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decap:ceramic_glass [2012/01/29 00:13] – mcmaster | decap:ceramic_glass [2016/12/03 20:49] – mcmaster | ||
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- | ====== Introduction ====== | + | JM 2016-11 advice: |
+ | * Use "Top Heat (gentle)" | ||
+ | * Use "Top Heat (quick)" | ||
- | I (JM) would recommend thermal fracture if you are comfortable with a torch. | ||
+ | ===== Top heat ===== | ||
- | ====== Thermal fracture | + | Gentle procedure: |
+ | - Place chip into heat spreader block | ||
+ | - Place chip + spreader into vice | ||
+ | - Torch heat spreader | ||
+ | * DIP28: ~10 seconds | ||
+ | * DIP40: ~20 seconds | ||
+ | - Begin torching top of chip | ||
+ | * Use the side of the flame, not the tip, for gentler and more even heating | ||
+ | - Every 5-10 seconds try to pry lid up. If it is starting to budge, immediately do the next few steps | ||
+ | - Stop torching | ||
+ | - Gently pull lid up and over chip, hinging on the far side | ||
+ | - Separate lid from package | ||
+ | |||
+ | {{: | ||
+ | |||
+ | {{: | ||
+ | |||
+ | Above: sample quick result | ||
+ | |||
+ | Quick procedure: | ||
+ | - Place chip into heat spreader block | ||
+ | - Place chip + spreader into vice | ||
+ | - Begin torching top of chip | ||
+ | * Side or tip of flame better? | ||
+ | - Every 5-10 seconds try to pry lid up. If it is starting to budge, immediately do the next few steps | ||
+ | * Listen for a small popping noise. | ||
+ | * If its not the lid, the package has probably cracked | ||
+ | - Stop torching | ||
+ | - Gently pull lid up and over chip, hinging on the far side | ||
+ | - Separate lid from package | ||
+ | |||
+ | General notes: | ||
+ | * Wave torch back and forth to keep heat even | ||
+ | * FIXME: torch model I use | ||
+ | * DO NOT torch while lid is lifting. | ||
+ | * Heat spreader can be aluminum or steel | ||
+ | * Steel won't be melted by propane torch | ||
+ | * Aluminum can melt if abused, but will conduct heat better | ||
+ | * If the package cracks, finish procedure and then assess damage. | ||
+ | |||
+ | |||
+ | ===== Thermal fracture | ||
Procedure | Procedure | ||
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* PDIPs should be supported (ie with a block of metal) as the leadframe will become very weak | * PDIPs should be supported (ie with a block of metal) as the leadframe will become very weak | ||
* If it does not shear open the first time try again. | * If it does not shear open the first time try again. | ||
- | |||
- | ===== Media ===== | ||
- | |||
- | Chip before: | ||
- | |||
- | |||
- | {{gallery>: | ||
- | {{gallery>: | ||
- | |||
- | {{: | ||
- | |||
- | |||
Advantages: | Advantages: | ||
* Can be very clean and low risk | * Can be very clean and low risk | ||
+ | * Tends to be pretty clean and not throw a lot of debris onto the die | ||
Disadvantages: | Disadvantages: | ||
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* The die is exposed but still in the package | * The die is exposed but still in the package | ||
+ | ==== Media ==== | ||
- | ====== Thermal | + | Chip before (both identical): |
+ | {{gallery>: | ||
- | Advantages | + | One of these was thrown into water and the other had water dripped on it. Comparison: |
- | * Can completely remove a die | + | {{gallery>: |
+ | Dunked chip close-up: | ||
+ | {{gallery>: | ||
+ | Dripped on chip close-up: | ||
+ | {{gallery>: | ||
- | Disadvantages | + | The motion of throwing the chip into the water caused the glass to flow and stick to the die. |
- | * Removed dies still may have an uneven bottom. | + | |
- | ====== | + | |
+ | ===== Lift-off | ||
+ | |||
+ | Requires some form of torch. Heat up and pry up. Be careful not to let molten glass land on the IC. The best way to avoid this is to lift straight up and let it cool a bit before moving off to the side. | ||
+ | |||
+ | |||
+ | ===== Shearing | ||
The glass tends to be much weaker than the ceramic. | The glass tends to be much weaker than the ceramic. | ||
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* Unpredictable how it will shear | * Unpredictable how it will shear | ||
- | ====== Manufacturing ====== | ||
- | Might provide some hints if we knew how these were produced | + | ===== Grinding ===== |
+ | |||
+ | I see no reason why you couldn' | ||
+ | |||
+ | |||
+ | ====== Die ====== | ||
+ | |||
+ | This has been a problem area and so the best advice I have is simply don't try to remove the die unless there is a good reason. | ||
+ | |||
+ | |||
+ | ===== Hot pull ===== | ||
+ | |||
+ | Procedure | ||
+ | * Heat lower package | ||
+ | * Gently pickup the die up with metal tweezers or lift up with a sharp knife (which can get between die and substrate easier) | ||
+ | |||
+ | Surface tension makes simply plucking the die up difficult and so a knife tends to work better. | ||
+ | |||
+ | |||
+ | ===== Crack-n-push ===== | ||
+ | |||
+ | Procedure: | ||
+ | * Score one side of the ceramic package well | ||
+ | * Heat package strongly | ||
+ | * Submerge scored side of package in water. | ||
+ | * Re-heat package | ||
+ | * Slide die out of open side of well with die | ||
+ | |||
+ | |||
+ | ===== Dissolve ===== | ||
+ | |||
+ | 70% HNO3 is known to dissolve the frit. However, it would probably dissolve other things (ie the pins) as well | ||
+ | |||
+ | It should be possible to use HF to dissolve the ceramic. | ||
+ | |||
+ | |||
+ | ===== References ===== | ||
+ | |||
+ | http:// | ||
+ | http:// | ||