{"id":16725,"date":"2026-09-10T16:42:05","date_gmt":"2026-09-10T09:42:05","guid":{"rendered":"https:\/\/pmac.asia\/may-do-do-day-xi-ma-trong-nganh-kim-hoan-va-ban-dan-khac-nhau-nhu-the-nao\/"},"modified":"2026-09-16T17:09:36","modified_gmt":"2026-09-16T10:09:36","slug":"how-do-coating-thickness-gauges-differ-between-the-jewelry-and-semiconductor-industry","status":"publish","type":"post","link":"https:\/\/pmac.asia\/en\/how-do-coating-thickness-gauges-differ-between-the-jewelry-and-semiconductor-industry\/","title":{"rendered":"How Do Coating Thickness Gauges Differ Between the Jewelry and Semiconductor Industry?"},"content":{"rendered":"

In manufacturing, metal coatings do more than define the appearance of a product. They also affect durability, material costs, and the ability to meet technical requirements<\/strong>. This is particularly evident in the jewelry industry, where gold, rhodium, and other precious-metal coatings need to be carefully controlled to maintain quality while minimizing material waste; and in the semiconductor industry, where extremely thin metal layers can directly affect electrical conductivity, interconnection performance, and component reliability.<\/p>\n

For this reason, coating thickness measurement<\/strong> has become an important part of quality control. Among the available techniques, XRF is widely used because it provides fast, non-destructive analysis and can be applied to a wide range of metallic coating systems.<\/p>\n

However, coating thickness gauges used in jewelry and semiconductor applications are not necessarily the same<\/strong>. A gold-plated ring and a semiconductor lead frame may both require coating inspection, but they differ significantly in measurement area, number of metal layers, coating thickness, and how the resulting data is used. How do these differences affect the selection and configuration of the measurement system?<\/strong><\/p>\n

I. Why Measure Coating Thickness Instead of Only Checking Metal Composition?<\/strong><\/h2>\n

1. Coating thickness directly affects coating quality and function<\/strong><\/h3>\n

In a metallic coating system, material composition and thickness are two different parameters. Identifying whether a coating contains gold, nickel, palladium, or another metal tells us which material is present<\/strong>, but it does not indicate whether the coating has been deposited to the thickness required for the product.<\/p>\n

Coating thickness needs to be controlled because each layer is designed to perform a specific function. In jewelry, gold, rhodium, and other precious-metal coatings contribute to color, surface finish, and wear resistance while also representing a significant portion of material costs. A coating that is too thin may reduce durability or surface quality, while excessive plating increases precious-metal consumption without necessarily creating additional value.<\/p>\n

In electronics and semiconductors, control requirements are even more demanding because metallic coatings often perform a technical function<\/strong> within the component structure. Gold, palladium, nickel, and copper layers may be used to form electrical contacts, support bonding and soldering, protect surfaces, or act as barriers between different materials. As a result, deviations in coating thickness can affect both the quality of the coating and the performance and reliability of the component.<\/p>\n

Coating control therefore cannot stop at identifying composition. Thickness must also be measured and compared with the technical limits specified for each product, material, and manufacturing process.<\/strong><\/p>\n

2. How does XRF measure coating thickness?<\/strong><\/h3>\n

Manufacturers can use several methods to control coating thickness. Among them, XRF \u2013 X-ray fluorescence<\/strong> is widely applied to metallic coatings because it can analyze the sample directly without cutting, stripping, or otherwise damaging the product.<\/p>\n

When X-rays irradiate the sample surface, the elements in the material emit fluorescent X-rays at characteristic energy levels. The instrument detects and analyzes these signals to determine elemental composition. When combined with an analytical model appropriate for the coating system and substrate, XRF can also determine the thickness of a single layer or multiple stacked metallic layers<\/strong>. Measurement capability, however, depends on factors such as material type, coating thickness, substrate material, number of layers, and the size of the area being analyzed.<\/p>\n

These factors are particularly important when selecting a coating thickness gauge<\/strong> for a specific industry. An instrument suitable for checking gold plating on jewelry may not meet the requirements for measuring extremely thin metal layers on very small semiconductor structures. Conversely, many specialized features designed for semiconductor applications may be unnecessary for routine jewelry inspection.<\/p>\n

Differences in the measurement object, measurement spot size, coating structure, and measurement objective<\/strong> therefore form the basis for distinguishing equipment requirements between the two industries. For a deeper understanding of the analytical principle, see PMAC\u2019s article What is XRF technology?<\/a>.<\/p>\n

\"Operating

Figure 1. Operating principle of an XRF instrument for metallic coating measurement<\/p><\/div>\n

II. Coating Thickness Measurement in the Jewelry Industry<\/strong><\/h2>\n

Inspection objects in the jewelry industry vary widely, from rings, necklaces, and bracelets to watches and decorative components. Their surfaces are often curved, irregular, or contain multiple edges rather than presenting the flat geometry typically found in laboratory samples. As a result, correct sample positioning and accurate measurement-point selection<\/strong> have a significant influence on the reliability of the result.<\/p>\n

