TW201724259A - Semiconductor processor and multi-area temperature-control heater applicable to semiconductor processor including a lower heating layer and an upper heating layer while the heating power of a heating wire in the upper heating layer is lower than the heating power of a heating wire in the lower heating layer - Google Patents

Abstract

A semiconductor processor includes a reaction chamber forming an air-tight space in a surrounding manner. The reaction chamber includes a reaction chamber sidewall and a base located in the reaction chamber. Above the base is set a heater. Above the heater is fixed an electrostatic clamping disk for fixing a to-be-processed substrate. The said heater includes a lower heating layer and an upper heating layer, in which the lower heating layer is fixed to the said base through a first insulation layer. A second insulation material layer is set between an upper heating layer and a lower heating layer, in which the heating power of a heating wire in the upper heating layer is lower than the heating power of a heating wire in the lower heating layer.

Description

Semiconductor processor and multi-zone temperature control heater for semiconductor processor

The present invention relates to the field of semiconductor manufacturing technology, and in particular, to a multi-zone temperature control heater for a plasma processor.

Plasma processors are widely used in the semiconductor industry to process substrates for high-precision processing such as plasma etching, chemical vapor deposition (CVD), and the like. The temperature of the substrate in the plasma treatment has a great influence on the treatment effect, and different temperature distributions on the substrate surface may make the treatment effect different. In order to better control the temperature, a conventional heater is provided between the base of the supporting substrate and the electrostatic chuck to control the heating power by inputting different powers to the heaters in different regions. The plasma processor structure of the prior art, as shown in FIG. 1, includes a reaction chamber 100, a susceptor 10 located at the bottom of the reaction chamber, and the susceptor is connected to at least one RF power source by a cable. The base 10 includes a conduit 11 for the coolant circulation to remove excess heat generated during the plasma treatment. Above the susceptor 10 includes a heater, which typically includes two layers of insulating material 21, 25 above and below to achieve electrical insulation between the heater and other components, and a heating resistor wire layer 23 sandwiched between the insulating materials. The upper surface of the heater fixes the electrostatic chuck 30 to the heater by the adhesive layer 32, and the substrate to be processed is fixed above the susceptor by the electrostatic chuck. The top of the reaction chamber further includes an upper electrode 40, and a gas nozzle 41 on the lower surface of the upper electrode realizes uniform access of the reaction gas. In order to make the substrate temperature uniform, the resistance wire in the heater is also required to perform zone control. The concentric circle distribution is common, and it can be 2 zones, 3 zones or even 4 zones. However, the circular distribution cannot compensate for the local temperature unevenness caused by the cooling gas (helium) through hole and the lifting foot, etc., so the prior art also proposes to divide the heater into a checkerboard shape (usually more than 9). Zone) Independent control unit enables independent control of various zones. Excessive independent control zone not only causes the structure of the heater to be complicated and costly, but also the temperature control is difficult to stabilize. If the temperature difference between each independent temperature zone and the adjacent heater zone is too large, the heat of the adjacent heater zone will tend to be caused. The destination area is introduced or guided away, and the ideal temperature distribution to be achieved requires multiple adjustments of the heating power of the multiple independent heating zones to achieve stability. For processing processes that require rapid processing temperatures, long-term adjustments to acceptable temperatures are unacceptable.

Therefore, the industry needs a new method or device, which not only can quickly achieve precise control of temperature distribution, but also has a simple structure and low cost.

The problem solved by the present invention is that the substrate in the plasma processor obtains a uniform temperature distribution during the plasma processing, and can achieve fast switching in different processing processes.

The invention provides a plasma processor, comprising: a reaction chamber surrounding an airtight space, the reaction chamber comprising: a side wall of the reaction chamber and a base located in the reaction chamber, the heater includes a heater above the base An electrostatic chuck is fixed on the upper surface for fixing the substrate to be processed, wherein the heater comprises an underlying heating layer and an upper heating layer, wherein the lower heating layer is fixed to the pedestal by the first insulating layer, the upper heating layer and the lower layer The second layer of insulating material is further included between the heating layers, wherein the heating power of the heating wire in the upper heating layer is less than the power of the heating wire of the lower heating layer. The electric wire in the upper heating layer has a higher electric resistance than the electric heating wire in the lower heating layer.

The upper insulating layer further includes a third insulating material layer fixed to the electrostatic chuck by a layer of bonding material.

