CSP Application note - Panasonic · results. The process includes solder printing, mounting and...

Notification about the transfer of the semiconductor business

The semiconductor business of Panasonic Corporation was transferred on September 1, 2020 to Nuvoton Technology Corporation (hereinafter referred to as "Nuvoton"). Accordingly, Panasonic Semiconductor Solutions Co., Ltd. became under the umbrella of the Nuvoton Group, with the new name of Nuvoton Technology Corporation Japan (hereinafter referred to as "NTCJ").

In accordance with this transfer, semiconductor products will be handled as NTCJ-made products after September 1, 2020. However, such products will be continuously sold through Panasonic Corporation.

Publisher of this Document is NTCJ.If you would find description “Panasonic” or “Panasonic semiconductor solutions”, please replace it with NTCJ.

※ Except below description page “Request for your special attention and precautions in using the technical information and semiconductors described in this book”

Nuvoton Technology Corporation Japan

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WL-CSP Application Notes

WL-CSP (Wafer Level Chip Size Package)

Application Notes

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Table of Contents Scope .......................................................................................................................................................... 3

Section 1 Preface ..................................................................................................................................... 3

Section 2 Panasonic WLCSP Package Sizes and Pad Designs ............................................................ 4

Section 3 PCB and Solder Stencil Designs ............................................................................................. 5 3.1 Solder Resist Design ......................................................................................................................... 5 3.2 Land Pattern Design .......................................................................................................................... 6 3.3 Solder Stencil Design ......................................................................................................................... 7

Section 4 PCB Mounting Conditions ..................................................................................................... 10 4.1 Solder Paste ..................................................................................................................................... 10 4.2 Reflow ...............................................................................................................................................11

4.2.1 Methods of Reflow Process ..................................................................................................... 111 4.2.2 Reflow Temperature and Limit count of Reflow runs ................................................................ 12 4.2.3 Temperature Profile ................................................................................................................... 12

Section 5 Solder Joint Failure and Solution........................................................................................... 15 5.1 Examples of Good or Defective Solder Joints ................................................................................. 15 5.2 Common Abnormalities .................................................................................................................... 17

5.2.1 Voids .......................................................................................................................................... 17 5.2.2 Solder Balls ............................................................................................................................... 18 5.2.3 Non-Wetting ............................................................................................................................... 20

Section 6 Design Recommendation Chart .......................................................................................... 211

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Scope The purpose of this Application Note is to provide guidelines and detail explanation for mounting technology of WLCSP (Wafer Level Chip Scale Package) but not to provide guarantee of perfect mounting technology. Needless to say, the results may differ depending on mounting conditions such as machine capability, material etc., but this information should be useful to reduce the occurrence of mounting failures. This document convers products which are listed in below table. For any products are not listed, please contact your Panasonic sales representative or send inquiry via URL stated at the last page of this document. Before proceeding to the context, please confirm if the Package Code is corresponding with your interested product.

Package Code Applicable Product ALGA004-W-0606-RA01 FK4B01110L, FJ4B01110L XLGA004-W-0808-RA01 FK4B01100L, FJ4B01100L ULGA004-W-1010-RA01 FK4B01120L, FJ4B01120L ULGA004-W-1212 FC4B21080L MLGA006-W-1726-RA FC6B22090L, FC6B22100L MLGA006-W-1727-RA FC6B21100L, FC6B21230L

Section 1 Preface In recent years, mobile electronic products such as Smartphones and Tablet PCs are constantly improving with more functions and applications squeezed into thin, compact and lightweight designs. Such features mean all components also need to enhance their performance as well as downsizing. In order to respond to these demands, Panasonic has ramped up Wafer-Level Chip-Size Package (WLCSP) products since 2011. The first product was 1.67mm square size WLCSP with a Ball Grid Array (BGA) type which was used for Lithium-Ion battery protection in Smartphones, after that 1.11mm square WLCSP in a Land Grid Array (LGA) type was ramped up, where the know-how and technology was later utilized to the products of 0606(0.6mm square), 0808 (0.8mm square) size, and 1010 (1.0mm square) size single-type MOSFETs, for load switch purposes. Panasonic aims to utilize our cut-edge chip process technologies to help customer applications to continually evolve “be smaller” and “be better”.

