SMT资料BGA双球枕头效应原因分析及改善对策
相关主题
- 1、下载文档前请自行甄别文档内容的完整性，平台不提供额外的编辑、内容补充、找答案等附加服务。
- 2、"仅部分预览"的文档,不可在线预览部分如存在完整性等问题,可反馈申请退款(可完整预览的文档不适用该条件!)。
- 3、如文档侵犯您的权益，请联系客服反馈,我们会尽快为您处理(人工客服工作时间：9:00-18:30)。
The black area has S 、Br elements, and higher C 、O content on the surface
Normal surface： C、O <10%
SEM-EDS analysis
The black area has S elements, and higher C 、O content on the surface
Normal surface has higher Oxygen content
SEM inspection
SEM inspection
SEM inspection
SMT reflow-Profile
Red setting profile Green real profile
SMT reflow - Shenmao solder paste
Surface finish
Cleanness & shelf life
Reflow condition Alloy composition
Bending Design
Pillow
Device Assembly
Solder Ball
Substrate Substrate (PCB)
Paste
Reflow Mounting
c. Missing ball
d. Crack
e. Head-in-Pillow
f. Non-wetting
g. de-wetting
h. shift
i. solder ball
Head-in-pillow heating
Peak Temp
heating cooling
BGA assembly problem analysis
Case Study BGA Head-in-pillow defect issue
Head-in-pillow cross-section view
Component inspection
There are some black areas on the solder ball
SEM-EDS analysis
SMT process (6.1%)
来自百度文库Component (84.8%)
Profile (3.0%) Pick & place (3.0%)
Pad pollution (18.2%) others (9.1%)
BGA ball pollution (45%)
warpage (12.1%)
BGA problem
Non-melting caused head in pillow
Thicker oxide and weaker flux activity caused non-melting
Classification of BGA soldering failure mode
a. Void
b. Bridge
Outline
In-situ observation of BGA soldering Classification of BGA soldering failure mode Case study for BGA soldering
In-situ observation of BGA soldering 1-1 Observation of BGA soldering ----gap change
Flux
Slump
Bending
Miss mounting
Dewetting
Paste BGA ball PCB substrate
Crack
Solder PCB substrate
Flux
Activator
Alloy composition
Oxidation contamination
Oxidation of pad
Surface issue
Shape Issue Composition design Bending Bending Tackiness decay
Contamination Residue of flux Surface oxidation
Split Co-planarity Ball size design
Printing
Height or volume insufficient
Flux activator efficiency Alloy composition design
Over-preheat
Heat insufficient Precision BGA Picking
Flux activator decay Oxidation of BGA ball Half-melting or non-melting
Solder paste (3.0%)
Weak activity
(3.0%)
PCB (6.1%)
warpage (3.0%)
PAD pollution
(3.0%)
Void Bridge
Paste
BGA ball PCB substrate
Reflow Solder Substrate Process
Flux
Activator
Viscosity Powder size alloy composition
Oxidation contamination
Oxidation of pad
Design of pad
Surface finish
Cleanness shelf life
Degauss timing
pre-heat
Heating to 210℃
Heating to 220℃
Heating to 230℃
SMT reflow - Shenmao solder paste
Heating to 240℃
Heating to 244℃
Cooling to 235℃
Cooling to 225℃
Peak Temp.
Cooling down
Reflow Profile of Process
During peak &cooling Solder ball & paste melt at melting point Flux clean tin oxide
PKG
PCB
Solder sphere Solder paste
Normal surface： C、O <10%
SEM-EDS analysis
The black area has S elements, and higher C 、O content on the surface
Normal surface has higher Oxygen content
SEM inspection
SEM inspection
SEM inspection
SMT reflow-Profile
Red setting profile Green real profile
SMT reflow - Shenmao solder paste
Surface finish
Cleanness & shelf life
Reflow condition Alloy composition
Bending Design
Pillow
Device Assembly
Solder Ball
Substrate Substrate (PCB)
Paste
Reflow Mounting
c. Missing ball
d. Crack
e. Head-in-Pillow
f. Non-wetting
g. de-wetting
h. shift
i. solder ball
Head-in-pillow heating
Peak Temp
heating cooling
BGA assembly problem analysis
Case Study BGA Head-in-pillow defect issue
Head-in-pillow cross-section view
Component inspection
There are some black areas on the solder ball
SEM-EDS analysis
SMT process (6.1%)
来自百度文库Component (84.8%)
Profile (3.0%) Pick & place (3.0%)
Pad pollution (18.2%) others (9.1%)
BGA ball pollution (45%)
warpage (12.1%)
BGA problem
Non-melting caused head in pillow
Thicker oxide and weaker flux activity caused non-melting
Classification of BGA soldering failure mode
a. Void
b. Bridge
Outline
In-situ observation of BGA soldering Classification of BGA soldering failure mode Case study for BGA soldering
In-situ observation of BGA soldering 1-1 Observation of BGA soldering ----gap change
Flux
Slump
Bending
Miss mounting
Dewetting
Paste BGA ball PCB substrate
Crack
Solder PCB substrate
Flux
Activator
Alloy composition
Oxidation contamination
Oxidation of pad
Surface issue
Shape Issue Composition design Bending Bending Tackiness decay
Contamination Residue of flux Surface oxidation
Split Co-planarity Ball size design
Printing
Height or volume insufficient
Flux activator efficiency Alloy composition design
Over-preheat
Heat insufficient Precision BGA Picking
Flux activator decay Oxidation of BGA ball Half-melting or non-melting
Solder paste (3.0%)
Weak activity
(3.0%)
PCB (6.1%)
warpage (3.0%)
PAD pollution
(3.0%)
Void Bridge
Paste
BGA ball PCB substrate
Reflow Solder Substrate Process
Flux
Activator
Viscosity Powder size alloy composition
Oxidation contamination
Oxidation of pad
Design of pad
Surface finish
Cleanness shelf life
Degauss timing
pre-heat
Heating to 210℃
Heating to 220℃
Heating to 230℃
SMT reflow - Shenmao solder paste
Heating to 240℃
Heating to 244℃
Cooling to 235℃
Cooling to 225℃
Peak Temp.
Cooling down
Reflow Profile of Process
During peak &cooling Solder ball & paste melt at melting point Flux clean tin oxide
PKG
PCB
Solder sphere Solder paste