M20_Ope_E - 第218页

Chapter 5 Libraries 5-68 5-1-5-12 BGAs and CSPs  Inapplicable Components Components with mold that reflects light , such as CBGA361T1.27-DC71, CBGA240T1.27-ISO, CCGA625T1.27-ISO, and TBGA240T1.27-DC56, cannot be vision-…

Chapter 5 Libraries

5-67

z Lead Search Direction

This function is peculiar for Connector mode which allows you to specify Lead Search

Direction. For example, a component which has difficult leads to be recognized by standard

process (Lead search from outside) could be recognized successfully by changing the

lead-search-direction from outside to inside.

Choose proper processing from 0 to 3 by referring to the descriptions below:

0: Lead search line is put on the outside leads. (Standard)

1: Lead search line is put on the inside leads.

2: Lead search line is put on the outside leads first, then it moves to further outside

until the lead tip is detected.

3: Lead search line is put on the inside leads first, then it moves to further inside until

the lead tip is detected.

Lead Search Direction: 0 Lead Search Direction: 1

Lead Search Direction: 3Lead Search Direction: 2

Chapter 5 Libraries

5-68

5-1-5-12 BGAs and CSPs

 Inapplicable Components

Components with mold that reflects light, such as CBGA361T1.27-DC71, CBGA240T1.27-ISO,

CCGA625T1.27-ISO, and TBGA240T1.27-DC56, cannot be vision-processed properly.

Some CSPs use polyimide tape as their packaging material. Note that the polyimide tape is

easily delaminated to rise above the ball bumps, resulting in mis-imaging of the component.

 Editing Placement Coordinates for BGAs and CSPs

Usually placement coordinates editied with teach entry may include some offsets, since the

operator manually aligns the camera center (cross hairs on the CRT monitor) to the placement

point. For components such as a chip, QFP, and SOP, whether their placement coordinates are

accurate can be checked by checking the placed components. But for a BGA or CSP, such visual

checking is not feasible. Unless the placement coordinates of a BGA or CSP are accurate,

satisfactory placement cannot be performed. Therefore we strongly recommend to use CAD

data as placement data for BGAs and CSPs.

When teaching placement coordinates of a BGA or CSP via the main teach camera, the

maximum allowable coordinate offset is one-third of the ball diameter.

 Ball check

For BGA and BGA/CSP components, the ball check method can be selected from

“Presence(outmost)”, “Presence(all)”, “Presence&Damage(all)” and “No Checks”. However,

“Presence&Damage(all)” cannot be selected in the case of scan camera.

Note: If “No Checks” is selected, ball positioning will be performed, starting with the ball that is

located, among those located inside the four-edged search area, at the most outside position.

Unlike “Presence(outmost)”, this method may judge that a ball is located on the circumference

even if it is not. In this case, deviation in position or angle may occur, so “No Checks” must be

selected only for special components that cannot be positioned by any other methods.

Note: The system can recognize missing balls that are lost during manufacturing. When the ball does

not appear white (not reflect the front lighting), the system recognizes ball absence.

Note: When a ball is flattened to a considerable extent, the system can detect it. However, this ability

is crucially affected by the illuminator settings including the side light’s.

Settings for BGA and BGA/CSP are respectively described in the following sections.

 Settings for BGA mode (ImageLibrary>SelectComponent>BGA)

BGAs can be handled either via the BGA mode or the BGA/CSP mode. But we

recommend you to use the BGA/CSP mode for handling BGAs.

As for Ball Pitch, Ball Size, Ball Count X, Ball Count Y, Upper-right Ball Coordinate, Lower-left

Ball Coordinate, click on each setting field and see the graphical description displayed in the

sub-windows.

Chapter 5 Libraries

5-69

z Component

Click <Mode> button to select a ball alignment pattern.

0: Full grid, matrix

1: Full grid, staggered

2: Perimeter grid, matrix

3: Perimeter grid, staggered

4: Partial grid, matrix

5: Partial grid, staggered

z Upper-right Ball Coordinate (When [Component] is 2 or 3)

Note: For information on how to identify the ball position, see Missing Ball Assignment later in this

section.

Enter the ball position number of the upper right corner of the innermost ball square. For both

examples shown below, the setting shall be “0303”.

z Lower-left Ball Coordinate (When [Component] is 2 or 3)

Enter the ball position number of the lower left corner of the innermost ball square. For both

examples shown below, the setting shall be “0909”.