A kind of method of measurement that improves sintering temperature measurement accuracy for electrode sintering platform
Technical field
The present invention relates to the sintering temperature measuring technique, relate in particular to a kind of method of measurement that improves sintering temperature measurement accuracy for electrode sintering platform.
Background technology
In field of semiconductor manufacture, electrode is passing through the physical vapor deposition (PVD) process deposits on substrate wafer, and, also need in electrode sintering board (being generally rapid thermal treatment (RTP) stove), carry out sintering through after the etching shaping, could form our required low-resistance electrode.Because of the substrate wafer behind sintering board sintering can't be done over again, so need the sintering temperature that the sintering board is provided is accurately measured to guarantee wherethrough reason back high rate of finished products.
Usually the sintering temperature that adopts following method to come measurement electrode sintering board in the prior art: (1), one group of non-impurity-doped and diameter are provided is 300 millimeters a testing wafer and a normal electrode sintering board, is coated with metal electrode layer (now being generally the nickel platinum layer) on this group testing wafer; (2), the sintering temperature of this normal electrode sintering board is set at different sintering temperature in 250 to 350 degrees centigrade respectively, preferable is set at 250,260,270,280,290,300,310,320,330,340 and 350 degrees centigrade respectively with sintering temperature; (3), will organize testing wafer and carry out sintering through the different sintering temperatures of normal electrode sintering board respectively; (4), record the square resistance of the testing wafer behind this difference sintering temperature sintering; (5), generate the relation curve of square resistance and sintering temperature, referring to Fig. 1, it has shown the relation curve of gained according to the square resistance that records and corresponding sintering temperature thereof; (6), a non-impurity-doped and diameter are provided is 300 millimeters a testing wafer and an electrode sintering board to be measured, is coated with metal electrode layer on this testing wafer; (7), this testing wafer is arranged on electrode sintering board to be measured and carries out sintering; (8), the square resistance of this testing wafer behind the measurement sintering is 26 ohm; (9), the sintering temperature that can draw electrode sintering board to be measured according to measured 26 ohm square resistance and relation curve as shown in Figure 1 is 290 degrees centigrade, i.e. the point of A on the relation curve.But during the substrate wafer of this electrode sintering board to be measured this moment on sintering product line, its actual sintering temperature is 320 degrees centigrade.
By above-mentioned data as can be known, the sintering temperature of the electrode sintering board that records by the electrode sintering board sintering temperature method of measurement that prior art provided can not the sintering temperature of accurate response electrode sintering board when normal operation, so will mislead the adjustment direction of technological parameter, cause a large amount of defective productss that cause because of sintering process, thereby cause serious economy loss.
Therefore, how to provide a kind of method of measurement that improves sintering temperature measurement accuracy for electrode sintering platform, become the technical problem that industry needs to be resolved hurrily to accurately measure the sintering temperature of electrode sintering board when the actual job.
Summary of the invention
The object of the present invention is to provide a kind of method of measurement that improves sintering temperature measurement accuracy for electrode sintering platform, can measure the sintering temperature of utmost point sintering board when carrying out normal operation accurately by described method of measurement.
The object of the present invention is achieved like this: a kind of method of measurement that improves sintering temperature measurement accuracy for electrode sintering platform, this sintering temperature is in a preselected temperature scope, this method may further comprise the steps: a, provide one a group of testing wafer and a normal electrode sintering board, be coated with metal electrode layer on this group testing wafer; B, in this preselected temperature scope, choose different temperature, and the sintering temperature of this normal electrode sintering board is set at selected different temperatures respectively; C, will organize testing wafer and be separately positioned on this normal electrode sintering board and carry out sintering with different sintering temperatures; D, record the square resistance of the testing wafer behind this difference sintering temperature sintering; Square resistance that e, foundation record and corresponding sintering temperature thereof generate the relation curve of square resistance and sintering temperature; F, provide a testing wafer and an electrode sintering board to be measured, be coated with metal electrode layer on this testing wafer; G, this testing wafer is arranged on electrode sintering board to be measured carries out sintering; The square resistance of this testing wafer behind h, the measurement sintering; I, the sintering temperature that draws this electrode sintering board to be measured according to measured square resistance and relation curve; In step a and f, this testing wafer is through P type heavy doping wafer.
