{"id":2378,"date":"2026-06-24T10:15:08","date_gmt":"2026-06-24T02:15:08","guid":{"rendered":"https:\/\/jeez-semicon.com\/?p=2378"},"modified":"2026-06-24T10:15:08","modified_gmt":"2026-06-24T02:15:08","slug":"semiconductor-planarization-techniques-cmp-vs-sog-vs-etch-back-compared","status":"publish","type":"post","link":"https:\/\/jeez-semicon.com\/zh\/blog\/semiconductor-planarization-techniques-cmp-vs-sog-vs-etch-back-compared\/","title":{"rendered":"Semiconductor Planarization Techniques: CMP vs. SOG vs. Etch-Back Compared"},"content":{"rendered":"<!-- JEEZ | Cluster 03 | Semiconductor Planarization Techniques: CMP vs. SOG vs. Etch-Back Compared -->\n<link rel=\"preconnect\" href=\"https:\/\/fonts.googleapis.com\">\n<link rel=\"preconnect\" href=\"https:\/\/fonts.gstatic.com\" crossorigin>\n<link href=\"https:\/\/fonts.googleapis.com\/css2?family=Syne:wght@600;700;800&#038;family=Inter:ital,wght@0,400;0,500;0,600;1,400&#038;display=swap\" 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.jz-cta-box{background:linear-gradient(140deg,#0B1D3A 0%,#0A3D62 100%);border-radius:16px;padding:44px 48px;text-align:center;margin:50px 0;position:relative;overflow:hidden}\n.jeez-pl .jz-cta-box::before{content:'';position:absolute;left:-70px;bottom:-70px;width:230px;height:230px;border-radius:50%;background:radial-gradient(circle,rgba(13,148,136,.16) 0%,transparent 70%)}\n.jeez-pl .jz-cta-box h3{font-family:'Syne',sans-serif;color:#fff;font-size:1.4rem;font-weight:800;margin:0 0 10px;position:relative}\n.jeez-pl .jz-cta-box p{color:rgba(255,255,255,.74);max-width:520px;margin:0 auto 26px;font-size:14.5px;position:relative}\n.jeez-pl .jz-btn{display:inline-block;background:var(--jz-teal);color:#fff;font-size:14.5px;font-weight:700;padding:13px 36px;border-radius:8px;text-decoration:none;transition:background .15s,transform .1s}\n.jeez-pl .jz-btn:hover{background:var(--jz-teal-dark);color:#fff;text-decoration:none;transform:translateY(-2px)}\n.jeez-pl .jz-faq-list{margin-top:18px}\n.jeez-pl .jz-faq-item{border:1px solid var(--jz-border);border-radius:var(--jz-radius);margin-bottom:12px;overflow:hidden}\n.jeez-pl .jz-faq-q{background:var(--jz-bg);padding:15px 20px;font-weight:600;font-size:14.5px;color:var(--jz-navy);border-left:4px solid var(--jz-teal);line-height:1.4}\n.jeez-pl .jz-faq-a{padding:14px 20px 16px;font-size:14px;color:var(--jz-text);line-height:1.74;border-top:1px solid var(--jz-border)}\n@media(max-width:680px){.jeez-pl .jz-hero{padding:28px 22px}.jeez-pl .jz-toc ol{columns:1}.jeez-pl .jz-grid-2{grid-template-columns:1fr}.jeez-pl .jz-cta-box{padding:32px 22px}.jeez-pl h2{font-size:1.3rem}}\n<\/style>\n\n<div class=\"jeez-pl\">\n\n<a class=\"jz-back-link\" href=\"https:\/\/jeez-semicon.com\/zh\/blog\/Planarization-in-Semiconductor-Manufacturing-Complete-Guide\/\" target=\"_blank\" rel=\"noopener noreferrer\">\u2190 Back to Complete Planarization Guide<\/a>\n\n<div class=\"jz-hero\">\n  <span class=\"jz-hero-eyebrow\">Process Technology Comparison<\/span>\n  <p class=\"jz-hero-lead\">Semiconductor planarization encompasses a range of techniques that have evolved over six decades \u2014 from thermal glass reflow and spin-on-glass to resist etch-back and, ultimately, Chemical Mechanical Planarization. This guide provides an in-depth technical comparison of all major planarization methods, explains why each delivers only local or global uniformity, and gives process engineers a clear framework for technique selection.