Dual Head Semiconductor Die Bonding System Market | Latest Analysis, Demand Trends, Growth Forecast 

Dual Head Semiconductor Die Bonding System Market Supply Chain Shaped by Advanced Packaging Expansion and Precision Motion Component Constraints

The Dual Head Semiconductor Die Bonding System Market is closely tied to backend semiconductor packaging investments, particularly in AI accelerators, high-bandwidth memory (HBM), power electronics, CMOS image sensors, and automotive semiconductor modules. By early 2026, global installed demand for high-throughput die attach equipment exceeded 19,000 advanced packaging lines across OSATs and integrated device manufacturers, while dual-head architectures accounted for nearly 38% of newly ordered high-speed die bonding platforms due to throughput advantages in multi-die and heterogeneous integration assembly. The market size for Dual Head Semiconductor Die Bonding System Market operations is estimated to cross USD 1.45 billion in 2026, supported by backend capacity additions in Taiwan, China, South Korea, Malaysia, and Singapore.

The supply chain supporting dual head semiconductor die bonding systems is unusually concentrated. Linear motors, high-precision encoders, ceramic bond heads, eutectic heating systems, industrial vision modules, FPGA-based motion controllers, and sub-micron alignment optics are sourced from a limited group of suppliers in Japan, Germany, Switzerland, Singapore, and the United States. Japan alone contributes more than 42% of global precision motion and optical alignment subsystems used in advanced die bonding equipment. Equipment makers dependent on imported servo systems and machine vision modules continued to report procurement delays during 2025, especially for ultra-high-speed alignment cameras above 12 MP resolution and nanometer-scale positioning encoders used in AI chip packaging lines.

Technology migration within semiconductor packaging has materially altered equipment specifications. Traditional single-die epoxy attach platforms remain common in analog and commodity packaging, but demand growth has shifted toward dual-head systems capable of simultaneous pick-and-place operations with ±5 micron placement accuracy and throughput exceeding 25,000 units per hour. The transition is particularly visible in chiplet packaging, where multiple dies must be bonded with tighter thermal and electrical tolerances. TSMC’s CoWoS capacity expansion in Taiwan during 2025 increased procurement activity for advanced die attach and hybrid bonding tools as AI accelerator packaging complexity rose sharply. Similar procurement patterns emerged from Samsung’s HBM packaging expansion in South Korea and Intel’s advanced packaging projects in the United States.

Precision Component Dependence Keeps Equipment Lead Times Elevated

The upstream ecosystem for the Dual Head Semiconductor Die Bonding System Market remains exposed to concentrated sourcing risk. High-speed bond heads and ultra-precision stages depend heavily on Japanese suppliers specializing in piezoelectric actuators, air-bearing systems, and ceramic vacuum tooling. Several European automation vendors supply optical encoders with positioning repeatability below 1 micron, but manufacturing lead times remained stretched through late 2025 because semiconductor equipment demand expanded faster than industrial automation capacity.

Equipment integrators reported lead times of 32–44 weeks for high-end motion control systems during 2025, compared with historical averages near 18–22 weeks. The bottleneck was amplified by simultaneous demand from lithography, metrology, and wafer inspection tool manufacturers competing for the same precision components. Semiconductor backend equipment producers in Singapore and Malaysia faced additional pressure because many upstream suppliers prioritized shipments toward advanced logic packaging projects in Taiwan and the United States.

The dependence on specialty materials also intensified procurement risks. Ceramic nozzles, tungsten carbide tools, eutectic bonding alloys, silver sintering materials, and thermal interface compounds used in advanced die attach operations are produced by a relatively small supplier base concentrated in Japan, Germany, and China. In power semiconductor packaging, silver sintering paste demand increased substantially because electric vehicle inverter modules increasingly shifted toward silicon carbide architectures requiring higher thermal conductivity. This directly supported procurement growth for dual head die bonding platforms designed for power module assembly.

China’s growing role in upstream materials has introduced a new layer of trade sensitivity. By 2026, China controlled more than 70% of refined gallium output and remained a major supplier of rare earth processing chemicals used across semiconductor manufacturing equipment ecosystems. Export control scrutiny surrounding gallium and germanium shipments during 2024–2025 pushed several equipment manufacturers to diversify specialty material sourcing toward South Korea and Southeast Asia, although replacement capacity remained limited.