In the method for measurement of above-mentioned improved sintering temperature measurement accuracy for electrode sintering platform, in step I, this measured square resistance pairing sintering temperature in relation curve is the sintering temperature of this electrode sintering board to be measured.
In the method for measurement of above-mentioned improved sintering temperature measurement accuracy for electrode sintering platform, this testing wafer prepares by following steps: a undoped wafer is provided; Remove the natural oxidizing layer of wafer surface; Carry out the heavy doping of P type; Remove the oxide layer on surface and generate a metal electrode layer by physical vapour deposition (PVD).
In the method for measurement of above-mentioned improved sintering temperature measurement accuracy for electrode sintering platform, the heavily doped dopant dose of this P type is 10
15/ square centimeter.
In the method for measurement of above-mentioned improved sintering temperature measurement accuracy for electrode sintering platform, also cover a protective layer on this metal electrode layer.
In the method for measurement of above-mentioned improved sintering temperature measurement accuracy for electrode sintering platform, this protective layer is a titanium nitride, and its thickness is 200 dusts.
In the method for measurement of above-mentioned improved sintering temperature measurement accuracy for electrode sintering platform, this electrode is the nickel platinum electrode, and its thickness range is 80 to 100 dusts.
In the method for measurement of above-mentioned improved sintering temperature measurement accuracy for electrode sintering platform, this preselected temperature scope is 250 to 350 degrees centigrade.
In the method for measurement of above-mentioned improved sintering temperature measurement accuracy for electrode sintering platform, this electrode sintering board is a rapid heat-treatment furnace.
In the method for measurement of above-mentioned improved sintering temperature measurement accuracy for electrode sintering platform, the diameter of this testing wafer is 300 millimeters.
Set up square resistance and sintering temperature relation curve with the undoped testing wafer of use in the prior art, and use undoped testing wafer in electrode sintering board to be tested, to carry out sintering, obtain the sintering temperature of electrode sintering board to be tested according to square resistance behind the sintering and relation curve, sintering temperature during the electrode sintering board normal operation can not accurate response to be tested of the sintering temperature of gained is compared, the present invention uses the heavily doped testing wafer of P type to set up square resistance and sintering temperature relation curve, and use the heavily doped testing wafer of P type in electrode sintering board to be tested, to carry out sintering, obtain the sintering temperature of electrode sintering board to be tested according to square resistance behind the sintering and relation curve, handled substrate wafer is more approaching when understanding because of heavily doped testing wafer of P type and the normal operation of electrode sintering board, and the sintering temperature more can the normal operation of reaction electrode sintering board the time so can improve the precision that electrode sintering board sintering temperature is measured greatly.
Description of drawings
The method of measurement that improves sintering temperature measurement accuracy for electrode sintering platform of the present invention is provided by following embodiment and accompanying drawing.
Fig. 1 is the relation curve of square resistance of the prior art and sintering temperature;
Fig. 2 is the flow chart that improves the method for measurement of sintering temperature measurement accuracy for electrode sintering platform of the present invention;
Fig. 3 is the square resistance of gained among Fig. 2 step S20 and the relation curve of sintering temperature;
Fig. 4 is the preparation method's of the testing wafer among Fig. 2 step S20 and the S25 a flow chart.
Embodiment
Below will be described in further detail the method for measurement that improves sintering temperature measurement accuracy for electrode sintering platform of the present invention.
Sintering temperature is in a preselected temperature scope described in the method for measurement that improves sintering temperature measurement accuracy for electrode sintering platform of the present invention.In the present embodiment, described metal electrode layer is the nickel platinum layer, and its thickness range is 80 to 100 dusts, and described preselected temperature scope is 250 to 350 degrees centigrade, and described electrode sintering board is a rapid heat-treatment furnace.
Referring to Fig. 2, the method of measurement that improves sintering temperature measurement accuracy for electrode sintering platform of the present invention is at first carried out step S20, an one group of heavily doped testing wafer of P type and a normal electrode sintering board are provided, are coated with metal electrode layer on the described group of testing wafer.In the present embodiment, the described group of heavily doped testing wafer of P type has 11.
