半导体 ESD 载具、托盘用导电PP，表面电阻 10⁶–10⁹Ω 到底怎么控？答案不是"越导电越好"，而是先按 ANSI/ESD S541、IEC 61340-5-1 把电阻分档，再定炭黑、碳纤维还是永久抗静电剂路线。这篇给出一张五列判据表、一套验证顺序，以及三个不该用改性PP 的条件。
一个做半导体后段设备的工程师问过我一句话：你们的导电改性PP，表面电阻能压到多低？
我说，先别问能压多低。你得先告诉我，这个件是把电荷泄掉，还是要把电荷挡住——这两件事要的电阻区间是反的。
他愣了一下，说，不是越低越好吗。
这就是 ESD 载具、托盘上用导电改性PP 最常见的误区：表面电阻不是越导电越好，是要落在区间里。
导电级（约 10³–10⁵ Ω）放电太快，未接地时一旦碰上来路不明的高压电荷，反而可能用一次"硬放电"伤到器件。
绝缘级（≥10¹¹ Ω）更直接：电荷根本泄不掉，全程在积。
真正适合直接接触敏感器件的，是中间那一段——静电耗散级。
下面按工况、路线、判据、验证四层往下拆。
一、半导体ESD载具的工况六维：温度和洁净度先定边界
ESD 载具选型的第一句话不是"电阻多少"，是"这个件会不会直接接触器件、在多高温度下工作"。 这两条先定边界，剩下的才是配方。
| 维度 | 载具 / 托盘的实际工况 | 对材料的要求 |
|---|
| 温度 | 常温仓储运输为主；若随制程走 150℃ 级烘烤，或需高温清洗，边界立刻抬高 | 导电PP 连续使用温度常见口径约 ≤90℃，高温段是硬约束 |
| 载荷 | 多层堆叠、机械手抓取、运输振动与跌落 | 抗翘曲、抗抓取变形，尺寸稳定 |
| 介质 | IPA 等清洗剂、稀酸、擦拭溶剂 | 耐化学 + 清洁后电阻不漂 |
| 寿命 | 载具反复周转、反复清洗 | 电阻与洁净度要经得起时间 |
| 外观 / 洁净 | 多为深色；不脱屑、不掉粉、低析出 | 与电阻同等重要 |
| 合规 | ESD 控制程序（ANSI/ESD S20.20、IEC 61340-5-1）；洁净室等级（常见 ISO Class 4–5） | 电阻区间 + 洁净度双门槛 |
六个维度里，温度和洁净度这两条是先定的。温度决定基材还能不能是 PP；洁净度决定填料体系能不能用碳纤维。这两条定不下来，后面讨论 10 的几次方没有意义。
二、导电PP的三条材料路线：炭黑、碳纤维、永久抗静电剂怎么分
三条路线没有谁更好，只有"分在哪个区间、付出什么代价"。
| 路线 | 拿到什么 | 代价 |
|---|
| 炭黑体系 | 导电级到耗散级都能覆盖；公开专利资料里，导电炭黑常见 15–30 份区间（A 级） | 力学与韧性下降；基本只能做深色；表面可能析出、掉粉 |
| 碳纤维体系 | 长径比大、导电效率高，填充量相对低 | 成本高；纤维在加工中会断损；摩擦中可能露纤脱落，高洁净件慎用 |
| 永久抗静电剂体系 | 表面电阻可达 10⁶–10¹¹ Ω（据厂商公开产品资料，B 级），浅色、不迁移 | 成本较高；需评估与基体的相容与析出 |
要理解这三条路的差别，先记住一件事：电阻不是随填料含量线性往下走的，是一条陡降曲线。
填料少的时候加一点几乎没反应；加到某个临界值附近，电阻会在很小的加量区间里掉好几个数量级，这就是渗流。
公开期刊资料里，熔融共混炭黑 / PP 的渗流阈值约 2.75 vol%，做成隔离结构可以低到 0.37 vol%（A 级）。
陡降段落在哪，决定了配方窗口有多窄——所以"填多少"不是算出来的，是打出来的。
改性的另外一个代价在颜色和洁净：炭黑、碳纤维都带不走，深色是配套的；永久抗静电剂能保住浅色，但要多算一笔相容性与成本的账。
电阻该落在哪个区间，先看这张表：
| 分级（贯通口径） | 表面电阻典型区间 | 主要用途 |
|---|
| 导电级 | 约 10³–10⁵ Ω | 需要快速泄放、接地与屏蔽场合 |
| 静电耗散级（ESD 级） | 约 10⁶–10⁹ Ω（广义 10⁴–10¹¹ Ω） | 载具、托盘、料箱的主用区间 |
| 抗静电级 | 约 10¹⁰–10¹² Ω | 抑制吸尘，不主动泄放 |
| 绝缘级 | ≥10¹¹ Ω | 对 ESD 敏感器件是危险的 |
来源口径：ANSI/ESD S541 把包装与材料分为导电（<1×10⁴ Ω）、静电耗散（1×10⁴ 至 <1×10¹¹ Ω）、绝缘（≥1×10¹¹ Ω）三类，测试方法为 ANSI/ESD STM11.11 / 11.12 / 11.31（A 级）；IEC 61340-5-1 给的是导电约 10²–10⁵ Ω、耗散 10⁵–10¹¹ Ω、绝缘 ≥10¹¹ Ω（A 级）。"载具与托盘常用 10⁶–10⁹ Ω"是行业通行的工程取法（B 级公开技术资料）。
这张表的核心判断只有一句：太低（纯导电）不一定好，太高等于绝缘，区间才是要求。
