Method for uncovering and repairing ceramic multi-chip shell after parallel seam welding

Abstract

The invention discloses a method for uncovering and repairing a ceramic multi-chip shell after parallel seam welding, which comprises the following steps of: pretreating a seam welding surface of a to-be-repaired shell, namely milling the seam welding surface for one or more times by using a milling machine, or polishing the seam welding surface to be flat by using abrasive paper or a polisher; the seam welding face of the pretreated shell faces downwards, and the shell is fixed to a cover opening machine through torque; starting a cover opening machine to mill the shell along the seam welding edge in sequence, wherein the cover plate is still kept on the shell after milling; flatly opening a cover plate of the milled shell by using a surgical knife blade; cleaning redundant materials on the enclosure frame of the shell and in the shell; and after a chip in the shell is repaired, the shell is placed on a tool clamp, and parallel seam welding after repairing is carried out by using a new cover plate. According to the method, large-batch high-quality uncovering repair after parallel seam welding can be achieved, uncovering repair after multiple parallel seam welding can be achieved, and the air tightness of the repaired shell is kept unchanged.

Description

Technical Field

[0001] This invention belongs to the field of electronic packaging technology, and specifically relates to a method for repairing ceramic multi-chip housings after parallel seam soldering by opening the cover. Background Technology

[0002] With the miniaturization and high-density integration of electronic information systems, modules based on ceramic multi-chip housings are widely used due to their high reliability, high performance, and good electrothermal properties. Parallel seam welding offers advantages such as low cost, high efficiency, and good hermeticity for achieving sealing of ceramic multi-chip housings. In the field of electronic packaging, product design or processes often encounter failures requiring rework, and traditional handling methods face numerous difficulties.

[0003] On the one hand, internal components such as chips are expensive. If repairs can be completed by opening the cover, not only can huge material costs be saved, but also assembly costs can be reduced. On the other hand, for some highly customized chips, the production cycle is long, and the delivery of repaired chips is more reliable than that of new production. The commonly used parallel seam soldering repair method mainly involves manually grinding open the cover and then resealing it. This method is prone to generating debris that enters the device during grinding, causing short circuits and other problems, and it is also inefficient.

[0004] As prior art, Chinese patent application CN119952410A discloses a method for repairing the airtightness of parallel seam welds. This method involves opening the casing with a casing opener, installing a debris baffle, sealing the perimeter of the debris baffle to the inside of the component housing with sealant, then grinding it on a grinder to clean debris from the debris baffle and the component housing. After cleaning, the sealant and debris baffle are removed, and the components inside the component housing are repaired before a second parallel seam weld is performed. This patented repair process is complex, the use of sealant is difficult to implement, and the repair efficiency is low, making it impractical for large-scale repairs.

[0005] Therefore, it is imperative to develop a high-quality parallel seam weld post-opening repair method that is efficient and feasible for batch repair. Summary of the Invention

[0006] The purpose of this invention is to provide a method for repairing ceramic multi-chip shells after parallel seam welding by opening the shell. This method can achieve high-quality repair of large quantities of shells after parallel seam welding by opening the shell. It can not only achieve multiple repairs after parallel seam welding by opening the shell, but also maintain the airtightness of the shell after repair.

[0007] To achieve the above objectives, one aspect of the present invention provides a method for rework of a ceramic multi-chip housing after parallel seam welding, comprising: Step S1: Pre-process the welded surface of the shell to be repaired. The pre-processing includes milling the welded surface once or multiple times with a milling machine, or grinding the welded surface smooth with sandpaper or a grinder. Step S2: Fix the pre-treated outer shell with the welded side facing down onto the lid opening machine using torque; Step S3: Start the cover opening machine to mill the outer shell along the weld seam in sequence. After milling, the cover plate is still left on the outer shell. Step S4: Use a scalpel blade to open the cover plate after milling the outer shell; Step S5: Clean the excess material from the outer casing frame and inside the casing; Step S6: After repairing the chip inside the casing, place the casing on a tooling fixture and use a new cover plate to perform parallel seam welding after repair.

