Reaction unit for atomic layer level thin film deposition
Technical field
The utility model belongs to solar cell manufacture assembling and processing technique field, is specially a kind of reaction unit for atomic layer level thin film deposition.
Background technology
Along with solar battery process technology continues to advance, wherein for the thickness evenness of thin-film technique and the requirement of quality, day by day raise.Traditional CVD deposition technique has been difficult to effectively accurately control film characteristics and meet day by day harsh Technology requirement, technique for atomic layer deposition (Atomic Layer Deposition; ALD) be called at first atomic layer epitaxy (Atomic Layer Epitaxy, ALE), also referred to as atomic layer chemical vapor deposition (Atomic Layer Chemical Vapor Deposition, ALCVD), it utilizes the gas-solid phase reaction between reactant gases and substrate, complete the demand of technique, owing to can completing the technique that precision is higher, be therefore regarded as one of development key link of advanced solar battery process technology.
Ald, be a kind of can be by material with the monatomic form membrane method that is plated in substrate surface in layer.Ald is by the pulse of at least two kinds of gas phase presomas alternately being passed into reactor and chemisorption reaction on depositing base, form a kind of method of deposited film, when precursor reaches depositing base surface, can and there is surface reaction in matrix surface chemisorption in them, between presoma pulse, need with rare gas element, ald reactor to be cleaned, by deposition cycle, constantly repeat until obtain required film thickness.ALD can simply accurately control the thickness of film by control number reaction time, form the film that reaches atomic layer level thickness precision; The film of its growth does not have pin hole, even and fabulous to the conformality of film pattern.
In US Patent No. 5483919, disclose a kind ofly for carrying out the reaction unit of atomic layer level thin film deposition, this reaction unit comprises pre-reaction material storage unit, gas circuit unit and reaction chamber; In reaction, by two kinds of different vapor reaction precursors are entered to reaction chamber by gas circuit units alternately, be vertically sprayed at silicon chip surface, formation of deposits atomic layer level thin film.But there is following defect in this device: (1) silicon chip load bearing unit once only can carry a slice silicon chip, and the silicon chip production capacity of deposit film is low, and equipment cost is high; (2) vapor reaction precursor is vertically sprayed at silicon chip surface center, and air-flow mind-set surrounding in silicon chip spreads, and causes vapor reaction precursor utilization ratio low; (3) the silicon chip load bearing unit easy residual gaseous state pre-reaction material in bottom and byproduct of reaction, be difficult to emptying so that formation vortex cavity, gas field, vapor reaction precursor and byproduct of reaction in vortex cavity, gas field are difficult to emptying, residue is attached to silicon chip surface, causes atomic layer level thin film deposition quality to reduce.
In US Patent No. 6015590, also disclose a kind of for carrying out the reaction unit of atomic layer level thin film deposition, the silicon chip load bearing unit of this device once can carry two silicon chips, in reaction chamber, can place a plurality of silicon chip load bearing units, this device improves silicon chip production capacity by increasing silicon chip load bearing unit quantity simultaneously.But there is following defect in this device: (1) improves silicon chip production capacity by increasing silicon chip load bearing unit quantity, causes the complex structure of reaction chamber, and processing maintenance cost is high, and silicon chip quantity increasing degree is limited; (2) between silicon chip load bearing unit and silicon chip, residual vapor reaction precursor is difficult to emptyingly, and residue is attached to silicon chip surface, causes atomic layer level thin film deposition quality to reduce; (3) the heating unit skewness of reaction chamber, makes reaction chamber inner wall surface have thermograde, makes silicon chip surface have thermograde, causes silicon chip surface atomic layer level thin film uneven thickness; (4) vapor reaction precursor is L shaped towards the path of silicon chip surface, need after a right-angled bend, could arrive silicon chip surface, and therefore, the power that vapor reaction precursor arrives silicon chip surface is not strong.
In sum, those skilled in the art need research and develop the reaction unit of a kind of new atomic layer level thin film deposition, to solve, in existing reaction unit, have that silicon chip production capacity is low, silicon chip surface exists that thermograde causes that vapor reaction precursor is slow at silicon chip surface skewness, sedimentation rate, vapor reaction precursor cannot be emptying etc. problem.