三、★ 表面电阻分级判据表：导电级、耗散级、绝缘级各用在哪
这张表最该先看清的不是"要看哪个指标"，是"用哪套电极、多大压力、读哪个电压测出来的"。 口径不统一，两个数没法比。
| 指标 | 门限值（典型） | 验证方法 / 标准 | 常见失效 | 通行解法 |
|---|
| 表面电阻 | 落在目标区间（载具常取 10⁶–10⁹ Ω） | ANSI/ESD STM11.11；GB/T 1410-2006 | 电阻漂出区间 | 配比 + 分散工艺 |
| 体积电阻 | 落入同一区间 | ANSI/ESD STM11.12；GB/T 1410 | 表面合格、内部不合格 | 走体导电体系 |
| 测试条件口径 | 23±2℃、50±5%RH（湿度敏感材料为 12%±3%RH，调节不少于 24h） | ANSI/ESD STM11.11 | 同料不同值 | 统一口径并把温湿度写进报告 |
| 静电荷衰减 | 1000V 衰减至 100V ≤2s（A 级口径） | GB/T 36340-2018 | 泄放太慢 | 把电阻往区间下方调 |
| 不脱屑 / 颗粒 | 不脱屑、不掉粉 | 洁净室颗粒计数（客户口径） | 露纤掉粉 | 低露纤体系 + 加工面倒角 |
| 低析出 / 低离子 | 低放气、低金属离子 | 客户洁净度规范 | 沾污器件背面 | 高纯炭黑或 CNT，避金属填充 |
| 耐化学 | 耐 IPA、稀酸、清洗剂 | 浸泡后复测电阻 | 开裂、电阻漂移 | 基材与体系相容 |
| 连续使用温度 | 常见口径 ≤90℃ | 热老化后复测 | 变形、尺寸漂 | 超温走 PEEK / PPS（见第六段） |
| 尺寸稳定 / 翘曲 | 与自动化配合公差常见 ±0.02–0.05mm | 三坐标、平面度 | 抓取失败 | 控收缩 + 结构加强 |
| 拉伸 / 缺口冲击 | 按件要求 | GB/T 1040.2、GB/T 1043.1 | 力学不足 | 降填充或换体系 |
| 熔体流动速率 | 按充填要求 | GB/T 3682.1 | 充填不足 | 选对应流动档 |
文字版结论：这十一项里，表面电阻是入口，不是全部。 只要件直接接触器件，洁净度这一组指标就不能省——不脱屑、低析出、低金属离子，和电阻是并列的门槛。把这张表当体检单，缺一项不判合格，比做完一批载具再回头找原因省钱得多。
半导体载具上，洁净度为什么值得单独列一张小表，原因很直接：
| 洁净项 | 要求 | 与电阻的关系 |
|---|
| 不脱屑 / 掉粉 | 表面颗粒可控 | 碳纤体系在摩擦中可能露纤，高洁净件优先高纯炭黑或 CNT |
| 低析出 / 低放气 | 真空与洁净室内低挥发 | 迁移型抗静电剂会析出，与洁净要求冲突 |
| 低金属离子 | 避免金属沾污 | 不用金属填充体系 |
| 耐化学 | 耐 IPA、稀酸、清洗剂 | 清洁后电阻不变，才算真耐 |
| 尺寸稳定 | 与自动化配合公差紧 | 高填充体系易翘曲，需结构配合 |
一句话：在洁净室里，掉一颗粉和电阻高一个数量级，是同一等级的事故。
四、常见失效与根因：电阻单点合格、整件不合格最常见
这类件最常见的问题不是电阻不合格，是"这一点合格、整个件不合格"。
失效一：单点测出来合格，多点一测离散很大。 根因是填料分散不均——渗流网络在临界值附近，对局部浓度极其敏感，同一个件不同位置的电阻能差出数量级。
这里要否定一个常见做法：拿一块标准试片、测一个点、报一个数就交货。 ESD 件的失效，往往就发生在没有测到的那个位置。
失效二：表面电阻"突然变很高"。 多数不是料变了，是表面被污染了。含硅的清洁剂、蜡质护理剂、残留脱模剂，都会在表面留下绝缘的一层。
擦拭之后测出来的，才是真实值——这也是验证顺序里要单独排一步清洁后复测的原因。
失效三：电阻慢慢漂出区间。 走迁移型抗静电剂的体系，靠表面迁移层起效，会被擦掉、会被洗掉，干燥环境里还会失效。
失效四：掉粉、露纤。 集中出现在碳纤维体系，尤其是摩擦接触面。高洁净件要么改体系，要么在接触面做倒角、控制露纤。
五、ESD载具用导电PP的验证顺序：先测电阻，还是先做跌落
顺序是先定义口径、再测电阻、再清洁后复测、再老化后复测，最后才是跌落与结构。
`
① 口径确认 电极形式、加压时间与测试电压、温湿度（23±2℃/50±5%RH 或 12%±3%RH）
↓ 口径不统一，后面的数都不可比
② 多点多次测电阻 同一件测 5 点以上、至少 3 件，看区间与离散度
↓ 离散度超过一个数量级，先解决分散，不往下走
③ 清洁后复测 按客户规定的清洁方式处理后复测
↓ 这一步才是"真实值"
④ 老化后复测 湿热、清洗循环、时间之后复测，看是否漂出区间
↓ 漂出区间，退回 ② 重新平衡配比
⑤ 跌落与结构验证 装机、抓取、跌落、装配公差