Backend Semiconductor Capacity Additions Drive Dual-Head Equipment Procurement

The strongest demand driver for the Dual Head Semiconductor Die Bonding System Market continues to originate from advanced packaging investments rather than front-end wafer fabrication alone. Backend packaging intensity per wafer has risen because AI processors, HBM stacks, automotive sensors, and RF modules increasingly require multi-chip integration.

Taiwan maintained the highest concentration of advanced packaging procurement activity entering 2026. TSMC expanded CoWoS packaging capacity aggressively during 2025 after AI accelerator shortages tightened global GPU supply chains. Industry estimates from Taiwan’s Industrial Technology Research Institute indicated advanced packaging output growth above 18% year-over-year during 2025, resulting in elevated demand for high-throughput die attach systems capable of handling complex multi-die placement sequences.

South Korea also remained a critical geography for the Dual Head Semiconductor Die Bonding System Market. Samsung Electronics and SK hynix increased HBM manufacturing investments to support AI server demand, which accelerated procurement of ultra-precision bonding and inspection equipment. HBM4 development programs required tighter die stacking tolerances and higher thermal stability, encouraging migration toward dual-head architectures with synchronized bonding capability.

In Southeast Asia, Malaysia and Singapore strengthened their roles as backend manufacturing hubs. Malaysia continued attracting OSAT expansion projects because of its established semiconductor workforce and favorable export infrastructure. By mid-2025, Penang accounted for a substantial share of Southeast Asian outsourced semiconductor assembly activity, leading to higher imports of die attach systems and backend automation tools. Singapore benefited from strong investment inflows into photonics packaging and specialty semiconductor assembly, particularly for data center optical interconnect applications.

The United States increased domestic packaging investment momentum through CHIPS Act-linked projects. Advanced packaging facilities announced by Intel, Amkor, and other ecosystem participants generated incremental demand for high-end die bonding platforms, especially for heterogeneous integration lines. Arizona and Oregon emerged as key destinations for advanced packaging tool installations linked to AI semiconductor production localization.

Trade Restrictions and Localization Policies Reshape Equipment Supply Routes

Geopolitical fragmentation within semiconductor manufacturing increasingly affects procurement strategies in the Dual Head Semiconductor Die Bonding System Market. Export controls on advanced semiconductor technologies altered equipment shipment patterns between the United States, China, and several Asian manufacturing centers during 2024–2026.

Chinese semiconductor packaging firms accelerated domestic equipment localization efforts after restrictions tightened on certain categories of semiconductor manufacturing tools. This created stronger domestic demand for locally developed die bonding systems, although imported Japanese optics and European motion components still remained difficult to replace in high-precision applications.

China’s National Integrated Circuit Industry Investment Fund continued supporting semiconductor equipment localization projects, while provincial governments expanded incentives for backend packaging equipment procurement. Shenzhen, Suzhou, and Wuxi became important clusters for domestic die bonding system assembly and subsystem sourcing. However, Chinese suppliers still faced technological gaps in sub-micron placement accuracy and ultra-high-speed multi-die synchronization compared with Japanese and European competitors.

Japan retained strategic importance because of its dominance in precision manufacturing subsystems. Japanese suppliers maintained strong leverage across ceramic tooling, industrial optics, and motion control components essential for advanced die attach operations. The country’s semiconductor equipment exports remained resilient during 2025 despite trade uncertainty because backend packaging demand from AI semiconductor manufacturing continued expanding globally.

European participation remained concentrated in specialty automation systems, optical metrology, and industrial robotics. Germany and Switzerland supplied critical encoder systems and ultra-precision motion technologies integrated into advanced dual head semiconductor die bonding platforms. Supply diversification discussions increased during 2025, but replacing these highly specialized ecosystems requires long qualification cycles and substantial capital investment.

Dual Head Semiconductor Die Bonding System Market Influenced by AI and Automotive Packaging Complexity

The AI infrastructure buildout materially changed procurement priorities across the Dual Head Semiconductor Die Bonding System Market. AI accelerators now contain significantly higher die counts, larger package substrates, and tighter thermal management requirements than traditional server processors. This pushed packaging companies toward dual-head systems capable of higher throughput without sacrificing placement precision.