WLCSP Single Type MOSFET Series

0808 size 0606 size

1010 size

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In general, it can be said that smaller devices, therefore narrower pitches of lands and pads, would require even more high-tech mounting technology to get a sufficient bonding or junction. Based on the vast know-how and experience of mounting technology, this application note has been compiled to support design of solder stencil and land pattern to help improve and maintain assembly productivity and reliability. * The design examples and recommendations stated in this application note are for reference and

may/will need adjustments, depending on the environment/equipment of the assembly line.

Section 2 Panasonic WLCSP Package Sizes and Pad Designs Panasonic WLCSP products and pad layouts for the products are listed in below table.

Package Code Pin count

Pin type

Outline size [mm]

Pad design [mm] Pad layout

X Y Z Pitch Pad Size

ALGA004-W-0606-RA01 4 LGA 0.6 0.6 0.1 0.3 0.15

Pitch

Pitch

Pad Size

Pitch

Pitch

Pad Size

XLGA004-W-0808-RA01 4 LGA 0.8 0.8 0.1 0.4 0.2

ULGA004-W-1010-RA01 4 LGA 1.0 1.0 0.1

0.5 0.25

ULGA004-W-1212 4 LGA 1.11 1.11 0.1

MLGA006-W-1726-RA 6 LGA 2.56 1.67 0.1

0.65 0.3

Pitch

Pitch

Pad Size

Pitch

Pitch

Pad Size

MLGA006-W-1727-RA 6 LGA 2.67 1.67 0.1

Table 1: WLCSP MOSFET package lineup and pad layout

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Section 3 PCB and solder stencil designs In this section, design information on (1) Solder Resist, (2) Land Pattern, and (3) Solder Stencil is provided. 3.1 Solder Resist Design There are two types of solder resist design. Solder Mask Defined (SMD) and Non Solder Mask Defined (NSMD). As shown in Figure 2, For SMD the solder resist overlays the wiring pattern of the PCB, whereas for NSMD the solder resist doesn’t overlay the wiring pattern of the PCB.

Figure 2: Comparison of SMD and NSMD

実装

前は

んだ印

刷後

実装

後

Solder resist Circuit

Solder paste

WL-CSP LGA electrode

Printed circuit board

SMD NSMD

Solder paste covers the entire wiring pattern to fill the space between the solder resist and wiring pattern

Initi

al

Afte

r mou

ntin

g Af

ter s

olde

r prin

ting

Figure 1: Section indication of materials used for mounting process

(3) Solder stencil ...... Section 3.3

(2) Land pattern ...... Section 3.2

(1) Solder resist ...... Section 3.1

Solder paste

WLCSP

Copper foil

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NSMD allows the solder paste to cover the entire land pattern of the PCB, making solder joint stronger and temperature life cycle longer, compared to SMD. Figure 3 shows a comparison of solder void occurance between the two types. (a) A PCB with SMD type solder resist design overlaying wiring pattern, and (b) A PCB with SMD type design on two sides, and NSMD type design on to the other two sides of the pad. We compared solder void on both designed PCBs with placement conditions to cause solder void intentionally (*1). Board (b), which combines SMD and NSMD types, keeps open space between the wiring pattern and solder resist and allows flux gas, which mainly causes the void, to be pushed out in the solder, thereby solder void occurrence rate is reduced, whereas for SMD designs the flux gas cannot be pushed out in the solder, thereby the occurrence is increased. However, for NSMD designs, uncovered portions of the wiring pattern, especially edge and corner part, we called “neck part”, can be peeled off by lower mechanical stress than SMD types. Therefore, the PCB designer should consider both pros and cons on the solder resist types and choose the types, according to target application and board design. *1: Refer to Section 5 for solder void.

