OrinewPCB · Logic and memory integration
Package-on-Package (PoP) Assembly Services
Package-on-package (PoP) assembly stacks compatible IC packages, commonly memory above a processor, using vertical solder connections. OrinewPCB reviews the package pair, board design and test requirements as part of a complete PCB assembly project.
Our one-stop service combines PCB fabrication, 100% new original components, assembly and agreed testing, with a focus on high-mix, low- and medium-volume builds. Send your BOM and package drawings for feasibility, cost and delivery review.
- Original component sourcing
- Nine-step quality workflow
- Complete PCBA project review
One team for the complete board
Coordinate fabrication, component supply, assembly, inspection and testing in the same project.
100% new original components
Manufacturer and distributor relationships support genuine parts, competitive material pricing and availability.
Quality and delivery planned together
Our nine-step quality workflow and your acceptance requirements inform the build and schedule.
What is PoP assembly?
A compact stack of separately packaged devices
PoP connects one finished IC package above another. It can reduce the board area used by a compatible processor-and-memory combination, but stack height, thermal behavior and assembly complexity still need review.
Save board footprint
Vertical stacking can free PCB area compared with placing the same packages side by side. Check the complete enclosure height, keep-outs and cooling arrangement before choosing the architecture.
Connect logic and memory
Short package-to-package connections can suit compact computing designs. Electrical performance depends on the device interfaces, signal integrity, power delivery and layout; stacking alone does not guarantee an improvement.
Choose compatible configurations
Separate packages can support different approved memory configurations. Compatibility requires matching ball maps, interfaces, mechanical dimensions and supplier guidance—not simply similar package sizes.
PoP is part of a broader surface mount assembly process. The service here concerns assembling compatible packaged components onto a PCB; semiconductor die fabrication is a different manufacturing activity.
Compatibility before setup
What must be checked before a PoP build?
Both packages must be compatible electrically, mechanically and thermally. Review the exact manufacturer part numbers and revisions before committing the PCB, buying materials or setting the process.
| Review item | Required information | Decision it supports |
|---|---|---|
| Logic and memory pair | Exact part numbers, electrical interface requirements and approved device combinations. | Confirm the stack can communicate and operate as intended. |
| Package geometry | Ball maps, pitch, body dimensions, stack height, orientation and supplier drawings. | Confirm interconnection and mechanical fit; equal body size is insufficient. |
| PCB land pattern | Released layout, pad and mask definitions, stencil requirements and fabrication notes. | Review the lower package-to-board solder interface. |
| Thermal and moisture limits | Reflow guidance for both packages, moisture handling requirements and storage history for supplied parts. | Define compatible handling and thermal conditions. |
| Verification plan | Inspection access, electrical coverage, firmware and functional acceptance limits. | Identify what can be verified and which fixtures or records are needed. |
Published package pitch examples are not a blanket statement of our production limits. Feasibility for your specific package pair, materials and quantity is confirmed during project review.
Package-on-package assembly process
Control both interfaces from material preparation to test
A PoP process must form reliable connections between the PCB and lower package and between the lower and upper packages. Flux or paste selection, placement and the thermal profile depend on the package supplier’s guidance and process validation.
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Review the released build package
Check the logic/memory combination, PCB land pattern, BOM, orientation, moisture handling and test scope. Confirm revisions and any approved component alternatives.
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Prepare materials and solder deposits
Follow the specified handling requirements. Define the lower-interface paste deposit and the applicable upper-package flux or solder-paste process; do not assume both interfaces use the same deposit method.
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Place and align the packages
Verify alignment at the board-to-package and package-to-package interfaces. A stack-on-board route or a pre-stacked component route may be considered where the supplier and project requirements permit.
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Validate the reflow process
Review the complete stack’s thermal limits and behavior. Package warpage during heating can affect contact formation, so a generic oven setting is not a substitute for a reviewed profile.
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Inspect and test the finished assembly
Use the agreed combination of inspection and electrical or functional checks. Define how suspected hidden-joint defects, rework and subsequent verification will be handled.
