Decapping

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Decapping (decapsulation) or delidding of an integrated circuit is the process of removing the protective cover or integrated heat spreader (IHS) of an integrated circuit so that the contained die is revealed for visual inspection of the micro circuitry imprinted on the die. This process is typically done in order to debug a manufacturing problem with the chip, or possibly to copy information from the device, [1] to check for counterfeit chips or to reverse engineer it. [2] [3] Companies such as TechInsights [4] and ChipRebel [5] decap, take die shots of, and reverse engineer chips for customers. Modern integrated circuits can be encapsulated in plastic, ceramic, or epoxy packages.

Contents

Delidding may also be done to test the chip for radiation-tolerance with a heavy-ion beam [6] [7] [8] or in an effort to reduce the operating temperatures of an integrated circuit such as a processor, by replacing the thermal interface material (TIM) between the die and the IHS with a higher-quality TIM. With care, it's possible to decap a device and still leave it functional. [9]

Method

Decapping is usually carried out by chemical etching of the covering, [2] [10] laser cutting, laser evaporation of the covering, [11] plasma etching [10] or mechanical removal of the cover using a milling machine, saw blade, [12] using hot air [13] or by desoldering and cutting. [14] The process can be either destructive or non-destructive of the internal die.

Chemical etching usually involves subjecting the (if made of plastic) IC package to concentrated or fuming nitric acid, heated concentrated sulfuric acid, white fuming nitric acid or a mixture of the two for some time, possibly while applying heat externally with a hot plate or hot air gun, [11] [3] which dissolve the package while leaving the die intact. [15] [2] [10] The acids are dangerous, so protective equipment such as appropriate gloves, full face respirator with appropriate acid cartridges, a lab coat and a fume hood are required. [11]

Laser decapping scans a high power laser beam across the plastic IC package to vaporize it, while avoiding the actual silicon die. [11]

In a common version of non-destructive, mechanical delidding, one removes the IHS of an IC such as a computer processor using an oven to soften the solder (if present) between the IHS and the die(s) and using a knife to cut the adhesive in the periphery of the IHS, which joins the IHS with the processor package substrate, which is often a specialized printed circuit board often only called a substrate or sometimes an interposer. In many processors the dies are also soldered to the IHS which can still be removed by applying heat until the solder melts, and removing the IHS while the solder is still liquid. The die(s) are mounted on the substrate using flip chip. [14]

See also

Related Research Articles

<span class="mw-page-title-main">Integrated circuit</span> Electronic circuit formed on a small, flat piece of semiconductor material

An integrated circuit, also known as a microchip, chip or IC, is a small electronic device made up of multiple interconnected electronic components such as transistors, resistors, and capacitors. These components are etched onto a small piece of semiconductor material, usually silicon. Integrated circuits are used in a wide range of electronic devices, including computers, smartphones, and televisions, to perform various functions such as processing and storing information. They have greatly impacted the field of electronics by enabling device miniaturization and enhanced functionality.

<span class="mw-page-title-main">Semiconductor device fabrication</span> Manufacturing process used to create integrated circuits

Semiconductor device fabrication is the process used to manufacture semiconductor devices, typically integrated circuits (ICs) such as computer processors, microcontrollers, and memory chips that are present in everyday electronic devices. It is a multiple-step photolithographic and physio-chemical process during which electronic circuits are gradually created on a wafer, typically made of pure single-crystal semiconducting material. Silicon is almost always used, but various compound semiconductors are used for specialized applications.

<span class="mw-page-title-main">Printed circuit board</span> Board to support and connect electronic components

A printed circuit board (PCB), also called printed wiring board (PWB), is a medium used to connect or "wire" components to one another in a circuit. It takes the form of a laminated sandwich structure of conductive and insulating layers: each of the conductive layers is designed with a pattern of traces, planes and other features etched from one or more sheet layers of copper laminated onto and/or between sheet layers of a non-conductive substrate. Electrical components may be fixed to conductive pads on the outer layers in the shape designed to accept the component's terminals, generally by means of soldering, to both electrically connect and mechanically fasten them to it. Another manufacturing process adds vias, plated-through holes that allow interconnections between layers.

