The primary goal of the lapping process is to rapidly remove the cutting-damaged layer from the substrate surface, correct geometric shape deviations, and provide a flat, uniform surface base for subsequent polishing. Precise control of process parameters directly impacts lapping efficiency and surface flatness. Through extensive process validation, Gizhi Electronics has developed a mature lapping process system.<\/p>\n
1. Core Equipment Selection<\/strong> 2. Control of Key Process Parameters<\/strong> \u2460\u00a0Lapping Pressure:<\/strong>\u00a0Optimal range: 150\u2013180 N. Insufficient pressure leads to low lapping efficiency and incomplete removal of the cutting-damaged layer, while excessive pressure can cause defects like crystal plane cracks and surface edge chipping. For thin substrates (thickness < 100 \u00b5m), the pressure should be further reduced to 120\u2013150 N.<\/p>\n \u2461\u00a0Lapping Plate Speed:<\/strong>\u00a0Lower plate speed is controlled at 4\u20138 RPM, with an upper-to-lower plate speed ratio of 1:1.2. Lower speeds reduce frictional heat between the wafer and the lapping plate, preventing surface oxidation of InP due to high temperatures. The speed ratio ensures uniform lapping trajectories and reduces surface waviness.<\/p>\n \u2462\u00a0Abrasive Particle Size:<\/strong>\u00a0Alumina (Al\u2082O\u2083) abrasive powder with a D50% of 4\u201312 \u00b5m is preferred. Particles that are too large can cause deep surface scratches, while particles that are too small significantly reduce the removal rate. Gizhi Electronics uses graded and screened abrasive powder to ensure particle size distribution deviation \u226410%.<\/p>\n 3. Lapping Slurry Formulation and Supply<\/strong> 4. Pre-Etching Auxiliary Process<\/strong> The polishing process is the critical step for eliminating residual lapping damage and achieving an atomically flat surface. Its core mechanism involves the synergistic action of “chemical corrosion + mechanical removal”: the oxidizer in the polishing slurry reacts chemically with the InP surface to form soluble phosphate compounds, which are then mechanically removed by the polishing pad and silica (SiO\u2082) colloidal particles through friction. This cycle repeats to refine the surface. Gizhi Electronics adopts a three-stage polishing process\u2014rough polishing, medium polishing, and fine polishing\u2014to progressively optimize surface quality.<\/p>\n 1. Staged Process: Three-Stage Polishing<\/strong><\/p>\n 2. Critical Matching of CMP Slurry and Pad<\/strong> 3. Polishing Environment and Post-Processing Control<\/strong> Indium Phosphide (InP), as a core material of the third-generation semiconductor, holds an irreplaceable position in high-end fields such as optical communications, millimeter-wave radar, and quantum communications due to its …<\/p>","protected":false},"author":1,"featured_media":1013,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"footnotes":""},"categories":[9,59],"tags":[],"class_list":["post-769","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-blog","category-industry"],"acf":[],"_links":{"self":[{"href":"https:\/\/jeez-semicon.com\/es\/wp-json\/wp\/v2\/posts\/769","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/jeez-semicon.com\/es\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/jeez-semicon.com\/es\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/jeez-semicon.com\/es\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/jeez-semicon.com\/es\/wp-json\/wp\/v2\/comments?post=769"}],"version-history":[{"count":1,"href":"https:\/\/jeez-semicon.com\/es\/wp-json\/wp\/v2\/posts\/769\/revisions"}],"predecessor-version":[{"id":773,"href":"https:\/\/jeez-semicon.com\/es\/wp-json\/wp\/v2\/posts\/769\/revisions\/773"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/jeez-semicon.com\/es\/wp-json\/wp\/v2\/media\/1013"}],"wp:attachment":[{"href":"https:\/\/jeez-semicon.com\/es\/wp-json\/wp\/v2\/media?parent=769"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/jeez-semicon.com\/es\/wp-json\/wp\/v2\/categories?post=769"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/jeez-semicon.com\/es\/wp-json\/wp\/v2\/tags?post=769"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}
\nDouble-sided planetary lapping machines \/ Chemical Mechanical Polishing (CMP) equipment are commonly used in industrial production. This equipment drives the InP substrates placed in carriers to perform compound motion through the counter-rotating planetary movement of the upper and lower plates, ensuring uniform force distribution and sufficient lapping across all areas of the wafer and effectively preventing edge warping issues common in single-sided belt lapping. The spindle accuracy and parallelism calibration of the lapping plates are prerequisites for ensuring lapping quality. Gizhi Electronics implements a regular calibration system for equipment to maintain operational accuracy within \u00b10.001 mm.<\/p>\n![\"\"](\"https:\/\/jeez-semicon.com\/wp-content\/uploads\/2025\/12\/11-13.png\")