Utility model content
Technical problem to be solved in the utility model is to provide a kind of reaction unit for atomic layer level thin film deposition, thereby promotes silicon chip production capacity effective deposition quality that improves atomic layer level thin film of atomic layer level thin film deposition apparatus.
The utility model object realizes by following technical proposals:
The utility model provides a kind of reaction unit for atomic layer level thin film deposition, comprising: reactive deposition chamber, reaction evacuation chamber and vacuum system; Described reactive deposition chamber is provided with rhombus cavity and connects with the described evacuation chamber that reacts, described reaction evacuation chamber is connected with described vacuum system, described vacuum system is used for described reaction evacuation chamber to bleed, and then makes described reactive deposition chamber in vacuum state;
Wherein, in described reactive deposition chamber, comprise silicon chip load bearing unit, heating unit, precursor feed unit, sweeping gas air admission unit;
The bottom that described silicon chip load bearing unit is provided with several silicon chip carrying positions and described silicon chip load bearing unit is provided with some ventilating pits, and described silicon chip load bearing unit is provided with hood for protecting rider for sealing described reactive deposition chamber;
Described heating unit is located at the wall outside, four chambeies in described reactive deposition chamber, for described reactive deposition chamber is heated;
Described precursor feed unit is for providing vapor reaction precursor or the vapor reaction precursor in described reactive deposition chamber is purged the silicon chip on described silicon chip load bearing unit;
Described sweeping gas air admission unit is for purging the vapor reaction precursor in described reactive deposition chamber and described silicon chip load bearing unit gap.
Load bearing unit described in the utility model is provided with several silicon chip carrying positions, improved the production capacity of silicon chip, the utility model further can increase the silicon chip carrying position on load bearing unit by changing the volume in the chamber of reactive deposition chamber, and the production capacity of silicon chip is further improved; In addition, on the chamber wall by the rhombus cavity in reactive deposition chamber, be equipped with heating unit, make the chamber wall homogeneous heating in reactive deposition chamber, and then make the silicon chip thermally equivalent in chamber.
Preferably, the wall thickness of described reactive deposition chamber four chamber walls equate and the left right chamber wall of described reaction evacuation chamber on be equipped with described heating unit.
The utility model arranges the chamber wall homogeneous heating that identical wall thickness makes reactive deposition chamber; On the left right chamber wall of described reaction evacuation chamber, be equipped with described heating unit, silicon chip lower edge place also can better be heated, the more uniform temperature of silicon chip surface.
Preferably, on described reactive deposition chamber, two chamber walls of drift angle connect by arc transition, and the upper drift angle in described reactive deposition chamber is 70 °~120 °.Described chamber wall connects by arc transition, avoids horn structure, and the air-flow in reactive deposition chamber is easily stuck in horn structure, and causing cannot emptying gaseous state pre-reaction material and byproduct of reaction.
Preferably, described reactive deposition also comprises heated air air admission unit in chamber, for spraying hot gas, makes described silicon chip load bearing unit and silicon chip heating.
Preferably, described precursor feed unit, described heated air air admission unit and described sweeping gas air admission unit are and are provided with the tubular body arranged inside of some production wells and rotatable with respect to described reactive deposition chamber.
Described precursor feed unit, described heated air air admission unit and described sweeping gas air admission unit one end are fixed on the wall of chamber, reactive deposition chamber and are rotatable with respect to chamber wall, and it is inner that the other end stretches to reactive deposition chamber.Rotatable precursor feed unit, heated air air admission unit and sweeping gas air admission unit can be by rotating tubular body arranged inside, thereby the discharge directions of the production well on adjusting tubular body arranged inside, described tubular body arranged inside is symmetrical set in reactive deposition chamber, make precursor feed unit be injected into more uniformly silicon chip surface, heated air can heat silicon chip more uniformly, the more directive selection purge position of blow device.