When measuring the gold coating on a ring, for example, the X-ray beam needs to be directed precisely at the surface area being evaluated. If the measurement spot falls too close to an edge, on a highly curved area, or at the boundary between two materials, the resulting signal may not accurately represent the coating under inspection. XRF instruments used in jewelry applications therefore often require a clear sample-viewing system, a convenient sample stage, and the ability to select an appropriate measurement area for different product geometries.<\/p>\n

Another characteristic of jewelry applications is that users are often interested in both coating thickness<\/strong> and precious-metal composition and content<\/strong>. The same XRF instrument can support measurement of gold, rhodium, and other coatings while also analyzing alloy composition without damaging the product. For this reason, coating thickness gauges for jewelry applications<\/strong> are often selected based on fast measurement, the ability to handle complex sample geometries, and support for precious-metal analysis.<\/p>\n

III. Coating Thickness Measurement in the Semiconductor Industry<\/strong><\/h2>\n

In semiconductor manufacturing and semiconductor packaging, metallic coatings are typically applied to much smaller structures. Measurement targets may include lead frames, contact areas, under-bump metallization layers, or conductive features within packaging structures<\/strong>. The challenge therefore involves both measuring a very thin metallic layer and accurately targeting a very small area.<\/p>\n

A lead frame provides a useful example. Some structures may contain several stacked metallic layers such as gold \u2013 palladium \u2013 nickel \u2013 copper<\/strong>. Gold and palladium may be extremely thin, while nickel acts as an intermediate layer with greater thickness. If the X-ray measurement spot is too large relative to the lead being inspected, the instrument may simultaneously collect signals from surrounding materials, causing the result to no longer accurately represent the intended measurement location.<\/p>\n

For this reason, XRF systems designed for very small structures<\/a> generally use smaller measurement spots and more precise positioning capabilities than instruments intended for more conventional applications. This is one of the key differences to consider when selecting equipment for semiconductor applications.<\/p>\n

In addition to measurement spot size, multilayer structures<\/strong> make the analysis more complex. The instrument must do more than determine \u201chow much gold is present\u201d; it needs to separate the signals from individual layers and calculate their respective thicknesses. As the number of layers increases and each layer becomes thinner, the requirements for the instrument, calibration, and analytical software also become more demanding.<\/p>\n

\"Multilayer

Figure 2. Multilayer Au\/Ni\/Cu metallic structure in semiconductor applications<\/p><\/div>\n

IV. The Difference Lies in the Purpose of Measurement<\/strong><\/h2>\n

In jewelry, measurement results are commonly used to verify whether a precious-metal coating has sufficient thickness, the correct composition, and the required surface quality. Effective control also helps avoid excessive use of gold and other high-value metals, allowing manufacturers to balance product quality with raw-material costs.<\/p>\n

In semiconductor applications, a metallic layer may directly perform a functional role within the component. The thickness of nickel, gold, palladium, or copper can influence bonding performance, solderability, electrical-contact stability, and the reliability of the packaged device. Measurement results therefore support both product acceptance and the monitoring of plating or metallization process stability<\/strong>.<\/p>\n

In high-volume production, manufacturers must also consider uniformity across multiple locations, repeatability between production lots, and process trends over time. In this environment, the coating thickness gauge becomes part of the manufacturing control system rather than simply an instrument for inspecting individual samples.<\/p>\n

When the two applications are compared, the main difference does not lie in the XRF principle itself but in the sample being measured, measurement spot size, coating structure, and required level of process control<\/strong>.<\/p>\n

 <\/p>\n\n\n\n\n\n\n\n\n\n\n\n
Criteria<\/strong><\/td>\nJewelry Industry<\/strong><\/td>\nSemiconductor \/ Semiconductor Packaging<\/strong><\/td>\n<\/tr>\n<\/thead>\n
Measurement objects<\/strong><\/td>\nRings, necklaces, watches, accessories, and precious-metal-plated products<\/td>\nLead frames, contacts, solder areas, under-bump metal layers, and packaging structures<\/td>\n<\/tr>\n
Primary objective<\/strong><\/td>\nVerify thickness, composition, and quality of precious-metal coatings<\/td>\nControl metallic layers that affect interconnection, solderability, and reliability<\/td>\n<\/tr>\n
Sample characteristics<\/strong><\/td>\nOften curved, with a wide variety of sizes and shapes<\/td>\nVery small measurement areas and high feature density<\/td>\n<\/tr>\n
Coating structure<\/strong><\/td>\nGenerally simpler; may include a precious-metal layer, intermediate layer, and substrate<\/td>\nOften consists of multiple very thin stacked metallic layers<\/td>\n<\/tr>\n
Measurement spot<\/strong><\/td>\nSmall enough to target the correct feature on the product<\/td>\nMay require an extremely small spot to avoid signals from adjacent areas<\/td>\n<\/tr>\n
Operational requirements<\/strong><\/td>\nFast, easy positioning, non-destructive<\/td>\nHigh repeatability, precise positioning, multilayer measurement, and potential automation<\/td>\n<\/tr>\n
Role of data<\/strong><\/td>\nQuality inspection and precious-metal consumption control<\/td>\nProduction-process monitoring and coating-process stability<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

