A New Level of Connectivity- 5G Package Considerations
Authors: Gerber Mark , Chang Harrison , Lu Wayne , Kao Gavin , Cho Jonathan , Hwang Roger 
Published: January 2025

Understanding the intricacies of 5G

and the various technology challenges leave most people confused especially when RF frequency spectrum is brought into the discussion. We hear today more and more about faster internet

speeds as the key benefit but what

does this really mean to most people

and how will this really be different

than 4G? For most, just downloading a

video or meme may be good enough, so

how will this next generation of 5G

really impact our lives? A good way

to understand the 5G revolution is by

looking at a similarity to what is happening with artificial intelligence (AI). Prior to Deep Learning, most AI

methods were not able to produce the

results that could exceed the human

error rate, but around 2015, this changed. Deep Learning leverages what

is called a “neural network” or basically a system of nodes that perform calculations but more in a parallel format vs a serial approach.

The evolution of Wide IO memory has

helped to enable this neural network

type approach of computing by storing

the outputs of these calculations into

a parallel node like format. 5G is like deep learning in that mMIMO (Massive Multiple in Multiple Out) essentially creates a parallel or

array approach to RF signals when

communicating from towers which allow

for many more device connections.

Fundamentally, this larger number of

connections can help prevent reduced

data rates due to traffic and can

allow multiple paths for data transfer. Setting data transfer speed aside, the ability for more devices to be connected reliabily and even using

each other for connections as well

begins to bring a true cross-linked network that has not existed. The ability to handle many connections and even segment the type of connections

depending on application space, begins to paint the picture of the future to come.

To enable these new technical approaches requires some new thinking for IC Packaging as well. To

understand the various RF frequencies, you need to understand how certain frequencies are being used today. When you think about AM/FM radio,

these are in the Kilohertz/Megahertz

ranges and generally their signals travel far- usually 10s to 100s of miles. Cellular phone technology

starting with 1G, 2G, 3G are in the Mhz to GHz and generally the higher the frequency, the higher the data rates. The challenge is that as you move up in frequency, the signal does not travel as far due to the energy

being absorbed into materials. For Sub6Ghz, this is not a problem but at

higher mmwave Ghz ranges, it can be

real challenge when the signal is being used for data transfer and not just a proximity sensor like what is being used in automotive. For

frequencies at 20Gh and higher, these

signals tend to get absorbed in solid

materials such as walls and thus a

direct line of sight is required for a

reliable signal. This can pose major

challenges when trying to roll out a

full network to support 5G and would

also require a lot of towers to support due to the short effective

signal distance for a good signal strength (around 1000 ft or less). For dense central business districts or on

commuter trains this may be ok but

wide area rollout continues to be

difficult. The IC Packaging challenges are even greater at these higher mmwave frequencies due to the material sensitivities to handle these very fast speeds. For a signal to travel at these speeds, they travel on the outside of the copper trace (Skin) and minor roughness of these traces can initiate a skin effect that causes

signal loss. The package design

considerations for Sub 6Ghz are very

different than for mmWave frequencies

and require a different approach.

Today, most of the world has focused

initially on the sub 6Ghz frequency

spectrum to roll out their 5G networks. This is primarily due to the similar RF considerations for

infrastructure, handsets and other

devices when moving from 4G/LTE. The

key benefit that keeps the industry working on mmWave is the much-improved

speed and low latency that it will provide. These challenges will take time to resolve and research in new

materials, new process techniques,

tighter tolerance process requirements, true 3D interaction

impacts, and other considerations will

be required to create a successful solution. The complexity of mmWave has driven several unique packaging solutions, one disadvantage to not having any design/package related standards in place. Which package solutions will end up winning in this

higher frequency area remains to be seen but RF test at the device level and the integrated final product level will be critical for validating their performance.

This presentation will step through a

background on the 5G market and will

also dive a little deeper into both

Sub6Ghz packaging solutions as well as

mmWave considerations.