Preferably, the angle of the chamber wall that the production well direction of described precursor feed unit is adjacent is 30 °~330 °, the angle of the chamber wall that the production well direction of described heated air air admission unit is adjacent is 30 °~330 °, and the angle of the chamber wall that the production well direction of described sweeping gas air admission unit is adjacent is 0 °~180 °.
Preferably, the production well on described precursor feed unit and described heated air air admission unit is uniformly distributed on tubular body arranged inside and the distribution range of production well covers each silicon chip, makes the gas in production well can be injected into uniformly each silicon chip surface.
The distribution range of the some production wells that distribute on described tubular body arranged inside is corresponding with the position of the silicon chip of carrying, makes silicon chip can be subject to uniformly the vapor reaction precursor spraying in production well; The direction of vapor reaction precursor of spraying in production well is identical with the radial direction of silicon chip, and the distribution range of production well also can be greater than the distribution range of the silicon chip of carrying.
Preferably, it is circular closed cavities that described reaction evacuation chamber is provided with cross section, and described vacuum system comprises vacuum-lines and vacuum pump, and vacuum pump is connected to described reaction evacuation chamber by vacuum-lines.In described vacuum system, can further be provided with filtration unit.
Preferably, described reactive deposition chamber downside center position is offered oblong aperture straight down, and oblong aperture and described round sealed chamber of reacting evacuation chamber intersect at the sidewall of oblong aperture, and described oblong aperture is communicated with described reactive deposition chamber and the described evacuation chamber that reacts.
The beneficial effects of the utility model:
1, the silicon chip load bearing unit described in the utility model is provided with several silicon chips carrying position, and the production capacity that has greatly improved silicon chip than existing reaction unit has been avoided the waste of vapor reaction precursor simultaneously; The utility model further can increase the silicon chip carrying position on load bearing unit by changing the volume in the chamber of reactive deposition chamber, and the production capacity of silicon chip is further improved.
2, the symmetrical and wall thickness of the chamber wall of the rhombus cavity in the reactive deposition chamber described in the utility model equates, make the chamber wall homogeneous heating in reactive deposition chamber, effectively reduced the thermograde on the wall of chamber, reactive deposition chamber, and then reduced the thermograde of silicon chip surface, improved the homogeneity of silicon chip surface atomic layer level thin film thickness.
3, in the utility model, the direction of motion of vapor reaction precursor is parallel with silicon chip surface, therefore, be conducive to vapor reaction precursor and be evenly distributed on silicon chip surface, improved the homogeneity of silicon chip surface atomic layer level thin film thickness and the utilization ratio of gaseous state pre-reaction material.
4, heated air air admission unit described in the utility model sprays hot gas flow to reactive deposition chamber, can shorten silicon chip heat-up time.
5, the cavity wall of reactive deposition described in the utility model surface adopts the design of streamline arc surface, has avoided horn structure design, has eliminated the gas field eddy current of inside, reactive deposition chamber.
Accompanying drawing explanation
In order to be illustrated more clearly in the technical scheme in the utility model embodiment, to the accompanying drawing of required use in embodiment be briefly described below, apparently, accompanying drawing in the following describes is only embodiment more of the present utility model, for those of ordinary skills, do not paying under the prerequisite of creative work, can also obtain according to these accompanying drawings other accompanying drawing.
Fig. 1 is that the utility model is provided with the structural representation of hood for protecting rider for the reaction unit of atomic layer level thin film deposition;
Fig. 2 is that the utility model is for the structural representation of the reaction unit carrying silicon chip of atomic layer level thin film deposition;
Fig. 3 is that the utility model is for the sectional view of the reaction unit of atomic layer level thin film deposition;
Fig. 4 is that the utility model is for the structural representation of the reaction unit of atomic layer level thin film deposition;
Fig. 5 is the structural representation of silicon chip load bearing unit described in the utility model;
Fig. 6 is the structural representation of silicon chip load bearing unit carrying silicon chip described in the utility model.
Number in the figure is described as follows:
1, reactive deposition chamber; 2, reaction evacuation chamber; 3, vacuum system; 31, vacuum-lines; 32, vacuum pump; 4, silicon chip load bearing unit; 5, heating unit; 6, precursor feed unit; 7, sweeping gas air admission unit; 8, heated air air admission unit; 9, silicon chip; 10, oblong aperture; 11, reaction unit back door; 12, reaction unit front end face; 13, hood for protecting rider.