`
跑完这一套才谈得上量产。最常见的错误是跳过 ② 和 ③，直接拿试模件测一个读数就去批量。
试模件的成型条件往往是临时的，读数没有代表性；清洁前的读数，也不是真实值。
文字版结论：验证顺序是 口径 → 多点电阻 → 清洁后复测 → 老化后复测 → 跌落结构。清洁后复测这一关必须在老化之前过，因为它决定的是"这个数到底算不算数"。
六、反向诚实：这三个条件出现时，ESD载具就不该用改性PP
前面讲的是怎么做，这里讲什么时候别做。
- 要求极高洁净度、器件直接接触面（如先进制程晶圆正面）：改性PP 的基体洁净度与低离子水平撑不住，该走碳系耗散的 PEEK，或 PPS / PEI。
- 要求长期高温（如随制程走 150℃ 级烘烤、需高温清洗）：导电PP 的连续使用温度常见口径约 ≤90℃，明显不够。PPS 约 200–220℃、PEI 约 170–180℃、碳填充 PEEK 约 260℃，且耐 NMP、THF 等溶剂。
- 要求电阻在极窄区间内长期不漂移：小分子抗静电 PP 做不到（会迁移、受湿度影响）；该走体导电的 PEEK / PPS 碳系体系。
- 明确需要电磁屏蔽：走金属纤维或金属化方案，不是靠"导电 PP"三个字。
规律是一致的：只要出现"两个方向相反的要求同时要"，就说明这个件不该用 PP 硬撑。
遇到这种情况，我们的做法是先把这条讲清楚，再谈有没有折中空间——硬接下来的单子，最后都要用返工和索赔还回去。
七、换料要动什么：一张先看再动的清单
| 要动的项 | 需要确认什么 | 不做会怎样 |
|---|
| 模具收缩率 | 新料收缩率与原方案的差 | 尺寸超差，抓取失败 |
| 浇口与排气 | 高填充体系对浇口更敏感 | 充填不足、料花 |
| 料温与模温 | 不同填料体系的窗口不同 | 表面缺陷、电阻不均 |
| 干燥 | 填充料通常不需要；看具体体系 | 银丝、气泡 |
| 保压与脱模 | 收缩差异带来变形与顶白 | 变形、顶出拉伤 |
| 色差 | 深色件先行确认色板 | 批次色差争议 |
| 验证顺序 | 口径 → 多点电阻 → 清洁后 → 老化后 | 风险全部压到最后一步集中爆发 |
文字版结论：换料要动的是模具、工艺、色差三块，其中最该先谈的是验证顺序。跳过 ① ② 直接试模，等于把成本提前花出去。
八、一页纸汇报表（可以直接贴进 PPT）
| 场景 | 推荐路线 | 关键指标 | 验证标准 | 需先确认的条件 |
|---|
| 常温仓储 / 运输托盘 | 炭黑耗散级改性PP | 表面电阻 10⁶–10⁹ Ω | ANSI/ESD STM11.11 | 是否接触器件正面 |
| 需走烘烤 / 高温清洗的载具 | 碳系耗散 PEEK / PPS | 耐温 + 电阻区间 | 热老化后复测 | 具体的温度与循环次数 |
| 高洁净接触件 | 高纯炭黑 / CNT 耗散体系，或 PEEK | 不脱屑、低析出、低离子 | 客户洁净度规范 | 洁净室等级 |
| 需窄区间长期稳定 | 体导电 PEEK / PPS 碳系 | 电阻区间 + 时间稳定性 | 老化后复测 | 允许的电阻上下限 |
| 一般电子装配周转 | 永久抗静电剂改性PP | 表面电阻 10⁶–10¹¹ Ω | 擦拭与时效后复测 | 是否要求浅色 |
文字版结论：这张表的作用是让技术员能把结论直接往上报。判断标准只有一条——客户拿这张表，能不能在一次会议里把材料方向定下来。
九、这个件上最容易出问题的，不是电阻不够低
ESD 载具、托盘上最典型的早期问题是电阻不稳定——同一批件里，有的落在区间内，有的漂出去；以及表面状态引起的读数失真（清洁剂残留、掉粉）。这两类里，由材料本身引起的只是一部分。
公开判据是清楚的：表面电阻按 ANSI/ESD STM11.11 测，试样按 23±2℃、50±5%RH（湿度敏感材料为 12%±3%RH）调节；导电 / 耗散 / 绝缘的分档按 ANSI/ESD S541 与 IEC 61340-5-1；载具常用的耗散区间是 10⁶–10⁹ Ω。
真正难的是分散一致性——渗流网络在临界值附近，配方窗口很窄，看的是批次稳定性，不是单点值。
行业通行的做法是把三件事一起定：填料体系的导电效率、配比落在陡降段的那一侧、以及分散工艺能不能稳住。关键不在"谁的电阻更低"，在电阻、洁净度、力学、加工性四件事能不能同时对上。
宁波市科隆新材料有限公司在这个件上常供的是改性聚丙烯（PP）粒子里的导电类与抗静电类方向，按件的目标电阻区间与洁净度要求给到对应的填料体系与基材档位。
主要用来解决上面说的"电阻漂出区间与表面读数失真"这两件事；配方按件调，可以配合做小样比对、多点电阻复测与清洁后复测，件级客户多品种小批量的需求也能接。
常见问答
问：表面电阻是不是越低越保险？