The upper and lower heating layers have a plurality of independently controlled heating zones, wherein the lower heating layer heats the entire electrostatic chuck and the upper heating layer covers a portion of the electrostatic chuck region. The number of independently controlled heating zones in the upper heating layer is greater than the number of independently controlled heating zones in the lower heating layer. The method further includes receiving, by the first heating driving circuit, a temperature of the plurality of heating regions in the lower heating layer, comparing the obtained temperature with a preset base temperature, and outputting heating power to the plurality of heating layers of the lower heating layer according to the comparison result. The heating wires in the region are such that the respective heating regions of the lower heating layer have a preset base temperature. The method further includes receiving, by the second heating driving circuit, a temperature of the plurality of heating regions in the upper heating layer, comparing the obtained temperature with a preset processing temperature, and obtaining a plurality of temperature difference values ΔT, and querying the temperature difference ΔT and Corresponding basic temperature correlation database, the power of input heating wire of a plurality of heating zones is obtained. The upper surface of the heater has a predetermined processing temperature.

2 is a schematic view of a heater of the present invention, which is substantially similar to the prior art shown in FIG. 1, and the main difference is that the heater of the present invention includes a double layer heating layer, including The heating layer HA located below and the heating layer HB located above, the heater further comprises an insulating layer 27 on the upper surface of the heating layer HB, an insulating layer 25 between the two heating layers, and an insulating layer on the lower surface of the heating layer HA. twenty one. The upper and lower heating layers HA and HB have the following differences in addition to the spatial position:

The heating wire material used in the two is different. The heating layer HA has a small electric resistance. When the same power source is applied, the heating power is large, and the target temperature can be quickly reached. However, since the power is too large, it is difficult to achieve a very precise temperature, and is suitable for temperature. Coarse adjustment. The heating layer HB has a large electrical resistance, and the heating power of the heating layer HA is relatively low, due to low power and precise fine adjustment of the temperature.

The pattern distribution of the heating wires of the two is different. The heating layer HA has a large range of independent temperature control regions due to only a large temperature adjustment in a wide range, and may be divided into a plurality of concentric circles as shown in FIG. 3a. Or the annular area A1-A4, so that the electrostatic chuck temperature as a whole has a close base temperature, and different areas may have a small amount of error (such as 1-2 degrees). The pattern of the upper heating layer HB may be as shown in FIG. 3b, and only the area where temperature unevenness is likely to occur in the periphery, such as the A3 and A4 areas corresponding to the lower HA, uniformly divides the entire ring to form a plurality of curved shapes. Independent heating zones B1-B16. The division of the independent heating zone is not limited to that shown in Fig. 3b. If the central zone has a local temperature unevenness due to the hard structure, an independent heating zone may be provided at a corresponding portion of the central zone. The number of independent heating zones is also not fixed. More than 16 zones can be set, or less, and the distribution and number of independent heating zones can be freely selected according to actual needs. By setting the heating layer HB, it is possible to compensate for the precise control of the temperature input to the respective independent temperature control regions B1-B16, and compensate for the damage caused by the lower HA annular region A1-A4 or other hardware causes. A small temperature difference allows for a more uniform temperature distribution across the electrostatic chuck.

The control method of the two is also different. The function of the heating layer HA is to quickly reach the target temperature required by the process, so the heating layer HA adopts the method of temperature feedback control. The first heating drive circuit collects the actual temperature detected by the temperature probe on A1-A4, compares it with the base temperature that needs to be set in the process, and sets the corresponding power input to A1-A4 according to the comparison result, and finally reaches the target base temperature. The function of the heating layer HB is to compensate for a small temperature difference that cannot be achieved by the heating layer HA. Since the heating layer HA has different temperatures in different processes, when the base temperature of the HA layer is different, the same heating power input in the heating layer HB will be Bring different temperature rises. Therefore, when the heating layer HB needs to record the heating layer HA having different base temperatures during the commissioning phase, different heating powers correspondingly generate temperature variables ΔT in the respective regions B1-B16, and these power parameters are stored in the database. In the actual plasma processing, a second heating driving circuit collects the detected actual temperature of the B1-B16 region, compares the preset processing temperature, obtains the temperature difference ΔT between the two in different temperature control regions, and finally according to △ The database obtained in the T and debugging stages queries the input power of the corresponding area, and inputs the input power obtained by the query into the area corresponding to the upper layer of the electric heating layer, thereby finally achieving uniform temperature distribution on the electrostatic chuck. The processing temperature in the present invention refers to the temperature actually reaching the insulating layer 27, and the base temperature obtained by the lower heating layer between the upper and lower heating layers is lower than the processing temperature measured on the upper surface of the upper heating layer. Where the processing temperature is closer to the actual temperature of the upper substrate.

In the present invention, since the lower layer heater has provided an approximate base temperature for the upper layer heater, the temperature difference between different regions of the B1-B16 region itself is small, and a large amount of heat flow does not occur between adjacent regions, and only needs to be directly A precise temperature can be achieved by looking up the set heating power input.

The invention realizes fast and precise control of the substrate temperature by providing double-layer heating layers with different functions, and can select different heating area arrangements to adapt to different hardware situations. The lower heating layer is heated by high power, so that the substrate quickly reaches the base temperature, and the upper heating layer is directly controlled to obtain the heating power required by the look-up table.