Embodiment
Below will coordinate graphic and embodiment to describe embodiment of the present utility model in detail, and by this utility model implementation procedure how utilisation technology means solve technical problem and reach technology effect can be fully understood and be implemented according to this.
Embodiment mono-
As shown in Figures 1 to 4, the utility model provides a kind of reaction unit for atomic layer level thin film deposition, comprising: reactive deposition chamber 1, reaction evacuation chamber 2 and vacuum system 3; Described reactive deposition chamber 1 is provided with rhombus cavity and connects with the described evacuation chamber 2 that reacts, described reaction evacuation chamber 2 is connected with described vacuum system 3, described vacuum system 3 is for described reaction evacuation chamber is bled, and then makes described reactive deposition chamber 1 in vacuum state; Wherein, in described reactive deposition chamber 1, comprise silicon chip load bearing unit 4, heating unit 5, precursor feed unit 6, sweeping gas air admission unit 7; The bottom that described silicon chip load bearing unit 4 is provided with several silicon chip carrying positions and described silicon chip load bearing unit is provided with some ventilating pits, and described silicon chip load bearing unit 4 is provided with hood for protecting rider 13 for sealing described reactive deposition chamber 1; Described heating unit 5 is located at the wall outside, four chambeies in described reactive deposition chamber 1, for described reactive deposition chamber 1 is heated; Described precursor feed unit 6 provides vapor reaction precursor for the silicon chip 9 on described silicon chip load bearing unit 4 or the vapor reaction precursor in described reactive deposition chamber 1 is purged; Described sweeping gas air admission unit 7 is for purging described reactive deposition chamber 1 and the vapor reaction precursor in described silicon chip load bearing unit 4 gaps.It is circular closed cavities that described reaction evacuation chamber 2 is provided with cross section, and described vacuum system 3 comprises vacuum-lines 31 and vacuum pump 32, and vacuum pump 32 is connected to described reaction evacuation chamber 2 by vacuum-lines 31.In described vacuum system 3, can further be provided with filtration unit.
As shown in Figure 5, Figure 6, the bottom that the load bearing unit of silicon chip described in the utility model 4 is provided with several silicon chips carrying position and described silicon chip load bearing unit 4 is provided with some ventilating pits.While using 3 pairs of described reaction evacuation chambers 2 of vacuum system to vacuumize, described vapor reaction precursor enters reaction evacuation chamber 2 after discharging by the ventilating pit of silicon chip load bearing unit 4 bottoms, 3 pairs of vacuum systems reaction evacuation chambers 2 vacuumize, the raising that the utility model is larger the production capacity of silicon chip.The utility model further can increase the silicon chip carrying position on silicon chip load bearing unit 4 by changing the volume in 1 chamber of reactive deposition chamber, and the production capacity of silicon chip is further improved; In addition, on the chamber wall by the rhombus cavity in reactive deposition chamber 1, be equipped with heating unit 5, make the chamber wall homogeneous heating in reactive deposition chamber 1, and then make silicon chip 9 thermally equivalents in chamber.
As shown in Figure 1 and Figure 2, the wall thickness of described reactive deposition chamber 1 four chamber walls equate and the left right chamber wall of described reaction evacuation chamber 2 on be equipped with described heating unit 5; In described reactive deposition chamber 1, also comprise heated air air admission unit 8, for spraying hot gas, make described silicon chip load bearing unit 4 and silicon chip 9 heating.The utility model arranges the chamber wall homogeneous heating that identical wall thickness makes reactive deposition chamber 1; On the left right chamber wall of described reaction evacuation chamber 2, be equipped with described heating unit 5, silicon chip 9 lower edge places also can better be heated, the more uniform temperature on silicon chip 9 surfaces.