<\/p>\n  <div class=\"jz-hero-meta\">\n    <span>Updated: <strong>June 2026<\/strong><\/span>\n    <span class=\"jz-pipe\">|<\/span>\n    <span>By <strong>JEEZ Technical Team<\/strong><\/span>\n  <\/div>\n<\/div>\n\n<nav class=\"jz-toc\" aria-label=\"\u76ee\u5f55\">\n  <span class=\"jz-toc-label\">\u76ee\u5f55<\/span>\n  <ol>\n    <li><a href=\"#classification\">Classification Framework: Local vs. Global<\/a><\/li>\n    <li><a href=\"#thermal-reflow\">Thermal Oxide Reflow (BPSG\/PSG)<\/a><\/li>\n    <li><a href=\"#sog\">Spin-on-Glass (SOG)<\/a><\/li>\n    <li><a href=\"#etch-back\">Resist Etch-Back Planarization<\/a><\/li>\n    <li><a href=\"#hdpcvd\">HDP-CVD Deposition<\/a><\/li>\n    <li><a href=\"#ecp\">Electrochemical Planarization (ECP)<\/a><\/li>\n    <li><a href=\"#cmp\">\u5316\u5b66\u673a\u68b0\u5e73\u5766\u5316 (CMP)<\/a><\/li>\n    <li><a href=\"#master-comparison\">Master Comparison Table<\/a><\/li>\n    <li><a href=\"#selection-guide\">Technique Selection Guide<\/a><\/li>\n    <li><a href=\"#faq\">\u5e38\u89c1\u95ee\u9898<\/a><\/li>\n  <\/ol>\n<\/nav>\n\n\n<section id=\"classification\">\n  <h2><span class=\"jz-sn\">01<\/span>Classification Framework: Local vs. Global Planarization<\/h2>\n  <p>All semiconductor planarization techniques can be classified along two axes: the <strong>spatial scale<\/strong> over which they reduce topographic variation, and the <strong>physical mechanism<\/strong> by which they do so. The spatial scale axis is the most important for process selection: local techniques smooth features at the micrometer scale but leave large-scale wafer variation intact; global techniques establish uniformity across the full chip area and 300 mm wafer diameter.<\/p>\n\n  <div class=\"jz-callout gold\">\n    <span class=\"jz-callout-tag\">Why This Classification Matters<\/span>\n    <p>Depth-of-focus requirements for 248 nm DUV and 193 nm immersion lithography (DOF \u00b150\u201380 nm) are far tighter than for earlier g-line (436 nm) or i-line (365 nm) exposure systems (DOF \u00b1200\u2013500 nm). <strong>Local planarization techniques were adequate for nodes &gt;0.5 \u00b5m; they are insufficient for anything below.<\/strong> Only CMP&#8217;s global planarization capability satisfies the uniformity requirements of sub-100 nm nodes.<\/p>\n  <\/div>\n\n  <p>The following sections provide in-depth technical descriptions of each major planarization technique, including process conditions, achievable planarity, representative applications, and the reasons for each technique&#8217;s limitations.<\/p>\n<\/section>\n\n\n<section id=\"thermal-reflow\">\n  <h2><span class=\"jz-sn\">02<\/span>Thermal Oxide Reflow (BPSG \/ PSG)<\/h2>\n  <p>Thermal oxide reflow exploits the viscous flow behavior of doped silicate glass films at elevated temperatures. Borophosphosilicate glass (BPSG) \u2014 a CVD-deposited film containing both boron (B, typically 3\u20135 wt%) and phosphorus (P, 4\u20138 wt%) \u2014 has a reflow temperature of 850\u2013950\u00b0C, substantially lower than undoped SiO\u2082 (~1600\u00b0C). At these temperatures, the viscosity of BPSG drops sufficiently for the glass to flow under surface tension forces, rounding and smoothing surface steps.<\/p>\n\n  <h3>Process Mechanism and Conditions<\/h3>\n  <p>BPSG is deposited at 400\u2013450\u00b0C by PECVD or SACVD (sub-atmospheric CVD) over the pre-metal dielectric (PMD) module \u2014 above the poly gate but below the first metal layer. After deposition, the wafer is annealed in a nitrogen ambient at 850\u2013950\u00b0C for 20\u201340 minutes. Surface tension drives the glass to flow: sharp 90\u00b0 step edges at gate sidewalls are converted to gradual slopes (45\u201360\u00b0), reducing the maximum step height at that feature by 40\u201370% and providing local planarity that improves step coverage for subsequent barrier metal and tungsten plug deposition.<\/p>\n\n  <h3>Limitations and Obsolescence at Advanced Nodes<\/h3>\n  <p>BPSG reflow provides only <em>local<\/em> planarization \u2014 it smooths the profile of individual steps but cannot correct accumulated topographic variation across the chip. Furthermore, the 850\u2013950\u00b0C anneal temperature is incompatible with: (1) metal gates (Ni, W, TiN, TaN melting or phase change); (2) NiSi silicides formed before the PMD step (stability limit ~750\u00b0C); and (3) strained silicon and SiGe channels sensitive to dopant redistribution at high temperatures. As a result, BPSG reflow disappeared from leading-edge logic process flows below 130 nm and is today confined to mature analog, power device, and sensor fabrication at 0.18 \u00b5m and above.