GB/T 43965-2024Electronic grade ethyl orthosilicate (English PDF)

3 Terms and definitions

3.1 The document states that it has no terms and definitions to define.

4 Technical requirements

4.1 Electronic grade ethyl orthosilicate is to meet Table 1, which sets the indicators for three grades: for photovoltaic use, marked 6N; for flat panel display use, marked 8N; and for integrated circuit use, marked 9N. The table starts with the purity of the ethyl orthosilicate itself, expressed as a percentage, at not less than 99.90 for the photovoltaic grade, not less than 99.95 for the flat panel display grade and not less than 99.99 for the integrated circuit grade.

4.1 (continued) The largest block of the table is the cation content, in micrograms per kilogram, listed element by element for forty-seven elements. In the order printed these are boron, aluminium, antimony, arsenic, barium, beryllium, bismuth, cadmium, calcium, cerium, chromium, cobalt, copper, gallium, germanium, gold, hafnium, indium, iridium, iron, lead, lithium, magnesium, manganese, mercury, molybdenum, nickel, niobium, palladium, platinum, potassium, rhenium, rhodium, rubidium, silver, sodium, strontium, tantalum, thallium, thorium, tin, titanium, tungsten, uranium, vanadium, zinc and zirconium. In the extraction the element names and the three columns of limits run as separate blocks and the first of those blocks holds one value fewer than there are elements, so the individual element limits cannot be matched to their rows with confidence and are not reproduced here. The two summary rows that close the block can be read: the total cation content is not more than 1 000 micrograms per kilogram for the photovoltaic grade, not more than 10 for the flat panel display grade and not more than 1 for the integrated circuit grade; and the purity expressed on a cation basis is not less than 99.9999 % for the photovoltaic grade, not less than 99.999999 % for the flat panel display grade and not less than 99.9999999 % for the integrated circuit grade.

4.1 (continued) The rest of the table is readable. The chloride content, in micrograms per kilogram, is not more than 500 for the photovoltaic grade, not more than 500 for the flat panel display grade and not more than 50 for the integrated circuit grade. The colour, in Hazen units, is 5 to 10 for all three grades. The water content, in milligrams per kilogram, is not more than 50, not more than 50 and not more than 5 respectively. The particle count, in pieces per millilitre, is given for four size bands. For particles from 0.2 micrometres up to 0.3 micrometres the limits are not more than 100, not more than 50 and not more than 20; from 0.3 micrometres up to 0.5 micrometres, not more than 50, not more than 30 and not more than 10; from 0.5 micrometres up to 1.0 micrometres, not more than 30, not more than 20 and not more than 5; and for particles of 1.0 micrometres and above, not more than 20, not more than 5 and not more than 2.

5 Test methods

5.1 Test environment. Cation and particle determinations are to be carried out in a cleanroom of at least ISO class 3 as defined in GB/T 25915.1. Solution preparation, sample handling, content testing and chloride testing for the cation and particle determinations should be carried out in a cleanroom environment of at least ISO class 2 as defined in GB/T 25915.1. Water testing is carried out in a nitrogen-purged glove box, the pressure inside the box being set at 0.42 mbar, the oxygen content not more than 2 parts per million by volume and the water content not more than 2 parts per million by volume.

5.2 Purity of ethyl orthosilicate. The reagents are high purity nitrogen and high purity helium, both of purity greater than 99.999 %. The column is a fused silica capillary 30 m long with an internal diameter of 530 micrometres whose inner wall has been film treated, or another equivalent capillary column. Detection is by gas chromatography with a flame ionization detector and electronic pneumatic control. The chromatographic conditions preferred are set in Table 2: injector temperature 200 °C, initial column temperature 80 °C, detector temperature 250 °C, injection volume 0.2 microlitres, carrier gas flow 40 millilitres per minute, split flow 35 millilitres per minute, hydrogen purity not less than 5N and nitrogen carrier gas purity not less than 5N. Impurities are measured with a temperature programme, the oven programme following Table 3, which gives two steps: step one at a rate of 0 degrees Celsius per minute to a value of 80 °C held for 3 min, and step two at a rate of 10 degrees Celsius per minute to a value of 180 °C held for 8 min. The test runs in four stages: the operating parameters of the chromatograph are set until the baseline is stable and normal; a 5 microlitre syringe is flushed several times with the sample to be tested and 0.2 microlitres injected each time, the resulting chromatogram of the ethyl orthosilicate sample being as shown in Annex A while the computer collects the peak area or peak height response of every organic component; after the run the purity is obtained by area normalization; and the sample is tested three times, the mean of the three results being taken as the final result.

