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The introduction by the manufacturer of a new microprocessor card includes a number of stages. Implementation begins with designing a card and developing a mask for it. After the prototypes of the card are produced by the card manufacturer, functional, operational, physical / electrical testing is performed, as well as an assessment of the security level of the card and its applications. After that, the card is sent for certification to payment systems and / or EMVCo. Having received the necessary certificates, the card manufacturer starts mass production of the new card.
The design of a new card begins with the formation of functional and operational requirements for it, as well as requirements for the security of the card and the operations performed with its use. These requirements are developed by the card manufacturer and include:
Based on the listed requirements, the card manufacturer determines the parameters of the microcircuit that can be used for the card being created. There are several chip parameters that must be derived from the requirements of the card applications. These parameters primarily include:
In practice, card manufacturers have at their disposal chipsets from various manufacturers for which the listed parameters are already defined. Therefore, the challenge is to select the right chip that meets the requirements of the card being created in terms of functionality, operational performance and security.
The mask specification defines the software loaded into ROM memory. It consists of the operating system software and, as a rule, a set of applications defined by the card manufacturer based on market needs.
The operating system of the card supports a hierarchical file system and a set of commands defined in the ISO 7816-4 standard. In addition, it contains libraries of cryptographic functions used by card applications in card and issuer authentication procedures, secure data transfer between card and issuer, card and terminal, and to ensure the integrity of data exchange between card and terminal, card and issuer.
The card application is loaded either into ROM memory, where it is usually "intertwined" (single executable code) with the operating system of the card, or into EEPROM memory. In the second case, it is possible to change the application without changing the card mask. This significantly reduces the cost of implementing a new application, while at the same time requiring the allocation of additional EEPROM resources for storing the application. In this case, it is also possible to download new applications / application data after the card has been issued.
The mask specifications are passed on to the manufacturer of the selected microcircuit, who implements them on their chip. After completing testing and certification of the card (see the beginning of this section), the card manufacturer starts their mass production. To do this, he orders the production of a batch of card chips from a chip manufacturer.
After receiving a batch of manufactured chips, the card manufacturer ensures that the chips are inserted into plastic cards, as well as pre-personalization of the cards, during which some software and data are loaded onto the chip. This process is called the card production process. Below attention is paid only to the issues of card production related to the introduction of a microcircuit on the card.
In the case of cards using flash memory, the loading of the operating system and applications can be carried out on the side of the card manufacturer.
The card production process consists of several stages, shown in Fig. 2.10.
The initial stage consists in the fact that a silicon wafer with a thickness of 100-500 microns and a diameter of 10-15 cm, containing 300-800 microcircuit blanks, is cut into separate crystals. This is done either by marking the contours of the crystal, performed using a special pointer with a diamond tip and then extruding the outlined chips while rolling a silicon wafer under pressure, or using a diamond saw.
MasterCard to J
Rice. 2.10. Card production process
Silicon crystals are the most commonly used material for microchip blanks. At the same time, crystals of gallium arsenide (GaAs) and silicon on sapphire are also used for the production of workpieces.
Then the process of mechanical thinning of the silicon wafer to a thickness of 100-250 microns (typical value - 180 microns) is started, so that the microcircuit made from the wafer can be placed in the thin case of the microprocessor card. A thin plastic film is glued to the silicon wafer, which remains after the wafer is cut into individual chips.
After that, the chip is glued to a special epoxy pad (the side with which the plastic film is glued to it), on which gold-plated copper contacts were previously placed (today, as a rule, 5-6 contacts). These pins are connected with gold, aluminum or copper wires to the corresponding pins on the chip using a combination of ultrasonic / thermal welding and pressure. Connecting wires using thermal compression requires the substrate to be able to withstand temperatures of 1500-2000 ° C. To mitigate the requirements for the substrate material, a combined ultrasonic and thermal welding method is used.
The microprocessor card industry uses other methods of attaching the chip to the pins of the substrate. For example, flip-chip reverse assembly and tape technology are used. In both technologies, gold bumps are placed on the chip, which are then soldered to the contacts of the substrate.
Next, the substrate with the chip is placed in an inert filler, which is often an epoxy resin. The resulting module is shown in Fig. 2.11.
Epoxy filler Smart card chip
Rice. 2.11. Chip module
The microcircuit module is glued to the plastic card blank (card body) in the place where a special recess is made for it. This process is also called cutting a chip into a card.
