FTIR Fourier transform infrared spectrum analyzer

is used in semiconductor manufacturing. FTIR is a spectral analyzer which uses infrared spectrum to analyze impurity concentration by Fourier transform.

objective: those who are mature enough for Routine application include: the prediction of phosphorus and boron content in A.BPSG/PSG. B. prediction of oxygen and carbon content of the chip. C. thickness measurement of epitaxial wafer.

those who need further Setup in the development are: a. prediction of hydrogen content in silicon nitride. B. prediction of oxygen content in polycrystalline silicon. C. analysis of photoresist characteristics. FTIR is a very convenient analytical instrument, and the establishment of STD is the focus of the whole measurement, because the optical principle and chip condition (I.E. wafer back processing condition) have great influence on the measurement results.

At present, all infrared spectrometers are Fourier transform type, and the spectrometers are mainly composed of light source (silicon carbon

rod, high-pressure mercury lamp), Michelson interferometer, detector and interferometer. The Michelson interferometer is the core part of Fourier transform infrared spectrometer. When the sample is placed in front of the detector, the intensity of interference light received by the detector changes because the sample absorbs infrared light of certain frequencies, so as to obtain interferograms of various samples. This interferogram is the curve of the moving distance of the optical follow-up mirror, and the frequency domain diagram of the light intensity changing with frequency can be obtained by means of Fourier transform function. This can be done by a computer.

Measuring the infrared spectrum of a sample with Fourier transform infrared spectrometer includes the following steps:

1) Collecting the interferogram of the background (when there is no sample) and the interferogram of the sample respectively;

2), respectively converting the interferogram into single-beam infrared light through Fourier transform;

3) Put the single-beam spectrum of the sample at the single-beam spectrum of the background to obtain the transmission spectrum or absorption spectrum of the sample.

EPI (Expanded Programme on Immunization), that is, Expanded Programme on Immunization, has its origin and development as follows:

In the early 197s, the World Health Organization counted developing countries in Asia, Africa and Latin America (excluding China), with more than 8 million babies born each year, but children immunized against pertussis, diphtheria, tetanus, measles, polio and tuberculosis also. Five million children die every year because of the above six infectious diseases, and at the same time, five million children are left with sequelae such as blindness and paralysis. However, in economically developed countries, due to extensive vaccination, the incidence and mortality of these infectious diseases have been successfully reduced.

Based on the experience of eliminating smallpox and controlling the above-mentioned infectious diseases in economically developed countries, the 27th World Health Assembly adopted a resolution in May 1974, requesting all member countries to develop and adhere to immunization methods and epidemic surveillance plans to prevent smallpox, diphtheria, pertussis, tetanus, measles, poliomyelitis, tuberculosis and other infectious diseases, and formally began to propose the Expanded Immunization Program (EPI). The congress also announced that on the basis of national equality, we should cooperate with governments of all countries to develop the above-mentioned plans, mobilize forces, ensure the quality of inoculation and necessary material equipment, and expand teaching and scientific research to promote the realization of the plans. In 1976 and 1977, the development direction of this plan was reiterated at the 29th and 3th World Health Assembly, and the EPI was required to be given priority in other plans of the World Health Organization. At the 31st World Health Assembly in 1978, Dr. Mahler, Director-General of the World Health Organization, proposed in his report that the continuation of EPI's smallpox eradication plan and other plans should be linked with medical and health assistance and maternal and child health care plans. The short-term and medium-term plan of EPI is put forward, that is, before 199, all children in the world should be vaccinated with BCG, polio vaccine, DTP mixed preparation and measles vaccine to reduce the incidence and mortality of corresponding diseases. At the same time, training cadres, improving vaccine quality and strengthening organization and management are regarded as the medium-term goals to realize the plan. At this conference, a resolution was also passed to establish a global EPI advisory group. In September of the same year, at the international primary health care conference held in Almaty, the former Soviet Union, it was emphasized that EPI activities were one of the contents of maternal and child health care and primary health care activities and an important part of the global strategic goal of "making health care available to all by the year 2", which was written into the Almaty Declaration and became a resolution unanimously endorsed by the United Nations General Assembly in 1979. China officially participated in the global EPI activities in 1981. ?

In 1987, the World Health Organization took "Immunization-an opportunity for every child" as the theme of World Health Day on April 7th of that year. Director-General Mahler pointed out in his "World Health Message" that the current global EPI activities are constantly developing with the strengthening of primary health care, and some remarkable achievements have been made. In countries with children, vaccines and health workers, about 8, children can be saved from death every year. But in most developing countries, whooping cough, diphtheria, tetanus, measles, polio and tuberculosis are still the main public health problems. He pointed out that today, with modern technology in our world, thousands of children have died of diseases that can be prevented by vaccines, and this phenomenon can no longer be tolerated. It is required to make immunization an opportunity for every child, and to popularize children's immunization as a milestone for everyone to enjoy health care. In this regard, the people's reasonable cooperation, the firm belief of leaders of various countries, the dedicated efforts of health workers, the careful care and cultivation of parents and the raising of funds and equipment are all components of a comprehensive measure needed to save the children of the world.

At present, more than 8% countries and regions in the world have participated in EPI activities. The immunization coverage of all developing countries is rapidly approaching the level of economically developed countries, and the incidence of diseases has also dropped significantly. One million children die of measles, neonatal tetanus and whooping cough every year, and more than 17, cases of polio have been prevented. Significant progress has been made in global health work. ?

Our government has always attached great importance to the prevention and health care of children and cared about their healthy growth. In the early days of the founding of the People's Republic of China, the policy of "prevention first" was formulated, and vaccinia vaccine was popularized nationwide, and then the large-scale popularization of BCG, DTP, polio sugar pill vaccine, measles vaccine and other vaccines was gradually expanded. Smallpox was eradicated in the early 196s, and the incidence of other corresponding infectious diseases also decreased year by year. In 1963, the Ministry of Health issued the Measures for the Implementation of Vaccination, and some areas began to gradually change from unscheduled vaccination to planned vaccination. In 1978 and 198, the Ministry of Health successively issued the Notice on Strengthening Planned Immunization and the Implementation Measures for Vaccination. Then, in October 1982, the first national conference on planned immunization was held, the special committee on planned immunization of the Medical Science Committee of the Ministry of Health and six regional cooperation committees were established, and the National Regulations on Planned Immunization, the 1982-199 National Plan for Planned Immunization and the assessment methods for planned immunization were issued.

In 1985, the national leaders made a commitment to the goal of universal child immunization by signing the relevant documents of the United Nations, and proposed to achieve the goal in two steps during the Seventh Five-Year Plan period. In order to strengthen the leadership of planned immunization, with the approval of the State Council in 1986, a national coordination group for planned immunization was established with the participation of the heads of the Ministry of Health, the State Education Commission, the All-China Women's Federation, the Ministry of Radio, Film and Television, the Ministry of Foreign Economic Relations and Trade, and the State Ethnic Affairs Commission, and April 25th of each year was designated as the National Children's Vaccination Publicity Day. Under the sponsorship of UNICEF and with the active support of governments at all levels, cold chain equipment has been equipped and put into normal operation nationwide, and more and more children can get effective immunization in time. In 1989 and 1991, the World Health Organization and the United Nations Children's Fund, in collaboration with the Ministry of Health of China, conducted two nationwide sampling reviews, and the immunization coverage rate reached the specified target as scheduled.

At present, the national planned immunization work is being carried out around the third goal, that is, the immunization coverage rate in towns and villages will reach more than 85% in 1995, and polio will be basically eliminated. Children's immune protection is developing towards institutionalization, standardization and legalization.