Please refer to Fig. 4, on described reactive deposition chamber 1, two chamber walls of drift angle connect by arc transition, and the upper drift angle in described reactive deposition chamber 1 is 70 °~120 °.Described chamber wall connects by arc transition, avoids horn structure, and the air-flow in reactive deposition chamber is easily stuck in horn structure, and causing cannot emptying gaseous state pre-reaction material and byproduct of reaction.In addition, by described reactive deposition chamber 1 downside center position, offer oblong aperture 10 straight down, and oblong aperture 10 and described round sealed chamber of reacting evacuation chamber 2 intersect at the sidewall of oblong aperture 10, described oblong aperture 10 is communicated with described reactive deposition chambeies 1 and the described evacuation chamber 2 that reacts, prevent oblong aperture 10 with react evacuation chamber 2 generation vortex cavityes, gas field, junctions.
As shown in Figure 3, described precursor feed unit 6, described heated air air admission unit 8 and described sweeping gas air admission unit 7 are and are provided with the tubular body arranged inside of some production wells and rotatable with respect to described reactive deposition chamber 1.Described precursor feed unit 6, described heated air air admission unit 8 and described sweeping gas air admission unit 7 one end are fixed on the 1 chamber wall of reactive deposition chamber and are rotatable with respect to chamber wall, and the other end stretches to 1 inside, reactive deposition chamber.Rotatable precursor feed unit 6, heated air air admission unit 8 and sweeping gas air admission unit 7 can be by rotating tubular body arranged inside, thereby the discharge directions of the production well on adjusting tubular body arranged inside, described tubular body arranged inside is symmetrical set in reactive deposition chamber 1, make precursor feed unit 6 be injected into more uniformly silicon chip 9 surfaces, heated air can heat silicon chip 9 more uniformly, the more directive selection purge position of blow device.
Please continue to refer to Fig. 4, the angle of the chamber wall that the production well direction of described precursor feed unit 6 is adjacent is 30 °~330 °, the angle of the chamber wall that the production well direction of described heated air air admission unit 8 is adjacent is 30 °~330 °, and the angle of the chamber wall that the production well direction of described sweeping gas air admission unit 7 is adjacent is 0 °~180 °.Production well on described precursor feed unit 6 and described heated air air admission unit 8 is uniformly distributed on tubular body arranged inside and the distribution range of production well covers each silicon chip 9, makes the gas in production well can be injected into uniformly each silicon chip 9 surfaces.The distribution range of the some production wells that distribute on described tubular body arranged inside is corresponding with the position of the silicon chip of carrying 9, makes silicon chip 9 can be subject to uniformly the vapor reaction precursor spraying in production well; The direction of the vapor reaction precursor spraying in production well is identical with the radial direction of silicon chip 9, and the distribution range of production well also can be greater than the distribution range of the silicon chip 9 of carrying.
Design parameter in the present embodiment is: 220 ℃ of the default internal temperatures in described reactive deposition chamber 1, the default internal pressure 5Torr in reactive deposition chamber 1, vapor reaction precursor is trimethyl aluminium (TMA) and water (H2O), and heated air and sweeping gas are the hot nitrogen (N of 200 ℃
2), reactive deposition chamber front end face 12 to the length at back door, reactive deposition chamber 11 is 300mm, the reactive deposition chamber 1 rhombus through hole length of side is 200mm, on the circular arc in reactive deposition chamber 1, apex angle α angle is 90 °, reactive deposition chamber 1 wall thickness is 25mm, reaction evacuation chamber 2 round sealed chamber diameters are 100mm, and the degree of depth is 285mm, and the oblong aperture 10 of 1 below, reactive deposition chamber is of a size of 270 * 40mm.
Wherein, the distance D 1 of described precursor feed unit 6 ends and reactive deposition chamber front end face 12 is 9mm, and the angle β 1 of precursor feed unit 6 production well directions and reactive deposition chamber 1 wall is 70 °; The distance D 2 of heated air air admission unit 8 ends and reactive deposition chamber front end face 12 is 9mm, and the angle β 2 of heated air air admission unit 8 production well directions and reactive deposition chamber 1 chamber wall is 60 °; The distance D 3 of sweeping gas air admission unit 7 ends and reaction chamber front end face 12 is 3mm, and the angle β 3 of sweeping gas air admission unit 7 production well directions and reactive deposition chamber 1 wall is 0 °.In the present embodiment, silicon chip load bearing unit 4 carrying silicon chip 9 quantity are 250, and 2 silicon chips 9 are 1 group, place back-to-back, and silicon chip 9 is axially evenly distributed along reactive deposition chamber 1 in silicon chip load bearing unit 4 inside.
