RU169301U1 - Hardware-software complex for studying the radiation resistance of high-speed integrated circuits based on Si and GaAs to individual charged particles based on a laser source of femtosecond pulses - Google Patents

Abstract

The invention relates to devices for testing semiconductor elements. The hardware and software complex for studying the radiation resistance of high-speed integrated circuits (ICs) based on Si and GaAs to individual charged particles contains a single-mode ultrashort pulse laser source, a beam expander, an optical autocorrelation pulse duration meter, a smooth laser radiation attenuator, a laser focusing module, the module for positioning the investigated IS, the module for its functional control and the computer control system for all modules but with a specialized software package. The technical result consists in providing the possibility of testing the radiation resistance of ultrafast ICs based on Si and GaAs. 2 ill.

Description

The utility model relates to devices for testing semiconductor elements for resistance to individual charged particles by laser methods.

The widespread use of large (LSI) and ultra-large (VLSI) integrated circuits (ICs), as well as power and high-voltage transistors as the electronic component base of space equipment and avionics, requires work to assess their sensitivity to local single radiation effects of individual charged particles - ions and protons of outer space. The most important local single radiation effects are single faults and thyristor effects.

The main method for evaluating the parameters of the sensitivity of IP to the effects of individual charged particles is based on the results of tests on accelerators of ions and protons, which are quite time-consuming and expensive. In addition, due to the statistical nature of the interaction of ionizing radiation with matter, these methods are ineffective when comparing various circuit-technological methods for ensuring the radiation resistance of IP.

Currently, alternative methods based on the use of pulses of focused laser radiation of ultrashort duration are being developed. It was shown that the effects caused in semiconductor devices by focused ultrashort laser pulses of picosecond duration are identical in electrical response to IP effects from the effects of individual charged particles. Modeling the effects of individual charged particles using a laser pulse has several advantages over traditional methods involving the use of ion beams:

- the ability to localize sensitive elements with micron accuracy;

- the ability to study the dynamic sensitivity to single failures in various operating modes of the IP;

- high reproducibility of laser pulsed excitation;

- the ability to repeatedly act on the element of IP, without causing the accumulation of irreversible changes;

- laser systems can be quite compact;

- no need to place the investigated device in a vacuum chamber;

- the possibility of the location of the functional control devices in close proximity to the studied object reduces the level of interference, which is of particular importance when conducting tests for single failures of devices with high speed;

- lasers are less expensive than sources of particle beams, more radiation-safe, environmentally friendly, easy to automate, easy to use and manage.

For example, a device is known for studying the radiation resistance of an IC (patent for utility model RU 110488 U1) to the effects of individual charged particles, containing a laser source for emitting ultrashort laser pulses of 70 ps duration, a radiation attenuation unit, a focusing device, a stage for placing the studied An IC configured to move in three directions, a laser pulse energy measuring unit, a visual control unit in the form of a CCD camera, and also a computer control system function and functional control.

The use in the known device of laser pulses with a wavelength of 1064 nm and a duration of 70 ps allows testing for sensitivity to single faults and thyristor effects of most CMOS ICs of relatively low speed. However, for modern ultrafast instruments with switching times of less than 0.1 ns, such a pulse duration may be too long. For VLSI with characteristic switching times of less than a few tens of picoseconds, it is preferable to use femtosecond pulses for tests for resistance to heavy charged particles. The adjustable pulse duration can be useful in studying the effect of laser radiation duration on the results of simulation laser tests of ultrafast ICs on their resistance to single radiation effects.

The technical result of the proposed utility model is to enable the radiation resistance of ultrafast ICs based on Si and GaAs to be tested.

It is realized due to a sharply focused radiation beam with a wavelength of 870 nm of a single-mode femtosecond laser source of ultrashort pulses with an adjustable duration.

The specified technical result is achieved in the proposed device, which is a hardware-software complex for studying the radiation resistance of high-speed ICs based on Si and GaAs to individual charged particles, containing the following main modules: a single-mode laser source of ultrashort pulses with a duration adjustable from 100 to 3000 fs; beam expander; optical autocorrelation pulse meter; smooth laser radiation attenuator with programmable attenuation coefficient from 1 to 10 ⁵ based on polarizing prisms; a laser radiation focusing module, consisting of a wide-aperture microscope equipped with a laser port with a telecentric LED illuminator and a visible range camera for visualizing and recording topology elements of the investigated IC; a module for precision positioning of the investigated IC based on three linear stepper drives, allowing the IP to be moved in three directions relative to the focus point of the laser beam; IS functional control module and a computer control system for all modules of the complex with a specialized software package.

The essence of the device is illustrated by drawings. The following notation is introduced in the drawings:

1. Laser source of ultrashort pulses

2. Beam expander

3. Autocorrelation pulse meter

4. The source of ultrashort pulses

5. Polarizing smooth laser pulse energy attenuator

6. Color video camera (visible range)

7. Focusing module (microscope)

8. Telecentric LED illuminator

9. Micro Lens

10. Management system

11. Module of functional control of IP

12. The investigated IP

12. Positioning module

13. Optical plate

In FIG. 1 is a general block diagram, and FIG. 2 is a layout of the main optical modules of the claimed device on a single vibration-proof optical plate 14.

