勛圖tv 繚 ENGINEERING GUIDE
0201 and Micro-BGA PCB Tolerances: Package, Mask and Via Budgets
0201 and micro-BGA PCB tolerances must begin with an exact component drawing. The label 0201 is ambiguous across naming systems: 0201 inch commonly describes a nominal 0.6 by 0.3 mm chip, while metric naming can refer to a different size. Package pitch, terminal geometry and the manufacturer's land pattern matter more than a short package nickname.
Identify the actual package
Record the manufacturer part number and package drawing revision. Confirm body size, terminal size, coplanarity and recommended land pattern. A passive chip and a wafer-level package may use similarly small dimensions but have different assembly behavior. Do not transfer a land pattern merely because both are described as miniature.
Murata's published 0201 inch example explicitly associates that name with 0.6 by 0.3 mm dimensions. Use such dimensional identification rather than allowing a purchase description to decide the PCB footprint. For the actual design, the selected part's current drawing remains the reference.
Separate copper, mask and paste geometry
The copper pad defines one boundary, the solder-mask opening another, and the stencil aperture a third. Each is produced by a different operation. A nominal mask opening does not guarantee a retained web between adjacent pads, and a larger copper land does not automatically improve assembly yield.
For BGA lands, establish whether the intended definition is copper-controlled or mask-controlled and follow the component and assembly guidance. For tiny chip components, assess the paired pad design and paste balance. Avoid making a generic change to every small footprint without assembly review.
Use the mask-web worksheet carefully
The tool subtracts the maximum opening diameter from pitch, then subtracts two independent local edge-growth allowances entered by the user. It reports a conservative residual web for two adjacent circular openings. A common translation of the entire mask image does not reduce their mutual web; that translation instead affects registration between mask and copper.
For example, 0.40 mm pitch and 0.30 mm maximum openings leave a nominal 0.10 mm web before extra local edge allowances. With 0.02 mm allowed on each facing edge, 0.06 mm remains in this simplified model. This is not a recommended fabrication limit or a declaration that the web will survive processing.
Adjacent circular mask-opening web
Adjacent circular mask-opening web
Use the current inputs and keep the assumptions
Start with the example to understand the units and output, then use Clear for my inputs before entering your project. Example mode stays visibly labeled even if you edit its numbers. The form begins without a result so an illustrative value cannot be mistaken for an approved requirement. Every field must have a valid value; zero is accepted only where it has a meaningful role in the particular model.
Read the input notes before calculating. They identify the physical boundary and what is excluded. Keep the same unit convention across the drawing and worksheet. Changing an input invalidates the previous result and disables its download until you calculate again. This prevents an old number from appearing to describe a revised geometry.
The result is a screening record. A negative margin or an out-of-range condition identifies a question to resolve; a positive margin is not a manufacturing approval. Use the record with the actual drawing, material and project requirement. The model does not load CAD files, inspect images or retrieve private factory data.
Download the current result if it helps the discussion. The text includes the entered inputs, result and limitations. It stays on your device until you choose to attach or share it. Contact is a separate step; this page does not automatically populate the enquiry form or upload a file. Avoid confidential identifiers if you only need an exploratory calculation.
| Input | What to establish before using it |
|---|---|
| Review reference | Use a nonconfidential reference that lets you connect this calculation to the correct drawing revision. |
| Center-to-center pitch 繚 mm | Use the physical spacing of the two openings. A package nickname does not establish this dimension. |
| Maximum circular opening diameter 繚 mm | Use the maximum opening basis for the minimum-web review. Copper land and stencil aperture dimensions are separate. |
| Additional local growth on each facing edge 繚 mm | Enter only unaccounted local edge growth. A common translation of the whole mask image does not reduce the web between its own openings. |
Coordinate vias under fine-pitch lands
An open via in or near a solder land can affect paste and solder behavior. If a filled and capped structure is proposed, specify the complete construction and surface condition. The capped-via guide explains why a cap, fill and finish need separate consideration.
Review the pad stack, hole location and mask opening together with the proposed stencil. Moving a via to solve escape routing can change assembly behavior. Keep that change visible to the assembly reviewer rather than hiding it in a late routing revision.
Design an informative first build
Define what the first build needs to establish: print behavior, placement, reflow response, inspection access and functional performance. Inspection methods have different coverage; a visible surface view cannot show every hidden joint condition. Agree the relevant evidence rather than assuming a generic inspection label guarantees all defects are detectable.
Record package lots, stencil revision, board construction and process conditions with findings. If a defect appears, distinguish footprint geometry, material, printing, placement and thermal causes before changing several variables at once.
Release and enquiry inputs
Send the exact package drawings, land pattern, mask and paste data, via treatment, stackup and critical assembly requirements. Mark any geometry that differs from the component recommendation and explain why. Ask for feedback on those exceptions before the board and stencil are ordered.
Does 0201 alone identify a footprint? No. Does a positive mask-web calculation approve manufacture? No. Is a smaller paste aperture always better? No, the deposition and release behavior must be assessed. The next useful step is a coordinated fabrication and assembly review of the actual component, not a universal small-parts tolerance table.
Coordinate small-feature tolerances across fabrication and assembly
Build a dimensional chain from the component drawing through the copper land, mask opening, paste aperture and placed component. Each boundary serves a different purpose and belongs to a different manufacturing operation. Treating all of them as one footprint size can obscure the source of an assembly problem. Use the exact component revision and preserve any approved land-pattern deviations.
Separate relative geometry from common movement. Two mask openings can retain their mutual spacing while both shift relative to copper. Paste apertures can be correctly spaced but misregistered to the board. A component can be positioned within one tolerance while a terminal shape or land definition creates another limitation. A useful tolerance budget names the two objects being compared rather than adding every available tolerance indiscriminately.
Review the smallest retained and exposed features with the relevant process owners. The fabricator assesses copper and mask formation; the assembler assesses printing, placement and soldering with the selected materials and equipment. A dimension that can be fabricated may still create an unstable assembly process. Conversely, a proposed assembly improvement may require a changed board construction or via treatment.
Plan inspection around hidden and visible features. Optical access, X-ray interpretation, electrical test and functional test have different coverage. A single method should not be advertised as detecting every defect. Define the observations needed for the first build and distinguish them from routine production checks. Preserve the board, component and stencil revisions with the findings so a later change can be assessed intelligently.
When a problem appears, compare evidence before changing the footprint. Unequal paste deposits, board support, component variation and thermal conditions can produce symptoms that resemble a land-pattern issue. A controlled trial isolates the proposed cause and records the result. Avoid making simultaneous broad changes that prevent the team from learning which adjustment helped.
For an enquiry, send the exact package drawing and the relevant copper, mask and paste views. Include the intended quantity and whether the request concerns a prototype, qualification or recurring assembly. A useful response should identify unresolved assumptions and the next evidence needed. The page worksheet helps make the geometry explicit, but it does not replace component guidance, stencil design review or an assembly process qualification.
Standards, source context and limits
Use the performance and acceptance documents named in the procurement agreement, including their revisions and any applicable addenda. A design guide explains choices; a product acceptance requirement defines what must be demonstrated. Neither a reference link nor a calculator result is a certification of the board or the supplier. Where a value is contractually important, check the controlled document and agree the measurement method with the responsible parties.
Examples on this page are deliberately labeled and are not advertised 勛圖tv limits. Supplier documentation is linked for the specific material or process context it explains. Equipment photographs and cross-section examples show the subject; they are not current production, inspection or qualification records for your order.