, if qualified, go to step 113;

Step 112: the integrated circuit component is judged as defective and discarded;

Step 113: judging that it is a qualified product and saving it; and

Step 114: end.

When the integrated circuit component manufacturer receives the unqualified integrated circuit components sent by the customer, they must first remove these unqualified integrated circuit components from the circuit carrier (or main board) (as shown in step 102 shown), and this removal action will naturally partially destroy the solder at the bottom of these ball grid array packaged integrated circuit devices. This is why it is necessary to re-solder these integrated circuit components before performing unqualified analysis later, in order to know for sure whether these so-called unqualified integrated circuit components are really faulty, or if they do To determine if there is a fault, which pin is faulty.

The initial inspection step shown in step 103 is to first (1) visually check whether the bottoms of these integrated circuit components have bulges or dents after removing the integrated circuit components from the circuit carrier board or the main board. phenomenon (the so-called Popcorn Failure), and further (2) check whether there is an abnormal open circuit and/or short circuit failure between the power and ground pins of these integrated circuit components. This open circuit/short circuit failure can be digitally Voltmeter (Digital Voltage Meier) detection and learned. Once one of the above two conditions is met, proceed to step 104 to directly determine that these integrated circuit components have failed and are defective products, and there is no value of further rework to salvage and discard them.

When the integrated circuit assembly is qualified after the initial inspection step, go to step 105 . Since these integrated circuit components have been exposed to the air for a period of time and have absorbed part of the moisture in the air, the internal structure of the integrated circuit components may be damaged due to instantaneous high heat during the subsequent solder removal or re-soldering process. Therefore a gentler way is needed to remove the moisture present inside it. Step 105 of the present invention is to bake at a predetermined temperature (such as 125 degrees Celsius) for a predetermined time (such as 8 to 12 hours) to achieve this purpose. Although in this embodiment, the baking is carried out at 125 degrees Celsius for 8 to 12 hours, the temperature and time can be adjusted according to the actual situation.

After the baking operation in step 105 is completed, step 106 can be performed to start removing the solder on the bottom of the integrated circuit component that was damaged when it was removed from the circuit carrier until all the solder is removed. Since the solder is arranged one-to-one at the relative position below the conductive pad at the bottom of the integrated circuit component, after removing the solder, if the conductive pad of the integrated circuit component is found to be oxidized, you need to use additional tin wire Re-tin these conductive pads.

After removing the solder, there is another cleaning step 107, which is to immerse the integrated circuit assembly in cleaning solution for 2 minutes and then wipe it dry. Then just start the action of re-welding the soldering tin (step 108). In the process of resoldering in this embodiment, the set temperature is 240 degrees Celsius, the heating time is 3 minutes, and the cooling time is 1 minute. Compared with the temperature (125 degrees Celsius) set by the previous baking to remove moisture, this temperature is relatively high temperature, so if you do not bake the integrated circuit components slowly to remove the contained moisture, you can directly re-solder , it is likely to cause damage to the internal structure of integrated circuit components, and the so-called popcorn damage occurs.

After re-soldering, the operating method 100 of the present invention further includes a re-inspection step 109 to visually inspect the integrated circuit components that have completed the re-soldering action, whether there is solder leakage or poor solder dissolution. If the above situation occurs, go back to step 108 to re-solder the defective integrated circuit component part again.

After the re-inspection step 109 ends, if the re-soldering solder of the integrated circuit assembly is qualified, then clean again (as shown in step 110), and then in step 111, the integrated circuit assembly is installed in the test slot seat (socket) to perform the function If the verification test is unqualified, then go to step 112 to discard the integrated circuit component, or use it for further unqualified analysis; if it is qualified, go to step 113, and judge it as a qualified product and be rescued. So far, the entire rework operation method 100 can be regarded as the end (as shown in step 114 ). If you want to know in more detail which IC component pins are faulty, you can pass the IC component discarded in step 112 through a more sophisticated testing machine to achieve this purpose. The focus of the present invention is a rework recovery. step process.

Please refer to FIG. 2 , which is a flowchart of another preferred embodiment of the present invention. The rework and salvage operation method 200 of the pin grid array packaged integrated circuit component disclosed in this embodiment includes the following steps.