答：不是。太低（导电级）在未接地状态下遇上来路不明的高压电荷，放电太快，反而可能伤器件；太高等于绝缘，电荷泄不掉。载具要的是受控泄放，所以区间才是要求。
问：炭黑和碳纤维，怎么选？
答：看两件事——目标准哪个区间，以及洁净度门槛。炭黑成本友好，但填充量高、力学掉得多、只能深色；碳纤维导电效率高、加量低，但成本高、可能露纤。高洁净件优先低露纤体系。
问：为什么供应商报一个电阻值，我做出来却不是这个数？
答：先对齐口径——电极、压力、电压、温湿度、调节时间。再确认你测的是不是表面的真实状态。清洁之后测，和多点取区间，比争论一个数字有用。
| 工况 | 关键判据 | 自产常规供应 |
|---|
| 常温 ESD 托盘 / 载具 | 表面电阻 10⁶–10⁹ Ω | 炭黑耗散级改性 PP 方向 |
| 一般电子周转 | 抗静电 + 浅色 | 永久抗静电剂改性 PP 方向 |
| 高洁净接触件 | 不脱屑、低析出 | 高纯炭黑 / CNT 方向（洁净度按客户规范评估） |
想提醒一句：这类件出问题，最常见的错法是先换料。电阻漂、读数失真、掉粉——每一条的原因都不止一个。先定位，再换料；顺序反了，往往换了几轮还在原地。
十、最后说三句
第一，ESD 件选型的第一句话是"电阻落在哪个区间"，不是"能压到多低"。 太低和太高，是两个方向的错。
第二，"填多少"不是算出来的，是打出来的。 电阻随填料含量是陡降曲线，配方窗口很窄；看的是批次稳定性，不是单点值。
第三，验证顺序比验证项更重要。 口径 → 多点电阻 → 清洁后复测 → 老化后复测 → 跌落结构；清洁后复测这一关，决定这个数算不算数。
关于我们
我们站在树脂厂和注塑厂之间。
上一格是石化和聚合，下一格是模具和机台。中间这一段最像翻译——把树脂的指标翻译成件的性能，把件的要求翻译回料的方向。
宁波市科隆新材料有限公司，自产改性聚丙烯（PP）造粒，覆盖均聚 / 无规共聚 / 抗冲共聚三档基材，以及填充、玻纤增强、增韧、阻燃、低气味低 VOC、耐候、免喷涂耐划伤等改性方向；兼营各大石化厂 PP 树脂、副牌料与大包料。
How to control conductive PP for semiconductor ESD carriers and trays, with surface resistance of 10⁶–10⁹Ω? The answer is not 'the more conductive, the better.' First, classify the resistance according to ANSI/ESD S541 and IEC 61340-5-1, and then decide whether to use carbon black, carbon fiber, or a permanent antistatic agent approach. This article provides a five-column criteria table, a set of verification sequences, and three conditions under which modified PP should not be used.
An engineer who works on back-end semiconductor equipment once asked me a question: For your electrically conductive modified PP, how low can the surface resistance be reduced?
I said, don’t ask how low it can go first. You need to tell me whether this component is supposed to discharge the electric charge or block it—the resistance ranges required for these two things are opposite.
He was stunned for a moment and said, 'Isn't lower better?'
This is the most common misconception about ESD carriers and pallets made with conductive modified PP: the surface resistance is not better the more conductive it is; it needs to fall within a certain range.