<span class="mw-page-title-main">Ball grid array</span> Surface-mount packaging that uses an array of solder balls

A ball grid array (BGA) is a type of surface-mount packaging used for integrated circuits. BGA packages are used to permanently mount devices such as microprocessors. A BGA can provide more interconnection pins than can be put on a dual in-line or flat package. The whole bottom surface of the device can be used, instead of just the perimeter. The traces connecting the package's leads to the wires or balls which connect the die to package are also on average shorter than with a perimeter-only type, leading to better performance at high speeds.

<span class="mw-page-title-main">Pin grid array</span> Type of integrated circuit packaging with the pins mounted on the underside of the package

A pin grid array (PGA) is a type of integrated circuit packaging. In a PGA, the package is square or rectangular, and the pins are arranged in a regular array on the underside of the package. The pins are commonly spaced 2.54 mm (0.1") apart, and may or may not cover the entire underside of the package.

<span class="mw-page-title-main">Flip chip</span> Technique that flips a microchip upside down to connect it

Flip chip, also known as controlled collapse chip connection or its abbreviation, C4, is a method for interconnecting dies such as semiconductor devices, IC chips, integrated passive devices and microelectromechanical systems (MEMS), to external circuitry with solder bumps that have been deposited onto the chip pads. The technique was developed by General Electric's Light Military Electronics Department, Utica, New York. The solder bumps are deposited on the chip pads on the top side of the wafer during the final wafer processing step. In order to mount the chip to external circuitry, it is flipped over so that its top side faces down, and aligned so that its pads align with matching pads on the external circuit, and then the solder is reflowed to complete the interconnect. This is in contrast to wire bonding, in which the chip is mounted upright and fine wires are welded onto the chip pads and lead frame contacts to interconnect the chip pads to external circuitry.

<span class="mw-page-title-main">Integrated circuit packaging</span> Final stage of semiconductor device fabrication

Integrated circuit packaging is the final stage of semiconductor device fabrication, in which the die is encapsulated in a supporting case that prevents physical damage and corrosion. The case, known as a "package", supports the electrical contacts which connect the device to a circuit board.

<span class="mw-page-title-main">Land grid array</span> Type of surface-mount packaging for integrated circuits

The land grid array (LGA) is a type of surface-mount packaging for integrated circuits (ICs) that is notable for having the pins on the socket — as opposed to pins on the integrated circuit, known as a pin grid array (PGA). An LGA can be electrically connected to a printed circuit board (PCB) either by the use of a socket or by soldering directly to the board.

<span class="mw-page-title-main">Hybrid integrated circuit</span> Type of miniature electronic circuit

A hybrid integrated circuit (HIC), hybrid microcircuit, hybrid circuit or simply hybrid is a miniaturized electronic circuit constructed of individual devices, such as semiconductor devices and passive components, bonded to a substrate or printed circuit board (PCB). A PCB having components on a Printed Wiring Board (PWB) is not considered a true hybrid circuit according to the definition of MIL-PRF-38534.

<span class="mw-page-title-main">Multi-chip module</span> Electronic assembly containing multiple integrated circuits that behaves as a unit

A multi-chip module (MCM) is generically an electronic assembly where multiple integrated circuits, semiconductor dies and/or other discrete components are integrated, usually onto a unifying substrate, so that in use it can be treated as if it were a larger IC. Other terms for MCM packaging include "heterogeneous integration" or "hybrid integrated circuit". The advantage of using MCM packaging is it allows a manufacturer to use multiple components for modularity and/or to improve yields over a conventional monolithic IC approach.