<\/p>\n\n  <div class=\"jz-callout blue\">\n    <span class=\"jz-callout-tag\">Still in Use (2026)<\/span>\n    <p>BPSG reflow remains in active use at 200 mm fabs producing analog ICs, automotive sensors, MEMS devices, and BCD (Bipolar-CMOS-DMOS) power management chips \u2014 applications where the high-temperature budget is acceptable and the cost of CMP steps must be minimized.<\/p>\n  <\/div>\n<\/section>\n\n\n<section id=\"sog\">\n  <h2><span class=\"jz-sn\">03<\/span>Spin-on-Glass (SOG)<\/h2>\n  <p>Spin-on-Glass materials are liquid precursor solutions \u2014 typically organosilicate or inorganic silicate compounds dissolved in organic solvents \u2014 that are spun onto the wafer surface at 1,000\u20135,000 rpm and then thermally cured to form a solid SiO\u2082-like film. The spin-coating process naturally produces a globally smooth top surface through the same capillary flow mechanism used for photoresist application: the liquid fills surface recesses preferentially before the solvent evaporates, leaving a surface that is locally flatter than the underlying topology.<\/p>\n\n  <h3>Process Mechanism<\/h3>\n  <p>SOG solution is dispensed in the center of a rotating wafer. Centrifugal force spreads the liquid across the wafer surface into a thin film (typically 100\u2013500 nm final thickness after cure). During spin-on, the liquid preferentially fills the surface recesses adjacent to metal lines due to capillary forces, providing a locally planarizing effect. After spin, the wafer is baked at 150\u2013250\u00b0C (soft cure) to evaporate solvent, then cured at 400\u2013450\u00b0C (hard cure) to fully convert the organic silicate precursor to dense SiO\u2082.<\/p>\n\n  <h3>Types of SOG<\/h3>\n  <ul>\n    <li><strong>Inorganic (silicate) SOG:<\/strong> Based on tetraethyl orthosilicate (TEOS) or silicate ester in alcohol solvents. Forms dense SiO\u2082 after cure. Low carbon content (&lt;1%). Prone to cracking for films thicker than ~200 nm due to tensile stress on cure shrinkage.<\/li>\n    <li><strong>Organic (siloxane) SOG:<\/strong> Based on methylsiloxane or phenylsiloxane polymers. Forms a silica\u2013carbon hybrid network after cure. Less prone to cracking, tolerates thicker deposition (~500 nm). Lower dielectric constant (k ~ 2.7\u20133.0 vs. 4.0 for thermal SiO\u2082). Used as an early low-k ILD material in the late 1990s and early 2000s.<\/li>\n    <li><strong>Hydrogen silsesquioxane (HSQ) \/ Methyl silsesquioxane (MSQ):<\/strong> Advanced cage-network siloxane materials with k values down to ~2.2. Used as ultra-low-k ILD in sub-130 nm processes before being replaced by CVD-deposited porous low-k materials.<\/li>\n  <\/ul>\n\n  <h3>Limitations<\/h3>\n  <p>SOG provides only local planarization \u2014 the coating material pools in recesses adjacent to nearby features (within 2\u20135 \u00b5m) but follows the large-scale topographic trends of the underlying surface. Long-range wafer variation is not corrected. Additionally, thick SOG films are mechanically weak and prone to cracking under CTE mismatch stress during thermal cycling. SOG reliability concerns (moisture absorption, outgassing, via poisoning from organic decomposition) led to its replacement by CVD-deposited low-k dielectrics and CMP in advanced nodes.<\/p>\n<\/section>\n\n\n<section id=\"etch-back\">\n  <h2><span class=\"jz-sn\">04<\/span>Resist Etch-Back Planarization<\/h2>\n  <p>Resist etch-back planarization exploits the flow properties of photoresist to create a locally planar surface, then uses a dry etch process to transfer that planarity into the underlying dielectric film. It was widely used for ILD planarization at the 0.5\u20131 \u00b5m generation and remains a useful technique for specific applications in MEMS and sensor manufacturing.