3.2 Land Pattern Design All WLCSP with pads on the bottom side of the device, will require reflow soldering (*2) to

A

A’

A

A’

A A’A A’ A A’A A’

A A’A A’

A

A’

A

A’ A A’A A’

Figure 4: Pad/Circuit peeling

SMD NSMD (Viewed from the top) (Cross Section view) (Top view) (Cross Section view)

Mechanical stress

Mechanical stress

(SMD)

(NSMD)

Neck part

X-ra

y in

spec

tion

Boar

d de

sign

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bond to the PCB. Upon reflow soldering, devices might be placed on unexpected location on PCB due to misalignment of placement machine and solder printing. The risk can be reduced by design same land pattern with the device pad layout. By using the land pattern, it helps the device to be placed into expected position during reflow soldering process. Thus, we recommend that same land pattern on the PCB with the device pad layout is designed with some exceptions. *2: Refer to Section 4 for reflow soldering method.

3.3 Solder Stencil Design Design solder stencil is very important to maintain high mounting reliability such as sufficient solder joint and no solder ball (*3). Excessive solder paste increases the risk of causing solder balls, and deficiency of solder paste also increases the risk of causing no solder connection. To prevent these defects, solder stencils need to be carefully designed to control amount of solder paste. Panasonic has studied a variety combination of PCB’s solder stencil designs and the materials, and recommends some combinations listed in Table 2 and Figure 5, which are confirmed to maintain high mounting reliability. Please refer to Table 2 for Stencil thickness and Figure 5 for land pattern and stencil designs. These reference designs should be evaluated together with actual assembly environment and also solder paste. *3: Refer to Section 5 for solder balls.

Package Code Solder stencil

thickness (recommendation)

Fig. 5 Ref No.

ALGA004-W-0606-RA01 80µm #1

XLGA004-W-0808-RA01 80µm #2

ULGA004-W-1010-RA01 100µm #3

ULGA004-W-1212 100µm #4

MLGA006-W-1726-RA 100µm #5

MLGA006-W-1727-RA 100µm #6 Table 2: Solder stencil thickness recommendation for each

type of WLCSP

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#1 ALGA004-W-0606-RA01

Device Outline Land Pattern Solder Stencil Pattern

#2 XLGA004-W-0808-RA01


#3 ULGA004-W-1010-RA01 Device Outline Land Pattern Solder Stencil Pattern

Figure 5: Design Recommendations of land patterns and stencils (Unit: mm)

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#4 ULGA004-W-1212


#5 MLGA006-W-1726-RA


#6 MLGA006-W-1727-RA Device Outline Land Pattern Solder Stencil Pattern

Figure 5: Design Recommendations of land patterns and stencils (Unit: mm)

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Section 4 PCB Mounting Conditions In this section, mounting process conditions we recommend are provided, based on our study results. The process includes solder printing, mounting and reflow process. Figure 6 shows an overview of the process.

4.1 Solder Paste The principal substances of solder paste are solder powder and flux. The most general type of solder paste contains approximately 80 to 95wt% of solder powder. The ratio of solder powder determines the viscosity of the paste, and the viscosity directly affects the thickness and solder wetting after reflow. And there are variety types of grain size of solder powder, which is shown in Table 3. The smaller grain size is, the more amount of solder powder unit area in solder paste. Therefore, in case of excessive amount of solder paste with small grain

Figure 6: Overview of Chip bonding process

(3) Reflow Process ... Sec. 4.2

(2) Mounting Process

(1) Solder Paste Printing Process

(Mask alignment) (Printing)

(Pickup) (Transfer) (Mounting)

(Preheat) (Cooling) (Solder joint forming)

Reflow machine Cooling unit Heating unit

(Supply) (Take out)


Circuit (pad) Solder Stencil Solder paste ... Section 4.1

Suction nozzle WL-CSP

Feeder

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size, there is a higher possibility that solder ball occurs, compared to large grain size. For your reference, our recommendation of solder grain size for various type of WLCSP products is shown in Table 4. Please be noted that surface oxidation of solder powder might cause solder ball, solder void and also no solder joint due to the paste wetting. Also the smaller grain size is, the more likely to cause surface oxidation. Thus, if you use solder paste with smaller grain size, you should handle and store the paste carefully. For this reason, it can be said that Picking up solder paste is important to maintain high mounting reliability as well as design solder stencil.