Thermal behavior and hidden joints
Manage warpage, heat and test coverage explicitly
A compact stack introduces interactions between packages, solder joints and the board. These risks should be addressed in the design and process plan rather than described as automatic benefits of PoP technology.
| Concern | What to review | Verification boundary |
|---|---|---|
| Package warpage | Supplier package data, thermal compatibility, material conditions and the actual heating profile. | Alignment at room temperature does not establish joint formation during reflow. |
| Thermal management | Power dissipation, heat paths, enclosure, board design and the operating environment. | Vertical stacking does not inherently improve cooling or reduce power consumption. |
| Hidden solder joints | Inspection strategy for both solder interfaces; appropriate X-ray methods where required. | Stacked features may overlap in 2D images; inspection coverage must be understood. |
| Electrical operation | Test access, firmware, memory initialization and defined operating checks. | Optical inspection cannot prove electrical continuity or memory function. |
| Rework exposure | Approved rework approach, device heat limits, replacement material and post-rework checks. | Additional heating can affect adjacent joints and parts; rework is not risk-free. |
Automated optical inspection is useful for accessible features, but it cannot directly inspect hidden PoP solder connections. The agreed test plan should distinguish visual condition, solder-joint assessment and functional operation.
Why work with OrinewPCB?
One-stop PCBA support for high-mix projects
OrinewPCB focuses on coordinating the complete assembly project, especially low- and medium-volume orders with several board designs or variants. PoP requirements are reviewed within that broader build scope.
Original materials and sourcing value
We use 100% brand-new original components. Deep cooperation with manufacturers and distributors helps support competitive component pricing and availability. Package substitutions require compatibility review and approval.
Nine-step quality workflow
Quality is a priority throughout the project. Our nine-step inspection and testing workflow is matched to the agreed build requirements; the applicable checks, acceptance criteria and records are confirmed before production.
Variants and delivery coordination
Identify each model’s quantity, revision and BOM differences. We review material readiness, setup, inspection and testing together to plan the earliest practical delivery date.
Our one-stop PCB assembly service brings fabrication, sourcing, assembly and testing into one project. Define the quality scope before comparing quotations so setup, fixtures and verification are evaluated consistently.
Cost and schedule planning
What affects a PoP assembly quotation and lead time?
Pricing and delivery depend on the complete BOM, package availability, process preparation, quantity and validation requirements. A board image or package count alone cannot define the full PCBA cost.
| Driver | Effect on the project | What to provide early |
|---|---|---|
| Approved components | Supply and procurement cost of the compatible logic and memory devices. | Exact manufacturer part numbers and approved alternatives. |
| Process preparation | Package review, stencil or fixture needs and process validation work. | Package drawings, PCB data and any existing process documentation. |
| Batch size and variants | Setup effort and material allocation across different configurations. | Quantity, revision and BOM differences for every variant. |
| Testing and acceptance | Inspection, firmware, fixture preparation and functional verification time. | Test procedure, interfaces, pass/fail limits and required records. |
Include your target date with the first inquiry. For urgent projects, the quick-turn review checks the design and material constraints before a delivery commitment is made.
One-stop assembly inquiry
Send the package pair and complete board requirements
Share the available files for a coordinated feasibility and quotation review. OrinewPCB will assess PCB fabrication, original component supply, PoP and surrounding assembly operations, agreed testing, cost and delivery.
- Package data: logic and memory part numbers, drawings, ball maps and supplier assembly guidance.
- PCB files: Gerbers, drill files, stack-up, fabrication notes and assembly drawings.
- Build data: BOM, placement/CPL data, quantities by variant, revisions and substitution rules.
- Acceptance: firmware, test requirements, required records and target delivery date.
Package-on-package assembly FAQ
Questions to resolve before a PoP order
What is the package-on-package assembly process?
Compatible packages are aligned and connected through solder joints, with the lower package also attached to the PCB. Material preparation, deposits, placement, reflow and verification must address both solder interfaces.
How does thermal management differ from a side-by-side layout?
Stacking changes the available heat paths and concentrates packages in a smaller footprint. Evaluate device power, board and enclosure design against the actual operating conditions; improved cooling is not an inherent PoP benefit.
What causes warpage during PoP assembly?
Package construction, material expansion and temperature exposure influence warpage. Review supplier data and the actual thermal process because movement during reflow can prevent some joints from forming correctly.
What does SMT PoP mean?
It describes integrating a PoP stack into a surface mount PCB assembly process. It still needs package-specific handling, compatible materials, placement controls and verification beyond ordinary visible-joint inspection.
Can any processor and memory packages be stacked?
No. The device interfaces, ball maps, mechanical dimensions, height and thermal limits must be compatible. Provide exact part numbers and supplier drawings before sourcing or approving alternatives.
Can you review small batches with several board variants?
Yes. High-mix, low- and medium-volume one-stop PCBA is a core focus. Provide the quantity, revision and component differences for each model; specific PoP feasibility and validation requirements are reviewed before confirmation.
Related assembly methods