CN103794456A - Structure and etching method of etching machine stand - Google Patents

Abstract

The invention discloses a structure of an etching machine stand. At least one aligning cavity is additionally arranged on the basis of an original cavity structure of the etching machine stand. The invention also discloses an etching method on the basis of the etching machine stand after refitting. According to the method, firstly a silicon chip is aligned via an original aligning cavity of the etching machine stand, and then etching technology is performed in a main etching cavity; and after completion of etching, the silicon chip enters into the additionally arranged aligning cavity to be aligned, then enters into the main etching cavity to be etched again and aligning and etching steps are repeated according to the number of the additionally arranged aligning cavities. The aligning cavities are additionally arranged on the etching machine stand, sequence of etching work is appropriately modified according to distribution situation of etching rate and an original one step of etching is divided into multiple steps to perform etching so that complementation is formed in non-uniform etching amount, and intra-surface uniformity of the etching technology is effectively enhanced.

Description

The structure of etching machine bench and lithographic method

Technical field

The present invention relates to integrated circuit fabrication process field, particularly relate to the structure of etching machine bench, and etching process based on this etching machine bench.

Background technology

Etching machine bench is the common equipment in semiconductor fabrication process.Take DPS(uncoupling plasma source) poly(polysilicon) etching machine bench is as example, the approximate location structure of its external cavity as shown in Figure 1, centre is transmission cavity, also have 5 cavitys around transmission cavity, be respectively: main etching chamber A, B, alignment cavity F, equipment end and space outerpace connection chamber LLA, LLB.

When silicon chip erosion, first take out the air in equipment end and space outerpace connection chamber LLA, LLB, make formation vacuum state in these two cavitys; Then, silicon chip is sent in alignment cavity F and is aimed at, generally by Notch(product silicon chip small gap) position be arranged on 6 directions of clock, etching angle is 0 °; After aligning, silicon chip is sent into main etching chamber A or B carries out plasma etching.

The main etching chamber A of DPS Poly etching machine bench, the Coil(coil of B) position distribution as shown in Figure 2, because the position distribution of Coil is inhomogeneous, if etching condition is take physical reactions as main, ER map(etch rate distribution map) will present the left side etch rate situation fast compared with the right, as shown in Figure 3, cause the internal homogeneity of etching poor.

The process gas flow direction of DPS Poly etching machine bench main etching chamber A, B and the position distribution of pumping hole are as shown in Figure 4, because gas nozzle and pumping hole are fixed position, if etching condition is take chemical reaction as main, ER map will present top etch rate slow situation below, as shown in Figure 5, it is poor that this also can cause the internal homogeneity of etching.

Summary of the invention

One of the technical problem to be solved in the present invention is to provide a kind of structure of etching machine bench, and it can improve the internal homogeneity of etching.

For solving the problems of the technologies described above, the structure of etching machine bench of the present invention, is to increase at least one alignment cavity on the original cavity body structure of etching machine bench basis again.

Two of the technical problem to be solved in the present invention is to provide a kind of etching process of the etching machine bench based on after above-mentioned repacking.

For solving the problems of the technologies described above, lithographic method of the present invention, step is as follows:

1) first silicon chip is aimed at by the original alignment cavity of etching machine bench, then in main etching chamber, carries out etching technics;

2) after the etching of step 1) completes, silicon chip enters the alignment cavity newly increasing and aims at, and then enters main etching chamber and again carry out etching technics;

3) according to the number of the alignment cavity newly increasing, repeat step 2).

The time of above-mentioned each etching is the sum of required total etch period divided by alignment cavity.

The present invention is by increasing alignment cavity at etching machine bench, and suitably revise the order of etching condition according to etch rate distribution situation, an original step etching is divided into multistep etching carries out, so make inhomogeneous etch amount form complementation, thereby effectively improved by the internal homogeneity that etch rate left and right distributes or upper and lower skewness causes bad.

Accompanying drawing explanation

Fig. 1 is the positional structure schematic diagram of existing DPS Poly etching machine bench external cavity.

Fig. 2 is the position distribution schematic diagram of the coil in the etching machine bench main etching chamber of Fig. 1.