<\/p>\n
\nThe matching of lapping parameters is key to achieving “efficient damage removal + low residual damage.” Considering InP’s high brittleness and susceptibility to cracking, Gizhi Electronics has optimized the following key parameter ranges:<\/p>\n
\nThe lapping slurry consists of water, alumina abrasive, suspending agents, and a small amount of pH adjuster. The Al\u2082O\u2083 abrasive is selected as high-purity particles (purity \u226599.9%) of 400\u2013600 mesh to minimize impurity contamination. Suspending agents such as Polyvinyl Alcohol (PVA) or Carboxymethyl Cellulose (CMC) are used to ensure uniform dispersion of the abrasive and prevent uneven lapping due to settling. A constant-pressure liquid delivery system supplies the slurry at a stable flow rate of 500\u2013800 mL\/min, ensuring the lapping area remains continuously moistened and promptly removes lapping debris and heat.<\/p>\n![\"\"](\"https:\/\/jeez-semicon.com\/wp-content\/uploads\/2025\/12\/22-8.png\")
<\/p>\n
\nFor high-hardness InP substrates, Gizhi Electronics innovatively employs a “chemical pre-etching + mechanical lapping” composite process. The substrate surface is mildly etched with a mixed solution of hydrobromic acid, phosphoric acid, hydrochloric acid, and acetic acid (volume ratio 3:2:1:1), forming a porous “trabecular” structure. This structure reduces the Mohs hardness by over 30% compared to the original InP, significantly enhancing lapping efficiency and effectively preventing scratch propagation during lapping. Pre-etching time is strictly controlled to 30\u201360 seconds, followed immediately by rinsing with pure water to avoid residual acid causing grain boundary corrosion.<\/p>\n
\nII. Polishing Process: Achieving a Mirror-Like Surface<\/strong><\/h3>\n
\n\n
\n \nPolishing Stage<\/th>\n Core Objective<\/th>\n Polishing Pad Selection<\/th>\n Polishing Slurry Configuration<\/th>\n Process Parameters<\/th>\n<\/tr>\n<\/thead>\n \n Pulido basto<\/strong><\/td>\n Quickly eliminate lapping scratches, initiate mirror finishing<\/td>\n Polyurethane\/Hard Polishing Pad (Shore D Hardness ~50)<\/td>\n SiO\u2082 Colloid (100-150 nm) + Perchlorate Oxidizer (Effective Chlorine 8-10%), pH=10-11<\/td>\n Pressure: 80-100 N, Speed: 10-15 RPM, Time: 15-20 min<\/td>\n<\/tr>\n \n Medium Polishing<\/strong><\/td>\n Correct local flatness, reduce waviness<\/td>\n Polyurethane\/Non-woven\/Composite Pad (Shore D Hardness ~40)<\/td>\n SiO\u2082 Colloid (50-80 nm) + Hydrogen Peroxide (3-5%), pH=9-10<\/td>\n Pressure: 50-70 N, Speed: 8-12 RPM, Time: 10-15 min<\/td>\n<\/tr>\n \n Fine Polishing<\/strong><\/td>\n Eliminate micro-defects, achieve atomic-level flatness<\/td>\n Suba\/Damping Cloth Fine Polishing Pad (Shore D Hardness ~30)<\/td>\n SiO\u2082 Colloid (20-40 nm) + Hydrogen Peroxide (1-2%), pH=8-9<\/td>\n Pressure: 30-50 N, Speed: 5-8 RPM, Time: 20-25 min<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n
\nInP’s high chemical stability necessitates the use of alkaline silica sol-based polishing slurries to enhance chemical corrosion. Oxidizer selection is particularly crucial: perchlorates, with their good solubility and oxidation potential, rapidly form a reaction layer during rough polishing, while hydrogen peroxide in the fine polishing stage allows controlled oxidation rates to prevent over-corrosion. Polishing pad selection must balance “removal rate” and “surface damage”: harder grooved pads improve efficiency during rough polishing, while softer suede-type pads minimize mechanical damage during fine polishing. Through customized pad surface textures, Gizhi Electronics achieves an optimal balance between removal rate and surface quality at each stage.<\/p>\n![\"\"](\"https:\/\/jeez-semicon.com\/wp-content\/uploads\/2025\/12\/33-5.png\")
<\/p>\n
\nPolishing must be conducted in a Class 1000 cleanroom to prevent secondary contamination from airborne particulate impurities. After polishing, a three-stage cleaning process\u2014”Ultrasonic Cleaning + Megasonic Cleaning + Spin Drying”\u2014is immediately employed: first, ultrasonic cleaning with a neutral detergent at 50\u00b0C for 10 minutes to remove residual slurry; followed by megasonic cleaning (1 MHz frequency) to remove adhered micro-particles; and finally, spin drying at 1000 RPM for 5 minutes to ensure a water-mark-free surface.<\/p>","protected":false},"excerpt":{"rendered":"