Conductive grade (about 10³–10⁵ Ω) discharges too quickly. If it is not grounded, once it comes into contact with an unknown high-voltage charge, it might actually damage the device with a single 'hard discharge.'
Insulation grade (≥10¹¹ Ω) is more direct: the charge simply doesn't leak and accumulates throughout.
The part truly suitable for direct contact with sensitive devices is the middle section—the electrostatic dissipative level.
Below, break down step by step according to operating conditions, routes, criteria, and verification.
1. The six operating conditions of semiconductor ESD carriers: Set the boundaries for temperature and cleanliness first
The first question in choosing an ESD carrier is not 'What is the resistance?', but 'Will this component come into direct contact with the device, and at what high temperature will it operate?' These two points set the boundaries first; the rest is just the formula.
| Dimension | Actual working conditions of carriers/pallets | Requirements for the materials |
|---|
| Temperature | Mainly stored and transported at room temperature; if it goes through the 150℃ level baking during the process, or requires high-temperature cleaning, the boundary is immediately raised. | Conductive PP commonly has a continuous use temperature of about ≤90°C, and the high-temperature range is a hard limit. |
| Load | Multi-layer stacking, robotic arm grabbing, transport vibration and dropping | Warp-resistant, scratch-resistant deformation, dimensionally stable |
| Medium | IPA and other cleaning agents, diluted acids, wiping solvents | Chemical resistant, resistance does not drift after cleaning |
| Lifespan | Repeated circulation and repeated cleaning of carriers | Resistance and cleanliness must withstand the test of time |
| Appearance / Cleanliness | Mostly dark colors; does not flake, does not shed powder, low deposition | As important as resistance |
| Compliance | ESD control procedures (ANSI/ESD S20.20, IEC 61340-5-1); cleanroom classification (commonly ISO Class 4–5) | Resistance range Cleanliness dual thresholds |
Among the six dimensions, temperature and cleanliness are determined first. Temperature decides whether the base material can still be PP; cleanliness decides whether the filler system can use carbon fiber. If these two are not determined, further discussion about powers of ten is meaningless.
2. The three material routes for conductive PP: how to differentiate carbon black, carbon fiber, and permanent antistatic agents
None of the three paths is better; it only depends on 'which range you fall into and what price you pay.'
| Route | Get what | Cost |
|---|
| Carbon black system | It can cover from conductive grade to dissipative grade; in publicly available patent information, conductive carbon black commonly ranges from 15–30 parts (Grade A). | Decreased mechanical strength and toughness; basically can only produce dark colors; surface may precipitate or powder off |
| Carbon fiber system | Large aspect ratio, high electrical conductivity, relatively low filling amount | High cost; fibers may break during processing; friction may cause fibers to be exposed and fall off, use cautiously for high-cleanliness parts |
| Permanent antistatic agent system | Surface resistance can reach 10⁶–10¹¹ Ω (according to publicly available product information from the manufacturer, Class B), light-colored, non-migrating | Higher cost; need to assess compatibility and precipitation with the substrate |
To understand the differences among these three paths, first remember one thing: resistance does not decrease linearly with filler content; it follows a steeply dropping curve.
When the filler is added in small amounts, there is almost no reaction; when it reaches a certain critical value, the resistance can drop by several orders of magnitude in a very small addition range, and this is percolation.
In publicly available journal data, the percolation threshold of melt-blended carbon black / PP is about 2.75 vol%, and it can be as low as 0.37 vol% (Grade A) when made into an isolated structure.
Where the steep drop section is determines how narrow the formula window is—so 'how much to fill' is not calculated, it is entered manually.
Another cost of modification is in color and cleanliness: carbon black and carbon fiber cannot be removed, so dark colors are standard; permanent antistatic agents can preserve light colors, but the compatibility and cost need to be considered additionally.
Which range the resistor should fall into, first look at this table:
| Grading (through-bore caliber) | Typical Range of Surface Resistance | Main Uses |
|---|
| conductive grade | Approximately 10³–10⁵ Ω | Situations requiring rapid discharge, grounding, and shielding |
| Electrostatic Discharge Level (ESD Level) | Approximately 10⁶–10⁹ Ω (generally 10⁴–10¹¹ Ω) | Main operating areas of vehicles, pallets, and material boxes |
| Anti-static grade | approximately 10¹⁰–10¹² Ω | Inhibit vacuuming, do not release actively |
| Insulation class | ≥10¹¹ Ω | ESD-sensitive devices are dangerous |
Source caliber: ANSI/ESD S541 classifies packaging and materials into three categories: conductive (<1×10⁴ Ω), static dissipative (1×10⁴ to <1×10¹¹ Ω), and insulative (≥1×10¹¹ Ω), with test methods ANSI/ESD STM11.11 / 11.12 / 11.31 (Class A); IEC 61340-5-1 specifies conductive about 10²–10⁵ Ω, dissipative 10⁵–10¹¹ Ω, insulative ≥10¹¹ Ω (Class A). 'Carriers and pallets commonly use 10⁶–10⁹ Ω' is an industry-standard engineering practice (Class B publicly available technical information).