The application of the present invention may be an inductively coupled processor (ICP) in addition to the capacitive coupling type plasma device shown in Fig. 1, and is also applicable to other semiconductor processing requiring fast and precise multi-zone temperature control. Devices, such as photoresist-removing reaction chambers, require applications where the substrate is accurately temperature controlled. The insulating layer 27 in the heater structure of the present invention shown in FIG. 2 can also be omitted, because the bottom material of the upper electrostatic chuck itself is an insulating ceramic material, so that the upper heating layer HB and the electrostatic chuck 30 can be realized. A structure in which electrodes are electrically insulated from each other can be applied to the present invention. The insulating material is mainly a ceramic material such as alumina, aluminum nitride or cerium oxide, and may also be an insulating material composed of an organic party material.

Although the present invention has been disclosed above, the present invention is not limited thereto. Any changes and modifications may be made by those skilled in the art without departing from the spirit and scope of the invention, and the scope of the invention should be determined by the scope of the claims.

10‧‧‧ Pedestal
11‧‧‧ Pipes
21, 25, 27‧‧‧Insulation, insulation
23‧‧‧heating resistance wire layer
30‧‧‧Electrical chuck
32‧‧‧ adhesive layer
40‧‧‧Upper electrode
41‧‧‧ gas nozzle
100‧‧‧Reaction chamber
HA‧‧‧Upper heating layer
HB‧‧‧lower heating layer
A1~A4‧‧‧Circular area
B1~B16‧‧‧Independent temperature control area

Figure 1 is a schematic diagram of a conventional plasma processor.

Figure 2 is a schematic view of the structure of the heater of the present invention.

Figure 3a is a schematic plan view of the underlying heating layer of the heater of the present invention.

Figure 3b is a schematic plan view of the upper heating layer of the heater of the present invention.

21, 25, 27‧‧‧Insulation materials, insulation

HA‧‧‧Upper heating layer

HB‧‧‧lower heating layer

Claims (10)

A semiconductor processor comprising: a reaction chamber surrounding an airtight space, the reaction chamber comprising: a reaction chamber sidewall; and a pedestal located in the reaction chamber, the heater including a heater above An electrostatic chuck is fixed on the heater for fixing the substrate to be processed, wherein the heater comprises a lower heating layer and an upper heating layer, and the lower heating layer is fixed to the base by a first insulating layer, the upper layer The heating layer and the lower heating layer further comprise a second insulating material layer, wherein the heating power of the heating wire in the upper heating layer is less than the power of the heating wire of the lower heating layer. The semiconductor processor of claim 1, wherein the upper heating layer further comprises a third insulating material layer fixed to the electrostatic chuck by a layer of bonding material. The semiconductor processor according to claim 1, wherein a resistance of the heating wire in the upper heating layer is greater than a resistance of the heating wire in the lower heating layer. The semiconductor processor of claim 1, wherein the upper and lower heating layers have a plurality of independently controlled heating regions, wherein the lower heating layer heats the entire electrostatic chuck, the upper heating layer covering a portion of the electrostatic chuck region. The semiconductor processor of claim 4, wherein the number of the independently controlled heating regions in the upper heating layer is greater than the number of the independently controlled heating regions in the lower heating layer. The semiconductor processor of claim 4, further comprising a first heating driving circuit receiving the temperature of the plurality of heating regions in the lower heating layer, and comparing the obtained temperature with a preset base temperature, according to The comparison result outputs heating power to the heating wire in the plurality of heating zones of the lower heating layer such that each of the heating zones of the lower heating layer has a predetermined base temperature. The semiconductor processor of claim 6, further comprising a second heating driving circuit receiving the temperature of the plurality of heating regions in the upper heating layer, and comparing the obtained temperature with a preset processing temperature, and Obtaining a plurality of temperature difference ΔT, querying the temperature difference ΔT and the corresponding base temperature correlation database, and obtaining the power of inputting the heating wires of the plurality of heating regions, so that the upper surface of the heater has a preset processing temperature . A multi-zone temperature control heater for a semiconductor processor, comprising a lower heating layer and an upper heating layer, wherein the lower heating layer comprises a first insulating layer, between the upper heating layer and the lower heating layer Further comprising a second insulating material layer, the upper heating layer comprises a third insulating layer, wherein a heating power of the heating wire in the upper heating layer is less than a power of the heating wire of the lower heating layer, the upper heating layer The electric heating wire has a higher electrical resistance than the electric heating wire in the lower heating layer. The multi-zone temperature control heater of claim 8, wherein the upper and lower heating layers have a plurality of independently controlled heating zones, wherein the plurality of heating zones of the lower heating layer cover the entire heater plane, the upper layer A plurality of heating zones of the heating layer cover a portion of the heater plane. The multi-zone temperature-controlled heater of claim 8, wherein the number of independently controlled heating zones in the upper heating layer is greater than the number of independently controlled heating zones in the lower heating layer.