Fig. 3 uses the etching machine bench of Fig. 1 at the figure of the ER map under main etching condition take physical reactions.

Fig. 4 is the flow direction of etching machine bench main etching chamber process gas of Fig. 1 and the position distribution schematic diagram of pumping hole.

Fig. 5 uses the etching machine bench of Fig. 1 at the figure of the ER map under main etching condition take chemical reaction.

Fig. 6 is the positional structure schematic diagram of the DPS Poly etching machine bench external cavity of the embodiment of the present invention.

Fig. 7 uses the etching machine bench of Fig. 6 at the figure of the ER map under main etching condition take physical reactions.

Fig. 8 uses the etching machine bench of Fig. 6 at the figure of the ER map under main etching condition take chemical reaction.

In figure, description of reference numerals is as follows:

A, B: main etching chamber

F, F1, F2: alignment cavity

LLA, LLB: equipment end is connected cavity with space outerpace

Embodiment

Understand for technology contents of the present invention, feature and effect being had more specifically, existing in conjunction with illustrated execution mode, details are as follows:

The present embodiment has carried out hardware repacking to DPS Poly etching machine bench, has newly increased an alignment cavity F2, as shown in Figure 6 on original cavity body structure (being structure shown in Fig. 1) basis.The alignment angle of former alignment cavity F1 is still set as 0 °, and Notch is in the position of 6 directions of clock.The alignment angle of the alignment cavity F2 newly increasing is set to 180 °, and Notch is in the position of 12 directions of clock.

While carrying out etching technics, the sequence of operation that etching apparatus end is set arranges as follows:

First product silicon chip is aimed at by former alignment cavity F1, then in main etching chamber A or B, carries out etching technics for the first time, the half that the time of this step etching technics is required total etch period.

After etching technics completes, then enter the alignment cavity F2 newly increasing and aim at, now product silicon chip has rotated 180 ° from origin-location.

After aligning, enter main etching chamber A or B carries out etching technics for the second time, the time is also the half of required total etch period again, this time etching technics of end after completing.

Above-mentioned whole process is carried out in board inside completely.The method is an original step etching, by the aligning through Rotate 180 ° again in technical process, is divided into two step etchings, so just makes inhomogeneous etch amount form complementation, thereby effectively improved the internal homogeneity of etching.Anti-carve condition (total etch period 60 seconds) as example take on-the-spot polysilicon, while adopting physical reactions to be the etching condition of leading, can make etching homogeneity from 2.6%(Fig. 3) be improved to 1.0%(Fig. 7); When to adopt chemical reaction be main etching condition, can make etching homogeneity from 4.1%(Fig. 3) be improved to 1.85%(Fig. 8).

Above-described embodiment has only increased an alignment cavity on the original cavity body structure of DPS Poly etching machine bench basis, in other possible embodiments, also can reequip other etching machine bench according to the method described above, increase multiple alignment cavities depending on concrete condition, then the actual conditions that distribute by etch rate arrange different alignment angle, realize and repeatedly aiming at and multiple etching, to improve the homogeneity of etching.

Claims (5)

1. the structure of etching machine bench, is characterized in that, on the original cavity body structure of etching machine bench basis, increases at least one alignment cavity.

2. the structure of etching machine bench according to claim 1, is characterized in that, described etching machine bench is uncoupling plasma source etching polysilicon board.

3. the structure of etching machine bench according to claim 1 and 2, is characterized in that, increases an alignment cavity, and the etching angle of this alignment cavity is set to 180 °, and silicon chip small gap is arranged on the position of 12 directions of clock.

4. the lithographic method based on any etching machine bench of claims 1 to 3, is characterized in that, comprises the following steps:

1) first silicon chip is aimed at by the original alignment cavity of etching machine bench, then in main etching chamber, carries out etching technics;

2) after the etching of step 1) completes, silicon chip enters the alignment cavity newly increasing and aims at, and then enters main etching chamber and again carry out etching technics;

3) according to the number of the alignment cavity newly increasing, repeat step 2).

5. method according to claim 4, is characterized in that, the time of each etching is the sum of required total etch period divided by alignment cavity.

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