Emitter 4 is designed and manufactured by Avesta (Troitsk, Moscow). The laser source of ultrashort pulses 1 included in it generates femtosecond pulses and amplifies them to an energy of 5000 nJ (with instability no more than 3%), providing an adjustment of their duration from 100 to 3000 fs. Then the pulses fall into the beam expander 2, which increases the beam diameter for subsequent matching with the input aperture of the lens 9, used for sharp focusing on the investigated IC 12. To control the output duration and pulse shape, the emitter has an autocorrelation pulse duration optimized for the above range of durations 3, to which a small portion of the radiation is directed.

Further, the energy of the ultrashort pulse is reduced to the required value using a three-prism polarizing smooth attenuator 5, the attenuation coefficient of which can be smoothly changed by rotating one of the prisms using a step drive in the range from 1 to 10 ⁵ . The smooth attenuator is controlled by a PC-based control system 10.

After passing through the attenuator 5, the laser radiation is directed to the focusing module, the basic element of which is an infinity-corrected microscope 7 Mic301LP with a laser port from OMEK (Israel). A feature of this microscope is the wide aperture of the observation channel, providing a field of view of about 1600 μm and a resolution of up to 0.06 μm / pixel on a camera with a matrix size of up to 1 ''.

In the practical implementation of the model, laser-resistant planar apochromatic in the visible and near infrared spectral range (Plan APO NIR) lenses 9 with an increased working distance from Mitutoyo (Japan) with a magnification of 5 ×, 20 × and 100 × magnifications, interchangeable with a turret are used Designed to mount from one to five lenses. A 5 × lens is convenient for observing large areas or taking panoramic shots of an object. 20 × and 100 × lenses - for sharp focusing of the laser beam. To provide shadowless illumination of the investigated IC, the microscope is equipped with a LED telecentric illuminator 8.

The positioning module 13 based on three linear step drives provides precise movement of the IC sample in the object plane XY and the alignment of the surface position of the investigated IC along the Z axis with the sharp focus plane of the laser beam. Visual observation and / or registration of sections of the topology of the active layer of the IC chip is carried out using a color video camera 6 in the visible high-resolution range, the signal from which is processed by a computer and displayed on a monitor.

The radiation pulse parameters are set, functional commands are supplied, and the operation of all modules of the measuring complex is synchronized by a unified PC-based control system 10. The setting of operating modes, monitoring and power management, checking the operability of the IC by performing tests and generating “feedback” signals for the control system is carried out by the module of functional control of the IP 11.

For the operation of the claimed installation requires a certain spatial arrangement of its modules relative to each other. To do this, on a single optical plate 14, all modules are structurally combined into a single test complex. Thus, the claimed installation can be recognized as a device, despite the fact that the elements (plate) providing the specified relative position are not included in the utility model formula.

The main characteristics of the proposed measuring complex for laser testing of semiconductor elements for resistance to individual charged particles are presented in table 1.

Table 1 Parameter Value Wavelength nm 870 Max. pulse energy, nJ 0.01 ... 5000 Pulse Duration, fs 100 ... 3000 Min spot diameter ^a) , microns 1.2 Max. pulse repetition rate, Hz one hundred Beam quality M ² , no more 1.6 Zoom lens 5 ^× , 20 ^× , 100 ^× XYZ positioning step, microns 0.15 ^a) For a 100 ^× lens

The used wavelength of 870 nm ensures high efficiency of excess charge generation in Si and GaAs based ICs, while the depth of charge collection is sufficient to excite single radiation effects in the active region of the IC. Given that the typical value of the threshold energy for the effect of single failures in CMOS ICs at a wavelength of 1064 nm and a spot diameter of 2 μm lies in the range from 0.01 to 0.2 nJ, and for thyristor effects from 0.5 to 1 nJ, and with a decrease in wavelength to 870 nm threshold energy becomes even lower, it can be argued that the range of energy changes used in this complex is sufficient to simulate almost all known single radiation effects from individual charged particles. The maximum energy of ultrashort pulses generated at this complex also allows one to cause irreversible effects, up to the destruction of the corresponding IP layers. The minimum spot diameter achievable using the proposed complex is 1.2 μm, which is comparable with the diffraction limit for a given wavelength and makes it possible to use this setup for local excitation of individual IP elements.

The claimed complex, by the totality of its parameters, is a unique measuring device for studying the radiation resistance of high-speed Si and GaAs based ICs to individual charged particles.

Claims (1)

A hardware-software complex for studying the radiation resistance of high-speed integrated circuits (ICs) based on Si and GaAs to the effects of individual charged particles, containing the following main modules: a single-mode laser source of ultrashort pulses with a duration adjustable from 100 to 3000 fs, a beam expander; optical autocorrelation pulse meter; a module for smooth attenuation of laser radiation with a programmable attenuation coefficient from 1 to 10 ⁵ based on laser polarizing prisms; a laser radiation focusing module, consisting of a wide-aperture microscope equipped with a laser port with a telecentric LED illuminator and a visible range camera for visualizing and recording the topology elements of the investigated IC; the module for positioning the investigated IC on the basis of three linear step drives, allowing precise movement of the IC in three directions relative to the focus point of the laser beam; IS functional control module and a computer control system for all modules of the complex with a specialized software package.

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