The utility model also provides the reaction method of the reaction unit for atomic layer level thin film deposition based on described above, comprises the following steps:
S1, by described reactive deposition chamber 1 preset temperature value and pressure values, temperature is that 220 ℃ and pressure are 5Torr;
The first vapor reaction precursor that the production well injection of S2, described precursor feed unit 6 is parallel to silicon chip 9 is to silicon chip 9 surfaces, when described silicon chip 9 surface adsorption the first vapor reaction precursors reach capacity, stop spraying the first vapor reaction precursor, described the first vapor reaction precursor is trimethyl aluminium (TMA) and water (H
2o);
S3, use 3 pairs of described reaction evacuation chambers 2 of vacuum system to vacuumize, so in emptying described reactive deposition chamber 1 residue the first vapor reaction precursor and gaseous state byproduct of reaction; Simultaneously, described sweeping gas air admission unit 7 pass into hot inert gas in described reactive deposition chamber 1 and described silicon chip load bearing unit 4 gaps residue the first vapor reaction precursor and gaseous state byproduct of reaction purge, described hot inert gas is hot nitrogen (N
2);
The second vapor reaction precursor that the production well injection of S4, described precursor feed unit 6 is parallel to silicon chip 9 is to silicon chip 9 surfaces, when described silicon chip 9 surface adsorption the second vapor reaction precursors reach capacity, stop spraying the second vapor reaction precursor, described the second vapor reaction precursor is water (H
2o);
S5, use 3 pairs of described reaction evacuation chambers 2 of vacuum system to vacuumize, so in emptying described reactive deposition chamber 1 residue the second vapor reaction precursor and gaseous state byproduct of reaction; Meanwhile, described sweeping gas air admission unit 7 pass into hot inert gas in described reactive deposition chamber 1 and described silicon chip load bearing unit 4 gaps residue the second vapor reaction precursor and gaseous state byproduct of reaction purge;
S6, circulate after 200 reaction times successively, the Al in the mode of monoatomic layer growth at silicon chip 9 surface deposition 20nm thickness
2o
3film;
In technological process, described vacuum system 3 remains described reaction evacuation chamber 2 is vacuumized, and then residue gaseous state pre-reaction material and gaseous state byproduct of reaction in emptying described reactive deposition chamber 1, and for described precursor feed unit 6, spray vapor reaction precursors and provide power to silicon chip 9 surfaces.Reaction unit in the present embodiment, can complete the Al to 250 P type silicon chips, 9 deposition 20nm thickness for every 25 minutes
2o
3film, production capacity is up to 600 slices/hour.
Embodiment bis-
On the basis of enforcement one, different from embodiment mono-: described reactive deposition chamber 1 internal pressure 3Torr, the first vapor reaction precursor is trimethyl aluminium (TMA) and ozone (O
3), the second vapor reaction precursor is ozone (O
3); The angle β 1 of precursor feed unit 6 production well directions and reactive deposition chamber 1 wall is 90 °, and the distance D 2 of heated air air admission unit 8 ends and reaction chamber front end face 12 is 3mm.Reaction chamber in the present embodiment, can complete the Al to 250 P type silicon chips, 9 deposition 20nm thickness for every 30 minutes
2o
3film, production capacity is up to 500 slices/hour.
Above-mentioned explanation illustrates and has described some preferred embodiments of the present utility model, but as previously mentioned, be to be understood that the utility model is not limited to disclosed form herein, should not regard the eliminating to other embodiment as, and can be used for various other combinations, modification and environment, and can, in utility model contemplated scope described herein, by technology or the knowledge of above-mentioned instruction or association area, change.And the change that those skilled in the art carry out and variation do not depart from spirit and scope of the present utility model, all should be in the protection domain of the utility model claims.