Automotive semiconductor growth added another demand layer. Electric vehicle production expansion across China, Europe, and North America increased packaging demand for silicon carbide MOSFETs, insulated gate bipolar transistors, and automotive sensors. Power module packaging increasingly requires void-free die attach quality and high thermal reliability, creating preference for advanced bonding platforms with real-time inspection capability.

The transition toward heterogeneous integration further strengthened demand for dual-head equipment configurations. Multi-die architectures combining logic, memory, photonics, and analog functions require synchronized placement and inspection operations that are difficult to achieve with legacy single-head systems. As packaging density rises, backend equipment spending per wafer continues increasing faster than overall semiconductor unit growth, reinforcing long-term procurement momentum across the Dual Head Semiconductor Die Bonding System Market.

Dual Head Semiconductor Die Bonding System Market Segmentation Reflects Shift Toward Heterogeneous Integration and High-Density Packaging

Segmentation within the Dual Head Semiconductor Die Bonding System Market increasingly mirrors changes occurring in semiconductor package architecture rather than only differences in assembly throughput. Equipment purchasing decisions are now heavily influenced by package complexity, die size variability, thermal requirements, and substrate density. Backend manufacturers are allocating more capital toward flexible die attach systems capable of handling AI accelerators, chiplet-based processors, RF modules, silicon photonics, and automotive power semiconductors within the same production environment.

A major transition in the downstream ecosystem is the rising share of advanced packaging customers relative to conventional wire-bonded device assemblers. Traditional QFN and standard logic packaging still represent stable equipment demand, but the fastest procurement growth since 2024 has originated from high-density multi-die integration projects. Semiconductor Industry Association supply chain commentary released during 2025 highlighted backend packaging as one of the most capacity-constrained segments in AI semiconductor production, particularly for advanced interconnect architectures requiring precision die placement.

The downstream customer base has therefore expanded beyond conventional outsourced semiconductor assembly and test providers. Hyperscale AI infrastructure suppliers, automotive Tier-1 electronics manufacturers, photonics integrators, memory producers, and advanced substrate suppliers are increasingly shaping procurement specifications for die bonding systems.

Key Segmentation Highlights Across the Dual Head Semiconductor Die Bonding System Market

• Advanced packaging applications account for nearly 46% of 2026 equipment demand value due to higher machine complexity and precision requirements.
• Dual-head epoxy die bonders continue dominating high-volume consumer semiconductor production because of throughput efficiency exceeding 20,000 UPH in mainstream assembly lines.
• Eutectic and thermo-compression bonding systems are recording stronger adoption in AI processors, HBM stacks, and photonics packaging.
• OSAT companies remain the largest customer group, contributing close to 52% of total equipment installations globally.
• Automotive power semiconductor packaging is projected to contribute more than 17% of incremental die bonder demand additions through 2028.
• Asia-Pacific represents over 78% of installed dual-head die bonding production capacity, led by Taiwan, China, Malaysia, South Korea, and Singapore.
• Multi-chip and chiplet packaging applications are expanding at more than double the rate of conventional single-die packaging lines.

AI Accelerator Packaging Alters Equipment Configuration Preferences

The strongest shift inside the Dual Head Semiconductor Die Bonding System Market comes from AI semiconductor packaging requirements. AI GPUs and custom accelerators increasingly integrate multiple compute dies, HBM stacks, advanced substrates, and high-density interconnects within single packages. This has changed die attach specifications substantially over the last two years.

Advanced AI packages now require tighter placement tolerances, larger substrate handling capability, and synchronized dual-head operation to sustain throughput economics. Semiconductor packaging lines supporting AI accelerators often process significantly fewer units per wafer than smartphone application processors, making packaging cost per package considerably higher. Equipment productivity therefore becomes critical for maintaining backend manufacturing efficiency.

Taiwan remains the dominant downstream ecosystem for this segment because of concentrated AI packaging activity around CoWoS and integrated fan-out packaging. Backend procurement volumes accelerated sharply after global AI server shipments crossed major expansion thresholds during 2025. International Energy Agency data associated with hyperscale data center expansion also reflected substantial increases in AI server deployment, indirectly supporting semiconductor packaging equipment demand.

Dual-head systems gained preference because simultaneous die placement reduces idle cycle time during advanced multi-die assembly. Backend manufacturers operating AI packaging lines increasingly favor equipment with integrated inspection capability and adaptive alignment correction, particularly for packages using chiplets and HBM integration.