[0008] According to the above-described method for repairing ceramic multi-chip housings after parallel seam welding, a large-scale, high-quality repair after parallel seam welding can be achieved. Not only can multiple repairs after parallel seam welding be performed, but the airtightness of the housing remains unchanged after repair. Attached Figure Description

[0009] To more clearly illustrate the technical solutions of the present invention, the accompanying drawings used in the description of the embodiments of the present invention will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort: Figure 1 This is a schematic diagram illustrating the process of pre-processing a ceramic multi-chip housing on a milling machine according to an embodiment of the present invention; Figure 2 This is a schematic diagram illustrating the process of pre-treating a ceramic multi-chip casing with sandpaper according to an embodiment of the present invention. Figure 3 This is a schematic diagram illustrating the pretreatment process of a ceramic multi-chip shell using a polishing machine according to an embodiment of the present invention. Figure 4 This is a side view schematic diagram of the process of opening a ceramic multi-chip shell in a shell-opening machine according to an embodiment of the present invention; Figure 5 This is a front view schematic diagram of the process of opening a ceramic multi-chip shell in a shell-opening machine according to an embodiment of the present invention; Figure 6 This is a schematic diagram of a process for opening the lid using a scalpel according to an embodiment of the present invention. Detailed Implementation

[0010] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. Based on the embodiments of this invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this invention.

[0011] An embodiment of the present invention provides a method for repairing ceramic multi-chip housings after parallel seam welding by opening the cover, including steps S1 to S6.

[0012] In step S1, the welded surface of the shell to be repaired is pre-treated; wherein, the pre-treatment method includes using a milling machine to mill the welded surface once or multiple times, or using sandpaper to grind the welded surface flat, or using a grinding machine to grind the welded surface flat.

[0013] In some embodiments, such as Figure 1 As shown, the ceramic multi-chip shell 2 is placed on the fixture 1. The number of shells 2 on the fixture 1 can be 1, 2×2=4, 3×3=9, etc. A milling machine is used to mill the entire seam weld surface of the ceramic multi-chip shell. The milling path is shown by the arrow in the figure. Preferably, the milling is done once, and the single milling depth is set to 0.03mm. If the height difference of the seam weld surface of the shell is greater than 0.03mm, preferably, the milling is done twice, and the single milling depth is half of the height difference.

[0014] In these embodiments, the milling machine performs one or more milling operations on the weld surface. The milling depth depends on the flatness of the weld surface after one parallel weld. Preferably, the milling depth is set to 0.01 to 0.05 mm.

[0015] The purpose of milling is to keep the welded surface flat before opening the cover; further, it can ensure that the sealing surface is flat after opening the cover; further, it saves the processing time for uneven sealing surfaces after opening the cover, reduces the processing difficulty, and avoids problems such as scratching the internal chip of the shell during this processing; further, it improves the yield of hermetic packaging for secondary or more parallel welds.

[0016] In some embodiments, such as Figure 2 As shown, sandpaper 4 is placed above workbench 3, and the welded surface 5 of the ceramic multi-chip shell is placed face down on sandpaper 4 for polishing. It can be polished back and forth and left and right several times. Preferably, the flatness can be quickly measured with vernier calipers, and the flatness of the welded surface after polishing is ≤0.02mm.

[0017] In some embodiments, such as Figure 3As shown, the ceramic multi-chip shell 2 is placed on the fixture 1. The number of shells 2 on the fixture 1 can be 1, 2×2=4, 3×3=9, etc. The entire weld surface of the ceramic multi-chip shell is polished using a polishing machine 6. Preferably, the flatness can be quickly measured using a vernier caliper. The flatness of the weld surface after polishing is ≤0.02mm.

[0018] In these embodiments, the purpose of using sandpaper or a grinder to smooth the weld surface is to keep the weld surface flat before opening the cover; further, it can ensure that the sealing surface is flat after opening the cover; further, it saves the processing time for uneven sealing surfaces after opening the cover, reduces the processing difficulty, and avoids problems such as scratches on the internal chip of the casing caused by this processing; further, it improves the yield of hermetic packaging for secondary or more parallel welds.

[0019] In some embodiments, the ceramic multi-chip housing includes CBGA, CQFN, CLCC, CPGA, and CQFP package types.

[0020] In step S2, the pre-treated outer shell with the welded surface facing down is fixed to the shell opening machine using torque. For example... Figure 4 As shown, the ceramic multi-chip shell is placed face down on the shell-opening machine worktable 7. Multiple shells can be placed at a time, preferably four shells. Figure 5 As shown; the fixing clamp 8 is fixed tightly against the center position of the bottom surface of the outer shell using torque, and the fixing force is verified by the process, and multiple shells are fixed with the same magnitude of force; the shell opening machine has real-time negative pressure exhaust capability, which can discharge the milled metal residue in real time; depending on the size of the shell, multiple shells can be opened at the same time, preferably, 4 shells can be opened at the same time. The torque setting is 1.5~3.5 N·m. Preferably, the torque setting is 2.5 N·m.