Step 201: start;

Step 202: remove the unqualified integrated circuit assembly from the main board, which is the target integrated circuit assembly to be inspected;

Step 203: Execute the preliminary inspection step to inspect the target integrated circuit component, if it is unqualified, go to step 204, if it is qualified, go to step 205;

Step 204: The integrated circuit component is judged as defective and discarded;

Step 205: Bake the target IC device at a predetermined temperature for a predetermined time;

Step 206: removing solder;

Step 207: cleaning the integrated circuit component;

Step 208: Install the integrated circuit component into the POGO Pin test socket for functional verification test, if it fails, go to step 209, if it passes, go to step 210;

Step 209: The integrated circuit component is judged as defective and discarded;

Step 210: re-soldering the integrated circuit component with solder;

Step 211: Perform a re-inspection step to check whether the solder balls of the target integrated circuit component are qualified, if qualified, go to step 212, and if unqualified, go back to step 210;

Step 212: cleaning the integrated circuit device again;

Step 213: judging that it is a qualified product and saving it; and

Step 214: end.

As shown in step 202, when the integrated circuit component manufacturer receives the unqualified integrated circuit components sent by the client, it must first remove these unqualified integrated circuit components from the circuit carrier (or main board) . This removal action will naturally partially or even completely destroy the solder on the bottom of the LGA packaged IC device.

The inspecting step shown in step 203 is to visually check whether the bottoms of these integrated circuit components have protrusions or depressions after removing the integrated circuit components from the circuit carrier board or the main board, and then further Verify that there has been an open/short failure between the power and ground pins of these IC components. Once one of the above two conditions is met, it is directly determined that these integrated circuit components have failed and there is no value for further rework and salvage, and they are discarded (as shown in step 204 ).

When the integrated circuit assembly is qualified after the inspection step 203, it proceeds to step 205, which is to bake at a predetermined temperature (such as 125 degrees Celsius) for a predetermined time (such as 8 to 12 hours). This method is to remove the moisture present in the interior in a relatively gentle manner, so as to prevent the internal structure of the integrated circuit assembly from being damaged due to instantaneous high heat during the subsequent solder removal or re-soldering process.

After the baking operation in step 205 is completed, step 206 can be performed to start removing the solder that is damaged at the bottom of the integrated circuit device when it is removed from the circuit carrier until all the solder is removed. Since the solder is arranged one-to-one at the relative position below the conductive pad at the bottom of the integrated circuit component, after removing the solder, if the conductive pad of the integrated circuit component is found to be oxidized, you need to use additional tin wire Re-tin these conductive pads.

After removing the solder, there is another cleaning step 207 to keep the bottom of the integrated circuit device clean and dry. Next, in this embodiment, a POGO Pin test socket is used to perform functional verification tests on these target integrated circuit assemblies (step 208). Due to the structural characteristics of the POGO Pin test socket itself, the operation method flow 200 of this embodiment does not require the action of re-soldering as in the previous embodiment. It is also because of the particularity of the POGO Pin socket compared to the general test socket, even if the solder is not re-soldered, the contact resistance between the test integrated circuit component and the POGO Pin test socket can also be kept very close to zero impedance a stable value of . To achieve the above purpose, as long as both the conductive pad at the bottom of the integrated circuit component and the POGO Pin test socket can be kept clean. If the result of the functional verification test is unqualified, go to step 209 to discard the integrated circuit component, or use it for further unqualified analysis; if it is qualified, go to step 210 to re-solder the integrated circuit component.

After re-soldering, the operation method 200 of the present invention further includes a re-inspection step 211 to visually inspect the integrated circuit components that have completed the re-soldering action, whether there is solder leakage or unqualified solder dissolving. If the above unqualified situation occurs, then go back to step 210 to re-solder the missing integrated circuit components again, otherwise if the re-soldered solder of the integrated circuit components is qualified, then go to step 212 to clean the integrated circuit components again , and then judged to be a qualified product in step 212 and rescued. At this point, the whole rework operation method 200 can be regarded as the end (as shown in step 214 ).

