{"id":2241,"date":"2026-06-03T13:44:23","date_gmt":"2026-06-03T05:44:23","guid":{"rendered":"https:\/\/jeez-semicon.com\/?p=2241"},"modified":"2026-06-03T13:44:23","modified_gmt":"2026-06-03T05:44:23","slug":"polysilicon-and-sti-cmp-slurry-guide","status":"publish","type":"post","link":"https:\/\/jeez-semicon.com\/de\/blog\/polysilicon-and-sti-cmp-slurry-guide\/","title":{"rendered":"Polysilicon and STI CMP Slurry Guide"},"content":{"rendered":"<!-- ===== JEEZ \u00b7 Polysilicon and STI CMP Slurry Guide \u2014 paste into Gutenberg \"Custom HTML\" block ===== -->\n\n<style>\n@import url('https:\/\/fonts.googleapis.com\/css2?family=Sora:wght@500;600;700;800&family=IBM+Plex+Sans:ital,wght@0,400;0,500;0,600;1,400&family=IBM+Plex+Mono:wght@500;600&display=swap');\n.jz-b5-wrap{\n  --ink:#0a1f33; --navy:#0d2a44; --navy2:#123a5c;\n  --acc:#2f7dd1; --accd:#245fa3; --accl:#e8f1fb;\n  --text:#1c2b3a; --muted:#5a6b7b; --line:#e1e8ef; --bg:#f6f9fb; --card:#fff;\n  --r:16px; --sh:0 12px 40px 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.ps-signoff{font-size:14px;color:var(--muted);border-top:1px solid var(--line);padding-top:20px;margin-top:38px;font-style:italic;}\n@media(max-width:760px){\n  .jz-b5-wrap{font-size:16px;}\n  .jz-b5-wrap .ps-hero{padding:40px 24px 36px;}\n  .jz-b5-wrap .ps-toc{padding:22px 20px;}\n  .jz-b5-wrap .ps-toc ol{grid-template-columns:1fr;gap:0;}\n  .jz-b5-wrap .ps-cards{grid-template-columns:1fr;}\n  .jz-b5-wrap .ps-cta{padding:34px 24px;}\n}\n<\/style>\n\n<div class=\"jz-b5-wrap\">\n  <header class=\"ps-hero\">\n    <div class=\"ps-eyebrow\">JEEZ \u00b7 Selection by Material<\/div>\n    \n    <p class=\"ps-lead\">Shallow Trench Isolation and polysilicon steps require carefully balanced selectivity so the process self-terminates at the right depth. This guide explains how to select a polysilicon and STI CMP slurry and why precise control matters far more than raw speed.<\/p>\n    <div class=\"ps-meta\"><span>By <b>JEEZ \u2014 Jizhi Electronic Technology Co., Ltd.<\/b><\/span><span>Updated <b>June 2026<\/b><\/span><\/div>\n  <\/header>\n\n  <nav class=\"ps-toc\" aria-label=\"Table of contents\">\n    <h2>Inhalts\u00fcbersicht<\/h2>\n    <ol><li><a href=\"#jz-b5-role\">The Role of STI and Polysilicon CMP<\/a><\/li><li><a href=\"#jz-b5-flow\">The STI Integration Flow<\/a><\/li><li><a href=\"#jz-b5-selectivity\">Selectivity Is the Whole Game<\/a><\/li><li><a href=\"#jz-b5-alt\">Fixed-Abrasive and Alternative Approaches<\/a><\/li><li><a href=\"#jz-b5-control\">Control Over Speed<\/a><\/li><li><a href=\"#jz-b5-defects\">Defect Modes<\/a><\/li><li><a href=\"#jz-b5-select\">Selecting Your STI or Polysilicon Slurry<\/a><\/li><\/ol>\n  <\/nav>\n\n  <section class=\"ps-sec\" id=\"jz-b5-role\"><h2>The Role of STI and Polysilicon CMP<\/h2><p>Shallow Trench Isolation (STI) electrically separates neighbouring devices and is one of the earliest CMP steps in the flow. After trenches are etched and filled with oxide, CMP removes the excess oxide and must stop precisely on a silicon-nitride layer so the active areas are protected and uniform. Polysilicon CMP, used for gates and certain structures, has its own balance of rate and control. For the selection method, see <a href=\"https:\/\/jeez-semicon.com\/de\/blog\/How-to-Select-a-CMP-Slurry-by-Material-and-Process\/\" target=\"_blank\" rel=\"noopener\">the selection framework<\/a>; the <a href=\"https:\/\/jeez-semicon.com\/de\/blog\/What-Is-Polishing-Slurry\/\" target=\"_blank\" rel=\"noopener\">pillar guide<\/a> gives the wider context.<\/p><\/section><section class=\"ps-sec\" id=\"jz-b5-flow\"><h2>The STI Integration Flow<\/h2><p>Understanding the slurry requires understanding the structure it polishes. In a typical STI flow, a pad oxide and nitride are deposited, trenches are etched through them into silicon, the trenches are filled with deposited oxide, and CMP then removes the oxide overburden down to the nitride. The nitride acts as both a polish stop and a protective cap over the active silicon. The slurry&#8217;s job is to clear the oxide and halt on the nitride with minimal dishing of the wide trenches in between.