5.3 Cation content. The reagents and materials preferred are ultrapure water meeting grade EW-I of GB/T 11446.1; a sampling bottle of perfluoroalkoxy resin; ultrapure nitric acid with each single metal ion below 10 nanograms per litre; ultrapure hydrofluoric acid with each single metal ion below 10 nanograms per litre; a nitric acid solution made by weighing 10 millilitres of 69 % electronic grade nitric acid into a 500 millilitre sampling bottle, adding 100 millilitres of ultrapure water and mixing; and a mixed nitric and hydrofluoric acid made by weighing 10 millilitres of 49 % electronic grade hydrofluoric acid into that nitric acid solution and adding a further 100 millilitres of ultrapure water and mixing. Before the metal ion and boron content of the product is measured the sample is pretreated, the whole pretreatment being carried out under class 100 ultraclean conditions. The inductively coupled plasma mass spectrometer is tuned before every run and warmed up for 0.5 h, after which a blank is measured and injection begins only once the baseline noise or the blank parameters are stable. Pretreatment has two steps: 5 g of the ethyl orthosilicate sample is weighed into a 100 millilitre open perfluoroalkoxy resin vessel and heated to 150 °C so that the sample evaporates completely; then 10 millilitres of the prepared mixed acid is added to the evaporated vessel and shaken well so that the metal ions in the sample dissolve fully in the mixed acid. The determination follows SJ/T 11637, with five mixed element standard solutions of proportionate mass concentration and a working curve whose linear coefficient is not less than 0.995. Another equivalent method may be used; where the result is disputed, the method of SJ/T 11637 is the arbitration method.

5.4 Chloride content. The determination runs in six steps: the ion chromatograph is brought to suitable working conditions; the ethyl orthosilicate is mixed with isopropanol in the ratio one to one; the mixture passes in turn through the sample loop and the concentrator column so as to be enriched; the concentrator column is backflushed with eluent into the ion chromatographic system for measurement; a Gaussian chromatographic peak is formed in the conductivity detector; and, the peak area or peak height being proportional to the concentration of the component, the chloride content is calculated from the peak area.

5.5 The colour is determined as GB/T 3143 requires.

5.6 The water content is determined as GB/T 26793 requires. Another equivalent method may be used; where the result is disputed, the method of GB/T 26793 is the arbitration method.

5.7 The particle count is determined as SJ/T 11638 requires.

6 Evaluation of the measurement results

6.1 The method detection limit for the cation content of ethyl orthosilicate is to meet GB/T 37837.

6.2 Precision is measured independently on the sample, with not fewer than seven determinations, and is expressed as the relative standard deviation. The calculation of the relative standard deviation is to meet GB/T 37837 and the relative standard deviation of the test result is to be not more than 5 %.

6.3 Spike recovery is obtained by taking two portions of the same sample, spiking one of them with standard solution and injecting both under the same conditions; the difference between the concentration found with the spike and the concentration found without it, divided by the theoretical value of the spike, is the spike recovery of the sample. It is to be kept within 80 % to 120 %. Spike recovery is prescribed only for the determination of the cation content and the chloride content.

7 Inspection rules

7.1 An inspection batch is made up of all the product filled from the same finished product tank, produced continuously and steadily on the same production line by the same process. Every indicator of Table 1 is to be tested on each inspection batch.

7.2 The first and the last item of each inspection batch are to be tested against the indicators, while the sampling of the items in between follows the sampling plan of GB/T 2828.1 with the acceptance quality limit calculated at 1.0, the sample size meeting Table 4. That table pairs the batch size, that is the total number of items, with the sample size: 2 to 8 items, 2; 9 to 15, 3; 16 to 25, 5; 26 to 50, 8; 51 to 90, 13; 91 to 150, 20; 151 to 280, 32; and 281 to 500, 50. The series is carried on under the heading Table 5, again titled sampling quantity, with 501 to 1 200 items, 80; 1 201 to 3 200, 125; 3 201 to 10 000, 200; 10 001 to 35 000, 315; and 35 000 to 150 000, 500.

7.3 Where any one item of the test result on a sample fails to meet Table 1, the batch is to be sampled and tested again; if after three samplings any one indicator still fails, every filled cylinder is to be sampled and tested, and if any one indicator still fails the batch is non-conforming.

7.4 Sampling safety is to meet the provisions of GB/T 3723 on hazardous substances and the sampling method is to meet the relevant provisions of GB/T 6680 on sampling operations.

8 Type inspection

8.1 Type inspection is carried out when, after formal production has begun, the raw material or the production process changes; when production is moved to another works; periodically or after a certain cumulative output; when production restarts after a long stoppage; when the delivery inspection result differs appreciably from the type inspection result; and when the national quality supervision body asks for it.

8.2 Type inspection takes in the purity test, the cation content test, the chloride content test, the colour test and the water content test.

9 Marking, packaging, transport and storage

9.1 Marking. The product leaves the works with a certificate of quality carrying at least the Chinese and English product name of the electronic grade ethyl orthosilicate; the name of the producer and the number of its hazardous chemicals production licence; the date of manufacture or the batch number, together with the safe use period or expiry date; the filling mass; and the number of the document and the purity of the product. The packaging marking is to meet GB 190 and GB/T 191, the colour marking GB/T 7144 and the label GB 15258 and GB/T 16804, with the safety information given in Annex B.

