422
S. Shi et al.
the requirements from 3D packaging can help accelerate some of the building blocks
for substrate materials development. To enable smaller packages, all the materials
from cores, to dielectric build-up layers, to solder mask to photoresist must be high
resolution definable. In order to make signal transfer fast and efficient, low dielectric
constant and low loss factor materials together with shorter electrical path such as
stacked vias are enablers. The materials must be easy to fabricate and enable easy
and high throughput substrate fabrication process for cost considerations. RoHS
requirements add another layer of challenge in new material developments. High
heat resistance and high T g materials such as new multifunctional epoxy resins are
the materials for these current applications. Another thing to note is that these material
sets should also be compatible with the chemistries used in the downstream processes,
such as the surface finish plating process, deflux process, etc.
14.4 Organic Substrate Fabrication—Process Overview
Organic PWB substrates have gradually evolved to become the platform of electronics assembly for many of the most important industries in the world from medical
to aerospace to consumer applications. The fabrication of organic PWB substrates
is an industry requiring the skills of many different engineering and science disciplines. Silicon IC fabrication geometries have pushed well into the nanometer feature
range, in order to keep up with the miniaturization revolution. There is often an
under-appreciation of the efforts required to successfully manufacture high density
interconnect substrates with the fine features using conventional packaging process
flows. This has led to a technology revolution that makes the substrates/ packaging
technology not just a space transformer but a critical component of the functionality
of the overall package.
The many details of the organic substrate production process cannot be dealt
justice in the space allocated in this particular text. In this context, a general high level
overview of the traditional organic substrate manufacturing process will be reviewed.
The reader is directed at several excellent resources that have become the standards
in the PWB industry, in addition to the electronics industry’s professional societies
for a wealth of knowledge and information on the varying topics and subtopics of
organic PWB fabrication, in addition to the newer advancements in materials and
process technologies [3, 10, 16–19].
This chapter will highlight the most important information during the substrate
manufacturing process for end users and design engineers hoping to obtain a high
level overview on the manufacturing process of organic substrates. This general flow
is presented in Fig. 14.6.
S. Shi et al.
the requirements from 3D packaging can help accelerate some of the building blocks
for substrate materials development. To enable smaller packages, all the materials
from cores, to dielectric build-up layers, to solder mask to photoresist must be high
resolution definable. In order to make signal transfer fast and efficient, low dielectric
constant and low loss factor materials together with shorter electrical path such as
stacked vias are enablers. The materials must be easy to fabricate and enable easy
and high throughput substrate fabrication process for cost considerations. RoHS
requirements add another layer of challenge in new material developments. High
heat resistance and high T g materials such as new multifunctional epoxy resins are
the materials for these current applications. Another thing to note is that these material
sets should also be compatible with the chemistries used in the downstream processes,
such as the surface finish plating process, deflux process, etc.
14.4 Organic Substrate Fabrication—Process Overview
Organic PWB substrates have gradually evolved to become the platform of electronics assembly for many of the most important industries in the world from medical
to aerospace to consumer applications. The fabrication of organic PWB substrates
is an industry requiring the skills of many different engineering and science disciplines. Silicon IC fabrication geometries have pushed well into the nanometer feature
range, in order to keep up with the miniaturization revolution. There is often an
under-appreciation of the efforts required to successfully manufacture high density
interconnect substrates with the fine features using conventional packaging process
flows. This has led to a technology revolution that makes the substrates/ packaging
technology not just a space transformer but a critical component of the functionality
of the overall package.
The many details of the organic substrate production process cannot be dealt
justice in the space allocated in this particular text. In this context, a general high level
overview of the traditional organic substrate manufacturing process will be reviewed.
The reader is directed at several excellent resources that have become the standards
in the PWB industry, in addition to the electronics industry’s professional societies
for a wealth of knowledge and information on the varying topics and subtopics of
organic PWB fabrication, in addition to the newer advancements in materials and
process technologies [3, 10, 16–19].
This chapter will highlight the most important information during the substrate
manufacturing process for end users and design engineers hoping to obtain a high
level overview on the manufacturing process of organic substrates. This general flow
is presented in Fig. 14.6.