Short answer: Choose a Gel-Pak Gel-Box (AD series) in four steps. Make sure your devices fit the usable gel area with spacing, check that the tallest device clears the internal height, choose a base and lid material for your ESD needs, and choose the gel retention (tack) level for the device backside. A 2 × 2 in box such as the AD-22C has 1.75 × 1.75 in of usable gel area and 165 mils of internal clearance. That suits most die and small parts. For larger quantities or taller parts, move up to the 3 × 2 in (AD-23) or the 4.625 × 3.5 in boxes.
Gel-Pak makes Gel-Box carriers. MST distributes them and is not the manufacturer. Dimensions below come from the Gel-Pak product pages for each part number, and retention levels come from the Gel-Pak tack level chart. Confirm the drawing for your exact part number before you order.
Step 1: Compare the box sizes
Drawn to scale by MST Engineering from the Gel-Pak product pages.
Product photo of the Gel-Pak AD-22C-00-X4 listed as SC-GEL-RFQ.
| Part number (Xn = tack level) | Outer X × Y × Z (in) | Usable gel area (in) | Internal clearance (mils) | Material |
|---|---|---|---|---|
| AD-11C-00-Xn / AD-11T-00-Xn | 1.0 × 1.0 × 0.25 | 0.75 × 0.75 | 165 | Conductive / transparent |
| AD-22C-00-Xn (also T, AS, CAS, CT) | 2.0 × 2.0 × 0.25 | 1.75 × 1.75 | 165 | Conductive (and other options) |
| AD-23C-00-Xn / AD-23T-00-Xn | 2.0 × 3.0 × 0.375 | 1.75 × 2.75 | 280 | Conductive / transparent |
| AD-803CAS-00-Xn | 2.50 × 3.50 × 0.50 | 2.25 × 3.25 | 375 | Conductive base, antistatic lid |
| AD-1135C-00-Xn / AD-4635075T-00-Xn | 3.50 × 4.625 × 0.50 | 3.25 × 4.25 | 375 | Conductive / transparent |
| AD-1155CAS-00-Xn | 3.50 × 4.625 × 0.875 | 3.25 × 4.25 | 655 | Conductive base, antistatic lid |
| AD-2025C-00-Xn | 6.00 × 4.00 × 0.50 | 5.75 × 3.75 | 375 | Conductive |
| AD-1980T-00-Xn | 9.9375 × 3.50 × 0.625 | 9.69 × 3.25 | 465 | Transparent |
Gel-Pak lists AD Gel-Boxes from 1 × 1 in up to 7 × 5 in. Larger sizes, including 2.875 × 2 in and 7 × 5 in boxes, are on the [Gel-Box product page](https://www.gelpak.com/gel-box/).
Step 2: Check fit and height
Representative photo of a 2 × 2 in Gel-Box pack.
1. Lay out your devices on the usable gel area, not the outer size, and leave room for tweezer or vacuum-pick access between parts. Gel-Pak's "Calculate number of devices per carrier" tool estimates the count for a given die size.
2. Compare the tallest device, including bumps or wire bonds, with the internal clearance. The 165-mil boxes (1 × 1 and 2 × 2 in) fit thin die. Use the 280, 375 or 655-mil boxes for packaged parts, stacked substrates or lensed optics.
3. If you load by hand on a 2-inch-format station, the 2 × 2 in footprint is the most common choice.
Step 3: Choose the box material
| Code | Meaning (Gel-Pak) |
|---|---|
| C | Conductive (black) |
| T | Transparent (clear styrene) |
| AS | Antistatic (tinted, translucent) |
| CAS | Conductive base, antistatic lid |
| CT | Conductive base, transparent lid |
Use a conductive or CAS box for ESD-sensitive die. Choose T or CT when you need to inspect parts through the lid.
Step 4: Choose the retention (tack) level
Diagram by MST Engineering from the Gel-Pak retention chart and Ted Pella guidance.
| Level | Gel-Pak description | Typical surface (Gel-Pak guidance as published by Ted Pella) |
|---|---|---|
| XT | Ultra low tack | Very small polished optics |
| X0 | Low tack | Highly polished surfaces |
| X4 | Medium tack | Pre-polished or etched surfaces |
| X5 | Medium tack | — |
| X6 | High tack | — |
| X8 | High tack | Rough surfaces such as ceramics |
Gel-Pak recommends testing samples. The tack must hold the device through shipping but still release it cleanly. Tap-test a closed, loaded box on a hard surface to check holding force. If unloading is difficult, step down one level. Choosing the highest tack "to be safe" often causes unload problems.
Example: the box listed on MST Store
Flowchart by MST Engineering.
[SC-GEL-RFQ](/store/gel-carrier-boxes/SC-GEL-RFQ) is the Gel-Pak AD-22C-00-X4: a conductive 2 × 2 × 0.25 in box with X4 (medium) tack. Any other size, material or tack level above can be sourced on request.
Original OEM documents (links only)
1. Gel-Pak, Gel-Box product family. https://www.gelpak.com/gel-box/
2. Gel-Pak, retention (tack) level chart. https://www.gelpak.com/retention-chart/
Ask an engineer
Send your device size, thickness, backside finish, ESD needs and quantity through [Ask an engineer](/rfq?entry_source=ask_engineer&search_term=Gel-Pak+Gel-Box&quantity=1&community_path=%2Fcommunity%2Fc%2Fwafer-die-handling). MST confirms the box and tack level with Gel-Pak and replies with price and lead time. Or post a [find-part request](/community/new?kind=part_request&mpn=AD-22C-00-X4). For parts outside this list, use a [sourcing RFQ](/services/sourcing-rfq?sourcing_mode=supplier_match).
Parts
Catalog parts in this guide