The core judgment of this table is only one sentence: too low (purely conductive) is not necessarily good, too high is equivalent to insulation, and the range is what is required.
3. ★ Surface Resistance Classification Criteria Table: Where the conductive level, dissipative level, and insulating level are used
The thing you should look at first in this table is not 'which indicator to check,' but 'which set of electrodes was used, how much pressure, and which voltage was measured.' If the standards aren't consistent, the two numbers can't be compared.
| Indicator | Threshold Value (Typical) | Verification Method / Standard | Common Failures | Common solution |
|---|
| Surface resistance | Falls within the target range (vehicles commonly take 10⁶–10⁹ Ω) | ANSI/ESD STM11.11; GB/T 1410-2006 | Resistance drifting out of range | Proportioning and Dispersion Process |
| Volume resistivity | Fall into the same interval | ANSI/ESD STM11.12; GB/T 1410 | Qualified on the surface, unqualified internally | Body conductive system |
| Test condition caliber | 23±2℃, 50±5% RH (for humidity-sensitive materials: 12%±3% RH, adjusted for no less than 24 hours) | ANSI/ESD STM11.11 | Same material, different value | Unify the standards and include temperature and humidity in the report |
| Electrostatic charge decay | 1000V attenuated to 100V ≤2s (Class A caliber) | GB/T 36340-2018 | Release too slowly | Adjust the resistor downward within the range |
| Non-flaking / Granules | No flaking, no powder loss | Cleanroom Particle Counting (Customer Specification) | Exposed fibers shedding powder | Low-exposure fiber system Processing surface chamfer |
| Low precipitation / low ions | Low outgassing, low metal ions | Customer Cleanliness Standards | Contaminated back of the component | High-purity carbon black or CNT, avoid metal filling |
| Chemical-resistant | Resistant to IPA, dilute acids, and cleaning agents | Re-measure resistance after soaking | Cracking, resistance drift | The substrate is compatible with the system |
| Continuous use temperature | Common caliber ≤90℃ | Retest after thermal aging | Deformation, dimensional drift | Exceeding temperature PEEK / PPS (see paragraph six) |
| Dimensional stability / Warping | Common tolerance with automation ±0.02–0.05mm | Coordinate measuring machine, flatness | Failed to fetch | Control shrinkage Strengthen structure |
| Tensile / Notch Impact | According to the requirements per item | GB/T 1040.2, GB/T 1043.1 | Insufficient strength | Reduce filling or change the system |
| Melt flow rate | According to filling requirements | GB/T 3682.1 | Underfilling | Select the corresponding flow gear |
Text Version Conclusion: Among these eleven items, surface resistance is the entry point, not everything. As long as parts directly contact the device, the cleanliness indicators cannot be skipped—no flaking, low outgassing, low metal ions—which are on par with resistance as a threshold. Treat this table like a medical check-up form: if even one item is missing, it is considered unqualified. It's much more cost-effective than completing a batch of carriers and then going back to find the reason.
On semiconductor carriers, why is cleanliness worth listing in a separate small table? The reason is very straightforward:
| Clean item | Requirement | Relationship with resistance |
|---|
| Does not flake / Lose powder | Surface particles controllable | Carbon fiber systems may expose fibers during friction; for high-cleanliness components, high-purity carbon black or CNTs are preferred. |
| Low precipitation / Low outgassing | Low volatility in vacuum and clean rooms | Migratory antistatic agents will precipitate, which conflicts with cleanliness requirements |
| Low metal ions | Avoid metal contamination | Metal-free filling system |
| Chemical resistant | Resistant to IPA, dilute acid, and cleaning agents | It is only considered truly durable if the resistance does not change after cleaning. |
| Dimensional stability | Tolerances are tight when coordinated with automation | High-fill systems are prone to warping and require structural coordination |
In a nutshell: in a cleanroom, dropping a particle and having a resistor increase by an order of magnitude are accidents of the same level.
4. Common failures and root causes: Resistors pass individually, but the entire component fails most often
The most common problem with this type of component is not that the resistance is out of specification, but 'this point passes, the whole component fails'.
Failure 1: It passes when tested at a single point, but shows large dispersion when measured at multiple points. The root cause is uneven filler dispersion—the percolation network is near the critical threshold and is extremely sensitive to local concentration, causing the resistance at different locations on the same part to differ by orders of magnitude.
Here, we need to negate a common practice: taking a standard test piece, measuring one point, reporting a number, and then delivering it. The failure of ESD components often occurs at the position that was not measured.
Failure 2: The 'surface resistance' suddenly becomes very high. In most cases, it is not that the material has changed, but that the surface has been contaminated. Silicone-containing cleaners, wax-based care products, and residual release agents can leave an insulating layer on the surface.
The value measured after wiping is the true value—this is also the reason why, in the verification sequence, a separate step of cleaning and retesting is arranged.
Failure three: The resistance slowly drifts out of range. In systems using migratory antistatic agents, which work through a surface migration layer, it can be rubbed off, washed away, and will also fail in dry environments.
