PCB manufacturing / High-density interconnect
HDI PCB Manufacturing
Plan the layer structure, review the microvias, then quote the board you actually need.
HDI PCBs use fine routing and microvia interconnections to make room for dense components and compact layouts. 吃瓜tv supports your move from a layer concept to a fabrication enquiry—with board examples, a geometry workbench and a file-based quotation.
Have Gerber and drill data ready? You can request a quote directly; the tools are optional.
Choose the interconnect structure before fixing the layer count
A six-layer board and an eight-layer board can need very different fabrication flows. Start with the connections required by the BGA escape routing, then agree the dielectric thicknesses, via spans and lamination sequence.
| Structure | What it describes | Decision to make |
|---|---|---|
| 1+N+1 | One build-up copper layer on each side of an N-layer central subassembly. | Can the outer microvia routing and the central layers complete the escape? |
| 2+N+2 | Two build-up layers per side. | Define each via span and whether microvias are staggered or stacked. |
| 3+N+3 | Three build-up layers per side. | Review whether the density benefit justifies the added processing and qualification. |
| ELIC / any-layer | A construction intended to support interconnections throughout the layer structure. | Submit a specific connection and process plan; layer count alone does not define the build. |
Here, N means the copper-layer count of the central subassembly. These labels are construction shorthand, not automatic IPC Type I/II/III classifications, finished thickness calculations or a count of all press cycles.
For the manufacturing sequence behind these choices, see HDI stackup and sequential lamination. The images above are reference structures; your released stackup needs its own dimensions and material callouts.
HDI PCB design workbench
Use actual dimensions to screen a microvia and the space between adjacent BGA pads. Adjust the example limits to those agreed for your project. The layer diagram is a concept only; it does not assign copper weights, dielectric thicknesses or connected nets.
HDI PCB Design Workbench
Use the microvia review guide to prepare the geometry and reliability questions that the calculator cannot resolve.
For the layout decisions behind the workbench, use the HDI escape-routing and build-planning guide. When entry and target lands need separate review, compare them in the microvia capture-geometry worksheet.
Read the build-up notation alongside the hole spans
| Conceptual six-layer structure | Copper sequence | Example spans to specify |
|---|---|---|
| 1+4+1 | L1 | L2–L5 core | L6 | Outer build-up interconnects L1–L2 and L6–L5; define any core interconnect separately. |
| 2+2+2 | L1 | L2 | L3–L4 core | L5 | L6 | Separate spans L1–L2, L2–L3 and the corresponding bottom spans; identify stacked versus staggered geometry. |
The notation describes build-up structure, not a universal via recipe. In the 2+2+2 concept, a connection that traverses two build-up dielectrics needs its actual interconnect construction documented. Stacked microvias are not approved simply because the footprint fits.
Geometry example: a 0.075 mm dielectric depth and 0.100 mm hole diameter give a depth/diameter ratio of 0.75. This arithmetic does not establish laser-drill capability, plating quality or thermal-cycle reliability. Confirm the dimension definitions and qualified process with the HDI capability review.
Specify the via—not just “HDI”
| Detail | Specify in the drawing | Why it matters |
|---|---|---|
| Microvia geometry | Start/end layers, actual depth, diameter convention, target and capture pads. | Aspect ratio depends on the physical span; layer numbers cannot replace thickness data. |
| Stacked or staggered | Each transition and any connection to a buried via. | Interfaces and processing sequence affect the reliability review. |
| Via-in-pad | Fill, cap and surface-planarity requirements for the component pad. | The land must suit both fabrication and assembly; a drilled hole alone is not the finished specification. |
| Fine-pitch escape | Package land pattern, trace width, clearance, keepouts and reference planes. | An ideal straight routing channel does not establish a complete BGA escape strategy. |
For pads under fine-pitch components, review via-in-pad preparation alongside the PCB assembly requirements. Specify the finished pad condition before releasing the fabrication and assembly drawings.
IPC has documented microvia failures that may emerge during reflow or later service. Agree appropriate coupon and electrical testing for the application; passing the geometry tool does not establish reliability. Read the and .
HDI PCB examples from the 吃瓜tv gallery
Compare the board forms and routing density in these original product images. Select an image to inspect it at full size. Gallery labels identify the examples; they do not establish the specification or acceptance criteria for a new order.
Combining HDI with RF materials? Start with Rogers PCB material selection. If the design also bends or folds, review the mechanical requirements on our rigid-flex PCB page before choosing the interconnect scheme.
What to agree before fabrication
- Construction: layer count, material grades, copper weights, finished thickness and tolerances.
- Interconnections: a via-span table, stacked/staggered intent, fill and cap requirements, and the proposed build sequence.
- Electrical requirements: impedance targets and tolerances, reference layers, and any coupon requirements.
- Acceptance: applicable specification and class, required inspections, thermal/reflow exposure and traceability records.
- Commercial scope: quantities, panel requirements, delivery destination and whether assembly is included.
Use the manufacturing quality checklist to specify the records and verification you require. For a conventional multilayer alternative, compare the broader PCB manufacturing options.
HDI PCB cost: explore an early budget
Layer count is one cost driver. Board area, build-up structure, volume, fill/plating requirements and qualification also matter. This optional estimator exposes its assumptions so you can prepare an enquiry; it is not a live price list.
HDI PCB Budget Estimator
Design and budget inputs are independent: select the same structure and layer count if you are comparing one project. The workbench does not silently change your pricing inputs. For the process decisions behind the estimate, see HDI PCB cost drivers.
Send the files that define your HDI board
For a fabrication quote
- Gerber or agreed fabrication data, plus drill files.
- Stackup drawing: materials, dielectric thicknesses and copper.
- Via-span table, fill/cap requirements and impedance notes.
- Board dimensions, quantities and requested delivery.
If assembly is included
- BOM with manufacturer part numbers.
- Placement file and assembly drawings.
- Testing, programming and supplied-part responsibilities.
Still defining the stackup? Send the current layout constraints and identify what needs engineering advice.
For a calculated project, download the tool results and include them with your files. The Contact form receives the information you submit there; calculator values are not transferred automatically.
HDI PCB questions before you order
Does more copper layers mean a more advanced HDI board?
No. The microvia spans, number of build-up layers, routing geometry and process sequence are also important. Compare complete constructions rather than layer counts alone.
Can 1+N+1 and 2+N+2 have the same total layer count?
Yes. An eight-layer concept could be 1+6+1 or 2+4+2. They have different build-up arrangements and are not interchangeable without a routing and process review.
Is the calculator’s aspect-ratio result a manufacturing approval?
No. It is a geometric ratio using your entered depth and diameter. Material, taper, registration, plating, fill, interface quality and the required reliability still need review.
Can I request HDI in Rogers material or rigid-flex?
Send the material grades and construction drawing for review. These combinations are outside the numeric budget model; the engineering and pricing requirements depend on the complete structure.
Why is the online budget different from a firm quotation?
The model uses uncalibrated planning coefficients. Your files determine the actual panel utilization, process sequence, tooling, inspections and delivery requirements. A firm quotation follows that review.
What should I send if the design is not finished?
Send the available stackup concept, package or pitch constraints, dimensions and target quantities. Mark the open questions. You do not need to finish the calculator before contacting us.