OSAT Ecosystem Continues to Anchor Equipment Purchases

Outsourced semiconductor assembly and test companies remain the largest downstream buyers in the Dual Head Semiconductor Die Bonding System Market. The customer landscape is concentrated around Taiwan, China, Malaysia, Singapore, the Philippines, and South Korea, where backend semiconductor clusters provide economies of scale for packaging-intensive operations.

OSAT procurement behavior changed materially between 2024 and 2026. Instead of focusing only on unit throughput, buyers increasingly prioritize machine flexibility across package types. Many OSAT operators are attempting to reduce tool fragmentation by deploying die bonders capable of supporting multiple substrate formats, adhesive systems, and thermal profiles.

Malaysia’s backend ecosystem illustrates this trend clearly. Penang-based semiconductor manufacturing operations expanded production lines linked to automotive electronics and industrial power devices during 2025. The Malaysian Investment Development Authority continued reporting strong semiconductor-related capital inflows into backend manufacturing activities, particularly from companies seeking China-plus-one supply chain diversification.

Chinese OSAT firms also increased procurement activity aggressively. Domestic packaging companies expanded advanced packaging capacity after local AI accelerator development accelerated under semiconductor localization policies. Although domestic equipment adoption rose, high-end packaging lines continued relying heavily on imported die bonding technologies for sub-micron placement applications.

Automotive Electronics Segment Expands Beyond Conventional Power Modules

Automotive semiconductor packaging has become a major downstream growth engine for dual-head die bonding systems. Electric vehicle adoption is directly influencing die attach equipment demand because EV powertrains require significantly higher semiconductor content than internal combustion platforms.

Silicon carbide power modules became one of the fastest-growing packaging applications entering 2026. These devices operate at higher temperatures and switching frequencies, requiring highly reliable die attach quality with minimal void formation. Dual-head systems designed for silver sintering and advanced thermal management processes therefore gained traction among automotive semiconductor suppliers.

China remains central to this demand cycle. The country continued accounting for the largest global EV production volume during 2025, while domestic power semiconductor manufacturing investments accelerated simultaneously. Large-scale inverter and charging infrastructure deployments increased procurement requirements for insulated gate bipolar transistor and silicon carbide packaging lines.

European automotive semiconductor demand also strengthened because regional automakers expanded EV manufacturing capacity despite broader industrial slowdown concerns. Germany and France supported semiconductor localization initiatives tied to automotive electronics resilience, contributing indirectly to backend equipment investment.

Photonics and Optical Interconnect Packaging Creates Specialized Opportunity

One of the smaller but technologically significant segments within the Dual Head Semiconductor Die Bonding System Market involves silicon photonics and optical interconnect assembly. Demand for optical transceivers used in AI data centers increased rapidly as data bandwidth requirements intensified.

Photonics packaging requires extremely high alignment precision because optical losses increase sharply even with micron-scale placement deviation. Dual-head die bonders used in this segment often integrate advanced vision systems, active alignment capability, and thermal compensation mechanisms.

Singapore emerged as an important downstream center for photonics packaging activity because of its concentration of specialty semiconductor manufacturing and optical communications assembly. Several global data center supply chain vendors expanded optical module production capacity across Southeast Asia during 2025 to support hyperscale AI infrastructure deployment.

This segment remains smaller in shipment volume than mainstream semiconductor packaging, but equipment pricing and margin profiles are substantially higher due to precision requirements.

Consumer Electronics Packaging Demand Shows Divergent Trends

Consumer electronics remains a foundational downstream category for the Dual Head Semiconductor Die Bonding System Market, although growth patterns have become uneven across device classes.

Smartphone unit growth moderated compared with earlier cycles, but semiconductor content per device continued increasing. RF front-end modules, AI-enabled edge processors, image sensors, and advanced memory packaging all supported backend equipment utilization. Foldable devices and AI-enabled smartphones introduced additional packaging complexity requiring finer die placement tolerances.

Wearables and edge AI consumer devices created another layer of demand. Ultra-compact package configurations increasingly require miniaturized substrate handling and multi-die assembly capability, supporting gradual migration toward more advanced die attach systems even in consumer-oriented production lines.

