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臺灣新北地方法院106年度訴字第2790號

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       1062790           姿          107 8 28 104 2 LED CREE CXB2530CXA2540 Taiwan Cree Electronics Co. ,Ltd .CREE使LED 106 6 15退CXB LEDsLED LED 使LED 使5,493,828 354 1 359 179 227 1 226 184 1 2 5,302,530 LED SGS)LED LED LED LED LED F Na) LED F LED 使 LED LED LED LED 使LED 使LED LED 5,302,530 CHIPLED LED 使LED LED 4 LED 3 3 Statement ofFailure ModeLED ROOT CAUSERoot Cause Analysis TBD To Be Defined LED LED 3 LED LED CREE CREECREECXA2540 LM-80 CREECREE 356 1 365 1 365 104 2 105 6 14105 9 1 -104/10 退82pcs 300pcs27% CXA2540 3000K 10 105 6 4 105 9 1 106 7 17356 1 6 105 6 30106 7 7 106 6 263 106 6 28106 9 12 2,179,719 5,302,350 359 退 435,736 104 2 CREE31171 454 使5,493,828 354 1 359 179 227 1 226 184 1 2 354 1 359 179 227 1 226 184 1 2 277 17917 43377 LED CREE4 355 431 RMA#Assigned for ALL Claims 7114470 Date Material Received6/20/2016 Problem Desription :Comments on Problem VerificationLamps flicker and dark after around 6 months of field application Discussionand Conclusion : 1,Emission abnormality : Emission abnormality the customer reported was confirmed on most of the returned samples . Evidence of electrical overstressEOS)damages , such as Epi damage near metal lineand/or underneath the bond pad , was observed on multiple LED chips in the failed LED strings from the CXA packages . The fact that majority o f the damaged chips are located either at the beginning orat the end of each string further suggests that the damage is caused by EOS .Meanwhile ,fused bond wire to the ESD chip was observed on lamps D6 and D7 during X-ray inspection also suggests that the damage is possibly caused by EOS damage .Overstress damage occurs when an LED is exposed tocurrent/voltage conditions above its rated operating limits .EOS damageis the result of excessiveheat generated during the EOS event . Identifying the root cause of the EOS can be difficult because the overstress events can happen infrequently , or under a uniqueset of conditions which may occurr andomly in time .The exact cause ofthe overstress that damaged the returned part was undetermined by this analysis .External biasing conditions ,such as drive rspikes ,hot-plugging or an electrical surge &om the mains source , are common causes o f EOS events .Please refer to Section D7 for Cree documents regarding to Electrical Overstress EOS . 2, High Vf :The reportedhigh Vffailure was not verified on lamp D5 .Photometric measurement confirmed tiiat the lamp was measured to be inaccordance to the chromaticity and luminous flux bin as specified . The measured Vf data also indicate no anomaly . The exactsource of the measurement discrepancy between Cree andthe customerwas not able to be detennined based on this investigation , but it is suspected to be due to thecustomer measurement system geometry ,method , test conditions and/or calibration . Please refer to application notes on XLamp LEDs Testing and Characterizationwhich will provide information on Cree LEDs test conditions and shows how differences in test conditions can lead to measurement discrepancies . http ://www .cree .eom//media/Files/Cree/LED-Components-and-Modules/XLamp/XLamp/XLamp-Application-Notes/XLamp Test Cal .pdf For the remaining lamps ,not "Vfdata" can be measured as they originally exhibited lighting emission failure or dim emission on LED chips in one or multiple LED strings firom the CXA package .After chemical de-encapsulation , bond pad and/or metal line peeled off from the LED chip was observed on these lamps . It is suspected that the" high Vf" failure customer observed were due to the result of bond pad or metal line peeling off that resulted from EOS damage failure , 1.