Before starting the production of cards, the card manufacturer tests the batch of chips received from the microcircuit manufacturer (not to be confused with testing prototype cards). The minimum set of tests includes testing the card insertion procedure (ATR value is checked) and the procedures for writing / reading data in the EEPROM memory.
Further, the card manufacturer carries out the process of its pre-personalization. This process may consist of loading the card applications (applets in the case of a Java card) into the EEPROM memory, as well as some data related to the initialization of the card file structure and entering the card keys.
The body of a smart card must be made of polyvinyl chloride (PVC) or "equivalent material" in accordance with international standards. The operating environment imposes strict requirements on the physical characteristics of the card case. A smart card is often carried in a wallet or wallet and is subject to a variety of mechanical stresses. The material from which the card is made must have considerable elasticity in order for the card to remain practically flat after bending. A flat shape is required for stable electrical contact when a card is inserted into a card reader or used in a handheld magnetic stripe reader.
The material of the card body must also resist the infrared or ultraviolet radiation sometimes used to fix ink when printed on the card. A problem is the brittleness that occurs in plastic as a result of printing card data on it, which causes cards to crack during use. Sometimes the cracks reach such dimensions that the microcircuit can be removed from the card without much effort.
Modern card designs use a layered structure of dissimilar materials. This layered structure increases the mechanical resistance of the card to bending. In addition, it minimizes the propagation of any damage caused by the printing operation into the plastic. Finally, the process of creating a layered structure allows special printing components (for example, a hologram) to be attached to the card during its manufacture, which makes it difficult to counterfeit cards.
The design of a new card begins with the formation of functional and operational requirements for it, as well as requirements for the security of the card and the operations performed with its use. These requirements are developed by the card manufacturer and include:
- a list of applications that must be supported by the card;
- the need to develop additional applications for the card to be loaded onto it at the stage of pre-personalization of the card and / or after the card is issued by its issuer;
- the need to download additional applications after the card is issued;
- requirements for the processing of transactions performed on the card (in particular, the mode of processing transactions is only offline or online transactions are allowed, restrictions on the time of the operation, the methods of authentication and verification of the cardholder used, for example, biometric authentication, the need to perform contactless transactions on the card, etc.) . NS.);
- requirements for the safety of operations performed on the card.
Based on the listed requirements, the card manufacturer determines the parameters of the microcircuit that can be used for the card being created. There are several chip parameters that must be derived from the requirements of the card applications. These parameters primarily include:
- type of microcontroller (operating clock frequency, bit width, set of supported instructions, speed of execution of various commands);
- the size of the ROM memory and its characteristics (access time);
- the size of the RAM and its characteristics (access time);
- the size of the non-volatile EEPROM memory and its characteristics (memory programming time);
- the presence of a control module and control of access to the memory of the microcircuit, as well as memory protection;
- bit width of the address bus and data bus;
- the supported range of values of the external clock frequency;
- presence of an internal clock frequency generator (internal clock) and its parameters (upper clock frequency value);
- electrical parameters of the chip (supported values of supply voltage and maximum current);
- communication parameters (asynchronous / synchronous, byte / block protocol, radio interface characteristics);
- availability of a cryptographic coprocessor to speed up computations using the RSA algorithm;
- availability of a cryptographic coprocessor to speed up computations using the 3DES algorithm;
- availability of a random number generator;
- presence of a coprocessor for calculating the check sequence of a data block in accordance with ISO 3309 and / or ISO 13239;
- availability of special sensors and filters to combat various types of attacks on the chip;
- compliance of the microcircuit with the standards ISO 7816 and especially ISO 7816-3 (Electronic signals and transmission protocol);
- support for "sleep" mode (hot standby mode with a low level of current in the microcircuit), etc.
In practice, card manufacturers have at their disposal chipsets from various manufacturers for which the listed parameters are already defined. Therefore, the challenge is to select the right chip that meets the requirements of the card being created in terms of functionality, operational performance and security.
The mask specification defines the software loaded into ROM memory. It consists of the operating system software and, as a rule, a set of applications defined by the card manufacturer based on market needs.
The operating system of the card supports a hierarchical file system and a set of commands defined in the ISO 7816-4 standard. In addition, it contains libraries of cryptographic functions used by card applications in card and issuer authentication procedures, secure data transfer between card and issuer, card and terminal, and to ensure the integrity of data exchange between card and terminal, card and issuer.