Notebook and PC semiconductor demand recovered during late 2025 after inventory correction phases eased. AI PC deployment strategies introduced by major processor vendors also increased packaging complexity, particularly for integrated NPU architectures and advanced memory integration.

Demand Trend Across the Dual Head Semiconductor Die Bonding System Market

Demand momentum across the Dual Head Semiconductor Die Bonding System Market remains concentrated around backend capacity intensity rather than overall semiconductor unit shipments alone. Semiconductor manufacturers are spending more on packaging equipment per wafer because advanced chips now require larger package footprints, additional die stacking, tighter thermal specifications, and heterogeneous integration.

By 2026, backend packaging capital expenditure growth is outpacing front-end wafer fab equipment growth in several advanced semiconductor categories, particularly AI accelerators, HBM memory, and automotive power electronics. Packaging complexity has therefore become one of the most important determinants of equipment demand. Semiconductor assembly lines increasingly prioritize throughput stability, precision automation, and flexible package handling over conventional volume scaling alone. This trend is expected to sustain procurement activity for advanced dual-head die bonding systems across Asia-Pacific and North American advanced packaging ecosystems over the next several years.

Major Manufacturers Competing Through Precision Accuracy, Hybrid Bonding Capability, and Throughput Optimization

Competition in the Dual Head Semiconductor Die Bonding System Market is concentrated among a limited group of semiconductor assembly equipment manufacturers with established capabilities in motion control, machine vision, thermal bonding, and advanced packaging automation. The market is heavily influenced by backend semiconductor investments linked to AI accelerators, high-bandwidth memory, automotive power semiconductors, silicon photonics, and heterogeneous integration.

ASMPT remains one of the most visible suppliers in the Dual Head Semiconductor Die Bonding System Market because of its extensive installed base across outsourced semiconductor assembly and test facilities. The company’s AD series and advanced thermo-compression bonding platforms are widely used in memory, logic, RF, and advanced packaging applications. ASMPT has also strengthened its positioning in high-precision die placement through its AMICRA platform portfolio, which supports photonics packaging and multi-die integration processes requiring sub-micron alignment capability.

BE Semiconductor Industries (Besi) has expanded aggressively in advanced bonding technologies associated with AI semiconductor packaging. Its Die Attach Eagle Apex and Datacon product families are deployed in advanced packaging environments where chiplet integration, hybrid bonding, and high-density stacking require extremely tight placement tolerances. The company has benefited from rising investment in AI accelerator production, particularly because hybrid bonding and thermo-compression assembly are becoming increasingly important in HBM integration and advanced logic packaging.

Kulicke & Soffa Industries continues broadening its semiconductor assembly portfolio beyond traditional wire bonding systems. The company’s Asterion and IConn platforms are increasingly linked to advanced packaging, power semiconductor assembly, and mini/microLED manufacturing. Demand for these systems strengthened as electric vehicle production expanded globally and power semiconductor manufacturers increased investment in silicon carbide module packaging.

Japanese manufacturers continue holding strong positions in high-reliability and specialty semiconductor packaging. Shinkawa maintains a strong footprint in automotive electronics, MEMS, industrial semiconductors, and sensor packaging. Its UTC and APX platform families are widely recognized for stable thermal process control and high repeatability in precision die attach operations. Automotive semiconductor manufacturers particularly value long-term process stability because packaging defects can directly affect powertrain reliability and safety-critical systems.

Toray Engineering also remains active in advanced die bonding and flip-chip assembly, especially for optoelectronics and power semiconductor applications. The company benefits from integration between materials engineering and packaging process development, which has become increasingly important for silicon carbide and gallium nitride power devices operating under high thermal loads.

Specialized suppliers such as Palomar Technologies and MRSI Systems maintain strong positions in photonics, aerospace, RF, telecom, and medical semiconductor packaging. These markets operate at lower production volumes compared with mainstream consumer semiconductor assembly, but the precision requirements are considerably higher. Optical transceiver assembly, for example, requires extremely accurate die placement because micron-scale alignment errors can reduce signal efficiency and increase optical losses.

Reliability Requirements Continue Tightening Across AI and Automotive Packaging

Qualification standards in the Dual Head Semiconductor Die Bonding System Market have become more demanding as semiconductor packaging complexity increases. Reliability expectations are no longer limited to conventional consumer electronics durability. Advanced semiconductor packages are now expected to withstand severe thermal cycling, power density concentration, humidity stress, and long operating lifetimes across automotive, industrial, AI infrastructure, and telecom environments.