9.2.1 Packaging. The cylinders are to meet GB/T 5099, all parts, and GB/T 33145, and the filling, storage and transport are to meet GB/T 14193 and TSG 23. The inner surface of the cylinder is to be treated and the inside of the cylinder is to suit the filling of electronic grade ethyl orthosilicate. Before filling, the inside of the cylinder is to be cleaned, preferably rinsed with neat ethyl orthosilicate, and the water and particle indicators checked; filling may follow once those indicators pass. The cylinder connection should preferably use a quarter inch fitting with a male thread in and a female thread out, or as agreed with the customer; the fitting is to carry a dust plug and the area around the valve is to carry protective material sealing the two valves against outside contamination. Filling should be at atmospheric pressure or at not more than 0.6 MPa, and the fill is to be not more than 90 % of the cylinder volume, so that at the highest working temperature of the liquid at least 3 % to 5 % of the volume is still left as vapour space at the top. A quantity of protective gas is to be kept in the cylinder at a pressure below 0.5 MPa, so that air cannot enter and the ethyl orthosilicate cannot hydrolyse; the protective gas may be high purity nitrogen or high purity helium of purity not less than 5N, the kind and the filling pressure being agreed between supplier and purchaser.

9.2.2 Transport. Filled cylinders are to be handled gently in transit, are not to be left in the sun or struck hard, and are not to be carried together with oxidizing agents or with toxic or harmful substances, so as to avoid contamination. Cylinders are to be moved carefully, without impact and set down gently, so that the container is not damaged.

9.2.3 Storage. The product is to be kept in a cool, dry, ventilated store out of the sun and away from heat sources. The storage temperature is to be within the range 0 °C to 40 °C, and the product is to be kept apart from oxidizing agents, acids and alkalis and not stored with them. The storage area is to use explosion-proof lighting and ventilation. Machinery and tools liable to strike sparks are not to be used. The storage area is to be equipped with emergency leak handling equipment and suitable containment material.

A Annex A (informative) Test information

A.1 Figure A.1 shows the gas chromatogram obtained by testing a sample of electronic grade ethyl orthosilicate that meets the indicators, with the integration applied.

A.2 The peaks present in the test sample are ethanol and ethyl orthosilicate. The retention time of ethanol is 3.84 min and that of ethyl orthosilicate 6.25 min.

B Annex B (informative) Safety information

B.1 Basic information. The chemical formula is Si(OC2H5)4, the Chinese name is the one used throughout the document and the English name is tetraethyl orthosilicate, TEOS. The relative molecular mass is 208.33, calculated on the 2018 international relative atomic masses. The codes are CAS number 78-10-4 and UN number 1292. The physical properties given are a boiling point of 168 °C, a melting point of -77 °C, a saturated vapour pressure of 0.13 kPa, a relative density, water taken as 1 at 20 °C, of 0.935 to 0.940, a lower explosive limit of 0.9 % and an upper explosive limit of 5.7 %. On toxicity the document gives, as the median lethal concentration, a rat oral inhalation LC50 over 4 h of 6 270 milligrams per litre.

B.2 Hazard statement. Ethyl orthosilicate is a colourless liquid with an odour, miscible with ethanol and diethyl ether, slightly soluble in benzene and almost insoluble in water, although water breaks it down gradually into silicon oxide; in damp air it grows cloudy by degrees and hydrolyses to precipitate silicic acid. In the absence of water it is stable in character and does not decompose on distillation. At high concentration it is narcotic. It irritates the skin, and its vapour or mist irritates the eyes, mucous membranes and respiratory tract, contact bringing on headache, nausea and vomiting. It is a flammable liquid, at risk of catching fire in high heat or an open flame, and its vapour can form an explosive mixture with air.

B.3 Emergency measures. In a fire the source is to be cut off; fire-fighters wear a gas mask and full fire and chemical protective clothing and fight the fire from upwind; containers are moved out of the fire area to open ground so far as possible; and if a container in the fire changes colour or a sound comes from its safety relief device, everyone withdraws at once. Water, foam and acid or alkali extinguishing agents are not to be used. Anyone who has inhaled the substance is moved quickly out into fresh air and the airway kept clear; oxygen is given if breathing is difficult; and if breathing or the heartbeat has stopped, cardiopulmonary resuscitation is started at once and medical help sought. On eye contact the eyelids are parted at once and the eye flushed thoroughly with plenty of running clean water or physiological saline, with medical help if there is any discomfort. On skin contact the contaminated clothing is removed at once and the skin washed thoroughly with soap and running clean water, with medical help if there is any discomfort.

B.4 Leak handling. The source of the leak is cut off and every source of ignition removed. A cordon is drawn around the area affected, judged from the flow of the liquid and the spread of the vapour, and people not involved withdraw crosswind and upwind to a safe area. Emergency staff wear a positive pressure self-contained breathing apparatus and antistatic chemical protective clothing. The leaked material is kept out of water bodies, drains, basements and confined spaces. A small leak is contained and absorbed with sand or another non-combustible material, the absorbent then being collected with clean, non-sparking tools. For a large leak a dyke is built or a containment pit dug and the liquid covered with an immiscible foam material so as to cut down evaporation.

B.5 Waste disposal. Before disposal, the remaining and unrecovered waste is handed to a qualified organization for treatment. Waste ethyl orthosilicate is not discharged directly.