退CXA LED LED / Epi EOS EOS X D6D7ESD EOS LED / EOS EOS EOS 使退EOS D7EOS Cree2.VfVfD5VfCree調/ XLamp LED Cree LEDCXA LED LED Vf/ LED VfEOS LED RMA#Assigned for ALL Claims 7114937 Date Material Received9/12/2016 Problem Desription Comments on Problem VerificationTrack lights were operated around 8 monthsturn on 12hr per dayat department store , and then some dark LED chips were found . D4b .Root Cause Analysis Statement ofRoot Cause s : Two possible root causes ofthe detached bond padsandmetal lines are : 1 chemical corrosion ; 2pooradhesion . EDX analysis did not detect any incompatible chemicals near the bond pad area . Therefore , the most likely root cause of the detached bond pads andmetal line is poor adhesion between the bond pad and the surface of the die .Based on our records ,we have not seen this failuremode from our customer returns of CXA products .Creesells a lot of CXA products to many different customers worldwide . By far , this is the only return with tiiis type of failure mode . We stronglybelieve this is a very isolated case .To ensure the quality o f outgoing product , the results of this analysis will be communicated with Cree manufacturing team for chip quality improvement . D5 . Corrective Actions decide on solution andplan its impiementation : Root Cause#Touching the wafers by hand and not usinga vacuum wand . Action item Description 1. Re-train operators in proper use of vacuum wand and not tousefingers .2. Revise OCAP software to prevent the escape .D4b . 1 2 EDX 退CXA CreeCXA 退Cree便 D5 . # 使. 1.使使2.OCAP RMA#Assigned for ALL Claims 7116148 Date Material Received5/3/2017D4b . Root Cause Analysis Figure 12Fixture A , Die S2-D12. The EDX spectrum acquired from the anode bond pad footprint after removing the lifted anode padout o f the way . FluorineF was detected . Figure 13 Fixture A , dieS2-D12. The EDX spectrum acquired from the bottom of anode bond pad . No abnormal elements were detected . Figure 14Fixture A ,die S2-D12. The EDX spectrum acquired from the die surface . No abnormal elementswere detected . Figure 15 Fixture A , Die S2-D12. The EDX spectrumaquired from the cathode bond pad footprint after removing the lifted cathode pad out of the way . No abnormal elements were detected . Figure 16 Fixture A , S2-D12. The EDX spectrum acquired from the bottom of cathode bond pad . FluorineF andsodium Naelements were detected. Figure 17 Fixture A The EDX spectrum acquired fromthe CXB package substrate . FluorineF and sodiumNaelements were detected . Statement of Root Causes : EDX analysis of the affected die and the CXB packagedetected the presence of fluorine F and sodiumNaon the failure faces of the bondpads and on the substrate area .Fluorine is a chemical with known incompatibility issues and its presence in the LED package can lead to corrosion o f the metals used in the LED die structure . The source of the fluorine and sodium was not determined in this analysis . It is recommended the customer review fixture assembly material and operating environmentsto prevent the LED from exposure fluorine containingchemicals . In addition to avoiding incompatible chemicals ,proper thermal maintenance is important for LED operation . The voids in the thermal interface materialTIM in the as-received assemblies should be avoided to achieve efficient heat dissipation from the CXB LED through the heat sink . Additional Update 6-27-2017 : Per customer's request , one of the failing die S3-D12in Fixture B was analyzed using EDX .EDX spectra shown in the images below showed fluorine F signal . Figure 18 Fixture B ~ Die S3-D12 The EDX spectra acquired from the cathode bond pad footprint after removing the lifted cathode pad out of the way . FluorineF was detected .D4b . EDX A CXB LED S2-D12EDX X PtEDX CXB LED 12A S2-D12EDX F 13A S -D12EDX 14A S2-D12EDX 15A S2-D12EDX 16A S2-D12EDX F Na17A CXB EDX F NaEDX CXB F NaLED LED 使LED LED TIM CXB LED 20176 27EDX B S3-D12EDX F 18B - S3-D12EDX F LED RMA#Assigned for ALL Claims 7116372 Date Material Received24/7/2017 Statement of Root Cause s :The broken / intermittent electrical contacts in the LED strings , which gave rise to the reported emission abnoimality , were due to lifted bond wires and bond pads at the affected die . EDX analysis detectedfluorine at several o f the failure sites onmultiple parts , indicating that the most likely cause of the lifted pads is exposure to an incompatible chemical . Fluorine has known incompatibility issues with LED devices , as its presence can corrode metals used in the LED die structure .It is recommended that thecustomer review the assembly and operating environments to avoid exposure to fluorine containingchemicals . LED / EDX LED LED 使LED 4 LED 354 1 359 179 227 1 226 184 1 2 354 1 359 179 227 1 226 184 1 2 78 107 9 21 20 107 9 21