<\/p><\/section><section class=\"ps-sec\" id=\"jz-b5-selectivity\"><h2>Selectivity Is the Whole Game<\/h2><p>The defining requirement for STI is <b>oxide-to-nitride selectivity<\/b>. The slurry must remove oxide quickly but slow dramatically when it reaches the nitride stop layer, so the step self-terminates at the correct depth across the whole wafer without over-polishing. This typically uses ceria-based high-selectivity chemistry tuned for a large selectivity ratio \u2014 see the <a href=\"https:\/\/jeez-semicon.com\/de\/blog\/Oxide-and-Dielectric-Ceria-CMP-Slurry-Guide\/\" target=\"_blank\" rel=\"noopener\">oxide and dielectric ceria guide<\/a> for the abrasive background and <a href=\"https:\/\/jeez-semicon.com\/de\/blog\/CMP-Slurry-Composition-Explained\/\" target=\"_blank\" rel=\"noopener\">the composition guide<\/a> for how additives set selectivity.<\/p><div class=\"ps-callout\"><span class=\"tag\">Self-stopping concept<\/span><p>A high-selectivity STI slurry is designed to be partly self-limiting: as nitride is exposed, removal slows automatically, widening the process window and reducing sensitivity to small variations in polish time.<\/p><\/div><\/section><section class=\"ps-sec\" id=\"jz-b5-alt\"><h2>Fixed-Abrasive and Alternative Approaches<\/h2><p>Beyond conventional high-selectivity slurries, some integrations have used fixed-abrasive pads (where the abrasive is embedded in the consumable rather than suspended in liquid) or reverse-tone and dummy-fill schemes to improve planarity on difficult layouts. These are integration choices that interact with slurry selection; the right combination depends on feature density and the planarity budget. For most flows, a tuned high-selectivity slurry remains the mainstream solution.<\/p><\/section><section class=\"ps-sec\" id=\"jz-b5-control\"><h2>Control Over Speed<\/h2><p>Unlike a bulk-removal step, STI rewards precise, uniform removal and a self-stopping characteristic far more than raw rate. Within-wafer uniformity and dishing of wide trenches are the key metrics. This is the opposite emphasis from a <a href=\"https:\/\/jeez-semicon.com\/de\/blog\/Tungsten-CMP-Slurry-Selection-Guide\/\" target=\"_blank\" rel=\"noopener\">tungsten plug step<\/a>, where high stable rate dominates \u2014 a good illustration of why slurry choice is always step-specific. Polysilicon steps similarly prize uniformity and stop control over speed.<\/p><\/section><section class=\"ps-sec\" id=\"jz-b5-defects\"><h2>Defect Modes<\/h2><p>Trench dishing, nitride erosion, residual oxide and scratches are the principal defects. Wide trenches are prone to dishing because there is less surrounding nitride to support planarity, while dense active arrays can suffer nitride erosion that thins the protective cap. Both are managed through selectivity, abrasive and particle control, downforce and layout-aware integration, supported by a stable slurry and accurate endpoint.<\/p><\/section><section class=\"ps-sec\" id=\"jz-b5-select\"><h2>Selecting Your STI or Polysilicon Slurry<\/h2><p>Specify the oxide-to-nitride selectivity your integration requires, set dishing and erosion limits for your widest and densest features, and prioritise process-window robustness and uniformity over speed. Validate the self-stopping behaviour and dishing on your own structures rather than relying on a reference selectivity figure, and confirm the slurry is stable through your distribution and dilution scheme.<\/p><\/section>\n\n  <section class=\"ps-related\">\n    <h2>Continue Learning<\/h2>\n    <p class=\"sub\">Explore the rest of the JEEZ polishing slurry knowledge series.