The card application is loaded either into ROM memory, where it is usually "intertwined" (single executable code) with the operating system of the card, or into EEPROM memory. In the second case, it is possible to change the application without changing the card mask. This significantly reduces the cost of implementing a new application, while at the same time requiring the allocation of additional EEPROM resources for storing the application. In this case, it is also possible to download new applications / application data after the card has been issued.
The mask specifications are passed on to the manufacturer of the selected microcircuit, who implements them on their chip. After completing testing and certification of the card (see the beginning of this section), the card manufacturer starts their mass production. To do this, he orders the production of a batch of card chips from a chip manufacturer.
After receiving a batch of manufactured chips, the card manufacturer ensures that the chips are inserted into plastic cards, as well as pre-personalization of the cards, during which some software and data are loaded onto the chip. This process is called the card production process. Below attention is paid only to the issues of card production related to the introduction of a microcircuit on the card.
In the case of cards using flash memory, the loading of the operating system and applications can be carried out on the side of the card manufacturer.
The card production process consists of several stages, shown in Fig. 2.10.
The initial stage consists in the fact that a silicon wafer with a thickness of 100-500 microns and a diameter of 10-15 cm, containing 300-800 microcircuit blanks, is cut into separate crystals. This is done either by marking the contours of the crystal, performed using a special pointer with a diamond tip and then extruding the outlined chips while rolling a silicon wafer under pressure, or using a diamond saw.
MasterCard to J
Rice. 2.10. Card production process
Silicon crystals are the most commonly used material for microchip blanks. At the same time, crystals of gallium arsenide (GaAs) and silicon on sapphire are also used for the production of workpieces.
Then the process of mechanical thinning of the silicon wafer to a thickness of 100-250 microns (typical value - 180 microns) is started, so that the microcircuit made from the wafer can be placed in the thin case of the microprocessor card. A thin plastic film is glued to the silicon wafer, which remains after the wafer is cut into individual chips.
After that, the chip is glued to a special epoxy pad (the side with which the plastic film is glued to it), on which gold-plated copper contacts were previously placed (today, as a rule, 5-6 contacts). These pins are connected with gold, aluminum or copper wires to the corresponding pins on the chip using a combination of ultrasonic / thermal welding and pressure. Connecting wires using thermal compression requires the substrate to be able to withstand temperatures of 1500-2000 ° C. To mitigate the requirements for the substrate material, a combined ultrasonic and thermal welding method is used.
The microprocessor card industry uses other methods of attaching the chip to the pins of the substrate. For example, flip-chip reverse assembly and tape technology are used. In both technologies, gold bumps are placed on the chip, which are then soldered to the contacts of the substrate.
Next, the substrate with the chip is placed in an inert filler, which is often an epoxy resin. The resulting module is shown in Fig. 2.11.
Epoxy filler Smart card chip
Rice. 2.11. Chip module
The microcircuit module is glued to the plastic card blank (card body) in the place where a special recess is made for it. This process is also called cutting a chip into a card.
Before starting the production of cards, the card manufacturer tests the batch of chips received from the microcircuit manufacturer (not to be confused with testing prototype cards). The minimum set of tests includes testing the card insertion procedure (ATR value is checked) and the procedures for writing / reading data in the EEPROM memory.
Further, the card manufacturer carries out the process of its pre-personalization. This process may consist of loading the card applications (applets in the case of a Java card) into the EEPROM memory, as well as some data related to the initialization of the card file structure and entering the card keys.
The body of a smart card must be made of polyvinyl chloride (PVC) or "equivalent material" in accordance with international standards. The operating environment imposes strict requirements on the physical characteristics of the card case. A smart card is often carried in a wallet or wallet and is subject to a variety of mechanical stresses. The material from which the card is made must have considerable elasticity in order for the card to remain practically flat after bending. A flat shape is required for stable electrical contact when a card is inserted into a card reader or used in a handheld magnetic stripe reader.
The material of the card body must also resist the infrared or ultraviolet radiation sometimes used to fix ink when printed on the card. A problem is the brittleness that occurs in plastic as a result of printing card data on it, which causes cards to crack during use. Sometimes the cracks reach such dimensions that the microcircuit can be removed from the card without much effort.
Modern card designs use a layered structure of dissimilar materials. This layered structure increases the mechanical resistance of the card to bending. In addition, it minimizes the propagation of any damage caused by the printing operation into the plastic. Finally, the process of creating a layered structure allows special printing components (for example, a hologram) to be attached to the card during its manufacture, which makes it difficult to counterfeit cards.