Then continue step S21, in described preselected temperature scope, choose different temperature, and the sintering temperature of described normal electrode sintering board is set at selected different temperatures respectively.In the present embodiment, in 250 to 350 degrees centigrade of described preselected temperature scopes, chosen 250,260,270,280,290,300,310,320,330,340 and 350 degrees centigrade temperature, and the sintering temperature of described normal electrode sintering board has been set at above-mentioned selected temperature respectively
Then continue step S22, described group of testing wafer is separately positioned on the normal electrode sintering board with different sintering temperatures carries out sintering.In the present embodiment, above-mentioned 11 built-in testing wafers being separately positioned on sintering temperature is respectively in 250,260,270,280,290,300,310,320,330,340 and 350 degrees centigrade the normal electrode sintering board and carries out sintering.
Then continue step S23, record the square resistance of the testing wafer behind described different sintering temperature sintering.In the present embodiment, recording respectively, the square resistance behind 250,260,270,280,290,300,310,320,330,340 and 350 degrees centigrade sintering temperature sintering is respectively 32.2,31.8,31.4,31.0,30.6,30.2,28.8,21.0,14.5,14.0,13.5 ohm.
Then continue step S24, generate the relation curve of square resistance and sintering temperature according to square resistance that records and corresponding sintering temperature thereof.Referring to Fig. 2, it has shown the square resistance of present embodiment and the relation curve of sintering temperature, as shown in the figure, described relation curve has the gradual district of first resistance that lays respectively at 250 to 310 degrees centigrade, 310 to 330 degrees centigrade resistance sudden turn of events district and 330 to 350 degrees centigrade the gradual district of second resistance, when sintering temperature is positioned at resistance sudden turn of events district, the square resistance of metallic resistance is the highest to the sensitivity of variations in temperature, can accurately record sintering temperature according to square resistance.
Then continue step S25, a heavily doped testing wafer of a P type and an electrode sintering board to be measured are provided, be coated with metal electrode layer on the described testing wafer.In the present embodiment, the actual sintered temperature of described electrode sintering board to be measured is 320 degrees centigrade.
Then continue step S26, described testing wafer is arranged on electrode sintering board to be measured carries out sintering.
Then continue step S27, measure the square resistance of the described testing wafer behind the sintering, to be positioned at the sensitivity that the resistance sudden turn of events district sintering temperature of relation curve measures the highest when measured square resistance.In the present embodiment, the square resistance that records behind the sintering is 21.0 ohm.
Then continue step S28, the sintering temperature that square resistance that foundation is measured and relation curve draw described electrode sintering board to be measured.In the present embodiment, 21.0 ohm of measured square resistances pairing sintering temperature in relation curve as shown in Figure 2 is 320 degrees centigrade, the sintering temperature that can draw described electrode sintering board to be measured is 320 degrees centigrade, measured sintering temperature this moment (320 degrees centigrade) is consistent with the actual sintered temperature (320 degrees centigrade) of electrode sintering board to be measured, so as seen, the present invention can measure the sintering temperature of electrode sintering board accurately.
The preparation method of the testing wafer among above-mentioned steps S20 and the S25 at first provides a undoped wafer (step S40) as shown in Figure 4; Remove the natural oxidizing layer (step S41) of wafer surface, remove described natural oxidizing layer by hydrofluoric acid solution; Carry out P type heavy doping (step S42); Remove the oxide layer on surface and generate a metal electrode layer (step S43), remove the oxide of wafer surface by the pre-clear technology of SiCoNi by physical vapour deposition (PVD).
It should be noted that, also can cover a protective layer on described metal electrode layer, described protective layer is that thickness is the titanium nitride of 200 dusts; The heavily doped dopant dose of P type described in the present invention is 10
15/ square centimeter.
Other it should be noted that, use the method for measurement that improves sintering temperature measurement accuracy for electrode sintering platform of the present invention the sintering temperature of electrode sintering board can be adjusted to resistance sudden turn of events district as shown in Figure 2, produce the variation of tangible square resistance in the variation of this regional temperature, can improve the sensitivity that sintering temperature is measured this moment.
In sum, the present invention uses the heavily doped testing wafer of P type to set up square resistance and sintering temperature relation curve, and use the heavily doped testing wafer of P type in electrode sintering board to be tested, to carry out sintering, obtain the sintering temperature of electrode sintering board to be tested according to square resistance behind the sintering and relation curve, handled semiconductor device is more approaching when understanding because of heavily doped testing wafer of P type and the normal operation of electrode sintering board, and the sintering temperature more can the normal operation of reaction electrode sintering board the time so can improve the precision that electrode sintering board sintering temperature is measured greatly.