<\/p>\n    <div class=\"ps-cards\"><a class=\"ps-card pillar\" href=\"https:\/\/jeez-semicon.com\/de\/blog\/What-Is-Polishing-Slurry\/\" target=\"_blank\" rel=\"noopener\"><span class=\"k\">Start here \u00b7 Pillar guide<\/span><span class=\"t\">What Is Polishing Slurry? The Complete Guide<\/span><\/a><a class=\"ps-card\" href=\"https:\/\/jeez-semicon.com\/de\/blog\/How-to-Select-a-CMP-Slurry-by-Material-and-Process\/\" target=\"_blank\" rel=\"noopener\"><span class=\"k\">Related guide<\/span><span class=\"t\">How to Select a CMP Slurry by Material and Process<\/span><\/a><a class=\"ps-card\" href=\"https:\/\/jeez-semicon.com\/de\/blog\/Oxide-and-Dielectric-Ceria-CMP-Slurry-Guide\/\" target=\"_blank\" rel=\"noopener\"><span class=\"k\">Related guide<\/span><span class=\"t\">Oxide and Dielectric Ceria CMP Slurry Guide<\/span><\/a><a class=\"ps-card\" href=\"https:\/\/jeez-semicon.com\/de\/blog\/CMP-Slurry-Composition-Explained\/\" target=\"_blank\" rel=\"noopener\"><span class=\"k\">Related guide<\/span><span class=\"t\">CMP-Slurry-Zusammensetzung erkl\u00e4rt<\/span><\/a><a class=\"ps-card\" href=\"https:\/\/jeez-semicon.com\/de\/blog\/Tungsten-CMP-Slurry-Selection-Guide\/\" target=\"_blank\" rel=\"noopener\"><span class=\"k\">Related guide<\/span><span class=\"t\">Tungsten CMP Slurry Selection Guide<\/span><\/a><\/div>\n  <\/section>\n\n  <section class=\"ps-sec ps-faq\" id=\"jz-b5-faq\"><h2>H\u00e4ufig gestellte Fragen<\/h2><details open=\"\"><summary>What is the key requirement for an STI CMP slurry?<\/summary><div class=\"ans\">High oxide-to-nitride selectivity. The slurry must remove trench-fill oxide quickly yet slow sharply on the nitride stop layer so the step self-terminates at the correct depth uniformly across the wafer, with minimal dishing of wide trenches.<\/div><\/details><details><summary>What does self-stopping mean in STI CMP?<\/summary><div class=\"ans\">A high-selectivity STI slurry is partly self-limiting: once nitride is exposed, removal slows automatically. This widens the process window and reduces sensitivity to small variations in polish time, improving uniformity and yield.<\/div><\/details><details><summary>How does the nitride layer function in STI?<\/summary><div class=\"ans\">The silicon-nitride layer serves as both the CMP polish stop and a protective cap over the active silicon. The slurry must clear the trench-fill oxide and halt on the nitride without eroding it, which is why high oxide-to-nitride selectivity is essential.<\/div><\/details><details><summary>Why is control more important than speed in STI CMP?<\/summary><div class=\"ans\">STI determines device isolation and must stop precisely on nitride with good uniformity and minimal dishing. A fast but poorly controlled slurry causes over-polish, dishing and erosion, so precise self-stopping behaviour matters far more than raw removal rate.<\/div><\/details><details><summary>What abrasive is typically used for STI slurry?<\/summary><div class=\"ans\">Ceria-based chemistry is common because it offers strong oxide removal and can be tuned for high oxide-to-nitride selectivity, giving the self-stopping behaviour that STI integration depends on.<\/div><\/details><\/section>\n\n  <section class=\"ps-cta\">\n    <h2>Talk to the JEEZ slurry engineering team<\/h2>\n    <p>From first slurry selection to defectivity optimisation and multi-source qualification, JEEZ \u2014 Jizhi Electronic Technology Co., Ltd. \u2014 helps you match the right polishing slurry to your material and process targets.<\/p>\n    <a class=\"ps-btn\" href=\"https:\/\/jeez-semicon.com\/de\/contact\/\" target=\"_blank\" rel=\"noopener\">Contact JEEZ <span>\u2192<\/span><\/a>\n  <\/section>\n\n  <p class=\"ps-signoff\">Part of the JEEZ Polishing Slurry knowledge series. Reviewed and updated June 2026 by Jizhi Electronic Technology Co., Ltd.<\/p>\n<\/div>\n\n<script type=\"application\/ld+json\">\n{\n  \"@context\":\"https:\/\/schema.org\",\"@type\":\"Article\",\n  \"headline\":\"Polysilicon and STI CMP Slurry Guide\",\n  \"description\":\"How to select a polysilicon and STI CMP slurry: oxide-to-nitride selectivity, self-stopping behaviour, the STI integration flow, fixed-abrasive alternatives, removal-rate control and defect management.\",\n  \"author\":{\"@type\":\"Organization\",\"name\":\"JEEZ \\u2014 Jizhi Electronic Technology Co., Ltd.\",\"url\":\"https:\/\/jeez-semicon.com\/\"},\n  \"publisher\":{\"@type\":\"Organization\",\"name\":\"Jizhi Electronic Technology Co., Ltd.