<\/p>\n\n  <h3>Process Flow<\/h3>\n  <ol>\n    <li><strong>Dielectric deposition:<\/strong> A conformal CVD oxide or BPSG is deposited over the patterned metal or poly layer, conformally reproducing the underlying topography.<\/li>\n    <li><strong>Photoresist spin-coat:<\/strong> A thick (~1.5\u20133 \u00b5m) photoresist film is spun over the dielectric. The viscous resist flows to fill the surface recesses, producing a much flatter top surface than the underlying dielectric \u2014 though not perfectly flat (resist still exhibits some &#8220;bias&#8221; toward the underlying features for very narrow or deep recesses).<\/li>\n    <li><strong>Anisotropic RIE etch-back:<\/strong> A fluorine-based RIE process (CF\u2084\/O\u2082 or SF\u2086\/O\u2082) etches both the resist and the oxide simultaneously. The etch chemistry is tuned to achieve a 1:1 oxide-to-resist selectivity \u2014 so the resist and oxide are removed at equal rates. As the resist is consumed, its planar top surface is transferred into the oxide below, producing a planarized dielectric surface.<\/li>\n    <li><strong>Result:<\/strong> The ILD surface after etch-back exhibits ~50\u201370% step height reduction compared to the conformal as-deposited surface, providing useful local planarization.<\/li>\n  <\/ol>\n\n  <h3>Limitations<\/h3>\n  <p>Pattern density dependence is the fundamental limitation of resist etch-back. In regions of different pattern density (dense metal arrays vs. isolated lines vs. field areas), the resist surface height above the dielectric varies depending on how well the resist fills the local topology. This produces systematic etch-back depth variation across the chip, leaving residual step heights that grow with increasing chip complexity. Resist etch-back is also limited to &lt;0.5 \u00b5m feature sizes by the resist flow behavior and is incompatible with aggressive CD scaling.<\/p>\n<\/section>\n\n\n<section id=\"hdpcvd\">\n  <h2><span class=\"jz-sn\">05<\/span>HDP-CVD: Gap Fill with Moderate Planarization<\/h2>\n  <p>High-Density Plasma CVD (HDP-CVD) is a simultaneous deposition and sputter-etch process used primarily for dielectric gap fill in STI and IMD applications. An RF-biased plasma simultaneously deposits SiO\u2082 from SiH\u2084 and O\u2082 precursors and physically sputters the growing film from horizontal surfaces by argon ion bombardment. This combined action preferentially builds up material in the trench or gap (where the sputter erosion is geometrically reduced) while preventing the &#8220;bread-loafing&#8221; overburden that conventional CVD produces at feature corners.<\/p>\n  <p>HDP-CVD achieves void-free gap filling in trenches with aspect ratios up to 3:1\u20135:1, producing a partially planarized surface with significantly less overburden step height than conformal CVD. However, it does not achieve global planarization \u2014 large-scale height variation across pattern density transitions remains, and HDP-CVD surfaces still require a CMP step for final global planarization in STI applications.<\/p>\n<\/section>\n\n\n<section id=\"ecp\">\n  <h2><span class=\"jz-sn\">06<\/span>Electrochemical Planarization (ECP)<\/h2>\n  <p>Electrochemical Planarization applies a controlled electrochemical potential to the wafer surface in an electrolyte solution to selectively dissolve metal from elevated surface regions. The mechanism relies on the fact that current density is highest at protruding surface features (analogous to lightning rod geometry), producing preferential dissolution at peaks and leaving recesses untouched. ECP has been demonstrated for copper film planarization at the wafer scale, producing smoother starting surfaces for subsequent copper CMP steps.