Grain size of solder powder 5-15 μm 15-25 μm 25-38 μm 24-45 μm 38-53 μm

4.2 Reflow 4.2.1 Methods of Reflow Process Reflow is the process to bond the device to the PCB. The device is first placed on the PCB and then put in furnace to form solder joint between the device pad and land on PCB with solder. Furnace is carefully tuned where the temperature is controlled depending on the stage of the process from pre-heating to cooling, as shown in Figure 8. There are two main methods of reflow, Infrared reflow method and Convection reflow method, which is shown in Figure 7 as well as the differences of the methods. For Infrared Reflow, devices are heated by infrared radiant heat. The advantages are lower

Recommend

ed Stencil Thickness

Recommended grain size of solder powder 5-15 μm 15-25 μm 25-38 μm 24-45 μm 38-53 μm

ALGA004-W-0606-RA01 80μm 〇

XLGA004-W-0808-RA01 80μm

100μm

〇

〇

ULGA004-W-1010-RA01

ULGA004-W-1212 100μm 〇

MLGA006-W-1726-RA 100μm 〇

MLGA006-W-1727-RA 100μm 〇

Table 3: Solder Powder Grain size in Solder Paste *Latest Electronics Packaging [Part 2], Ch. 5. Sec.4 0603 Chip Component Assembly Technology, by Technical Information Institute Co. Ltd.

Table 4: List of solder powder grain size recommended for each type of WLCSP

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operating cost and easier maintenance than Convection reflow. However, it is hard to control temperature in furnace, because the radiant heat is affected by material and shape of the heated devices and the pads aren’t directly heated but through the PCB by conductive heat. It causes uneven temperature in furnace, so may make solder joint strength weak. For Convection Reflow, devices are heated in air and/or nitrogen atmosphere. Compared to Infrared Reflow, it takes longer heating time, however, the devises and solder pastes in furnace can be heated at more even temperature, because both convection and conductive heat help materials in the furnace keep the even temperature. Thus, we recommend Convection Reflow method for WLCSP devices.

Infrared Reflow method Convection Reflow method

4.2.2 Reflow Temperature and Limit count of Reflow runs Reliability test has been performed for all Panasonic WLCSP products, based on IPC/JEDEC J-STD-020C specifications. The test samples are exposed to moisture and reflowed 5 times at the maximum temperature of 260°C, then we confirm the samples pass the tests. So the products can withstand heat stress which deserves to five reflow operations, however according to the IPC/JEDEC J-STD-020C specification, it is preferred to perform within 3 times reflow operations. The number of reflow cycles must be set considered to solder paste and manufacturing environment and/or equipment if the product applied additional heat stress such as rework operation and double-sided mounting.

4.2.3 Temperature Profile We have performed several evaluations with variety types of solder paste. Figure 8 is shown the temperature profile we recommend, based on the evaluation results. The profile can be used for reference when you set reflow temperature.

Figure 7: Heat transmission path of infrared reflow method and convection reflow method


WLCSP

Radiation heat

Conducted heat

Convected heat

Conducted heat

Chip, Pin, solder paste, pad, PCB

(from top to bottom)

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Inappropriate reflow temperature may cause solder balls and solder voids, and then reduce solder joint strength. Thus, when setting up reflow temperature, you should consider appropriate thermal stress applied to device to avoid the mounting issues. Below three items from Figure8 are required for the reflow temperature profile. Preheating Thermal mass of each device on PCB is different due to each size and the difference causes unevenness of temperature during reflow. To prevent the unevenness, the furnace temperature must be preheated to equalize each device temperature on the PCB before ramping up to peak temperature. The preheat helps evaporate volatile material in solder paste hat is the major cause of solder voids, and also helps reduce surface oxidation of solder prouder. In addition to temperature, time is also an important factor in preheating process. If the temperature is set too low or the time is set too short, the flux material may remain until the heating time and causes voids and/or solder balls. On the other hand, when the preheating temperature is too high or the time is too long, the solder wetting is affected and may cause making poor and weak solder joint. When mounting Panasonic WLCSP products, the preheating time should be set in between 65 to 85 sec (74 sec is recommended) and the average temperature at 165°C. In this case, the “Preheating time” is defined as the time span the temperature rises from 150°C to 170°C. Critical Zone The Critical zone, shown in Figure 8, is the temp zone in which Sn (tin) - Ag (silver) lead-free solder melts. Generally, it is defined as the time in between 210°C to 221°C. we define the critical zone time as the time during more than 217°C. Since excessively long and high temperature exposure causes weak solder joint and/or connection failures as discussed in 4.2.2., in the Critical zone the time should be approximately 48 sec or less and the peak temperature should be approximately 245°C. Temperature Ramp Rate The temperature ramp rate from the Preheat zone to the Critical zone must also be controlled. Based on our experience, the ramp rate should be set around between 1 to 3 °C/sec (1.9°C/sec we recommend). An immediate and sudden temperature rise applies thermal shock to the device and it may cause cracks, flux boiling, solder voids and solder balls.

