ED-7306_E - 第18页

JEITA ED-7306 - 16 - 3.6 Maximum permissible package warpage of FLGA Given that PWB is an ideal seating plane, the maxi mum package warpage is defined to be the thickness of molten solder paste. (S ee Explanatory Fig. 3 …

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Explanatory Table 1 Maximum permissible package warpage for BGA and FBGA

Unit: mm

Solder ball pitch 0.4 0.5 0.65 0.8 1.0 1.27

Condition of solder ball height

0.20 0.25 0.33 0.35 0.40 0.50 0.60

Condition of solder paste thickness after reflow

0.08 0.10 0.11 0.13 0.14 0.15

Nominal solder joint height of the ideally flat package 0.18 0.23 0.29 0.31 0.36 0.43 0.5

Highest solder joint height of BGA without open

solder joint

0.28 0.35 0.44 0.48 0.53 0.64 0.75

Lowest solder joint height of BGA without open

solder joint

0.16 0.20 0.25 0.27 0.31 0.37 0.44

Highest solder joint height of BGA without solder

bridge

0.24 0.29 0.38 0.40 0.46 0.55 0.66

Lowest solder joint height of BGA without solder

bridge

0.12 0.15 0.20 0.19 0.25 0.28 0.34

Max relative displacement of BGA without open

solder joint

0.12 0.15 0.19 0.21 0.22 0.27 0.31

Max relative displacement of BGA without solder

bridge

0.12 0.14 0.18 0.21 0.21 0.28 0.32

Max permissible package warpage (Absolute value)

0.10 0.11 0.14 0.17 0.17 0.22 0.25

Coplanarity at room temperature (For reference) 0.08 0.08 0.10 0.10 0.10 0.20 0.20

NOTE: Assumptions of the calculations are

• The structure of the lands on PWB is non solder mask defined;

• The diameter of the lands on PWB is the same as that of package;

• Solder joint height between package and PWB is the distance between the face-to-face copper

lands;

• Thicknesses of the metal masks for solder paste printings are

- 0.10 mm for 0.4 mm pitch FBGA,

- 0.12 mm for 0.5 mm and 0.65 mm pitch FBGA, and

- 0.15 mm for 0.8 mm, 1.0 mm, and 1.27 mm pitch BGA;

• Opening diameter of the solder printing mask is the same as that of the lands on PWB.

Table footnote:

It follows the specification in JEITA EDR-7315 and JEITA EDR-7316.

It is the thicknesses of molten solder paste on copper lands without any component attached,

supposed 50 % of solder paste is metal content (solder).

It is the sum of the solder ball height and the molten solder-paste thickness, where the solder

connections are immune from open circuit.

It is 87 % of the nominal standoff height of the ideally flat package. The ratio is obtained from the

empirical data taken from the intentionally concave-warped sample.

It is 130 % of the nominal standoff height of the ideally flat package. The ratio is obtained from the

empirical data taken from the intentionally convex-warped sample.

It is the sum of the molten solder and the solder ball height when the ball diameter expands to 80 % of

the ball pitch. It is known that the balls do not bridge as far as the collapse of solder balls does not

make the ball diameter expand beyond 80 % of the ball pitch.

It is the difference between the highest and the lowest solder joint height, where open solder joint is

not seen.

It is the difference between the highest and the lowest solder joint height, where solder ball bridge is

not seen.

It is 80 % of the maximum relative displacement.

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3.6 Maximum permissible package warpage of FLGA

Given that PWB is an ideal seating plane, the maximum package warpage is defined to be the thickness of

molten solder paste. (See Explanatory Fig. 3) However the maximum permissible package warpage

depends on the amount of the solder paste, the criteria for FLGA are specified in Explanatory Table 2 for

semiconductor suppliers.

Explanatory Fig. 3 Package warpage of FLGA at elevated temperatu

Explanatory Table 2 Maximum permissible package warpage for FLGA

Unit: mm

Land pitch 0.4 0.5 0.65 0.8

Condition of thickness of molten solder 0.08 0.10 0.11 0.13

Maximum permissible package warpage (Absolute value) 0.08 0.10 0.11 0.13

Coplanarity at room temperature (For reference) 0.08 0.08 0.10 0.10

3.7 Discussion with the TSC on Jisso Technology Standardization

After drafting this specification, the task force requested the TSC on Jisso Technology Standardization to

review this specification and to hold the joint ad hoc meeting to promote harmonization of the opinions

between suppliers and users. Most of the issues raised by TSC were corrected or added, but there were

some disagreements left. Chief request was to verify if the measurement data from different types of

instruments are well accorded with. With the collaboration of measuring instrument suppliers, the bimetal

samples were measured by 3 types of instruments.

Since the TSC on Jisso Technology Standardization did not have enough data to comment on the criteria of

the maximum permissible package warpages, they would review the criteria one year later after the

collection of the data of the package warpages and the board assembly yields.

4. Industry property rights

The task force surveyed the industrial property rights that directly related to the measurement methods and

the maximum permissible warpage but did not find any of them.

FLGA

Maximum permissible

package warpage at

elevated temperature

Molten solder paste

PWB

The lowest point where

FLGA settles on PWB.

FLGA warpage

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5. Relation to the international standard

There is not any international standard (IEC) related to the warpage measurement method at elevated

temperature but the JESD22B112 published by JEDEC, USA. The comparisons between JESD22B112

and this specification are shown below:

Item

JESD22B112 This specification (JEITA)

Object Surface mount devices BGA, FBGA, FLGA, but excluding QFP

Warpage

direction

Convex warpage results in the package

corners being closer to the seating plane than

the center of the bottom surface of the

package. Concave warpage results in the

package corners being farther from the seating

plane than the center of the bottom surface of

the package.

Same as JESD22B112

Measuring

zone

Unspecified a) For the packages whose standoff height is

more than 0.1 mm, such as BGA and FBGA,

the measuring zone is the area where

terminals are located. This area is bordered

by the lines connecting the centers of the

outermost neighboring solder balls. If there

are thermal balls at the package center,

their area is also considered as a part of

measuring zones.

For the packages whose standoff height is

0.1 mm or less, such as FLGA, the

measuring area is the substrate surface

except certain edge margin. The width of

this margin L depends on the capability of

each measuring instrument (0.2 mm

recommended).

Package

warpage sign

Convex warpage is plus.

Concave warpage is minus.

Plus or minus sign of package warpage

determined by the sign of the sum of the

largest positive displacement and the largest

negative displacement of the package profile

on both measurement zone diagonals.

Package

warpage

“Deviation from planarity” is the difference in

height between the highest point and the

lowest point on the package body bottom

surface measured with respect to the seating

plane.

The difference of the largest positive and the

largest negative displacements of the package

warpage in the measuring zone with respect to

the reference plane, preceded by package

warpage sign. This reference plane is derived

using the least square method with the

measuring zone data.

Measuring

instrument

Shadow moiré only The measurement methods of the package

warpage are shadow moiré or laser reflection

method.

Calibration Concave or convex ground glass made of

ultra-low expansion material

Unspecified

Measurement

points

Warpage measurements should be viewed on

the substrate side without solder balls

attached.

The measurement points shall not be on the

crown of solder balls but on the substrate

surface of the package. Only when the

behavior of the package top surface (mostly

marking surface) is verified to coincide with

that of the substrate surface, the measurement

from the top surface is allowed.