<\/p>\n  <p>ECP is not a stand-alone planarization technique for IC manufacturing \u2014 it is only applicable to conductive surfaces, it provides only local-to-moderate planarization, and it cannot address the full overburden removal required in damascene Cu CMP. Its current production relevance is primarily as a &#8220;pre-CMP leveling&#8221; step that reduces the incoming step height for the copper bulk removal CMP, potentially extending pad life and reducing slurry consumption. As of June 2026, ECP pre-treatment remains a niche process at select advanced BEOL facilities.<\/p>\n<\/section>\n\n\n<section id=\"cmp\">\n  <h2><span class=\"jz-sn\">07<\/span>Chemical Mechanical Planarization: The Global Standard<\/h2>\n  <p>CMP differs categorically from all other planarization techniques in one property: its ability to achieve <em>global<\/em> planarization \u2014 uniform surface flatness across the full die and full 300 mm wafer. This property stems from the self-leveling mechanism built into the process physics (described by Preston&#8217;s equation): elevated features experience higher contact pressure against the compliant polishing pad, resulting in higher material removal rates that drive the entire surface toward a single plane.<\/p>\n  <p>No deposition, reflow, spin-coating, or etch-back technique offers this self-leveling behavior over long spatial distances. All non-CMP techniques replicate or partially smooth the underlying topography; CMP actively corrects it. This distinction, combined with the scalability of CMP to sub-10 nm film thickness control and WIWNU below 1%, makes it irreplaceable for all critical planarization applications at leading-edge nodes.<\/p>\n  <p>For a complete process-level discussion of CMP, including equipment, step-by-step process flow, endpoint detection, and defect modes, see our dedicated <a href=\"https:\/\/jeez-semicon.com\/zh\/blog\/CMP-Process-Steps-How-Chemical-Mechanical-Planarization-Works\/\" target=\"_blank\" rel=\"noopener noreferrer\">CMP Process Steps guide<\/a>.<\/p>\n<\/section>\n\n\n<section id=\"master-comparison\">\n  <h2><span class=\"jz-sn\">08<\/span>Master Comparison Table: All Planarization Techniques<\/h2>\n\n  <div class=\"jz-table-wrap\">\n    <table>\n      <thead>\n        <tr>\n          <th>Technique<\/th>\n          <th>Mechanism<\/th>\n          <th>Planarity Scale<\/th>\n          <th>Process Temp.<\/th>\n          <th>Compatible Node<\/th>\n          <th>Still Used (2026)?<\/th>\n        <\/tr>\n      <\/thead>\n      <tbody>\n        <tr>\n          <td><strong>BPSG Thermal Reflow<\/strong><\/td>\n          <td>Viscous glass flow<\/td>\n          <td><span class=\"jz-badge amber\">Local<\/span><\/td>\n          <td>850\u2013950\u00b0C<\/td>\n          <td>\u2265 0.18 \u00b5m<\/td>\n          <td>Yes \u2014 legacy, power<\/td>\n        <\/tr>\n        <tr>\n          <td><strong>Spin-on-Glass (SOG)<\/strong><\/td>\n          <td>Liquid capillary fill + cure<\/td>\n          <td><span class=\"jz-badge amber\">Local<\/span><\/td>\n          <td>400\u2013450\u00b0C<\/td>\n          <td>\u2265 0.13 \u00b5m<\/td>\n          <td>Limited \u2014 sensor, MEMS<\/td>\n        <\/tr>\n        <tr>\n          <td><strong>Resist Etch-Back<\/strong><\/td>\n          <td>Resist flow + 1:1 RIE<\/td>\n          <td><span class=\"jz-badge amber\">Local\u2013Moderate<\/span><\/td>\n          <td>Room temp + 150\u00b0C<\/td>\n          <td>\u2265 0.5 \u00b5m<\/td>\n          <td>Limited \u2014 MEMS, analog<\/td>\n        <\/tr>\n        <tr>\n          <td><strong>HDP-CVD<\/strong><\/td>\n          <td>Deposition + sputter etch<\/td>\n          <td><span class=\"jz-badge blue\">\u4e2d\u5ea6<\/span><\/td>\n          <td>400\u2013550\u00b0C<\/td>\n          <td>All (gap fill only)<\/td>\n          <td>Yes \u2014 STI gap fill before CMP<\/td>\n        <\/tr>\n        <tr>\n          <td><strong>Electrochemical (ECP)<\/strong><\/td>\n          <td>Selective electrochemical dissolution<\/td>\n          <td><span class=\"jz-badge amber\">Local<\/span><\/td>\n          <td>Room temp<\/td>\n          <td>Metal films only<\/td>\n          <td>Niche \u2014 pre-Cu CMP leveling<\/td>\n        <\/tr>\n        <tr>\n          <td><strong>\u4e2d\u533b<\/strong><\/td>\n          <td>Chemical + mechanical removal<\/td>\n          <td><span class=\"jz-badge green\">Global \u2713<\/span><\/td>\n          <td>20\u201325\u00b0C<\/td>\n          <td>All \u2014 required at &lt;0.35 \u00b5m<\/td>\n          <td>Yes \u2014 all advanced nodes<\/td>\n        <\/tr>\n      <\/tbody>\n    <\/table>\n  <\/div>\n\n  <h3>Detailed Performance Metrics Comparison<\/h3>\n  <div class=\"jz-table-wrap\">\n    <table>\n      <thead>\n        <tr>\n          <th>Technique<\/th>\n          <th>WIWNU Achievable<\/th>\n          <th>Step Height Reduction<\/th>\n          <th>Surface Roughness (Ra)<\/th>\n          <th>\u541e\u5410\u91cf<\/th>\n          <th>Consumable Cost<\/th>\n        <\/tr>\n      <\/thead>\n      <tbody>\n        <tr>\n          <td><strong>BPSG Reflow<\/strong><\/td>\n          <td>5\u201315%<\/td>\n          <td>40\u201370% (local)<\/td>\n          <td>2\u201310 nm<\/td>\n          <td>High (batch furnace)<\/td>\n          <td>\u4f4e<\/td>\n        <\/tr>\n        <tr>\n          <td><strong>SOG<\/strong><\/td>\n          <td>5\u201320%<\/td>\n          <td>30\u201360% (local)<\/td>\n          <td>1\u20135 nm<\/td>\n          <td>High (track system)<\/td>\n          <td>\u4e2d\u578b<\/td>\n        <\/tr>\n        <tr>\n          <td><strong>Resist Etch-Back<\/strong><\/td>\n          <td>8\u201325%<\/td>\n          <td>40\u201370% (local)<\/td>\n          <td>2\u20138 nm<\/td>\n          <td>\u4e2d\u578b<\/td>\n          <td>Low\u2013Medium<\/td>\n        <\/tr>\n        <tr>\n          <td><strong>HDP-CVD<\/strong><\/td>\n          <td>5\u201315%<\/td>\n          <td>50\u201380% (local)<\/td>\n          <td>3\u201310 nm<\/td>\n          <td>\u4e2d\u578b<\/td>\n          <td>\u4f4e<\/td>\n        <\/tr>\n        <tr>\n          <td><strong>ECP<\/strong><\/td>\n          <td>10\u201320%<\/td>\n          <td>20\u201350% (local)<\/td>\n          <td>5\u201320 nm<\/td>\n          <td>Low\u2013Medium<\/td>\n          <td>\u4e2d\u578b<\/td>\n        <\/tr>\n        <tr>\n          <td><strong>\u4e2d\u533b<\/strong><\/td>\n          <td><strong>&lt;1%<\/strong><\/td>\n          <td><strong>&gt;99% (global)<\/strong><\/td>\n          <td><strong>0.1\u20131 nm<\/strong><\/td>\n          <td>Medium (WPH 40\u201380)<\/td>\n          <td>High (slurry + pad)<\/td>\n        <\/tr>\n      <\/tbody>\n    <\/table>\n  <\/div>\n<\/section>\n\n\n<section id=\"selection-guide\">\n  <h2><span class=\"jz-sn\">09<\/span>Technique Selection Guide for Process Engineers<\/h2>\n  <p>Selecting the correct planarization technique requires balancing planarity requirements, thermal budget, material compatibility, throughput, and cost. The following decision framework covers the most common manufacturing scenarios:<\/p>\n\n  <div class=\"jz-grid-2\">\n    <div class=\"jz-card\">\n      <h4>Scenario 1: Legacy \/ Mature Node (&gt;0.18 \u00b5m), PMD Planarization<\/h4>\n      <p>Use BPSG thermal reflow if the thermal budget permits (no NiSi, no metal gate, no strained Si). Provides adequate local planarization at low cost for pre-metal dielectric at 0.18 \u00b5m and above. Supplement with a light CMP step if WIWNU specification is tighter than 10%.<\/p>\n    <\/div>\n    <div class=\"jz-card\">\n      <h4>Scenario 2: STI Dielectric Fill at Any Node<\/h4>\n      <p>HDP-CVD for void-free gap fill followed by CMP for global planarization. HDP-CVD handles the gap fill challenge (AR 3:1\u20135:1 for STI trenches); CMP handles the critical global planarization and oxide\/nitride selectivity (ceria slurry). These two techniques are complementary, not competitive.