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(1) Preheating time 74 [sec] (6) Preheat Max temperature 170 [°C]

(2) Critical temperature zone time 48 [sec] (7) Preheat Min temperature 150 [°C]

(3) Heating time 23 [sec] (8) Preheating average temperature 165 [°C]

(4) Peak temperature 245 [°C] (9) Ramp rate 1.9 [°C/sec]

(5) Min temperature in critical zone 217 [°C]

-50

0

50

100

150

200

250

300

(1)Preheating time (2)Critical zone time

(3)Heating time(9) Ramp-up rate

(8) Preheating average temperature

(7) Preheat Min temperature

(4) Peak temperature

(5) Critical zone Min temperature

温度

[ ℃]

時間 [ sec ]

(6) Preheat Max temperature

-50

0

50

100

150

200

250

300

(1)Preheating time (2)Critical zone time

(3)Heating time(9) Ramp-up rate

(8) Preheating average temperature

(7) Preheat Min temperature

(4) Peak temperature

(5) Critical zone Min temperature

温度

[ ℃]

時間 [ sec ]

(6) Preheat Max temperature

Figure 8: Temperature Profile Example of Reflow Processing

Cooling unit Heating unit

(Preheat) (Critical temperature range)

Transport by a feeder

Temperature [°C]

Time [sec]

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Section 5 Solder Joint Failure and Solution As discussed up to this point, optimizing the land pattern and solder stencil design, and also evaluating reflow conditions with the combination of solder pastes are the keys to success. However, before reaching the ideal conditions, it is most likely that many problems or abnormalities will be encountered through many evaluations. In this section, some abnormalities and failures most commonly seen have been described to provide a better understanding of perfecting the process. In addition, The X-ray inspection system is the most effective method for confirming the solder state after mounting. 5.1 Examples of Good or Defective Solder Joints Shown in Figure 9 is an X-ray photo of a good sample. The red square in dotted line indicates the outline of the WL-CSP, and the black circular objects being the solder joints of the device and PCB. The gray area is the circuit pattern of the PCB. In Table 5, listed are some samples of Solder joints that are Good and Unacceptable.

Figure 9: Good sample

Circuit pattern of PCB

Outline of WLCSP

Solder joint

Outline of WLCSP

Circuit pattern of PCB

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Condition Example Reference

Good sample

Figure 9

Void

Section 5.2.1

Solder ball

Section 5.2.2

Non-wetting

Section 5.2.3

Table 5: Examples of good and failure solder joints

*Note: Failure samples were made intentionally strictly for explanatory purposes in the note.

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5.2 Common Abnormalities 5.2.1 Voids Figure 10 is an X-ray photo showing a void that can be seen in the bottom right solder joint, circled in red. In most cases, the voids are caused by flux-gas trapped inside the solder paste after mounting process. These type of Solder voids happen randomly but can be minimized by optimizing the reflow temperature profile (Refer to “4.2.3 Temperature Profile” for details). Voids can also be avoided by allowing the gas to be pushed out by design the PCB with a combination of SMD and NSMD patterns (Refer to “3.1 Solder Resist Design”, Figure 3). In Figure 11, the behavior of solder voids can be observed during the several cycles of reflow the device was put into. This void, which intentionally generated, in first cycle reflow process is fairly small but continues to grow until 3 cycles reflow. After 4 cycles, the void cannot be seen, and has basically disintegrated. No void is also confirmed after 5 cycles. The mechanism of the phenomenon is shown in Figure 12. As the diameter of the void grows during 3cycles reflow, the edge of the void eventually reaches the end of the pad, and finally allow the gas to be pushed out from the solder paste. According to the evaluation result, boiling flux gas in solder paste is important to avoid the solder void thus you should preheat with appropriate condition and carefully design circuit pattern. According to many industry standards such as IPC-A-610, the tolerance for void is stated, “less than 25%” of each solder joint area. And based on the standard, we have made various void size samples then have performed evaluations of electrical characteristics, thermal characteristics, and reliability evaluations, then less than 25% void size samples have passed all evaluations. In X-ray visual inspections, the defect limit should be, as stated above, all solder voids to be smaller than 25% of solder joint area of each pad.

