Large Area and Fine Pitch testing using Silicon Micro-cantilever June 3 rd 2003 Kim, DONG IL Tel : +82-31-217-6168 Fax : +82-31-217-6169 E-mail : dikim@amst.co.kr
Contents 1. Company Introduction 2. Silicon Micro Cantilever Probe 3. Large Area Probing 4. Fine Pitch Probing 5. Cleaning 6. Auto-Align 7. Characteristics
1. Company Introduction AMST stands for Advanced Micro Silicon Technology. The main goal of the company is manufacturing and marketing of Micro Electro- Mechanical Systems (MEMS)
2-1. Purpose of Presentation As a follow up after SWTW 2000 presentation Show applicability of simple Microcantilever probe for Semiconductor testing Introduction of Repairable Large-area testing Probe card
2-2. Introduction to MProbe Single Crystal Silicon Cantilever Semiconductor fabrication process Great design freedom of the cantilever(position, length, width, thickness)
2-3. Probe Movement The Probe mark is made only by the back half of the tip. The length of the scrub action is only few microns The size of the probe mark is less than 20 micron. Overdrive is achieved by bending of cantilever Overdrive limit is set by the space between the cantilever and substrate
2-4. Wiring Schematics Probe Tip Probe Tip Wire Tile Block Main PCB Substrate Wire Substrate Main PCB To ATE Multi Die testing To ATE LDI testing FPC Probe Tip LCD Testing To LDI Probe Cantilever Substrate ACF Gold layer
3-1. Large Area Probe card Needle Block Zig Guide Main PCB Single Array Probe Tip Glass Zig Side PCB Back PCB Wire Multiple Array
3-2. Assembly 11. Needle Tiles 12. Support block 13. Positioning Block 19. Pogo pins 27. Pogo pin guide 14. Main PCB 18. Backing Plate
3-3. Card Pictures 60 Parallel Tiling Mprobe (7 tiling blocks) 48 Parallel Tiling Mprobe (4 tiling blocks)
3-4. SEM of MProbe Large Area Array Enlarged View of the Probe Tip
3-5. Tip Planarity (1) 600 500 Planarity Plot 32 parallel, 4 tiling blocks (4um step for planarity measurement) 400 count 300 200 100 505 392 318 0 1 0 4 8 12 um
3-6. Tip Planarity (2) D1~D8 D17~D24 20 15 10 20 15 10 5 0 0 38 76 114 152 190 228 266 304 5 0 0 38 76 114 152 190 228 266 304 20 D9~D16 20 D25~D32 15 15 10 10 5 5 0 0 38 76 114 152 190 228 266 304 0 0 38 76 114 152 190 228 266 304
3-7. Pin Position Accuracy count 200 180 160 140 120 100 80 60 40 20 Alignment error from pad center 32 parallel, 4 tiling blocks 0 0 1 2 3 4 5 6 7 8 9 10 11 12 13 μm
3-8. Contact Resistance 400 Path Resistance (Ω) (32 parallel, 4 tiling blocks) 350 300 250 count 200 150 100 50 0 0.05 0.25 0.45 0.65 0.85 1.05 1.25 1.45 ohm 1.65 1.85 2.05 2.25 2.45 2.65 2.85
4-1. Fine Pitch Probing -Schematics Probe Tip Wire FPC Wire Metal Line Wire Cap Substrate Supporter Main PCB To ATE
4-2. Product Sample Pictures LDI Probe Card LDI Probe Card Needle
4-3. SEM Pictures (low magnification) 35 um staggered I/O s
4-4. SEM Picture(medium magnification)
4-5. SEM Picture (high magnification) 35 um staggered I/O s Probing tips
4-6. Planarity 140 120 100 count (ea) 80 60 40 20 0 0.5 1.5 2.5 3.5 4.5 5.5 6.5 7.5 8.5 height (um)
4-7. Pin Position Accuracy 250 200 Alignment Error from pad center count (ea 150 100 50 0 0.5 1.5 2.5 3.5 4.5 5.5 distance (um)
4-8. Path Resistance 250 Path Resistance 200 Count (ea) 150 100 50 0 0.5 1.5 2.5 3.5 4.5 5.5 Resistance (ohm)
5-1. Cleaning (1) Gel-Pak Cleaning (ITS PC-1012) 1500 Touchdown on Aluminum Pad 90 micron OD, 10 touchdown Before Cleaning -After Cleaning
5-2. Cleaning (2) Gel-Pak Cleaning (ITS PC-1012) 20,000 Touchdown on Aluminum Pad 90 micron OD, 10 touchdown Before Cleaning After Cleaning On Gel-Pak
5-3. Cleaning (Cres change) - Signal Path : PCB -> I/O Pin -> Aluminum Pad -> Ground Pins -> PCB - Contact condition : 10 touch down at same location on Aluminum pad (for example : 500 touchdown =10 touchdown on one location X 50 location) Touch Down 0 500 1000 1500 Maximum 3.8 3.8 3.9 3.8 Minimum 2 2.5 2.2 2.3 Mean 3.31 3.12 3.14 3.13 -There is no significant relation between touch down and contact resistance -Test performed after 20,000 touchdown and cleaning -Cleaning Cycle not fixed
6. Auto-align Bright tip Dark surrounding (special treatment to surrounding materials) Microscope Fiducial align possible Prober CCD Adding alignment marks and making the program to recognize the pin tips from the marks
7-1. Characteristic of Mprobe High resilience No plastic deformation Fine pitch possible Accurate pin position (guaranteed throughout its lifetime) Large Area Probing Possible (Currently Probing Area 90mmX150mm) (Near future 100mmX200mm) Repairable by replacement of defective block Small scrub mark(<20 μm ) Auto Align possible
7-2. Specification ITEM Large Area Testing LCD LDI Lifetime > 200,000 > 150,000 > 150,000 (touchdown) Pin Force(g/mil) 0.8~1.5 0.8~1.5 0.8~1.5 Planarity <±10 μm (80mmx100mm) <±3 μm <±5 μm Position Accuracy <±10 μm (80mmx100mm) <±3 μm <±5 μm Minimum Pitch >70 μm >50 μm >35 μm Path Resistance <3Ω <3Ω <5Ω Leakage Current <10nA <20nA < 20nA (With PCB) (With PCB) (With PCB) Delivery First Order 10 week 8 week 10 week Reorder 4 week 4 week 4 week
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