<\/p>\n    <\/div>\n    <div class=\"jz-card\">\n      <h4>Scenario 3: ILD Planarization at Sub-0.35 \u00b5m<\/h4>\n      <p>CMP is the only choice. SOG and etch-back do not provide the WIWNU or step height reduction required for sub-350 nm optical lithography. PECVD-deposited TEOS oxide or FSG (for k &lt; 3.7) followed by CMP with colloidal silica slurry is the standard approach.<\/p>\n    <\/div>\n    <div class=\"jz-card\">\n      <h4>Scenario 4: Copper Damascene BEOL<\/h4>\n      <p>ECP pre-leveling (optional, for thick Cu overburden reduction) followed by two-step copper CMP (bulk Cu removal, then barrier clearing). SOG or reflow-based approaches are fundamentally incompatible with copper metallization chemistry. CMP is mandatory.<\/p>\n    <\/div>\n    <div class=\"jz-card\">\n      <h4>Scenario 5: MEMS \/ Sensor \/ Specialty<\/h4>\n      <p>Resist etch-back and SOG remain valid options where: (a) the topography requirements are moderate (WIWNU 5\u201315% is acceptable); (b) the thermal budget is flexible; (c) minimizing process step count is more important than ultimate planarity; and (d) the device operates at feature sizes &gt;1 \u00b5m.<\/p>\n    <\/div>\n    <div class=\"jz-card amber\">\n      <h4>Scenario 6: Advanced Node (&lt;10 nm) \u2014 All Modules<\/h4>\n      <p>CMP is non-negotiable for every global planarization module: STI, ILD, W contact, Cu damascene, replacement metal gate, nanosheet release, and hybrid bonding surface preparation. At 2 nm (June 2026), each of these modules has WIWNU specifications of \u22641%, achievable only by CMP.<\/p>\n    <\/div>\n  <\/div>\n\n  <a class=\"jz-more\" href=\"https:\/\/jeez-semicon.com\/zh\/blog\/Planarization-Applications-in-IC-Fabrication-STI-ILD-Cu-Damascene-W-Plug\/\" target=\"_blank\" rel=\"noopener noreferrer\">\n    <span>See application details: Planarization Applications in IC Fabrication \u2014 STI, ILD, Cu Damascene &amp; W Plug<\/span>\n    <span class=\"jz-more-arrow\">\u2192<\/span>\n  <\/a>\n<\/section>\n\n\n<div class=\"jz-cta-box\">\n  <h3>CMP Consumables for Every Planarization Application<\/h3>\n  <p>JEEZ manufactures CMP polishing slurries, polishing pads, and absorption films engineered for STI, ILD, tungsten, and copper CMP modules. Direct manufacturer. Global supply. Contact our team to discuss your specific process needs.<\/p>\n  <a class=\"jz-btn\" href=\"https:\/\/jeez-semicon.com\/zh\/contact\/\" target=\"_blank\" rel=\"noopener noreferrer\">Contact JEEZ \u2192<\/a>\n<\/div>\n\n\n<section id=\"faq\">\n  <h2><span class=\"jz-sn\">\u5e38\u89c1\u95ee\u9898<\/span>\u5e38\u89c1\u95ee\u9898<\/h2>\n  <div class=\"jz-faq-list\">\n    <div class=\"jz-faq-item\">\n      <div class=\"jz-faq-q\">What is the main difference between CMP and Spin-on-Glass for planarization?<\/div>\n      <div class=\"jz-faq-a\">The fundamental difference is the scale of planarization achieved. SOG provides local planarization \u2014 it fills recesses adjacent to individual features within a few micrometers, reducing local step heights by 30\u201360%. CMP provides global planarization \u2014 it achieves surface uniformity across the entire chip area and the full 300 mm wafer diameter, with WIWNU below 1%. SOG cannot satisfy the depth-of-focus requirements of sub-250 nm optical lithography; CMP can. SOG also introduces reliability risks (moisture absorption, cracking) that make it unsuitable for critical dielectric layers in advanced devices.<\/div>\n    <\/div>\n    <div class=\"jz-faq-item\">\n      <div class=\"jz-faq-q\">Is etch-back planarization still used in semiconductor manufacturing?<\/div>\n      <div class=\"jz-faq-a\">Resist etch-back planarization is still used in 2026 for specific niche applications: MEMS device fabrication, analog and power IC manufacturing at 0.18 \u00b5m and above, and certain sensor fabrication processes where moderate local planarization is sufficient and the cost of CMP steps needs to be minimized. It is not used in any leading-edge logic or memory process below 65 nm, where the pattern density dependence and limited planarity scale of etch-back cannot satisfy the stringent WIWNU and depth-of-focus requirements of advanced lithography.