V. Why Might an XRF System That Works Well for Jewelry Be Unsuitable for Semiconductors?<\/strong><\/h2>\n

An XRF system may provide excellent results when measuring a gold coating on a ring yet still be insufficient for inspecting an extremely thin gold or palladium layer on a semiconductor lead. The first reason is measurement spot size<\/strong>. In jewelry, the surface being evaluated is often large enough for a relatively wide measurement spot to remain representative. In semiconductor applications, if the X-ray spot is larger than the feature itself, signals from surrounding materials may affect the result.<\/p>\n

The second factor is multilayer analysis capability<\/strong>. XRF does not directly visualize the boundary between individual layers in the same way that a cross-section can be physically cut and observed. Instead, the instrument relies on spectral signals together with a predefined material model to calculate layer thickness. The greater the number of layers and the thinner those layers become, the higher the requirements for the detector, calibration, and analytical software.<\/p>\n

The third factor is measurement automation<\/strong>. In jewelry applications, an operator can position each item and select the measurement point manually. In electronics or semiconductor production, a component tray may contain dozens or hundreds of locations that need to be inspected. Automated sample stages, pattern recognition, and multi-point measurement programs can therefore improve consistency and make the inspection process more suitable for high-volume production.<\/p>\n

For this reason, the selection of a coating thickness gauge<\/strong> should begin with the actual sample and measurement requirements rather than simply with whether the instrument uses XRF technology.<\/p>\n

VI. Criteria for Selecting a Coating Thickness Gauge<\/strong><\/h2>\n

For jewelry applications, equipment selection should begin by identifying whether the product involves gold, silver, rhodium, or a multilayer system; whether the surface is curved or difficult to position; the smallest area that needs to be inspected; whether precious-metal content must also be determined; and how many samples need to be measured each day.<\/p>\n

In electronics and semiconductor applications, these questions need to be more detailed. Manufacturers need to know which metallic layers must be measured, the expected thickness of each layer, the smallest feature requiring inspection, the substrate material, the number of layers in the structure, and whether automated measurement across multiple locations is required<\/strong>.<\/p>\n

For example, a jewelry facility that mainly checks gold coatings on finished products will have very different requirements from a semiconductor plant measuring multiple Au\/Pd\/Ni layers across large numbers of lead-frame contacts. Both may search for an \u201cXRF coating thickness gauge,\u201d but the appropriate configuration can differ significantly. Therefore, the most suitable instrument is not necessarily the one with the highest specifications<\/strong>, but the one whose measurement spot, layer-analysis capability, sample stage, and software best match the product being controlled.<\/p>\n

\"SpectraX

Figure 3. SpectraX 55 for coating thickness measurement and metal composition analysis<\/p><\/div>\n

VII. Conclusion<\/strong><\/h2>\n

From gold coatings on jewelry to extremely thin metallic layers in semiconductor packaging, XRF demonstrates a broad range of applications. However, differences in the products themselves lead to substantially different equipment requirements.<\/p>\n

In jewelry, the focus is typically on precious metals, coating thickness, product geometry, and non-destructive inspection<\/strong>. In semiconductor applications, measurement requirements extend further into very small areas, multilayer structures, repeatability, and the ability to feed measurement data back into manufacturing process control<\/strong>.<\/p>\n

Therefore, when selecting a coating thickness gauge<\/strong>, manufacturers should not focus solely on the name of the technology or the list of elements an instrument can measure. The more important consideration is whether the instrument truly matches the coating structure and control objectives of the product.<\/p>\n

These differences also reflect the close relationship between materials, plating processes, and measurement technology<\/strong>. In semiconductor applications, PMAC has explored this relationship in greater depth in the article Semiconductor Plating Materials<\/a>.<\/p>\n

For companies beginning to explore XRF equipment, PMAC\u2019s articles on XRF technology<\/a> and handheld XRF analyzers<\/a> provide further context on the differences between instrument types and their intended applications.<\/p>\n

Contact PMAC to learn more about coating thickness gauges, XRF technology, and analytical and metrology solutions for jewelry, electronics, and semiconductor applications.<\/strong><\/a><\/p>\n

PMAC Joint Stock Company<\/span><\/h3>\n

Ho Chi Minh City Office:<\/strong>
4th Floor, HUTECH Building, D1 Road, Saigon Hi-Tech Park, Tang Nhon Phu Ward, Ho Chi Minh City, Vietnam<\/p>\n

Hanoi Office:<\/strong>
22B O2, Linh Dam Peninsula, Hoang Liet Ward, Hanoi, Vietnam<\/p>\n

Hotline:<\/strong>\u00a0+84 387 235 878<\/p>\n

Facebook:<\/strong>\u00a0PMAC<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

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