Compared with the conventional technology, the rework and salvage method of the ball pin grid array package integrated circuit component of the present invention can be especially aimed at when using the elastic probe (POGO Pin) to test the socket, choose not to re-solder the solder first Test, and then only re-solder the integrated circuit components that are judged as qualified products, and discard the unqualified products without re-soldering, so as to save the time, manpower and material costs of soldering and re-soldering.

The probe (pin) used in the elastic probe test slot is characterized by the fact that the probe itself is elastic and can expand and contract in response to the force it receives, so it can be used on the contact part of the ball grid array integrated circuit component (such as When there is a large error in height, it still has a better electrical contact effect, thus improving its electrical contact effect with the solder joint area that is not soldered, so as to achieve the purpose of correct testing. Because of this, some integrated circuit components that may continue to be used due to misjudgment by the client will not be scrapped due to misjudgment, causing losses to the client and even the manufacturer.

Although a motherboard is taken as an example in the operation methods 100, 200 of each preferred embodiment of the present invention, on other circuit boards, such as additional cards (add-on card) etc., carry out rework and rescue Ball grid array integrated circuit components also do not depart from the scope of the present invention.

The above descriptions are only preferred embodiments of the present invention, and any equivalent changes according to the present invention shall belong to the protection scope of the patent of the present invention.

Claims (10)

1. A method of reworking and rescuing an integrated circuit assembly, the integrated circuit assembly is packaged in a ball-pin lattice array, characterized in that the steps are: (a) inspecting the integrated circuit component with a preliminary inspection step to screen out damaged and failed integrated circuit components; (b) baking the target integrated circuit assembly at a predetermined temperature for a predetermined time; (c) removing at least one solder of the integrated circuit component; and (d) re-soldering the solder-removed portion of the integrated circuit component; Wherein the soldering tin is arranged under a conductive pad of the integrated circuit component, and is used to establish electrical connection with a socket. 2. The operation method for reworking and rescuing integrated circuit components as claimed in claim 1, wherein said step (d) further comprises the following steps after re-soldering the removed solder position of the integrated circuit components : (e) Carry out a functional verification test to judge whether it is a qualified product or a non-conforming product. 3. The operation method for reworking and rescuing integrated circuit components as claimed in claim 1, wherein said step (d) also includes a re-inspection after re-soldering the removed solder position of the integrated circuit components. Steps to confirm whether the resoldering solder ball is qualified. 4. The operation method for reworking and salvaging integrated circuit components as claimed in claim 1, characterized in that said initial inspection step includes checking whether the bottom of the integrated circuit component has bulges or depressions. 5. The operation method for reworking and rescuing integrated circuit components as claimed in claim 1, wherein said initial inspection step includes checking whether there is an unqualified open circuit/short circuit between the power supply and the ground pin of the integrated circuit component Case. 6. A method for reworking and rescuing an integrated circuit assembly, the integrated circuit assembly is packaged in a ball grid array, characterized in that the steps are: (a) inspecting the integrated circuit component with a preliminary inspection step to screen out damaged and failed integrated circuit components; (b) baking the target integrated circuit assembly at a predetermined temperature for a predetermined time; (c) removing at least one solder of the integrated circuit component; and (d) Conduct functional verification tests to determine whether it is a qualified product or a non-conforming product; Wherein the soldering tin is arranged one-to-one under at least one conductive pad of the integrated circuit component, and is used to establish electrical connection with a socket. 7. The operating method for reworking and salvaging integrated circuit components as claimed in claim 6, wherein said step (d) carries out a functional verification test to judge whether it is a qualified product or a non-conforming product, and further includes the following: Step: (e) re-soldering the solder-removed portion of the integrated circuit component. 8. The operation method for reworking and rescuing integrated circuit components as claimed in claim 6, characterized in that after said step (e) re-solders the removed solder position of the integrated circuit component, it also includes a re-inspection Steps to confirm whether the resoldering solder ball is qualified. 9. The operation method for reworking and salvaging integrated circuit components as claimed in claim 6, wherein when performing the step (d) to carry out the functional verification test, the integrated circuit components are inserted into a device Conducted on the test socket of the elastic probe. 10. The operating method of reworking and salvaging integrated circuit components as claimed in claim 6, characterized in that after said step (d) carries out a function verification test, the following steps are also included; (e) the integrated circuit components Re-solder the solder part that has been removed.