(1st) (2nd) (3rd) (4th) (5th)

Figure 11: X- ray photos for samples with each reflow cycle

Figure 10: Solder void

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In addition to flux gas remainders, there are other possibilities to cause solder voids, which are PCB pattern contamination, oxidization of solder. In some cases, restored gas from the oxidization of solder remains in solder paste and causes solder void. Thus, you should avoid contamination on PCB and oxidization of solder paste surface to prevent from causing the solder void. 5.2.2 Solder Balls The red circles highlighted in Figure 13 show circular objects near the solder joints, which are called Solder Balls. The following three cases are described how solder balls happen, which is mentioned briefly in the previous pages.

Figure 12: X- ray photos scooped up the solder void

Solder void grows in a circular shape by heat Edge of WLCSP Electrode pad

Solder void Flux gas is pushed out when the solder void reaches the pad edge

Figure 13: X – ray photos of solder ball example

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Case (1) In case of excessive amount of solder paste, some solder paste is pushed out of the pad during reflow process by the weight of device itself and hardens into a spherical shape near the land pattern. To avoid the excessive amount of it, you should design solder stencil pattern. Refer to 3.3 Solder Stencil Design. Case (2) When the placement force is too strong. The outcome is the same as in Case (1). Case (3) In case the temperature profile is inappropriate. As explained previously, extreme high temperature at preheat and/or excessively high ramp-up rate may cause a boiling or explosion of flux and other gases.

Figure 14: Solder ball occurrence machoism (1)

Figure 15: Solder ball occurrence mechanism (2)

(Printing) (Mounting) (Reflow processing) (Finish) Excessive placement force

Solder paste (appropriate quantity)

Pushed out of solder from land pattern

Pushed-out solder melts and then hardens

Appropriate heat treatment

Figure 16: Solder ball occurrence mechanism (3)

(Printing) (Mounting) (Reflow processing) (Finish)

Solder paste (appropriate quantity)

Appropriate placement force Excessive heat treatment

(Printing) (Mounting) (Reflow processing) (Finish)

Land Pattern Printed circuit board

Solder paste (excessive)

Solder stencil Suction nozzle

Appropriate placement force

Appropriate heat processing

Sink in by own weight

Excessive solder pushed out and hardens WL-CSP

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Although Solder balls do not always affect the function and reliability in a critical way, “foreign objects” are not desirable and should be controlled as much as possible. In the worst case, Solder balls can form a bridge between the pins and may cause short-circuits. Electrical characteristic tests are recommended to screen out such bridge form.

5.2.3 Non-Wetting In Figure 17, the dotted red circles indicate the area of the pin/pad, which if properly processed should be covered with solder and look entirely “Black” in the X-ray photo. Although three of the four pins have a sufficient finish, the pin on the lower left hand has a smaller “Black” area, covering only a portion of the said pin. This is called Non-wetting. Non-wetting will most likely cause poor reliability performance, as well as increase the risk of open failures. Non-wetting can occur in many cases. For example, when the solder stencil opening is designed too small limiting the solder output amount. Clogging of the stencil opening or solder paste related issues may also be root causes for poor solder printing. For

corrective actions, the solder stencil design and solder paste type, especially the grain size of the solder powder should be reevaluated. For the stencil design, please refer to Section 3.3, Solder Stencil Design. For the solder paste and grain size, please refer to Section 4.1, Solder Paste as well as Table 4. Along with design issues and selection of material, maintenance issues should not be overlooked. Keeping the equipment clean, namely the stencil, will go a long way to improve the finish and reliability.