Failure Four: Fiber Loss and Fiber Exposure. This is concentrated in carbon fiber systems, especially at friction contact surfaces. Highly clean components either need to change the system or perform chamfering and control fiber exposure at the contact surfaces.
5. Verification sequence for conductive PP used in ESD carriers: should the resistance be measured first, or should the drop test be done first?
The sequence is first to define the caliber, then measure the resistance, then clean and re-measure, then age and re-measure, and finally perform drop test and structural test.
`
① Caliber Confirmation Electrode type, pressing time and test voltage, temperature and humidity (23±2℃/50±5%RH or 12%±3%RH)
↓ The calibers are not uniform, so the following numbers are not comparable
② Measure resistance at multiple points and multiple times: Measure the same item at more than 5 points, at least 3 items, and observe the range and dispersion.
↓ If the dispersion exceeds an order of magnitude, address the scattering first before proceeding further.
③ Retest after cleaning Retest after handling according to the cleaning method specified by the customer
↓ This step is the 'real value'
④ Retest after aging Retest after humidity, washing cycles, and time to see if it drifts out of the range
↓ Float out of the range, go back to ② to rebalance the ratio
⑤ Drop Test and Structural Verification Installation, Grasping, Drop, Assembly Tolerance
`
You can only talk about mass production after running through this whole set. The most common mistake is skipping steps ② and ③, and directly using the trial mold part to take a measurement before going into batch production.
The forming conditions of the trial mold are often temporary, and the readings are not representative; the readings before cleaning are also not the real values.
Text version conclusion: The verification sequence is caliber → multi-point resistance → re-test after cleaning → re-test after aging → drop structure. The re-test after cleaning must be completed before aging because it determines whether this number actually counts.
6. Reverse Honesty: When these three conditions occur, ESD carriers should not use modified PP
Previously we talked about how to do it; here we talk about when not to do it.
- For extremely high cleanliness requirements and direct contact surfaces of devices (such as the front side of advanced process wafers): the matrix cleanliness and low ion levels of modified PP cannot support this; carbon-based dissipative PEEK, or PPS / PEI should be used.
- For long-term high temperatures (such as baking at around 150°C during processing or requiring high-temperature cleaning): the continuous use temperature of conductive PP is commonly around ≤90°C, which is obviously insufficient. PPS is about 200–220°C, PEI about 170–180°C, and carbon-filled PEEK about 260°C, and they are resistant to solvents such as NMP and THF.
- Requires the resistance to remain stable in an extremely narrow range over a long period: small-molecule anti-static PP cannot achieve this (it will migrate and be affected by humidity); a bulk conductive PEEK/PPS carbon-based system should be used.
- Clearly need electromagnetic shielding: go with metal fiber or metallized solutions, not just the words 'conductive PP'.
The rule is consistent: whenever 'requirements in two opposite directions must be met at the same time' appear, it indicates that this part should not be forced using PP.
In situations like this, our approach is to first clarify this point, and then discuss whether there is any room for compromise — pushing through the order forcefully will ultimately result in rework and claims being sent back.
7. What to touch when changing materials: a checklist to look at before you act
| Items to move | What needs to be confirmed | What will happen if I don't do it? |
|---|
| Mold shrinkage rate | Difference in shrinkage rate between the new material and the original plan | Size out of tolerance, grab failed |
| Gate and Venting | High-filling systems are more sensitive to the gate | Underfilling, flash |
| Material Temperature and Mold Temperature | The windows of different filler systems are different | Surface defects, uneven resistance |
| Dry | Fillers are usually not needed; it depends on the specific system. | Silver threads, bubbles |
| Pressure Holding and Demolding | Shrinkage differences cause deformation and whitening on the surface | Deformation, extrusion strain |
| Color difference | Confirm color swatch for dark items first | Batch color difference dispute |
| Verification order | Caliber → Multi-point resistance → After cleaning → After aging | All the risks are concentrated to explode at the final step |
Text version conclusion: Changing materials affects three areas: molds, processes, and color differences, among which the verification sequence should be discussed first. Skipping ① and ② and directly testing the mold is equivalent to spending the cost in advance.
8. One-page report sheet (can be directly pasted into PPT)
| Scene | Recommended Route | Key indicators | Verification Standard | Conditions that need to be confirmed first |
|---|
| Ambient Temperature Storage / Transport Pallet | Carbon Black Dissipative Grade Modified PP | Surface resistance 10⁶–10⁹ Ω | ANSI/ESD STM11.11 | Whether to contact the front of the device |
| Carriers that require baking / high-temperature cleaning | Carbon-based dissipative PEEK / PPS | Temperature Resistance Range | Retest after thermal aging | Specific temperature and number of cycles |
| High-purity contact parts | High-purity carbon black / CNT dissipative system, or PEEK | Non-flaking, low precipitation, low ionization | Customer Cleanliness Standards | Cleanroom Level |
| Requires a narrow range and long-term stability | Conductive PEEK / PPS Carbon Series | Resistance Range Time Stability | Retest after aging | Allowed resistance upper and lower limits |
| General electronic assembly turnover | Permanently antistatic agent modified PP | Surface resistance 10⁶–10¹¹ Ω | Retest after wiping and aging | Is a light color required? |
Text Version Conclusion: The purpose of this form is to allow technicians to directly report their conclusions upward. There is only one criterion—whether the client can finalize the material direction in a single meeting using this form.