[0021] In step S3, the cover-opening machine is started to mill the outer shell sequentially along the sealing edge, and the cover plate remains on the outer shell after milling. Preferably, the milling sequence is long side 1 (first long side) → long side 2 (second long side) → short side 1 (first short side) → short side 2 (second short side); the milling depth of long side 1 and long side 2 is the cover plate thickness + 0.005 mm; the milling depth of short side 1 and short side 2 is the cover plate thickness + 0.01 mm.

[0022] In step S4, the milled outer shell is opened using a surgical blade 10 to remove the cover plate; the blade includes a straight blade and a round blade. Preferably, a slit is first made at one corner using a round blade, and then a straight blade is used to cut into the slit, pushing the cover plate open parallel to the welded surface of the outer shell. A schematic diagram of the opening process using a surgical blade 10 is shown below. Figure 6 As shown.

[0023] In step S5, remove excess material from the outer casing frame and inside the casing.

[0024] In step S6, after the chip inside the casing is repaired, the casing is placed on a tooling fixture, and a new cover plate is used to perform parallel seam welding after the repair.

[0025] In summary, the ceramic multi-chip housing parallel seam welding post-opening repair method of the present invention can ensure that the sealing surface is flat after opening by pre-processing the ceramic multi-chip housing, saving the processing time of uneven sealing surface after opening, reducing the processing difficulty, avoiding problems such as scratches on the internal chips of the housing caused by this processing, and improving the yield of hermetic packaging for secondary or more parallel seam welding.

[0026] The ceramic multi-chip shell rework method after parallel seam welding in this invention can achieve high-quality rework of large quantities after parallel seam welding. It can perform multiple (≥2) parallel seam welding reworks while maintaining the shell's airtightness. Practical verification has shown that this method has good rework performance and a high rework yield.

[0027] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A method of ceramic multi-chip package decap rework after parallel seam welding, characterized by, The application relates to a method for opening a ceramic multi-chip shell. Step S1: the seam welding surface of the shell to be repaired is pretreated, the pretreatment comprising milling the seam welding surface one or more times by using a milling machine or polishing the seam welding surface by using sandpaper or a polisher; Step S2: the pretreated seam welding surface of the shell is fixed on a cover opening machine by using torque; Step S3: the cover opening machine is started to mill the shell along the seam welding edge in sequence, and the cover plate is still retained on the shell after milling; Step S4: the milled shell is opened by using a scalpel to open the cover plate; Step S5: the shell frame and the inside of the shell are cleaned of excess materials; Step S6: after the inside of the shell is repaired, the shell is placed on a tool clamp, and a new cover plate is used for parallel seam welding after repair.

2. The ceramic multi-chip package backside seam weld decap repair method of claim 1, wherein, The ceramic multi-chip shell comprises CBGA, CQFN, CLCC, CPGA and CQFP packaging types.

3. The ceramic multi-chip package backside cover repair method according to claim 1 or 2, characterized by, In step S1, the seam welding surface is milled one or more times by using a milling machine, and the milling depth depends on the flatness of the seam welding surface after one-time parallel seam welding.

4. The ceramic multi-chip package backside seam weld decap repair method of claim 3, wherein, The milling depth is 0.01-0.05 mm.

5. The ceramic multi-chip package backside seam weld decap repair method of claim 1 or 2, wherein, In step S1, the seam welding surface is polished by using sandpaper or a polisher, and the flatness is less than or equal to 0.02 mm.

6. The ceramic multi-chip package backside seam weld decap repair method of claim 1 or 2, wherein, In step S2, the cover opening machine has real-time negative pressure exhaust capacity.

7. The ceramic multi-chip package backside seam weld decap repair method of claim 1 or 2, wherein, In step S2, according to the size of the shell, a plurality of shells are fixed on the cover opening machine at a time.

8. The ceramic multi-chip package backside seam weld decap repair method of claim 1 or 2, wherein, In step S2, the torque is set to 1.5-3.5 N.m.

9. The ceramic multi-chip package backside seam weld decap repair method of claim 1 or 2, wherein, In step S3, the milling sequence is first long edge, second long edge, first short edge and second short edge; the milling depth of the first long edge and the second long edge is the thickness of the cover plate + 0.005 mm; and the milling depth of the first short edge and the second short edge is the thickness of the cover plate + 0.01 mm.

10. The ceramic multi-chip package backside seam weld decap repair method of claim 1 or 2, wherein, In step S4, the scalpel comprises a straight scalpel and a round scalpel; a gap is first opened at one corner by using the round scalpel, then the straight scalpel is used to cut into the gap, and the cover plate is pushed open along the seam welding surface of the shell.

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