\",\"logo\":{\"@type\":\"ImageObject\",\"url\":\"https:\/\/jeez-semicon.com\/wp-content\/uploads\/jeez-logo.png\"}},\n  \"datePublished\":\"2026-06-01\",\"dateModified\":\"2026-06-01\",\n  \"mainEntityOfPage\":{\"@type\":\"WebPage\",\"@id\":\"https:\/\/jeez-semicon.com\/blog\/Polysilicon-and-STI-CMP-Slurry-Guide\"}\n}\n<\/script>\n<script type=\"application\/ld+json\">\n{\n  \"@context\":\"https:\/\/schema.org\",\"@type\":\"FAQPage\",\"mainEntity\":[\n    {\"@type\":\"Question\",\"name\":\"What is the key requirement for an STI CMP slurry?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"High oxide-to-nitride selectivity. The slurry must remove trench-fill oxide quickly yet slow sharply on the nitride stop layer so the step self-terminates at the correct depth uniformly across the wafer, with minimal dishing of wide trenches.\"}},\n    {\"@type\":\"Question\",\"name\":\"What does self-stopping mean in STI CMP?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"A high-selectivity STI slurry is partly self-limiting: once nitride is exposed, removal slows automatically. This widens the process window and reduces sensitivity to small variations in polish time, improving uniformity and yield.\"}},\n    {\"@type\":\"Question\",\"name\":\"How does the nitride layer function in STI?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"The silicon-nitride layer serves as both the CMP polish stop and a protective cap over the active silicon. The slurry must clear the trench-fill oxide and halt on the nitride without eroding it, which is why high oxide-to-nitride selectivity is essential.\"}},\n    {\"@type\":\"Question\",\"name\":\"Why is control more important than speed in STI CMP?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"STI determines device isolation and must stop precisely on nitride with good uniformity and minimal dishing. A fast but poorly controlled slurry causes over-polish, dishing and erosion, so precise self-stopping behaviour matters far more than raw removal rate.\"}},\n    {\"@type\":\"Question\",\"name\":\"What abrasive is typically used for STI slurry?\",\"acceptedAnswer\":{\"@type\":\"Answer\",\"text\":\"Ceria-based chemistry is common because it offers strong oxide removal and can be tuned for high oxide-to-nitride selectivity, giving the self-stopping behaviour that STI integration depends on.\"}}\n  ]\n}\n<\/script>","protected":false},"excerpt":{"rendered":"<p>JEEZ \u00b7 Selection by Material Shallow Trench Isolation and polysilicon steps require carefully balanced selectivity so the process self-terminates at the right depth. This guide explains how to select a  &#8230;<\/p>","protected":false},"author":1,"featured_media":2243,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[9,59],"tags":[],"class_list":["post-2241","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog","category-industry"],"acf":[],"_links":{"self":[{"href":"https:\/\/jeez-semicon.com\/de\/wp-json\/wp\/v2\/posts\/2241","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/jeez-semicon.com\/de\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/jeez-semicon.com\/de\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/jeez-semicon.com\/de\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/jeez-semicon.com\/de\/wp-json\/wp\/v2\/comments?post=2241"}],"version-history":[{"count":2,"href":"https:\/\/jeez-semicon.com\/de\/wp-json\/wp\/v2\/posts\/2241\/revisions"}],"predecessor-version":[{"id":2244,"href":"https:\/\/jeez-semicon.com\/de\/wp-json\/wp\/v2\/posts\/2241\/revisions\/2244"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/jeez-semicon.com\/de\/wp-json\/wp\/v2\/media\/2243"}],"wp:attachment":[{"href":"https:\/\/jeez-semicon.com\/de\/wp-json\/wp\/v2\/media?parent=2241"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/jeez-semicon.com\/de\/wp-json\/wp\/v2\/categories?post=2241"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/jeez-semicon.com\/de\/wp-json\/wp\/v2\/tags?post=2241"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}