9. The part that is most likely to have problems is not that the resistance is too high.
The most typical early problems with ESD carriers and pallets are unstable resistance — within the same batch, some fall within the range while others drift out — as well as reading distortion caused by surface conditions (cleaner residue, flaking). Among these two categories, only a part is caused by the material itself.
The public criteria are clear: surface resistance is measured according to ANSI/ESD STM11.11, with the sample conditioned at 23±2°C and 50±5% RH (for moisture-sensitive materials, 12%±3% RH); the classification of conductive/dissipative/insulative follows ANSI/ESD S541 and IEC 61340-5-1; the commonly used dissipative range for carriers is 10⁶–10⁹ Ω.
The real difficulty is distributed consistency—the percolation network is near the critical point, and the formulation window is very narrow. What matters is batch stability, not single-point values.
The common practice in the industry is to determine three things together: the conductivity efficiency of the filler system, whether the ratio falls on the steep decline side, and whether the dispersion process can be stabilized. The key is not 'whose resistance is lower,' but whether resistance, cleanliness, mechanical properties, and processability can all be aligned simultaneously.
Ningbo Cologne New Materials Co., Ltd. usually supplies conductive and antistatic types of modified polypropylene (PP) pellets in this item, providing the corresponding filler system and substrate grade according to the target resistance range and cleanliness requirements of the item.
It is mainly used to address the two issues mentioned above: 'resistor drifting out of range and surface reading distortion'; the formula is adjusted per piece, allowing for small sample comparisons, multi-point resistor re-testing, and re-testing after cleaning. It can also accommodate the needs of customers with multiple varieties in small batches at the piece level.
Frequently Asked Questions
Question: Is it safer if the surface resistance is lower?
Answer: No. If it's too low (conductive grade), encountering an unknown high-voltage charge while not grounded will discharge too quickly, which could actually damage the device; if it's too high, it equals insulation, and the charge cannot dissipate. What the carrier needs is controlled discharge, so a range is required.
Question: How to choose between carbon black and carbon fiber?
Answer: Look at two things—the target range and the cleanliness threshold. Carbon black is cost-friendly, but requires high loading, reduces mechanical properties significantly, and can only be dark in color; carbon fiber has high conductivity efficiency and requires low loading, but is expensive and may expose fibers. For high cleanliness parts, systems with low fiber exposure are preferred.
Question: Why does the supplier quote a resistor value, but the one I make does not match this number?
Answer: First, align the calibers—electrodes, pressure, voltage, temperature and humidity, adjustment time. Then confirm whether what you are measuring is the real state of the surface. Measuring after cleaning, and taking multiple points over a range, is more useful than arguing over a single number.
| Operating condition | Key criterion | Self-produced regular supply |
|---|
| Room Temperature ESD Tray / Carrier | Surface resistance 10⁶–10⁹ Ω | Direction of carbon black dissipative grade modified PP |
| General electronic circulation | Anti-static Light color | Direction of permanent anti-static agent modified PP |
| High-purity contact parts | Non-flaking, low deposition | High-purity carbon black / CNT direction (cleanliness assessed according to customer specifications) |
I want to give a reminder: when this kind of component has problems, the most common mistake is to replace the material first. Resistance drifting, distorted readings, powder flaking—each of these issues has more than one possible cause. First identify the problem, then replace the material; if you reverse the order, you often end up replacing several times and still being in the same place.
Ten, Lastly, Say Three Sentences
First, the first thing to consider when selecting an ESD component is 'which resistance range it falls into,' not 'how low it can go.' Too low or too high are mistakes in two different directions.
Second, the 'how much to fill in' is not calculated, it is entered. The resistance decreases sharply with the filler content, and the formulation window is very narrow; what matters is batch stability, not a single point value.
Third, the verification sequence is more important than the verification items. Caliber → multipoint resistance → retest after cleaning → retest after aging → drop structure; the retest after cleaning determines whether this number counts.
About Us
We are standing between the resin factory and the injection molding factory.
The previous section is about petrochemicals and polymerization, and the next section is about molds and machinery. This middle part is most like translation——translating the resin's specifications into the part's performance, and translating the part's requirements back into the direction for the material.
Ningbo Cologne New Materials Co., Ltd. produces modified polypropylene (PP) granules, covering homopolymer, random copolymer, and block copolymer base materials, as well as modifications including filled, glass fiber reinforced, toughened, flame-retardant, low odor and low VOC, weather-resistant, and scratch-resistant without coating; it also deals in PP resins from major petrochemical plants, off-spec materials, and bulk materials.
