Embedded boards increase due to high performance of smartphones and tablet PCs

It is predicted that the use of high-power substrates will increase significantly this year as demand for electric and hybrid electric vehicles increases.

According to the Electronic Circuit Board Industry Status (2017) report published by the Korea Electronics Circuit Industry Association, the technological level of the boards currently being mass-produced is continuously growing in the direction of becoming narrower, smaller, and thinner, but flexible boards are showing an upward leveling due to the saturation of the product market.

As embedded board adoption increases due to the high performance of smartphones and tablet PCs, build-up boards are being widely used in all electronic products that process miniaturization and high-speed, large-capacity data. Build-up boards used as main boards of mobile devices have 8 to 12 layers and have a 1+N+1 (1 build) to 4+N+4 (4 build) structure. The form is changing to 'Stacked via', and the adoption of All layer Build up (Full stacked via) structure is increasing.

Flexible PCBs Maintain Leveling-Off Status Due to Market Saturation

As for flexible substrates, the number of low- to mid-priced products is increasing, and it seems likely that they will continue at the current level without significant growth. Most of the flexible substrates and multilayer flexible substrates for mobile phones have build-up technology applied to them, and the build-up technology applied to flexible substrates seems to be generally a 1+4+1 or 2+2+2 structure with 2 builds or less.

The circuit width of multilayer flexible substrates is expected to decrease from 50 ㎛ in 2017 to 30 ㎛ in 2019, the hole diameter is expected to decrease from 100 ㎛ in 2017 to 75 ㎛ in 2019, and the micro via diameter is expected to decrease from 100 ㎛ in 2017 to 50 ㎛ in 2019.

PBGA (Plastic Ball Grid Array) currently applies 200 to 900 I/O pins, and Line/Space is expected to be maintained at the 20/20㎛ level in 2017 until 2019, then narrow to 15/15㎛ in 2021. In addition, the market share is showing a downward trend due to flip chips.

CSP(Chip Scale Package) is led by ultra-thin plate technology using Coreless and microcircuit technology using ETS(Embedded Trace Substrate). The mass production application level of ultra-thin plate technology is 3L 90㎛, 4L 130㎛ thickness, and wire bonding pitch is Tenting 75㎛, MSAP(Modified Semi-Additive Process) 70㎛. Recently, ETS wire bonding is being attempted for mass production, and only ETS can meet the requirement of 30㎛ bonding pad width with 60㎛ pitch.

FC-BGA is used for MPU, GPU, and logic devices, and the package size is 20~55mm. It features build-up ABF, and Line/Space 10/10㎛ is applied to mass production. In particular, for high-performance logic devices, 8/10㎛, via dia 50㎛, and bump pitch 130㎛ are being promoted. As the pattern requires high-difficulty technology of 8㎛/10㎛ and bump pitch of 120㎛, the existing SOP (Solder on pad) Bump FC-BGA products need to be replaced with micro ball mounting or copper bumper by electroplating.

FC-CSP is thin and small, and is leading the AP, base band, and controller markets of mobile devices with excellent electrical characteristics and a high pin count. ETS technology is leading, and it is being applied to mass production because it can reduce the circuit width and implement fine circuits, which were shortcomings of existing Primer SAP. Currently, ETS is mass-produced with Line/Space 10/10㎛, but it is expected to be reduced to 7/7㎛ in the future. Coreless flip chip application cases are increasing due to package thickness issues, and the ability to control warpage at high temperatures of 250 to 260 degrees is a competitive advantage.

BOC (Board on Chip) is mainly 1~2L for DRAM memory chip package, and the slot width is 90~100㎛. The chip and the substrate are connected by wire bonding, and the slot is punched with a mold or processed with a route bit. The minimum thickness is 250㎛, and the line/space pitch is 80㎛ minimum with low-cost tenting method, and 20/20㎛ is expected to continue in the future.

SIP (System In Package) is characterized by coreless multilayer modularization through component fusion and is being led by the automotive industry. The substrate surface requires ENEPIG, Thin Ni ENEPG, Direct Au, etc., and interlayer alignment of ±25㎛ and Thermal Via technology are required. The pattern is expected to be 20㎛ pitch in 2017 and 16㎛ pitch in the future, and it is analyzed that CNC drill and pad size will require 60/130㎛, and SR ink thickness will require 15㎛ technology.

The lead thickness of COF (Chip on Film) is expected to be maintained at 8μm until 2019, and the pattern pitch is scheduled to start mass production from 22 pitches in 2017 to 20 pitches in 2019. However, 25-pitch products are expected to be mass-produced primarily for important display applications due to increased quality costs for pattern miniaturization. Recently, demand for COF adoption is increasing due to the thin bezel, ultra-slim, and flexible display of mobile devices, and the pattern count is likely to increase rapidly as the resolution of mobile devices increases.

Optical substrates to be used for high-speed, large-capacity signal processing

Since 2017, the trend of embedding active components in embedded boards has been more active than embedding them in electronic packaging companies, and the demand for cost-effective embedded boards is increasing. Starting with the embedding of ICs with relatively few pins and simple numbers, it is gradually expanding to the Embedding Die Substrate of PMIC and RFIC, and the mainstream is embedding discrete chips, especially MLCCs, in passive components.

Optical substrates are still being applied to some communication and computer backplanes, but in the future, with the trend toward larger, more flexible, and more transparent displays, they are expected to be applied to high-speed, large-capacity signal processing between display panels and set-top boxes. In addition, waveguides for optical substrates require high transmittance and high heat resistance, and DOW CORNING is producing small quantities of materials that satisfy both requirements for R&D purposes.

Rigid LED substrates occupy 80% of the domestic market, and most of them are single-sided/double-sided products. It is expected that products will be applied in the direction of eliminating pores rather than reducing the groove diameter. Metal PCBs, which replaced the backlight of LCD TVs, are seen to have lost their market dominance due to changes in specifications. The largest market, excluding the TV market, is the lighting market, but the use of metal PCBs is slowing down due to the decline in lighting prices.

In 2016, global automobile shipments were 88 million units, and while the general automobile market is expected to grow by an average of about 2.1% until 2020, the electric vehicle market grew by 6.8% in 2016 and is expected to grow by 18.8% this year. Accordingly, in the past, electrical circuit boards were used for ECUs, telematics, ABS, TCUs, etc., but with the advent of the electric vehicle era, the use of high-power heavy Cu circuit boards is expected to increase due to the increased use of inverters and converters that supply electricity to electric motors.