Memory devices employ a wide range of packaging technology from wire-bond leadframe and BGA to TSV.
BY SANTOSH KUMAR, Yole Développement, Lyon-Villeurbanne, France
The memory market is going through a strong growth phase. The total memory market grew by >50% YoY to more than US$125 billion in 2017 from US$79.4 billion in 2016.  RAM and NAND dominate the market, representing almost 95 % of standalone memory sales. There is a supply/demand mismatch in the market which is impacting on the ASP of memory devices, and as a result the large memory IDMs are reaping record profits. The memory industry has consolidated with the top five players – Samsung, SKHynix, Micron, Toshiba and Western Digital – accounting for 90% of the market.
The demand for memory is coming from all sectors but the mobile and computing (mainly servers) market is showing particularly strong growth. On average, the DRAM memory capacity per smartphone will rise more than threefold to reach around 6GB by 2022. DRAM cost per smartphone represents >10% of the bill of materials of the phone and is expected to increase further. The NAND capacity per smartphone will increase more than fivefold to reach >150GB by 2022. For servers, the DRAM capacity per unit will increase to a whopping 0.5TB by 2022, and the NAND capacity per SSD for the enterprise market will be in excess of 5TB by 2022. The growth in these markets is led by applications like deep learning, big-data, networking, AR/ VR, and autonomous driving. The automotive market, which traditionally used low density (low-MB) memory, will see the adoption of DRAM memory led by the emerging trend of autonomous driving and in-vehicle infotainment. The NOR flash memory market also saw a resurgence and is expected to grow at an impressive 16% CAGR to reach ~US$4.4 billion by 2022, due to its application in new areas such as AMOLED displays, touch display driver ICs and industrial IoTs.
On the supply side, the consolidation of players, the difficulty in migrating to advanced nodes due to technical challenges, and the need for higher investment to migrate from 2D to 3D NAND, has led to shortfall in both DRAM & NAND flash supply. DRAM players want to retain high ASPs (& high profitability) to justify the huge capex investment for advanced node migration and as such are not inclined to increase capacity. Entry of Chinese memory players will ease the supply side constraint, but it’ll not happen before 2020.
Memory device packaging
There are many variations of memory device packaging. This implies a wide range of packaging technology from the low pin count SOP package to the high pin-count TSV, all depending upon the specific product requirements such as density, performance, cost, etc. We have broadly identified five packaging platforms for memory devices: viz lead frame, wire-bond BGA, flip-chip BGA, WLCSP and TSV, even though in each platform there are many varia- tions and different nomenclature in industry.
The total memory package market is expected to grow at 4.6% CAGR2016-2022 to reach ~US$26 billion by 2022.  Wire-bond BGA accounted for more than 80% of the packaging market in dollar terms in 2016. Flip-chips, however, started making inroads in the DRAM memory packaging market and is expected to grow at ~20% CAGR in the next five years to account for more than 10% of the memorypackagingmarket.Currentlytheflip-chipmarket is only around 6% of the total memory packaging market. Flip-chip growth is led by its increased adoption in the DRAM PC/server segment fueled by a high bandwidth requirement.
Currently Samsung has already converted >90% of its DRAM packaging line. SK Hynix have started the conversion and other players will also adopt it in future. At Yole Développement (Yole), we believe that all DDR5 memory for PC/servers will move to flip-chip.
TSV is employed in high bandwidth memory devices requiring high bandwidth with low latency memory chips for high performance computing in various applications. In 2016 the TSV market was <1% of the total memory market. However, it is expected to grow by >30% CAGR to reach ~8% of memory packaging in dollar terms. WLSCP packaging is used in NOR flash and niche memory devices (EEPROMs/EPROM/ROM). It is expected to grow at >10% CAGR, but in terms of value will remain <1% of the market by 2022.
In mobile applications, memory packaging will mainly remain on the wire-bond BGA platform but will start to move into the multi-chip package (ePoP) for high end smartphones.
The main requirement of NAND flash devices is high storage density at low cost. NANDs are stacked using wire bonding to provide high density in a single package. The NAND packaging market is expected to reach ~ US$ 10 billion by 2022. NAND flash packaging will remain on the wire bond BGA platform and will not migrate to flip-chip. Toshiba, however, will start using TSV packaging in NAND devices to increase the data transfer rate for high end applications. Following Toshiba, we believe Samsung and SKHynix will also bring TSV packaged NAND devices into the market.
OSATs account for <20% of the memory packaging business
The total memory packaging market is estimated to have been ~US$20 billion in 2016. There are many OSATs involved in the memory packaging business, and >80% of the packaging (by value) is still done internally by OSATs. The majority of these are small OSATs and have only low-end packaging capability. Global memory IDMs have much experience in packaging, accumulated over years, and have their own internal large capacity. Therefore, there is limited opportunity for OSATs to make inroads into the packaging activity of IDMs. Many Chinese players, however, are entering the memory market with more than US$50 billion investment committed.  These new entrants do not have experience in memory assembly / packaging, unlike global IDMs, and they will outsource major packaging activities to OSATs. The flip-chip business for memory packaging will increase to 13% of the total market to reach US$3.5 billion in 2022. This is an opportunity for low-end memory OSATs to invest in flip-chip bumping and assembly capacity. Otherwise they will lose business to the big OSATs with advanced packaging capability.
The memory industry is going through a golden phase with strong demand coming from all sectors, particularly from the mobile and computing (mainly servers) markets.
Memory devices employ a wide range of packaging technology from wire-bond leadframe and BGA to TSV. Wire-bond BGA still accounts for the bulk of the memory packaging market. However, flip-chip technology will start making inroads in DRAM memory packaging and will grow at 20% CAGR (by revenue) over the next five years, accounting for ~13% of the total memory packaging market by 2022. The memory packaging market is mainly controlled by IDMs. OSATs have limited opportunity to impact IDM packaging activity. Many Chinese players, however, are entering the memory business and, unlike global IDMs, these new players lack experience in memory assembly/packaging and they outsource most of their packaging activity to OSATs.
SANTOSH KUMAR is a Senior Technology and Market Research Analyst at Yole Développement in France.
1. Memory Packaging Market and Technology Report 2017, Yole Développement