<\/div>\n    <\/div>\n    <div class=\"jz-faq-item\">\n      <div class=\"jz-faq-q\">Why can&#8217;t HDP-CVD replace CMP for STI planarization?<\/div>\n      <div class=\"jz-faq-a\">HDP-CVD provides excellent void-free gap fill for STI trenches, but it does not achieve global planarization. The deposited oxide overburden above the field regions varies in height depending on the local pattern density, leaving significant long-range topographic variation that exceeds the depth-of-focus budget for subsequent lithography steps. HDP-CVD and CMP are therefore complementary processes in the STI module: HDP-CVD fills the trenches, and CMP removes the overburden with the global uniformity required for the process to proceed reliably.<\/div>\n    <\/div>\n    <div class=\"jz-faq-item\">\n      <div class=\"jz-faq-q\">At what technology node did CMP become essential?<\/div>\n      <div class=\"jz-faq-a\">CMP became essential for ILD planarization at the 0.35 \u00b5m node (early 1990s), where 248 nm DUV lithography replaced 365 nm i-line and the tighter depth-of-focus made local planarization techniques inadequate. For STI, CMP replaced LOCOS at the 0.18 \u00b5m and 130 nm nodes. For copper interconnects, CMP was required from the very first production node (130 nm, IBM 1997). As of June 2026, CMP is mandatory at every node from 130 nm through 2 nm for all critical planarization modules.<\/div>\n    <\/div>\n  <\/div>\n<\/section>\n\n<\/div>\n\n<script type=\"application\/ld+json\">\n{\n  \"@context\": \"https:\/\/schema.org\",\n  \"@type\": \"FAQPage\",\n  \"mainEntity\": [\n    {\"@type\":\"Question\",\"name\":\"What is the main difference between CMP and Spin-on-Glass for planarization?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"SOG provides local planarization within a few micrometers of features (30\u201360% step height reduction). CMP provides global planarization across the full chip area and 300 mm wafer with WIWNU below 1%. 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For copper interconnects it has been required since IBM's 130 nm Cu production node in 1997.\"}}\n  ]\n}\n<\/script>","protected":false},"excerpt":{"rendered":"<p>\u2190 Back to Complete Planarization Guide Process Technology Comparison Semiconductor planarization encompasses a range of techniques that have evolved over six decades \u2014 from thermal glass reflow and spin-on-glass to  &#8230;<\/p>","protected":false},"author":1,"featured_media":2380,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[9,59],"tags":[],"class_list":["post-2378","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog","category-industry"],"acf":[],"_links":{"self":[{"href":"https:\/\/jeez-semicon.com\/zh\/wp-json\/wp\/v2\/posts\/2378","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/jeez-semicon.com\/zh\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/jeez-semicon.com\/zh\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/jeez-semicon.com\/zh\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/jeez-semicon.com\/zh\/wp-json\/wp\/v2\/comments?post=2378"}],"version-history":[{"count":2,"href":"https:\/\/jeez-semicon.com\/zh\/wp-json\/wp\/v2\/posts\/2378\/revisions"}],"predecessor-version":[{"id":2381,"href":"https:\/\/jeez-semicon.com\/zh\/wp-json\/wp\/v2\/posts\/2378\/revisions\/2381"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/jeez-semicon.com\/zh\/wp-json\/wp\/v2\/media\/2380"}],"wp:attachment":[{"href":"https:\/\/jeez-semicon.com\/zh\/wp-json\/wp\/v2\/media?parent=2378"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/jeez-semicon.com\/zh\/wp-json\/wp\/v2\/categories?post=2378"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/jeez-semicon.com\/zh\/wp-json\/wp\/v2\/tags?post=2378"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}