<span class="mw-page-title-main">System in a package</span> Electronic component

A system in a package (SiP) or system-in-package is a number of integrated circuits (ICs) enclosed in one chip carrier package or encompassing an IC package substrate that may include passive components and perform the functions of an entire system. The ICs may be stacked using package on package, placed side by side, and/or embedded in the substrate. The SiP performs all or most of the functions of an electronic system, and is typically used when designing components for mobile phones, digital music players, etc. Dies containing integrated circuits may be stacked vertically on the package substrate. They are internally connected by fine wires that are bonded to the package substrate. Alternatively, with a flip chip technology, solder bumps are used to join stacked chips together and to the package substrate, or even both techniques can be used in a single package. SiPs are like systems on a chip (SoCs) but less tightly integrated and not on a single semiconductor die.

The transistor count is the number of transistors in an electronic device. It is the most common measure of integrated circuit complexity. The rate at which MOS transistor counts have increased generally follows Moore's law, which observes that transistor count doubles approximately every two years. However, being directly proportional to the area of a chip, transistor count does not represent how advanced the corresponding manufacturing technology is: a better indication of this is transistor density.

<span class="mw-page-title-main">Tape-automated bonding</span> Places a microchip on a flexible circuit board

Tape-automated bonding (TAB) is a process that places bare semiconductor chips (dies) like integrated circuits onto a flexible circuit board (FPC) by attaching them to fine conductors in a polyamide or polyimide film carrier. This FPC with the die(s) can be mounted on the system or module board or assembled inside a package. Typically the FPC includes from one to three conductive layers and all inputs and outputs of the semiconductor die are connected simultaneously during the TAB bonding. Tape automated bonding is one of the methods needed for achieving chip-on-flex (COF) assembly and it is one of the first roll-to-roll processing type methods in the electronics manufacturing.

<span class="mw-page-title-main">Thermal copper pillar bump</span>

The thermal copper pillar bump, also known as the "thermal bump", is a thermoelectric device made from thin-film thermoelectric material embedded in flip chip interconnects for use in electronics and optoelectronic packaging, including: flip chip packaging of CPU and GPU integrated circuits (chips), laser diodes, and semiconductor optical amplifiers (SOA). Unlike conventional solder bumps that provide an electrical path and a mechanical connection to the package, thermal bumps act as solid-state heat pumps and add thermal management functionality locally on the surface of a chip or to another electrical component. The diameter of a thermal bump is 238 μm and 60 μm high.

A semiconductor package is a metal, plastic, glass, or ceramic casing containing one or more discrete semiconductor devices or integrated circuits. Individual components are fabricated on semiconductor wafers before being diced into die, tested, and packaged. The package provides a means for connecting it to the external environment, such as printed circuit board, via leads such as lands, balls, or pins; and protection against threats such as mechanical impact, chemical contamination, and light exposure. Additionally, it helps dissipate heat produced by the device, with or without the aid of a heat spreader. There are thousands of package types in use. Some are defined by international, national, or industry standards, while others are particular to an individual manufacturer.

<span class="mw-page-title-main">Zen 2</span> 2019 AMD 7-nanometre processor microarchitecture

Zen 2 is a computer processor microarchitecture by AMD. It is the successor of AMD's Zen and Zen+ microarchitectures, and is fabricated on the 7 nm MOSFET node from TSMC. The microarchitecture powers the third generation of Ryzen processors, known as Ryzen 3000 for the mainstream desktop chips, Ryzen 4000U/H and Ryzen 5000U for mobile applications, as Threadripper 3000 for high-end desktop systems, and as Ryzen 4000G for accelerated processing units (APUs). The Ryzen 3000 series CPUs were released on 7 July 2019, while the Zen 2-based Epyc server CPUs were released on 7 August 2019. An additional chip, the Ryzen 9 3950X, was released in November 2019.

<span class="mw-page-title-main">Epyc</span> AMD brand for server microprocessors

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Glossary of microelectronics manufacturing terms

<span class="mw-page-title-main">Die shot</span>

A die shot or die photography is a photo or recording of the layout of an integrated circuit, showings its design with any packaging removed. A die shot can be compared with the cross-section of an (almost) two-dimensional computer chip, on which the design and construction of various tracks and components can be clearly seen. Due to the high complexity of modern computer chips, die-shots are often displayed colourfully, with various parts coloured using special lighting or even manually.

References

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