Figure 17: Solder non-wetting

Red broken line = Electrode pad position

Solder non-wetting

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■ Section 6 Design Recommendation Chart

Package Code ALGA004-W-0606-RA01 XLGA004-W-0808-RA01 ULGA004-W-1010-RA01

Land Pattern (3.2 Land Pattern Design)

Solder Stencil Pattern (3.3 Solder Stencil Design)

Stencil Thickness (3.3 Solder Stencil Design) 80μm 80μm 100μm

Solder Paste Grain Size (4.1 Solder Paste) 15～25μm 15～25μm 25～38μm

Reflow profile(4.2.3 Temperature Profile) Refer to Figure 8

Table 6: WLCSP “MOSFET” Design Recommendation Chart

*The recommendations stated in this chart are for reference and may/will need adjustments, depending on the environment/equipment of the assembly line.

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Package Code ULGA004-W-1212 MLGA006-W-1726-RA MLGA006-W-1727-RA

Land Pattern (3.2 Land Pattern Design)

Solder Stencil Pattern (3.3 Solder Stencil Design)

Stencil Thickness (3.3 Solder Stencil Design) 100μm 100μm 100μm

Solder Paste Grain Size (4.1 Solder Paste) 25～38μm 25～38μm 25～38μm

Reflow profile(4.2.3 Temperature Profile) Refer to Figure 8

Table 6: WLCSP “MOSFET” Design Recommendation Chart

*The recommendations stated in this chart are for reference and may/will need adjustments, depending on the environment/equipment of the assembly line.

Request for your special attention and precautionsin using the technical information and semiconductors described in this book

(1) If any of the products or technical information described in this book is to be exported or provided to non-residents, thelaws and regulations of the exporting country, especially, those with regard to security export control, must be observed.

(2) The technical information described in this book is intended only to show the main characteristics and application circuitexamples of the products. No license is granted in and to any intellectual property right or other right owned byPanasonic Corporation, Nuvoton Technology Corporation Japan or any other company. Therefore, no responsibility isassumed by our company as to the infringement upon any such right owned by any other company which may arise as aresult of the use of technical information de-scribed in this book.

(3) The products described in this book are intended to be used for general applications (such as office equipment,communications equipment, measuring instruments and household appliances), or for specific applications as expresslystated in this book.Please consult with our sales staff in advance for information on the following applications, moreover please exchangedocuments separately on terms of use etc.: Special applications (such as for in-vehicle equipment, airplanes, aerospace,automotive equipment, traffic signaling equipment, combustion equipment, medical equipment and safety devices) inwhich exceptional quality and reliability are required, or if the failure or malfunction of the products may directlyjeopardize life or harm the human body.Unless exchanging documents on terms of use etc. in advance, it is to be understood that our company shall not be heldresponsible for any damage incurred as a result of or in connection with your using the products described in this bookfor any special application.

(4) The products and product specifications described in this book are subject to change without notice for modificationand/or improvement. At the final stage of your design, purchasing, or use of the products, therefore, ask for the most up-to-date Product Standards in advance to make sure that the latest specifications satisfy your requirements.

(5) When designing your equipment, comply with the range of absolute maximum rating and the guaranteed operatingconditions (operating power supply voltage and operating environment etc.). Especially, please be careful not to exceedthe range of absolute maximum rating on the transient state, such as power-on, power-off and mode-switching. Other-wise, we will not be liable for any defect which may arise later in your equipment.Even when the products are used within the guaranteed values, take into the consideration of incidence of break downand failure mode, possible to occur to semiconductor products. Measures on the systems such as redundant design,arresting the spread of fire or preventing glitch are recommended in order to prevent physical injury, fire, social damages,for example, by using the products.

(6) Comply with the instructions for use in order to prevent breakdown and characteristics change due to external factors(ESD, EOS, thermal stress and mechanical stress) at the time of handling, mounting or at customer's process. We donot guarantee quality for disassembled products or the product re-mounted after removing from the mounting board.When using products for which damp-proof packing is required, satisfy the conditions, such as shelf life and the elapsedtime since first opening the packages.

(7) When reselling products described in this book to other companies without our permission and receiving any claim ofrequest from the resale destination, please understand that customers will bear the burden.

(8) This book may be not reprinted or reproduced whether wholly or partially, without the prior written permission of ourcompany.

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CSP Application note - Panasonic · results. The process includes solder printing, mounting and...

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