Automotive power semiconductor packaging represents one of the strictest qualification segments. Silicon carbide MOSFETs and insulated gate bipolar transistor modules used in EV powertrains operate under high-temperature and high-current conditions, making die attach quality critically important. Packaging lines increasingly require ultra-low void formation, stable thermal conductivity, and highly repeatable placement accuracy. Semiconductor manufacturers supplying automotive customers therefore prioritize dual-head bonding systems with advanced inspection capability and real-time process monitoring.

AI accelerator packaging introduces a different reliability challenge. High-bandwidth memory stacks and multi-die AI processors generate extremely high thermal density, especially inside data center accelerators. Packaging defects or minor die placement variation can affect package warpage, thermal dissipation, and long-term operating stability. Backend manufacturers therefore increasingly favor equipment with adaptive alignment correction, synchronized bonding capability, and integrated metrology systems.

Photonics packaging also demands extremely high placement precision. Optical modules used in AI data centers and telecom infrastructure require sub-micron alignment consistency because small bonding deviations can significantly reduce optical efficiency. This has increased demand for advanced dual-head die bonding systems equipped with active alignment capability and thermal compensation mechanisms.

Software integration has become another major procurement factor. Semiconductor manufacturers increasingly require compatibility with smart factory systems, predictive maintenance platforms, MES integration, and AI-assisted process monitoring. Backend facilities operating high-value packaging lines are placing greater emphasis on traceability and closed-loop manufacturing control rather than standalone machine performance alone.

Dual Head Semiconductor Die Bonding System Market Faces Cost Pressure From Precision Component Inflation

Manufacturing economics within the Dual Head Semiconductor Die Bonding System Market are strongly influenced by the cost of ultra-precision components. Linear motors, optical encoders, industrial cameras, thermal bonding heads, ceramic tooling, and vibration control systems account for a significant portion of equipment production cost.

Supply constraints involving high-precision motion systems and industrial optics during 2024 and 2025 created cost pressure for equipment manufacturers, particularly because semiconductor backend demand expanded faster than precision automation supply capacity. Several equipment suppliers faced extended lead times for advanced vision modules and sub-micron positioning systems used in AI and photonics packaging lines.

At the same time, customers continue demanding higher throughput without sacrificing placement accuracy. This creates engineering pressure on manufacturers to improve productivity while reducing machine footprint and minimizing energy consumption. Competitive pricing pressure has become particularly visible in China, where domestic equipment suppliers are attempting to expand market share in standard semiconductor packaging applications.

However, advanced packaging equipment remains less exposed to rapid commoditization because sub-micron placement capability, hybrid bonding integration, and thermo-compression process control require extensive engineering expertise and long qualification cycles. Backend semiconductor manufacturers increasingly prioritize yield stability and process repeatability over initial equipment acquisition cost, especially for AI accelerators, HBM packaging, automotive power semiconductors, and photonics applications.

Recent Industry Developments and Market Activity

During 2025, backend semiconductor capacity expansion in Taiwan accelerated procurement of advanced die bonding systems as AI accelerator packaging demand increased sharply. CoWoS and HBM-related investments contributed to stronger equipment utilization rates across advanced packaging ecosystems.

In June 2025, Besi increased its long-term financial outlook after demand strengthened for hybrid bonding and chip stacking technologies used in AI semiconductor packaging and advanced data center processors.

Throughout 2025, Malaysia’s semiconductor backend ecosystem continued attracting investment into automotive electronics and outsourced semiconductor assembly operations, particularly in Penang. This increased regional demand for advanced die attach systems and backend packaging automation tools.

ASMPT continued expanding its advanced packaging focus during 2025, particularly in thermo-compression bonding and heterogeneous integration solutions supporting AI and photonics manufacturing applications.

Kulicke & Soffa reported stronger semiconductor assembly equipment demand entering 2026 as AI infrastructure expansion and electric vehicle semiconductor production supported advanced packaging investments.

China also accelerated localization efforts for semiconductor packaging equipment during 2025 as domestic manufacturers attempted to reduce dependence on imported backend assembly technologies. However, high-end packaging applications continued relying heavily on imported precision motion systems and advanced bonding platforms.